PTC THERAPEUTICS, INC. [PTCT] Filings

Table of Contents

​

​

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

​

FORM 10-K

​

​

For the fiscal year ended: December 31, 2023

​

or

​

​

Commission file number: 001-35969

​

PTC THERAPEUTICS, INC.

(Exact name of registrant as specified in its charter)

​

​

(908) 222-7000

​

(Registrant’s telephone number, including area code)

​

Securities registered pursuant to Section 12(b) of the Act:

​

​

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☑    No ☐

​

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐    No ☑

​

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☑    No ☐

​

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☑    No ☐

​

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

​

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☑   

​

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐    No ☑

​

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. □

​

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to § 240.10D-1(b). □

​

The aggregate market value of the Common Stock held by non-affiliates of the registrant, based upon the last sale price of the Common Stock reported on the Nasdaq Global Select Market on June 30, 2023, the last business day of the registrant’s most recently completed second fiscal quarter, was $2,330,616,515. For purposes of this calculation, shares of Common Stock held by directors and officers have been treated as shares held by affiliates.

​

As of February 27, 2024, the registrant had 76,608,030 shares of Common Stock, $0.001 par value per share, outstanding.

​

​

​

​

Table of Contents

TABLE OF CONTENTS

PTC Therapeutics, Inc.

​

​

​

​

i

Table of Contents

FORWARD-LOOKING STATEMENTS

This Annual Report on Form 10-K contains forward-looking statements that involve substantial risks and uncertainties. All statements, other than statements of historical facts, contained in this Annual Report on Form 10-K, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, are forward-looking statements. The words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “might,” “plan,” “predict,” “project,” “target,” “potential,” “will,” “would,” “could,” “should,” “continue,” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words.

The forward-looking statements in this Annual Report on Form 10-K include, among other things, statements about:

1

Table of Contents

2

Table of Contents

We may not actually achieve the plans, intentions or expectations disclosed in our forward-looking statements, and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included in this Annual Report on Form 10-K, particularly under the heading “Summary of Risk Factors” and the risk factors detailed further in Part I, Item 1A. Risk Factors that we believe could cause actual results or events to differ materially from the forward-looking statements that we make.

Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make.

You should read this Annual Report on Form 10-K and the documents that we have filed as exhibits to this Annual Report on Form 10-K completely and with the understanding that our actual future results may be materially different from what we expect. We do not assume any obligation to update any forward-looking statements whether as a result of new information, future events or otherwise, except as required by applicable law.

In this Annual Report on Form 10-K, unless otherwise stated or the context otherwise requires, references to “PTC,” “PTC Therapeutics,” “we,” “us,” “our,” “the Company,” and similar references refer to PTC Therapeutics, Inc. and, where appropriate, its subsidiaries. The trademarks, trade names and service marks appearing in this Annual Report on Form 10-K are the property of their respective owners.

All website addresses given in this Annual Report on Form 10-K are for information only and are not intended to be an active link or to incorporate any website information into this document.

​

​

​

​

​

​

​

​

​

​

​

​

3

Table of Contents

SUMMARY OF RISK FACTORS

Below is a summary of the principal risk factors that make an investment in our common stock speculative or risky. This summary does not address all of the risks and uncertainties that we face. Additional risks and uncertainties not presently known to us or that we presently deem less significant may also impair our business operations. Additional discussion of the risks summarized in this risk factor summary, and other risks that we face, can be found in Item 1A. Risk Factors, of this Annual Report on Form 10-K, and should be carefully considered, together with other information in this Annual Report on Form 10-K and our other filings with the Securities Exchange Commission, before making an investment decision regarding our common stock. The forward-looking statements discussed above are qualified by these risk factors. If any of the following risks occur, our business, financial condition, results of operations and future growth prospects could be materially and adversely affected.

​

Summary of Risk Factors

​

4

Table of Contents

​

​

5

Table of Contents

PART I

Item 1.   Business

Overview

We are a global biopharmaceutical company focused on the discovery, development and commercialization of clinically differentiated medicines that provide benefits to patients with rare disorders. Our ability to innovate to identify new therapies and to globally commercialize products is the foundation that drives investment in a robust and diversified pipeline of transformative medicines. Our mission is to provide access to best-in-class treatments for patients who have little to no treatment options. Our strategy is to leverage our strong scientific and clinical expertise and global commercial infrastructure to bring therapies to patients. We believe that this allows us to maximize value for all of our stakeholders.

Our Pipeline

We have a diversified therapeutic portfolio that includes several commercial products and product candidates in various stages of development, including discovery, research and clinical stages, focused on the development of new treatments for multiple therapeutic areas for rare diseases relating to neurology and metabolism. The chart and the disclosure directly below summarizes the status of our significant clinical-stage programs and commercial products as of the date of this report, including those with our strategic partners:

​

​

​

6

Table of Contents

​

​

7

Table of Contents

Global Commercial Footprint

Global DMD Franchise

Duchenne muscular dystrophy (DMD)

Muscular dystrophies are genetic disorders involving progressive muscle wasting and weakness. DMD is the most common and one of the most severe types of muscular dystrophy. DMD occurs when a mutation in the dystrophin gene prevents the cell from making a functional dystrophin protein. Dystrophin is a muscle membrane associated protein and is critical to the structural and membrane stability of muscle fibers in skeletal, diaphragm and heart muscle. The absence of normally functioning dystrophin results in muscle fragility, such that muscle injury occurs when muscles contract or stretch during normal use. As muscle damage progresses, connective tissue and fat replace muscle fibers, resulting in inexorable muscle weakness.

Because the dystrophin gene is located on the X chromosome, DMD occurs primarily in young boys, although approximately 10% of female carriers show some disease symptoms. DMD is rare, and estimates of occurrence include approximately 1 in every 3,500 live male births, according to the National Organization for Rare Diseases and approximately 1 in every 5,000 live male births according to Ryder (2017) in the European Journal of Human Genetics. We estimate that there are between approximately 10,000 to 15,000 DMD patients in the United States. Several different types of mutation in the dystrophin gene can result in DMD, including deletion, duplication and nonsense mutations. A test known as multiplex ligation-dependent probe amplification (MLPA) can detect large deletions and duplications, which account for approximately 75% of all mutations. However, gene sequencing is required to identify small mutations such as nonsense mutations. We estimate that nonsense mutations account for approximately 13% of cases of DMD. Without treatment, patients with DMD typically lose walking ability by their early teens, require ventilation support in their late teens, and eventually experience premature death due to heart and lung failure. Even with medical care, most people with DMD die from cardiac or respiratory failure before or during their 30s.

Marketing authorization matters

Translarna for the treatment of nonsense mutation Duchenne muscular dystrophy

European Economic Area

We received marketing authorization from the EC in August 2014 for Translarna for the treatment of nmDMD in ambulatory patients aged five years and older in the member states of the EEA, subject to annual renewal and other conditions. In July 2018, the EC approved a label-extension request to our marketing authorization for Translarna in the EEA to include patients from two to up to five years of age. In July 2020, the EC approved the removal of the statement “efficacy has not been demonstrated in non-ambulatory patients” from the indication statement for Translarna.

The marketing authorization is subject to annual review and renewal by the EC following reassessment by the EMA of the benefit-risk balance of continued authorization, which we refer to as the annual EMA reassessment. In September 2022, we submitted a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization, which included a report on the placebo-controlled trial of Study 041 and data from the open-label extension as further described below. In February 2023, we also submitted an annual marketing authorization renewal request to the EMA. In September 2023, the CHMP gave a negative opinion on the conversion of the conditional marketing authorization to full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of Translarna for the treatment of nmDMD. On January 25, 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In accordance with EMA regulations, the EC has 67 days to adopt the opinion. If the EC adopts the negative opinion, Translarna would no longer have marketing authorization in the member states of the EEA. We are exploring other potential mechanisms in which we may provide Translarna to nmDMD patients in the EEA if the negative opinion is adopted by the EC.

8

Table of Contents

Marketing authorization is required in order for us to engage in any commercialization of Translarna in the EEA, which allows us to participate in pricing and reimbursement negotiations, on a country-by-country basis with each country in the EEA. Individual countries in the EEA have the ability to make Translarna available under early access programs, or EAP programs, or through similar styled programs. There is substantial risk that if the EC adopts the CHMP’s negative opinion or we are otherwise unable to renew our EEA marketing authorization during any annual renewal cycle or we are unable to identify other potential mechanisms in which we may provide Translarna to nmDMD patients in the EEA should the CHMP’s negative opinion be adopted by the EC or our product label is materially restricted, we would lose all, or a significant portion of, our ability to generate revenue from sales of Translarna in the EEA and other territories. For more information regarding the risks associated with the a potential EC adoption of the CHMP’s negative opinion on Translarna’s marketing authorization, see Item 1A. Risk Factors, “We may be unable to continue to commercialize Translarna for nonsense mutation Duchenne muscular dystrophy in the European Economic Area if the European Commission adopts the negative opinion issued by the Committee for Medicinal Products for Human Use of the European Medicines Agency for the renewal of the existing conditional authorization for Translarna.”

See “Item 1. Business-Commercial Matters-Market Access Considerations” and “Item 1A. Risk Factors-Risks Related to the Development and Commercialization of our Product and our Product Candidates” and “-Risks Related to Regulatory Approval of our Product and our Product Candidates” for further information regarding the marketing authorization in the EEA, the market access process and related risks.

As the marketing authorization holder, we are obligated to monitor the use of Translarna for nmDMD to detect, assess and take required action with respect to information that could impact the safety profile of Translarna and to report this information, through pharmacovigilance submissions, to the EMA. Following its assessment of these submissions, the EMA can recommend to the EC actions ranging from the continued maintenance of the marketing authorization to its withdrawal.

United States

Translarna is an investigational new drug in the United States. During the first quarter of 2017, we filed an NDA for Translarna for the treatment of nmDMD over protest with the FDA. In October 2017, the Office of Drug Evaluation I of the FDA issued a Complete Response Letter, or CRL, for the NDA, stating that it was unable to approve the application in its current form. In response, we filed a formal dispute resolution request with the Office of New Drugs of the FDA. In February 2018, the Office of New Drugs of the FDA denied our appeal of the CRL. In its response, the Office of New Drugs recommended a possible path forward for our ataluren NDA submission based on the accelerated approval pathway. This would involve a re-submission of an NDA containing the current data on effectiveness and safety of ataluren with new data to be generated on dystrophin production in nmDMD patients’ muscles. We followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that we designed, such dystrophin data in a new study, Study 045, and announced the results of Study 045 in February 2021. Study 045 did not meet its pre-specified primary endpoint. In June 2022, we announced top-line results from the placebo-controlled trial of Study 041, which was our 18-month, placebo-controlled trial, followed by an 18-month open-label extension, of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. Following this announcement, we submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential re-submission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support NDA re-submission. We held a Type C meeting with the FDA in the fourth quarter of 2023 to discuss the totality of Translarna data. Based on this discussion, the FDA suggested we request a pre-submission Type C meeting to discuss the specific contents of an NDA resubmission based on results from Study 041 and from our international drug registry study for nmDMD patients receiving Translarna. This meeting is scheduled for March 2024.

See “Item 1. Business-Government Regulation-The new drug and biologic approval process” below for further discussion with respect to the NDA process. See “Item 1. Business-Translarna (ataluren)” and “Item 1A. Risk Factors-Risks Related to the Development and Commercialization of our Product and our Product Candidates” and “-Risks Related to Regulatory Approval of our Product and our Product Candidates” for further detail regarding the results of our completed trials and studies of Translarna for the treatment of nmDMD, our regulatory strategy in the United States, our history with submissions to the FDA and the related risks to our business.

9

Table of Contents

Other Territories

Translarna received marketing authorization for the treatment of nmDMD in Israel and South Korea in 2015, Chile in 2018, Brazil in 2019 and Russia in 2020, in addition to approvals from other countries, and these licenses are currently active. Many territories outside of the EEA, including Israel, South Korea and Chile, reference and depend on the determinations by the EMA when considering the grant of a marketing authorization. It is possible that we would not be able to maintain our marketing authorizations in these regions in the event the EMA decides not to renew or otherwise modifies or withdraws our marketing authorization in the EEA.  In addition, Translarna is authorized in the United Kingdom and will undergo a national assessment. The marketing authorization for Translarna in Brazil and Russia are subject to renewal every five years. We have been pursuing and expect to continue to pursue marketing authorizations for Translarna for the treatment of nmDMD in other regions.

Emflaza for the treatment of Duchenne muscular dystrophy in the United States

Emflaza, both in tablet and suspension form, received approval from the FDA in February 2017 as a treatment for DMD in patients five years of age and older in the United States. In June 2019, the FDA approved our label expansion request for Emflaza for patients two to five years of age. We estimate that there are between approximately 10,000 and 15,000 DMD patients in the United States.

Emflaza received a seven-year marketing exclusivity period in the United States for its approved indications, commencing on the date of FDA approval, under the provisions of the Orphan Drug Act of 1983, or the Orphan Drug Act. We have previously relied on this exclusivity period to commercialize Emflaza in the United States. Emflaza’s seven-year period of orphan drug exclusivity related to the treatment of DMD in patients five years and older expired in February 2024. We expect the expiration of this orphan drug exclusivity to have a significant negative impact on Emflaza net product revenue. Emflaza’s orphan drug exclusivity related to the treatment of DMD in patients two years of age to less than five expires in June 2026. See “Item 1. Business-Government Regulation” for further discussion with respect to marketing protection we rely on.

Upstaza

Upstaza is a gene therapy for the treatment of AADC deficiency, a rare CNS disorder arising from reductions in the enzyme AADC that results from mutations in the dopa decarboxylase gene. In July 2022, the EC approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the EEA. In November 2022, the Medicines and Healthcare products Regulatory Agency approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the United Kingdom. We are also preparing a BLA for Upstaza for the treatment of AADC deficiency in the United States. In October 2022, we held a Type C meeting with the FDA to discuss the details of a potential submission package for Upstaza. At that meeting, the FDA asked for additional bioanalytical data in support of comparability between the drug product used in the clinical studies and the commercial drug product. We completed these analyses and provided the results to the FDA for review. The FDA stated that the data that we provided were still not sufficient. However, the FDA also said that the available data from the ongoing clinical study in the United States assessing the safety of the drug delivery cannula for Upstaza could be used to support a BLA for accelerated approval based on biomarker data demonstrating a treatment-related increase in de novo dopamine production. At the FDA’s suggestion, we held a pre-BLA meeting in December 2023. We expect to submit a BLA to the FDA for Upstaza for the treatment of AADC deficiency in March 2024.

AADC is the enzyme responsible for the conversion of L-dopa to dopamine. Dopamine is a key neurotransmitter that acts within the striatum (caudate and putamen), a component of the brain’s deep grey matter, to modulate output of neurons that project to the motor and premotor cortices of the brain that plan and execute normal motor function. Dopamine is required in the brain for humans to develop and maintain proper motor function.

AADC deficiency is a monogenic disorder of neurotransmitter synthesis that manifests in young children and most commonly results in profound developmental delay, often seen as complete arrest of motor development. AADC deficiency generally causes the inability to develop motor control, resulting in breathing, feeding, and swallowing problems, frequent hospitalizations, and the need for life-long care. On average, patients with AADC deficiency die in the

10

Table of Contents

first decade of life due to profound motor dysfunction and secondary complications such as choking, hypoxia, and pneumonia. Currently, no treatment options are available for the underlying cause of the disorder, and care is limited to palliative options with significant burden on caregivers.

The prevalence of AADC deficiency has been estimated to be approximately 5,000 patients worldwide, with a live-birth incidence of up to 1 in 40,000 worldwide. While several diagnostic tests for AADC deficiency are available, we believe the condition remains largely undiagnosed or misdiagnosed and may be confused with cerebral palsy.

Upstaza is an adeno-associated virus, or AAV, gene therapy, which has been assessed in three completed clinical trials, AADC-1601, AADC-010 and AADC-011. The three completed trials included a total of 30 children with AADC deficiency who were treated with Upstaza during a single procedure in which the gene therapy was administered directly to the region of the brain, called the putamen, where dopamine is made and released. The targeted micro-dosing approach administering small amounts of gene therapy directly to focal regions of affected cells in the putamen has the benefit of keeping the supply requirements for materials low, improving access of the therapeutic gene to key cells, potentially limiting immune and complement-mediated responses and reducing the risk of off-target uptake and excretion of the gene therapy by the liver and kidneys. Results from these trials suggest that patients may have a gain of motor functions and improvement in cognitive scales following gene therapy administration and have shown significant increases in motor function, which contrasts with the published natural history.

AADC-1601, AADC-010 and AADC-011, were each single-arm, open-label, interventional trials. The primary and secondary objectives of these trials were to assess the safety and efficacy of Upstaza administered via bilateral putaminal-infusions in patients with severe AADC deficiency. Study enrollment required a diagnosis of AADC deficiency, defined as decreased homovanilic acid, or HVA, and 5-hydroxyindoleacetic acid, or 5-HIAA, and elevated levels of L-DOPA in the cerebrospinal fluid, or CSF, the presence of more than one DDC gene mutation, and the presence of clinical symptoms of AADC deficiency (including developmental delay, hypotonia, dystonia, and oculogyric crisis), and a patient age of older than 2 years.

Patients were evaluated monthly for safety assessments and every three months for efficacy assessments that included tests of motor developmental testing (Peabody Developmental Motor Scale, Second Edition, or PDMS-2, and Alberta Infant Motor Scale, or AIMS) through the first year after treatment with Upstaza and at periodic intervals thereafter through five years following treatment. The PDMS-2 and AIMS are validated scales used to assess motor skills in young children. Pharmacodynamic testing of CNS AADC activity over time included analyses of CSF neurotransmitter metabolites and F-DOPA PET imaging intervals, also through five years.

At baseline, patients had no functional movement and failed to achieve any motor milestones, including head control, sitting or standing capabilities, consistent with the published natural history of severe AADC deficiency. Compared to baseline, at one-year and at five-years after Upstaza administration, patients had objective evidence of de novo dopamine production as visualized by F-DOPA PET imaging of the brain, consistent with successful and stable gene expression and enzyme activity over time. Additionally, HVA levels, which is the major metabolite of dopamine metabolism, were measured at month 12 to determine if new dopamine was synthesized. HVA levels increased significantly from baseline at month 12, consistent with de novo dopamine synthesis.

Following administration of Upstaza, the combined group of patients showed significant improvements from baseline capabilities at one-year post-treatment in functional motor skills assessed with the PDMS-2 total score, as well as on the locomotion, grasping, visual-motor integration and stationary subscales. Significant improvements from baseline at one-year post-treatment were also observed for the combined group of patients on the AIMS total score and on the prone, supine, sit and stand subscales.

Compared to published natural history data, patients in these trials showed statistically significant improvements at both two- and five-year post-treatment in achievement of motor milestones of full head control (at 2 and 5 years), sitting unassisted (at 2 and 5 years), standing with support (at 5 years) and walking with assistance (at 5 years), reinforcing the clinical benefit and sustainability of functional motor improvements.

11

Table of Contents

Surgical injection of Upstaza in the completed trials was well tolerated. Adverse events were generally associated with the disease state. The most frequent adverse event associated with Upstaza was dyskinesia and these events completely resolved over time. No serious adverse events have been attributed to Upstaza.

Patients from our completed trials have been offered to continue to follow up in Study 1602, which is intended to assess long-term safety and efficacy of Upstaza. Additionally, Study AADC-002, a multicenter, open-label trial to assess and efficacy of Upstaza, is ongoing.  We have enrolled 13 patients in this study.

Upstaza for the treatment of AADC deficiency has orphan drug designation in the United States and EU, and rare pediatric disease designation in the United States, and upon BLA approval the FDA may grant us a priority review voucher, depending on the timing of the approval.

Due to its orphan medicinal product designation by the EMA, we rely on a ten-year exclusive marketing period for Upstaza in the EEA, which may potentially be extended for two additional years if we receive approval for a pediatric exclusivity incentive. If Upstaza for the treatment of AADC deficiency receives FDA approval, we expect that Upstaza would have a twelve-year exclusive marketing period in the United States for the approved indication, commencing on the date of FDA approval, under the provisions of the Biologics Price Competition and Innovation Act of 2009, or BPCIA, as well as a concurrent seven-year exclusive marketing period, which would commence on the date of FDA approval, under the provisions of the Orphan Drug Act. We expect to rely on the twelve-year BPCIA regulatory exclusivity and concurrent seven-year Orphan Drug Act exclusivity to commercialize Upstaza in the United States, if it is approved.

See “Item 1. Business-Government Regulation-The new drug and biologic approval process” below for further discussion with respect to the BLA process.

Tegsedi and Waylivra

In August 2018 we entered into a Collaboration and License Agreement with Akcea Therapeutics, Inc., or Akcea, a subsidiary of Ionis for the commercialization by us of Tegsedi, Waylivra and products containing those compounds in countries in Latin America and the Caribbean, or the PTC Territory. See “Item 1. Business-Our Collaborations, License Agreements and Funding Arrangements-Tegsedi and Waylivra” below for further discussion with respect to this collaboration and license agreement.

Tegsedi

Tegsedi, a product of Ionis’ proprietary antisense technology, is an antisense oligonucleotide, or ASO, inhibitor of human transthyretin, or TTR, production. Tegsedi is the world’s first RNA-targeted therapeutic to treat patients with hereditary transthyretin amyloidosis, or hATTR amyloidosis. In October 2019, it received marketing authorization from ANVISA, the Brazilian health regulatory authority, for the treatment of stage 1 or stage 2 polyneuropathy in adult patients with hATTR amyloidosis in Brazil. Our marketing authorization for Tegsedi in Brazil is subject to renewal every five years. It has also received marketing authorization in the United States and EU for the same indication.

hATTR amyloidosis is a progressive, systemic and fatal inherited disease caused by the abnormal formation of the TTR protein and aggregation of TTR amyloid deposits in various tissues and organs throughout the body, including in peripheral nerves, heart, intestinal tract, eyes, kidneys, central nervous system, thyroid and bone marrow. The progressive accumulation of TTR amyloid deposits in these tissues and organs leads to sensory, motor and autonomic dysfunction often having debilitating effects on multiple aspects of a patient’s life. Patients with hATTR amyloidosis often present with a mixed phenotype and experience overlapping symptoms of polyneuropathy and cardiomyopathy.

Ultimately, hATTR amyloidosis generally results in death within three to fifteen years of symptom onset. Therapeutic options for the treatment of patients with hATTR amyloidosis are limited and there are currently no disease-modifying drugs approved for the disease. There are an estimated 50,000 patients with hATTR amyloidosis worldwide, including approximately 6,000 patients with polyneuropathic hATTR amyloidosis in Latin America.

12

Table of Contents

Waylivra

Waylivra is an ASO that has received marketing authorization in the EU for the treatment of FCS, subject to certain conditions. The United States and EU regulatory agencies have granted orphan drug designation to Waylivra for the treatment of FCS. In connection with the marketing approval for Waylivra in the EU, the EC is requiring Akcea to provide results of a study based on a registry of patients to investigate how blood checks and adjustments to frequency of injections are carried out in practice and how well they work to prevent thrombocytopenia and bleeding in FCS patients taking Waylivra. In August 2021, ANVISA approved Waylivra as the first treatment for FCS in Brazil. Our marketing authorization for Waylivra in Brazil is subject to renewal every five years.

FCS is an ultra-rare disease caused by impaired function of the enzyme lipoprotein lipase, or LPL, and characterized by severe hypertriglyceridemia (>880mg/dL) and a risk of unpredictable and potentially fatal acute pancreatitis. Because of limited LPL function, people with FCS cannot break down chylomicrons, lipoprotein particles that are 90% triglycerides. In addition to pancreatitis, FCS patients are at risk of chronic complications due to permanent organ damage. They can experience daily symptoms including abdominal pain, generalized fatigue and impaired cognitions that affect their ability to work. People with FCS also report major emotional and psychosocial effects including anxiety, social withdrawal, depression and brain fog. There is no effective therapy for FCS currently available.

Additionally, we received approval of Waylivra for the treatment of FPL in Brazil in December 2022. FPL is a rare genetic metabolic disease characterized by selective, progressive loss of body fat (adipose tissue) from various areas of the body leading to ectopic fat deposition in liver and muscle and development of insulin resistance, diabetes, dyslipidemia and fatty liver disease. Individuals with FPL often have reduced subcutaneous fat in the arms and legs and the head and trunk regions may or may not have loss of fat. Conversely, affected individuals may also have excess subcutaneous fat accumulation in other areas of the body, especially the neck, face and intra-abdominal regions.

Evrysdi

Evrysdi was approved by the FDA in August 2020 for the treatment of SMA in adults and children two months and older and by the EC in March 2021 for the treatment of 5q SMA in patients two months and older with a clinical diagnosis of SMA Type 1, Type 2 or Type 3 or with one to four SMN2 copies. Evrysdi has also received marketing authorization for the treatment of SMA in over 100 countries. In May 2022, the FDA approved a label expansion for Evrysdi to include infants under two months old with SMA. In August 2023, the EC approved an extension of the Evrysdi marketing authorization to include infants under two months old in the EU. Evrysdi is a product of our SMA program and our collaboration with Roche and the SMA Foundation. For additional information, see “Item 1. Business – Our Collaborations, License Agreements and Funding Arrangements – Roche and the SMA Foundation.”

SMA is a genetic neuromuscular disease characterized by muscle wasting and weakness. The disease generally manifests early in life. SMA is caused by mutation or deletion of the Survival of Motor Neuron 1, or SMN1, gene that encodes the survival of motor neuron, or SMN, protein. The SMN protein is critical to the health and survival of the nerve cells in the spinal cord responsible for muscle contraction. A second gene, Survival of Motor Neuron 2, or SMN2, is very similar to SMN1, contains a T nucleotide at position 6 in exon 7 and produces low, insufficient levels of functional SMN protein due to alternative splicing of exon 7. According to the SMA Foundation, SMA is the leading genetic cause of death in infants and toddlers. Approximately 1 in 10,000 children is born with the disease. We estimate that there are between 20,000 to 30,000 children and adults living with SMA in the United States, Europe and Japan.

13

Table of Contents

Diversified Development Pipeline

Our pipeline includes a number of programs at various stages of development including sepiapterin, PTC518 and other programs from our splicing and ferroptosis and inflammation platforms. Additionally, we have ongoing clinical studies of our current commercial product for maintaining authorizations and enabling additional authorizations.

Sepiapterin

Sepiapterin is a precursor to intracellular tetrahydrobiopterin, which is a critical enzymatic cofactor involved in metabolism and synthesis of numerous metabolic products. Sepiapterin has been pursued as a possible treatment for orphan metabolic diseases associated with defects in the tetrahydrobiopterin biochemical pathways, including PKU. PKU is an inborn error of metabolism caused predominantly by mutations in the phenylalanine hydroxylase gene resulting in toxic buildup of the amino acid phenylalanine, or Phe, in the brain, and, if left untreated, severe and irreversible disabilities such as permanent intellectual disability, seizures, delayed development, behavioral problems and possibly psychiatric disorders can occur. We believe that there are approximately 58,000 PKU patients globally. In May 2023, we announced that the primary endpoint was achieved in our registration-directed Phase 3 trial for sepiapterin for PKU. The primary endpoint of the study was the achievement of statistically-significant reduction in blood Phe level. The primary analysis population included those patients who have a greater than 30% reduction in blood Phe levels during the Part 1 run-in phase of the trial. Sepiapterin demonstrated Phe level reduction of approximately 63% in the overall primary analysis population and Phe level reduction of approximately 69% in the subset for classical PKU patients. Additionally, sepiapterin was well tolerated with no serious adverse events. Following the placebo-controlled study, patients were eligible to enroll in a long-term open-label study, which is still ongoing and will evaluate long-term safety, durability and Phe tolerance. We expect to submit an MAA to the EMA for sepiapterin for the treatment of PKU in the EEA in March 2024. Additionally, we participated in a pre-NDA meeting with the FDA in the third quarter of 2023. At that meeting, the FDA stated that the sepiapterin clinical safety and efficacy data supported NDA submission for the treatment of pediatric and adult PKU patients. However, the FDA has requested that we complete a 26-week nonclinical mouse study to assess sepiapterin carcinogenicity potential prior to NDA submission. This nonclinical study was not initially required when we acquired sepiapterin, as the NDA submission was planned under the Section 505(b)(2) pathway. Given that sepiapterin is a novel therapy with distinct pharmacology, biodistribution, mechanism of action and differentiated efficacy, we subsequently decided to make the NDA submission under the Section 505(b)(1) pathway, which requires the 26-week study, which is considered a required NDA component needed to inform labeling and is typically completed prior to submission. Based on the timing to complete this study, we expect to submit an NDA to the FDA for sepiapterin for the treatment of PKU no later than the third quarter of 2024 and we intend to discuss with the FDA the potential for an earlier submission if we are permitted to submit the 26-week mouse study report during the NDA review process.

Splicing Platform

Our splicing platform focuses on the development of innovative therapies for diseases, such as SMA, that involve regulation of mRNA splicing in the cell.

In addition to Evrysdi and our SMA program, our splicing platform also includes PTC518, which is being developed for the treatment of HD. HD is a neurodegenerative and progressive brain disorder caused by a toxic gain-of-function triplet repeat expansion in the Huntingtin gene resulting in uncontrolled movements and cognitive loss. There are currently no disease-modifying therapies approved to delay the onset or slow the progression of HD. We believe that there are approximately 135,000 HD patients globally. PTC518 is an orally bioavailable molecule with broad central nervous system and systemic distribution that has been designed to target Huntingtin protein expression with high selectivity and specificity. We announced the results from our Phase 1 study of PTC518 in healthy volunteers in September 2021 demonstrating dose-dependent lowering of huntingtin messenger ribonucleic acid and protein levels, that PTC518 efficiently crosses blood brain barrier at significant levels and that PTC518 was well tolerated.  We initiated a Phase 2 study of PTC518 for the treatment of HD in the first quarter of 2022, which consists of an initial 12-week placebo-controlled phase focused on safety, pharmacology and pharmacodynamic effects followed by a nine-month placebo-controlled phase focused on PTC518 biomarker effect. In June 2023, we announced interim data from the 12-week placebo-controlled phase. The study demonstrated dose-dependent lowering of Huntingtin, or HTT, protein levels in peripheral blood cells, reaching an approximate mean 30% reduction in mutant HTT levels at the 10mg dose level. In

14

Table of Contents

addition, PTC518 exposure in the cerebrospinal fluid was consistent with or higher than plasma unbound drug levels. Furthermore, PTC518 was well tolerated with no treatment-related serious adverse events. The Phase 2 study is actively ongoing outside the United States, while it has been paused within the United States as the FDA requested additional data to allow the Phase 2 study to proceed. We expect to provide 12-month interim data from the Phase 2 study of PTC518 for the treatment of HD in the second quarter of 2024. We expect to submit a safety data update to the FDA in the second quarter of 2024 to support lifting of the partial clinical hold on the program.

Ferroptosis and Inflammation Platform

Our ferroptosis and inflammation platform consists of small molecule compounds that target oxidoreductase enzymes that regulate oxidative stress and inflammatory pathways central to the pathology of a number of CNS diseases. Oxidation-reduction, or redox, reactions are an essential component of the generation and regulation of energy in living systems. These reactions are regulated through a set of enzymes known as oxidoreductase enzymes that uniquely require the transfer of an electron, or a redox chemical reaction, to affect their biological activity.

One of the advanced molecules in our ferroptosis and inflammation platform is vatiquinone. Vatiquinone is a small molecule orally bioavailable compound that has been in development for inherited mitochondrial diseases and related genetic disorders of oxidative stress. Vatiquinone targets 15-lipoxygenase, or 15-LO, a key regulator of oxidative stress, lipid-based neuro-inflammation, alpha-synuclein oxidation and aggregation and cell death. We are developing vatiquinone for the treatment of Friedreich ataxia. Friedreich ataxia is a rare and life-shortening neurodegenerative disease caused by a single defect in the FXN gene which causes reduced production of the frataxin protein. We believe that there are approximately 25,000 Friedreich ataxia patients globally. Vatiquinone has previously been studied in Friedreich ataxia patients in a Phase 2 trial that included a six-month placebo-controlled phase followed by an 18-month open label extension. In this trial, long-term vatiquinone treatment (18-24 months) was associated with an improvement in overall disease severity and neurological function relative to natural history. Vatiquinone has been generally well-tolerated in the clinic.

We announced topline results from our MOVE-FA trial, a registration-directed Phase 3 trial of vatiquinone in children and young adults with Friedreich ataxia, in May 2023. While the trial did not meet its primary endpoint of statistically significant change in modified Friedreich Ataxia Rating Scale, or mFARS, score at 72 weeks in the primary analysis population, vatiquinone treatment did demonstrate significant benefit on key disease subscales and secondary endpoints. In addition, in the population of subjects that completed the study protocol, significance was reached in the mFARS endpoint and several secondary endpoints, including the upright stability subscale. Furthermore, vatiquinone was well tolerated. In the first quarter of 2024, we met with the FDA, who expressed willingness to review an NDA for vatiquinone for the treatment of Friedreich ataxia based on the MOVE-FA trial as well as data from the ongoing open label extension study following the MOVE-FA trial, potentially allowing for the submission of an NDA in late 2024. In the first quarter of 2024, we also received scientific advice from the EMA on the MOVE-FA trial results, in which the EMA stated that the MOVE-FA data would likely not be sufficient for conditional authorization.

The other advanced molecule in our ferroptosis and inflammation platform is utreloxastat, a small molecule orally bioavailable compound that targets 15-LO and is in development for the potential treatment of adult CNS patients, including ALS. ALS is a rapidly progressing neurodegenerative disease caused by oxidative damage which leads to neuronal cell death and muscular atrophy. We believe that there are approximately 150,000 ALS patients globally. In the third quarter of 2021, we completed a Phase 1 trial in healthy volunteers to evaluate the safety and pharmacology of utreloxastat. Utreloxastat was found to be well-tolerated with no reported serious adverse events while demonstrating predictable pharmacology. We initiated a Phase 2 registration directed trial of utreloxastat for ALS in the first quarter of 2022. We expect topline results from this trial in the fourth quarter of 2024.

Translarna (ataluren)

Mechanism of action

We discovered Translarna by applying our technologies to identify molecules that promote or enhance the suppression of nonsense mutations. Nonsense mutations are implicated in a variety of genetic disorders. Nonsense mutations create a

15

Table of Contents

premature stop signal in the translation of the genetic code contained in mRNA and prevent the production of full-length, functional proteins. Based on our research, we believe that Translarna interacts with the ribosome, which is the component of the cell that decodes the mRNA molecule and manufactures proteins, to enable the ribosome to read through premature nonsense stop signals on mRNA and allow the cell to produce a full-length, functional protein. As a result, we believe that Translarna has the potential to be an important therapy for genetic disorders which are the result of a nonsense mutation. Genetic tests are available for many genetic disorders, including those noted above, to determine if the underlying cause is a nonsense mutation. Translarna has been generally well-tolerated in all of our clinical trials, which have enrolled over 1,000 individuals to date.

Planned and ongoing clinical development of Translarna in nonsense mutation Duchenne muscular dystrophy

Study 041

Overview. As a specific obligation to our marketing authorization in the EEA, we were required to conduct and submit to the EMA the results of a three-year clinical trial to confirm the efficacy and safety of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. The trial was comprised of two stages: an 18-month randomized, double-blind, placebo controlled clinical trial followed by an 18-month open label extension period. We refer to the 18-month clinical trial portion as “Stage 1” and the 18-month extension period as “Stage 2”. We refer to Stage 1 and Stage 2 together as Study 041. In September 2022, as part of our specific obligation, we submitted a report on Stage 1 and data from Stage 2 in connection with a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization.

For a discussion of the risks related to conducting clinical trials, in general, and Study 041, in particular, please see “Item 1A. Risk Factors-Risks Related to the Development and Commercialization of our Product and our Product Candidates” and “-Risks Related to Regulatory Approval of our Product and our Product Candidates”.

Enrollment. According to the study protocol, Study 041 enrolled nmDMD patients aged five years and above who achieve a 6-minute walk distance, or 6MWD, equal to or greater than 150 meters at three pre-treatment evaluation times (screening, baseline day one and baseline day two), tested as set forth in the protocol. Qualified participants also needed to perform timed function tests of running/walking 10 meters, climbing/descending four stairs and standing from supine within 30 seconds at both screening and baseline, and meet the other criteria set forth in the protocol.

We completed enrollment of Study 041 in the fourth quarter of 2020. Of the 363 patients enrolled in Study 041, 185 patients meet the criteria for inclusion in the primary analysis population, which we refer to as the modified intention-to-treat population, or mITT. Patients included in the mITT must be at least 7, but less than 16, years old, with a 6MWD of equal to or greater than 300 meters and a stand from supine time of five seconds or more, each as tested at screening and baseline.

Objectives and endpoints. The primary objective of Study 041 was to evaluate the effect of Translarna on ambulation and endurance as assessed by the 6-minute walk test, or 6MWT. Based on the study protocol, the primary analysis of Stage 1 was to evaluate the difference in slope of change in 6MWD from baseline to week 72 between Translarna and placebo in the mITT population. Data from participants who did not qualify for inclusion in the mITT were used for summary and analysis of efficacy endpoints in the ITT (full date set) population.

A secondary objective of Study 041 was to determine the effects of Translarna on ambulation and burst activity as assessed by timed function tests (10-meter run/walk, 4-stair stair-climb, and 4-stair stair descend). Each timed function test was analyzed as a secondary endpoint for both the mITT and ITT populations at the end of Stage 1 and was also analyzed at the end of Stage 2. A separate analysis evaluates 10-meter run/walk results in participants with a baseline 6MWD below 300 meters. An additional analysis evaluates a composite endpoint of average change in times to run/walk 10 meters, climb 4 stairs, and descend 4 stairs. We also assess each of time to loss of ambulation, stair-climbing and stair-descending over 72 weeks and over 144 weeks.

Determination of the effects of Translarna on lower-limb muscle function as assessed by the North Star Ambulatory Assessment, or NSAA, a functional scale designed for boys affected by DMD, serves as an additional secondary objective.

16

Table of Contents

NSAA scores were analyzed as secondary endpoints for both the mITT and ITT populations at the end of Stage 1 and were also analyzed as at the end of Stage 2. A separate analysis for Stage 2 evaluated changes in total score in participants with a baseline 6MWD of equal to or greater than 400 meters and under 7 years of age. We also assessed the risk of loss of NSAA items over 72 weeks and 144 weeks.

Slope of change in 6MWD over 144 weeks was also assessed as a secondary endpoint at the conclusion of Stage 2. Changes in 6MWD from baseline to week 72 and week 144 respectively were also addressed as secondary endpoints.

The safety profile of Translarna was evaluated throughout Stage 1 and Stage 2 as a secondary objective.

Certain exploratory endpoints were also assessed in Study 041. In patients aged 7 years and above, change from baseline in upper limb function is assessed using both functional testing and parent/caregiver-reported questionnaires. In patients under 7 years of age, muscle strength was assessed by change from baseline in myometry parameters. At pre-qualified sites only, magnetic resonance imaging were used to assess change from baseline in muscle fat fraction. The effects of Translarna on pulmonary function were assessed by change from baseline in forced vital capacity. In addition, subject- and parent/caregiver-reported questionnaires and at-home diaries were assessed to evaluate the effect of Translarna on health-related quality of life (HRQL) changes from baseline.

Stratification. In Stage 1, participants were randomized 1:1 to placebo or Translarna (10, 10, 20 mg/kg). The randomization was stratified based on type of concomitant corticosteroid used at baseline (deflazacort versus prednisone/prednisolone), maximum of the two valid 6-minute walk tests performed at baseline day 1 and day 2 (<300 meters versus ≥300 to <350 meters, versus ≥350 to <400 meters, versus ≥400 meters), and time to stand from supine at baseline (<5 seconds versus ≥5 seconds).

Results. In June 2022, we announced top-line results from Stage 1. Within Stage 1, Translarna showed a statistically significant treatment benefit across the entire ITT population as assessed by the 6MWT as assessed by the NSAA. Additionally, Translarna showed a statistically significant treatment benefit across the ITT population within the 10-meter run/walk and 4-stair stair climb, while also showing a positive trend in the 4-stair stair descend although not statistically significant. Within the mITT population, Translarna demonstrated a positive trend across all endpoints, however, statistical significance was not achieved. Translarna was also well tolerated with no new safety findings noted.

Observational study, data collection, and open label, extension trials of Translarna for treatment of nmDMD

We are undertaking a multi-center, observational post-approval study of patients receiving Translarna on a commercial basis, or Study 025o, as required by the Pharmacovigilance Risk Assessment Committee of the EMA and in collaboration with TREAT-NMD and the Cooperative International Neuromuscular Research Group. During the study we will gather data on the safety, effectiveness, and prescription patterns of Translarna in routine clinical practice. We have successfully enrolled more than 300 patients in Study 025o and we expect to follow their progress over five years.

An open label, extension trial, Study 016, involving patients who participated in ACT DMD is also ongoing, across multiple sites in the United States and Canada with patients on commercial supply. We ended the two open label extension trials involving patients who had participated in our prior trials for nmDMD and have transitioned U.S. and Canadian patients from these trials to Study 016 while other patients have transitioned to commercial supply via commercial pathways or EAP programs.

Completed clinical trials of Translarna in nonsense mutation Duchenne muscular dystrophy

Phase 2 pediatric study

As part of our pediatric development commitments under our marketing authorization in the EEA and to support the potential expansion of the Translarna label to younger patients with nmDMD, we initiated a Phase 2 pediatric clinical study to evaluate the safety and pharmacokinetics of Translarna in patients two to five years of age. The study, initiated in June 2016, included a four-week screening period, a four-week study period, and a 48-week extension period for patients who complete the four-week study period (52 weeks total treatment). In July 2018, the EMA approved a label-extension

17

Table of Contents

request to our marketing authorization for Translarna in the EEA to include patients from two to up to five years of age, based on data from this study.

Phase 3 clinical trial of Translarna for nmDMD (ACT DMD)

In October 2015, we announced results from ACT DMD, also referred to as Study 020, our Phase 3, double-blind, placebo-controlled, 48-week clinical trial to evaluate the safety and efficacy of Translarna in patients with nmDMD. ACT DMD involved 228 patients at 53 sites across 18 countries.

In the overall intent-to-treat, or ITT, study population, the primary endpoint of change from baseline at week 48 in the 6MWT, showed a 15 meter benefit in favor of Translarna, which did not meet statistical significance.

A summary of the safety and efficacy results from ACT DMD is outlined below.

Safety and tolerability.   The results of ACT DMD confirmed the favorable safety profile of Translarna seen in our 48-week, 174-patient Phase 2b double-blind, placebo controlled clinical trial evaluating the long-term safety and efficacy of Translarna in patients with nmDMD completed in 2009, or the Phase 2b trial.

Translarna was generally well tolerated at both dose levels in our Phase 2b clinical trial. There were no study discontinuations due to adverse events. Most treatment-emergent adverse events were mild or moderate in severity. Investigators’ attributions of drug-related adverse effects were generally similar across the placebo and Translarna arms. The most common adverse events in this trial were vomiting (46.6% overall), headache (29.3%), diarrhea (24.1%), nasopharyngitis (20.7%), fever (19.0%), cough (19.0%) and upper abdominal pain (17.8%). These events were generally balanced across treatment arms and are typical of pediatric illnesses. Adverse events with at least a 10% incidence in any treatment arm that were seen with increased frequency from the placebo group to the Translarna 40 mg dose group to the Translarna 80 mg dose group were nausea (12.3% for placebo, 14.0% for the Translarna 40 mg group and 16.7% for the Translarna 80 mg group), abdominal pain (7.0% for placebo, 12.3% for the Translarna 40 mg group and 16.7% for the Translarna 80 mg group), pain in extremity (10.5% for placebo, 12.3% for the Translarna 40 mg group and 13.3% for the Translarna 80 mg group), flatulence (7.0% for placebo, 8.8% for the Translarna 40 mg group and 11.7% for the Translarna 80 mg group) and nasal congestion (7.0% for placebo, 8.8% for the Translarna 40 mg group and 10.0% for the Translarna 80 mg group). There were no serious adverse events observed during the trial that were considered possibly or probably related to Translarna. Determination of relatedness of the serious adverse event to Translarna was made by the trial investigator, based on his or her judgment.

Translarna was generally well tolerated in ACT DMD. There were two study discontinuations due to adverse events, including one in the Translarna arm (constipation) and one in the placebo arm (disease progression). Most treatment-emergent adverse events were mild or moderate in severity. The most common adverse events in this trial were vomiting (20.4% overall), nasopharyngitis (20.0%), headache (18.3%), and fall (17.8%). These events were generally balanced across treatment arms and are typical of pediatric illnesses and/or patients with DMD. Adverse events with at least a 10% incidence in either treatment arm that were seen with increased frequency from the placebo group to the Translarna 40 mg dose group were vomiting (18.3% for placebo, 23.6% for the Translarna 40 mg group), nasopharyngitis (19.1% for placebo, 20.9% for the Translarna 40 mg group), fall (17.4% for placebo, 18.3% for the Translarna 40 mg group), cough (11.3% for placebo, 16.5% for the Translarna 40 mg group) diarrhea (8.7% for placebo, 17.4% for the Translarna 40 mg group), and pyrexia (10.4% for placebo, 13.9% for the Translarna 40 mg group). An overview of adverse events in this trial is shown in the table below.

Overview of treatment-emergent adverse events in Phase 3 clinical trial (as-treated population)

​

18

Table of Contents

​

There were no serious adverse events observed during the trial that were considered possibly or probably related to Translarna. Determination of relatedness of the serious adverse event to Translarna was made by the trial investigator, based on his or her judgment.

Intent to Treat (ITT) Population.   The primary efficacy endpoint in ACT DMD was change in 6MWD from baseline to week 48. In the ITT population, a 15 meter benefit (p=0.213) was observed in the primary endpoint which did not meet statistical significance.

Secondary endpoints in the trial included the proportion of patients with at least 10% worsening in 6MWD at week 48 of the trial compared to baseline, or 10% 6MWD worsening, and change in timed function tests of time to run/walk 10 meters, climb four stairs and descend four stairs. The hazard ratio for Translarna versus placebo was 0.75 (p=0.160) for 10% 6MWD worsening. Benefits trended in favor of Translarna over placebo in the timed function tests in the ITT population, including observed results in time to run/walk 10 meters (1.2 seconds; p=0.117), time to climb four stairs (1.8 seconds; p=0.058), and time to descend four stairs (1.8 seconds; p=0.012).

Additional endpoints included the NSAA test and the Pediatric Outcomes Data Collection Instrument, or PODCI, a validated tool for measuring quality of life in pediatric patients with orthopedic conditions. These additional endpoints favored Translarna in the ITT population but did not meet statistical significance.

Pre-Specified Analyses.   The statistical analysis plan submitted to the FDA for ACT DMD set forth pre-specified analyses of efficacy to be conducted, including subgroups of patients with baseline 6MWD less than 350 meters and patients with baseline 6MWD of greater than or equal to 300 and less than 400 meters, which we refer to as our key subgroups.

The pre-specification of our key subgroups was scientifically justified based upon knowledge of the biology and natural history of the disease and the evolving understanding of the of the six minute walk test as used to assess DMD patients. We considered the pre-specified less than 350 meter baseline 6MWD population as a key subgroup based on the knowledge that 350 meters represents a transition point for patients towards a more rapid decline in walking ability as supported by analysis from our Phase 2b trial. Furthermore, we considered the pre-specified 300 to 400 meter baseline 6MWD population as a key subgroup based on an increasing understanding of the sensitivity limitations of the six minute walk test as an endpoint in 48-week studies. Natural history data suggest that the 6MWT may not be the optimal tool to demonstrate efficacy in patients with either a baseline 6MWD of less than 300 meters, as these patients have significant muscle loss as monitored by magnetic resonance spectroscopy and are at high risk for losing ambulation regardless of treatment, or in high walking patients, such as those with a baseline 6MWD at or greater than 400 meters, as these patients are likely to remain stable over a 48 week testing period.

By defining these key subgroups, we thereby also defined corresponding subgroups of patients with baseline 6MWD greater than or equal to 350 meters, greater than or equal to 400 meters, and less than 300 meters. We also pre-specified a meta-analysis of the combined results from ACT DMD and the Phase 2b ambulatory decline phase patients.

Pre-specified sub-group analysis.   We saw strong evidence of clinical benefit in the pre-specified subgroup of patients with baseline 6MWD between 300 and 400 meters. Specifically, we observed a benefit in Translarna-treated patients of 47 meters (nominal p=0.007) in the 6MWT in this subgroup. This was consistent with an observed benefit of 49 meters

19

Table of Contents

(nominal p=0.026) in our Phase 2b clinical trial in the 300 to 400 meters baseline 6MWD population. We also saw clinically meaningful benefit for Translarna over placebo in each of the timed function tests, including observed results in time to run/walk 10 meters (2.1 seconds; nominal p=0.066), time to climb four stairs (3.6 seconds; nominal p=0.003), and time to descend four stairs (4.3 seconds; nominal p<0.001). The hazard ratio for Translarna versus placebo was 0.79 (nominal p=0.418) for 10% 6MWD worsening. In addition, a benefit of 4.5 points over placebo (nominal p=0.041) was observed in the NSAA test, which we believe is clinically meaningful. We believe that the benefits observed in this key pre-specified subgroup support the use of the 6MWT in the patients with a walking ability in the 300 to 400 meters range and the understanding that the reliability of the 6MWT over a 48 week period was limited at both the lower and upper ends of our 6MWD enrollment range.

In the pre-specified subgroup of patients with baseline 6MWD less than 350 meters, we observed a benefit of 24 meters (nominal p=0.210) in favor of Translarna in the 6MWT. An analysis of the results from our Phase 2b clinical trial in the less than 350 meters baseline 6MWD population, defined post-hoc, demonstrated a 68 meter benefit in the 6MWT (nominal p=0.006). In the timed function tests for the subgroup of ACT DMD patients with baseline 6MWD less than 350 meters, we observed benefits for Translarna over placebo in time to run/walk 10 meters (2.3 seconds; nominal p=0.033), time to climb four stairs (4.2 seconds; nominal p=0.019) and time to descend four stairs (4.0 seconds; nominal p=0.007).

Typically, a trial result is statistically significant if the chance of it occurring when the treatment is like placebo is less than one in 20, resulting in a p-value of less than 0.05. A nominal p-value is the result of one particular comparison when more than one comparison is possible, such as when two active treatments are compared to placebo or when two or more subgroups are analyzed.

As described above, we believe the 6MWT lacks sensitivity to detect a clinical effect in patients with baseline less than 300 meters in a 48-week trial. However, the timed function tests trended in favor of patients treated with Translarna with a baseline 6MWD below 300 meters, including observed benefit over placebo in time to run/walk 10 meters (2.5 seconds; nominal p=0.066), time to climb four stairs (2.4 seconds; nominal p=0.790), and time to descend four stairs (2.1 seconds; nominal p=0.595). We believe the positive trends in this population reflect that short muscle burst activity tests may be a better clinical measure for patients that are at a more advanced stage of disease progression. Consistent with the natural history of ambulatory DMD patients with 6MWD greater than 400 meters, which indicates stability in walking ability over a 48 week period, we observed no meaningful difference in 6MWT between patient groups. Similarly, we observed no meaningful difference in 6MWT between patient groups with baseline 6MWD greater than 350 meters.

Pre-specified meta-analysis.   The meta-analysis combined efficacy results from the ACT DMD ITT population and Phase 2b ambulatory decline phase subgroup. The Phase 2b ambulatory decline phase group includes the patients from our randomized, double-blind, placebo controlled, Phase 2b clinical trial in patients with nmDMD who would have met the enrollment criteria of ACT DMD.

Results from the meta-analysis showed a statistically significant 21 meter improvement in 6MWD (p = 0.015) favoring Translarna.

Additionally, the meta-analysis showed statistically significant benefit for Translarna over placebo across each timed function test including time to run/walk 10 meters (1.4 seconds; p=0.025), time to climb four stairs (1.6 seconds; p =0.018) and time to descend four stairs (2.0 seconds; p=0.004). The hazard ratio for Translarna versus placebo was 0.66 (p=0.023) for 10% 6MWD worsening. We believe that we are able to demonstrate a statistically significant outcome in the 6MWD in the meta-analysis, despite the significant variability in baseline 6MWD among patients in both ACT DMD and the Phase 2b trial’s ambulatory decline phase, due to the substantially larger patient population available in the pooled analysis.

Retrospective Analysis.   We also looked back at the observed results in the meta-analysis for all patients with a baseline 300 to 400 meter 6MWD from ACT DMD and the Phase 2b trial. The meta-analysis of these data demonstrated a 45 meter benefit (nominal p<0.001) in the 6MWT as well as clinically meaningful benefits across each secondary endpoint timed function test, including benefit over placebo in time to run/walk 10 meters (2.2 seconds; nominal p=0.008), time to climb four stairs (3.4 seconds; nominal p<0.001) and time to descend four stairs (4.3 seconds; nominal p<0.001). This meta-analysis of patients with baseline 6MWD of 300 to 400 meters was not pre-specified and is defined post-hoc.

20

Table of Contents

A retrospective analysis performed after unblinding trial results can result in the introduction of bias if the analysis is inappropriately tailored or influenced by knowledge of the data and actual results. In addition, nominal p-values cannot be compared to the benchmark p-value of 0.05 to determine statistical significance without being adjusted for the testing of multiple dose groups or analyses of subgroups. Because of these limitations, regulatory authorities typically give greatest weight to results from pre-specified analyses and adjusted p-values and less weight to results from post-hoc, retrospective analyses and nominal p-values.

Statistical Considerations.   The pre-specified meta-analysis results, which favored Translarna in the 6MWT and each of the timed function tests, are considered statistically significant. In the pre-specified subgroups of ACT DMD patients with a baseline 6MWD less than 350 meters and 300 to 400 meters, the p-values for the 6MWT and each of the timed function tests are considered nominal. For information with respect to the use of nominal p-values and post-hoc analyses, see Item 1A. Risk Factors, “Subgroup, retrospective, post-hoc, and certain statistical analyses may not be reliable and typically will not form the basis for regulatory approval.”

Participation Criteria and Stratification.   Certain key inclusion criteria were specified in the ACT DMD trial protocol for enrollment: the patient had to be 7 through 16 years of age; at the screening visit the patient had to be able to walk no more than 80% of predicted 6MWD compared to healthy boys matched for age and height, but had to be able to walk at least 150 meters during the 6MWT; and the patient must have used systemic corticosteroids for a minimum of six months prior to start of treatment. The ACT DMD trial protocol provided for the exclusion of patients from the trial if, among other things, they recently used systemic aminoglycoside antibiotics, recently initiated or changed corticosteroid therapy or previously received Translarna treatment. Patients enrolled in ACT DMD underwent 48 weeks of blinded treatment prior to the final analysis and the randomization was stratified based on age (<9 years versus ≥9), baseline 6MWD (<350 versus ≥350 meters), and duration of prior use of corticosteroids (<12 months versus ≥12 months).

Study 045

In the fourth quarter of 2018, following the FDA’s recommendation to collect dystrophin data using validated quantification methods, we initiated Study 045, a Phase 2 open label clinical study of 20 boys with nmDMD from ages two to seven, to evaluate the ability of ataluren to increase dystrophin protein levels in boys with nmDMD. Study 045 did not meet its pre-specified primary endpoint. Patients received baseline biopsies prior to the initiation of treatment and follow-up biopsies scheduled at 40 weeks following the start of treatment. However, certain patients were delayed in obtaining the final study muscle biopsies performed at our clinical trial site at the University of California, Los Angeles as a result of the COVID-19 pandemic. 8 of 20 patients were unable to undergo biopsies at week 40, and these patients had their second biopsies between 62 and 70 weeks of treatment. Full-length dystrophin levels were measured using both the Electrochemiluminescence, or ECL assay, as the primary endpoint and Immunohistochemistry, or IHC, assay as the secondary endpoint.

The ITT population included the 20 patients enrolled in the study. However, one subject was determined to be non-compliant, as he only took half of the study drug, and one subject did not have adequate biopsy samples to establish baseline levels. Therefore, 18 patients were compliant with the study drug and had evaluable biopsy samples. These 18 patients are considered the evaluable population. 10 of these 18 patients had their second biopsy at week 40 and 8 had their second biopsy between weeks 62 and 70. Patient characteristics, including age and steroid use were consistent across both cohorts.

Overall in the ITT population, there was an increase in dystrophin expression from baseline, on both ECL as the primary endpoint and IHC as the secondary endpoint, but these did not meet a p-value of <0.05. Nevertheless, when studying the 18 patients in the evaluable cohort, we identified a greater increase in dystrophin expression, and this increase did reach a nominal p-value of 0.04 in the analysis of the IHC assay. Also, over 80% of the evaluable subjects demonstrated an increase in dystrophin expression. 8 patients in the evaluable population had longer treatment exposure, ranging from 62-70 weeks, and these 8 patients had markedly greater levels of dystrophin increase with an average of approximately 24% in the ECL assay. We believe that these results suggest that longer duration of treatment resulted in greater biological effect, which is consistent with the long-term Translarna treatment benefit we have previously reported from our other clinical studies and our international drug registry study for nmDMD patients receiving Translarna.

21

Table of Contents

We also measured creatine kinase, or CK, levels of patients in Study 045 as an objective measure of muscle damage. Dystrophin acts as a shock absorber during a muscle contraction and would be expected to protect against muscle damage and therefore reduce CK levels. Consistent with an increase in the level of dystrophin, we observed a marked reduction of approximately 20% in creatine kinase and that longer treatment with Translarna was associated with a greater magnitude of biological effect.

Strategic Pipeline Prioritizations

In May 2023 and September 2023, we announced strategic pipeline prioritizations following reviews of our portfolio.  In connection with the strategic pipeline prioritizations, we reduced our workforce by 32%, which primarily affected employees in the United States, including those employees involved in early-stage research and gene therapy manufacturing and associated selling, general and administrative functions. We substantially completed the reduction in workforce in January 2024. We also decided to discontinue our preclinical and early research programs for our gene therapy platform, which included programs for Friedreich ataxia and Angelman syndrome, as well as our oncology platform, which included programs for unesbulin for the treatment of diffuse intrinsic pontine glioma and leiomyosarcoma.

Multi-platform Discovery

We continue to invest in our pre-clinical product pipeline by committing significant resources to research and development programs to provide access to best-in-class treatments for patients who have an unmet medical need.

Our Approach

We use multiple drug discovery platforms to discover and develop therapies to target diseases with high-unmet need. Our platforms focus on identifying small molecules that intervene in pathways required for RNA processing and energy production. Careful control and manipulation of these processes allow us to address a wide range of deficiencies.

Splicing

Post-transcriptional control processes are the events that occur in a cell following the transcription of DNA into RNA. These processes regulate, for example, how long RNA molecules last in the cell, how exons in precursor messenger RNA, or pre-mRNA, molecules are spliced, and how efficiently mRNA molecules are translated to proteins. In the majority of human protein-encoding genes, the sequence encoding the mature mRNA transcript is not contiguous in the pre-mRNA but rather has intervening non-coding regions called introns that interrupt the coding sequences, called exons. These introns are removed from the final mRNA product by a process called splicing that also joins the exons together such that only the exons are retained in the mature mRNA.

We use our splicing technology to identify molecules that modulate splicing of the pre-mRNA. Pre-mRNA splicing is a series of highly organized biochemical reactions. Approximately 94% of all human genes encode pre-mRNAs that undergo splicing. In addition, through splicing, one gene can often generate several mRNA products that include a different set of exons through a process called alternative splicing which results in mature mRNA that encodes different, related proteins. Splicing can be therapeutically targeted, in many human diseases, including SMA, Huntington’s disease, muscular dystrophy and various forms of cancer. We have developed several high-throughput drug discovery technology platforms that enable us to identify small molecule modifiers of pre-mRNA splicing. These technologies rely on sensitive quantification of pre-mRNA isoforms directly in human cells or tissue samples. Using this technology, we have successfully identified orally bioavailable small molecules that correct splicing of SMN2 mRNA. An example of one of these molecules is Evrysdi, which was approved in August 2020 by the FDA for the treatment of SMA in adults and children two months and older. Based on our knowledge of the mechanism of splicing and how small molecules interact with the cellular splicing machinery, we have identified additional small molecule drug candidates that modify splicing of pre-mRNA, promote inclusion of specific exons into mRNA, including pseudoexons, or force skipping of undesired exons from the mature mRNA. We believe that this technology is potentially widely applicable to a large number of target genes across many therapeutic areas.

22

Table of Contents

Ferroptosis and Inflammation

Energy production in cells is critical to their survival. On the other hand, processes that induce oxidative stress in cells can negatively impact them. Energy production takes place in a part of the cell called mitochondria. The mitochondria use the transport of electrons via chemical reactions called redox reactions in their cell membranes to produce adenosine triphosphate, or ATP, which is the central energy molecule inside cells. This process of moving electrons to produce ATP is termed electron transfer or transport. The redox reactions, however, can also cause oxidative stress. We use our expertise in energy production via electron transfer chemical reactions and in oxidative stress to develop potentially first-in-class therapeutics for unmet medical needs. One area of our focus is on inherited mitochondrial diseases. Mitochondrial diseases often derive from defects in energy production and oxidative stress pathway. These diseases commonly result in severe neurological impairment and death at an early age. Through our screening processes, we have identified multiple drug targets which we are assessing in nonclinical studies with the aim of identifying additional product candidates to take into clinical development. Similar strategies potentially can be used for broader sets of diseases. We believe such approaches to these types of intractable diseases have the potential to lead to novel therapies to address areas of high unmet medical need.

Our Collaborations, License Agreements and Funding Arrangements

We currently have ongoing collaborations with Roche and the SMA Foundation for SMA, a license agreement with National Taiwan University, or NTU, for Upstaza, a collaboration and license agreement with Akcea for Tegsedi and Waylivra and a license agreement with Shiratori Pharmaceutical Co., Ltd., or Shiratori, relating to the manufacturing processes and technology for sepiapterin.

Roche and the SMA Foundation

Overview.   In November 2011, we entered into a License and Collaboration Agreement with Roche and the SMA Foundation, dated as of November 23, 2011, or the SMA License Agreement, to further develop and commercialize compounds identified under our SMA sponsored research program with the SMA Foundation and to research other small molecule compounds with potential for therapeutic use in patients with SMA. The research term of this agreement was terminated effective December 31, 2014. The ongoing collaboration is governed by a joint steering committee consisting of an equal number of representatives of us, the SMA Foundation and Roche. We, the SMA Foundation and Roche have agreed to endeavor to make decisions by consensus, but if the joint steering committee cannot reach agreement after following a specified decision resolution procedure, Roche’s decision will control. However, Roche may not exercise its final decision-making authority with respect to certain specified matters, including any decision that would increase our or the SMA Foundation’s obligations, reduce our or the SMA Foundation’s rights, expand Roche’s rights, or reduce Roche’s obligations under the license and collaboration agreement.

Commercialization.   We have granted Roche worldwide exclusive licenses, with the right to grant sublicenses, to our patent rights and know-how with respect to such compounds and products. Roche is responsible for pursuing worldwide clinical development of compounds from the research program and has the exclusive right to develop and commercialize compounds from the collaboration.

Payments and Contingent Payments.   Pursuant to the SMA License Agreement, Roche paid us an upfront non-refundable payment of $30.0 million. During the research term, which was terminated effective December 31, 2014, Roche provided us with funding, based on an agreed- upon full-time equivalent rate, for an agreed-upon number of full- time equivalent employees that we contributed to the research program. We are eligible to receive up to an aggregate of $135.0 million in payments if specified development and regulatory milestones are achieved and up to an aggregate of $325.0 million in payments if specified sales milestones are achieved. We are also entitled to tiered royalties ranging from 8% to 16% on worldwide net product sales of products developed pursuant to the collaboration. Roche’s obligation to pay us royalties will expire generally on a country-by- country basis at the latest of the expiration of the last-to-expire patent covering a product in the given country, the expiration of regulatory exclusivity for that product in such country or 10 years from the first commercial sale of that product in such country. However, the royalties payable to us may be decreased in certain circumstances. For example, the royalty rate in a particular country is reduced if the product is not protected by patents in that country and no longer entitled to regulatory exclusivity in that country. We remain responsible for making any

23

Table of Contents

payments to the SMA Foundation that may become due under our pre-existing sponsored research agreement with the SMA Foundation.

As of December 31, 2023, we had recognized a total of $310.0 million in milestone payments and $341.8 million royalties on net sales pursuant to the SMA License Agreement. As of December 31, 2023, there are no remaining development and regulatory event milestones that we can receive. The remaining potential sales milestones as of December 31, 2023 are $150.0 million upon achievement of certain sales events.

In October 2023, we entered into an Amended and Restated Royalty Purchase Agreement, or the A&R Royalty Purchase Agreement, with Royalty Pharma Investments 2019 ICAV, or Royalty Pharma, and, for the limited purposes set forth in the agreement, Royalty Pharma plc, which amends and restates in its entirety that certain Royalty Purchase Agreement dated as of July 17, 2020, or the Original Royalty Purchase Agreement, with RPI Intermediate Finance Trust, or RPI, and for the limited purposes set forth in the agreement, Royalty Pharma PLC.  Pursuant to the A&R Royalty Purchase Agreement, we have sold or agreed to sell to Royalty Pharma certain portions of our remaining retained right, title and interest in and to our right to receive sales-based royalty payments, or the Royalty, on worldwide net sales of Evrysdi and any other product developed pursuant to the SMA License Agreement under the SMA program (all such Royalty rights retained by us, are referred to as the Retained Royalty Rights, and all such Royalty rights that are sold to Royalty Pharma pursuant to the A&R Royalty Purchase Agreement, are referred to as the A&R Assigned Royalty Rights).  At closing, Royalty Pharma paid us $1.0 billion in cash consideration for 38.0447% of our Retained Royalty Rights (which is in addition to the 42.9330% assigned to Royalty Pharma in connection with the Original Royalty Purchase Agreement and referred to as the Original Assigned Royalty Rights, for a total of 80.9777% of the total Royalty) until such time as Royalty Pharma has received payments in respect of the Original Assigned Royalty Rights equal to $1.3 billion in the aggregate, and thereafter 66.6667% of the total Royalty.  In addition, we may sell to Royalty Pharma the remainder of our Retained Royalty Rights in exchange for an aggregate of $500.0 million in additional cash consideration after the closing of the A&R Royalty Purchase Agreement, less royalties received in respect of the Retained Royalty Rights put to Royalty Pharma, which will be payable by Royalty Pharma pursuant to five put options held by us that are exercisable at our option between January 1, 2024 and December 31, 2025.  If we exercise two or fewer of the put options, Royalty Pharma may exercise a call option during the period from and after January 1, 2026 until and including March 31, 2026 for up to 50% of the remainder of our Retained Royalty Rights less amounts exercised by us via our put options at a purchase price that is proportional to the purchase price of our unexercised put options. Royalty Pharma’s exercise of the call option would result in Royalty Pharma owning 90.4888% of the total Royalty until such time as Royalty Pharma has received payments in respect of the Original Assigned Royalty Rights equal to $1.3 billion in the aggregate, and thereafter 83.3333% of the total Royalty.

Termination.   Unless terminated earlier, the SMA License Agreement will expire on the date when no royalty or other payment obligations are or will become due under the agreement. Roche’s termination rights under the license and collaboration agreement include the right to terminate the agreement at any time after November 22, 2013 on a product-by-product and country-by-country basis upon three months’ notice before the launch of the applicable product or upon nine months’ notice thereafter; and the right to terminate the agreement in specified circumstances following a change of control of us. The license and collaboration agreement provides that we or Roche may terminate the agreement in the event of an uncured breach by the other party of a material provision of the agreement, or in the event of the other party’s bankruptcy or insolvency. Upon termination of the collaboration agreement by Roche for convenience or termination by us as a result of Roche’s breach, bankruptcy, change of control or patent challenge, we have the right to assume the development and commercialization of product candidates arising from the license and collaboration agreement. In that event, we may become obligated to pay royalties to Roche on sales of any such product.

SMA Foundation

Overview.   In June 2006, we entered into a sponsored research agreement with the SMA Foundation under which we and the SMA Foundation have collaborated in the research and preclinical development of small molecule therapeutics for SMA. As discussed above, we are also collaborating with the SMA Foundation and Roche to further develop these compounds. Pursuant to the sponsored research agreement, as amended, the SMA Foundation provided us with $13.3 million in funding. The SMA Foundation is not obligated to provide any further funding under this agreement.

24

Table of Contents

Continuing financial obligations.   We may become obligated to pay the SMA Foundation single-digit royalties on worldwide net product sales of any collaboration product that we successfully develop and subsequently commercialize or, with respect to collaboration products we outlicense, including Evrysdi, a specified percentage of certain payments we receive from our licensee. As discussed above, we have outlicensed rights to Roche pursuant to a license and collaboration agreement. We are not obligated to make such payments unless and until annual sales of a collaboration product exceed a designated threshold. Since inception, the SMA Foundation has earned $52.5 million, $35.3 million which was paid and $17.2 million which was accrued as of December 31, 2023. We have reached our obligation to make such payments to the SMA Foundation of an aggregate of $52.5 million as of December 31, 2023.

Reversion rights.   In specified circumstances, including those involving our decision to discontinue development or commercialization of a collaboration product, our uncured failure to meet agreed timelines or those that might arise following our change of control, we may be obligated to grant the SMA Foundation exclusive or non-exclusive sublicensable rights under our intellectual property, in certain collaboration products, among other rights, to assume the development and commercialization of such collaboration products and to provide the SMA Foundation with other transitional assistance, which we refer to as a reversion. In some such cases, we may be entitled to receive licensing fee payments from the SMA Foundation and single-digit royalties on sales of the applicable collaboration product, which amounts we collectively refer to as reversion payments. In other cases, the SMA Foundation is not required to make any payments to us in connection with the licenses it receives from us.

Termination.   Unless terminated earlier, the sponsored research agreement will continue until the earliest of the SMA Foundation’s receipt of the repayment amount or, if there was a reversion, either our receipt of all reversion payments that the SMA Foundation may be obligated to make to us or, if the SMA Foundation is not obligated to make reversion payments, the expiration of the last-to-expire patent we licensed to the SMA Foundation in connection with such reversion. The sponsored research agreement provides that either party may terminate the agreement in the event of an uncured material breach by the other party or in the event of the other party’s bankruptcy or insolvency.

National Taiwan University

Overview. Pursuant to the license and technology transfer agreement, originally entered into between Agilis Biotherapeutics, Inc., or Agilis, NTU and Professor Wuh-Liang (Paul) Hwu, in December 2015, or the NTU Licensing Agreement, NTU granted to us an exclusive, perpetual license, with the right to grant sublicenses through all tiers, to research and use the intellectual property, data, chemistry, manufacturing and controls, or CMC, records, documents, confidential information, materials and know-how pertaining to the Research, including Upstaza for the treatment of AADC deficiency, under the NTU Collaboration Agreement (as defined below), or the Technology, and to develop, make, manufacture, use, sell, import and market the Technology and any other products made, invented, developed or incorporated by or with the Technology, or the Licensed Products. Subject to any regulatory delays or issues, we are obligated to research, use and develop the Technology to manufacture Licensed Products by December 23, 2025. Additionally, we are obligated to obtain marketing approval of Upstaza for the treatment of AADC deficiency, either by the FDA or by the EMA, by December 31, 2024. In July 2022, the EC approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the EEA, satisfying that obligation.

Funding Obligations. NTU received a lump sum of $100,000 upon execution of the NTU Licensing Agreement, as well as $2.0 million milestones payments based on the achievement of certain clinical and regulatory milestones, including $1.2 million that became due and payable in July 2022 upon the EC’s approval of Upstaza for the treatment of AADC deficiency. Additionally, NTU will be entitled to receive contingent payments from us based on (i) annual license maintenance fees, (ii) a low double-digit percentage royalty of annual net sales of Licensed Products, and (iii) a percentage of sublicense revenue, ranging from low-twenties to mid-twenties. The annual license maintenance fees are non-refundable, but creditable against annual net sales payments.

Intellectual Property. All intellectual property relating to the manufacture, production, assembly, use or sale of Technology and any Licensed Products derived thereof are owned by NTU.

Termination. The NTU Licensing Agreement expires on December 23, 2035. Upon expiration, we will have a fully paid-up, perpetual, royalty-free exclusive license to the Technology. We may terminate the NTU Licensing Agreement upon

25

Table of Contents

60 days’ written notice to NTU in the event of (a) the failure of a pivotal clinical study, or serious adverse event in a clinical study, with respect to Upstaza for the treatment of AADC deficiency, that prevents continuing such clinical study under reasonable circumstances or (b) the rejection of a BLA with the FDA or an MAA with the EMA, or equivalent biologics approval application in another territory with respect to Upstaza for the treatment of AADC. In such termination event, we must pay $100,000 to NTU within 30 days of termination and NTU would retain all rights to the Technology. We may terminate the NTU Licensing Agreement for material breach by another party following a 30-day cure period. NTU may terminate the NTU Licensing Agreement for our failure to pay any undisputed license fees or net sales or sublicensing royalty fees within the applicable deadline following a 30-day cure period.

We are also a party to collaborative research agreements with NTU, or the NTU Collaboration Agreements, that govern the collaboration between us and NTU with respect to the research and clinical trials for AADC deficiency gene therapy. NTU is responsible for performing the research and clinical trials and we are responsible for providing related funding. As of December 31, 2023, an aggregate amount of $3.7 million in funding payments has been paid to NTU pursuant to the NTU Collaboration Agreements.

Tegsedi and Waylivra

Overview. PTC Therapeutics International Limited, our subsidiary, entered into a Collaboration and License Agreement, or the Tegsedi-Waylivra Agreement, dated August 1, 2018 by and between us and Akcea, for the commercialization by us of Tegsedi, Waylivra and products containing those compounds, which we refer to collectively as the Products, in countries in Latin America and the Caribbean, or the PTC Territory. We are responsible for all meetings, communications and other interactions with regulatory authorities in the PTC Territory. The activities of the parties pursuant to the Tegsedi-Waylivra Agreement is overseen by a Joint Steering Committee, composed of an equal number of representatives appointed by each of us and Akcea.

Commercialization. Under the terms of the Tegsedi-Waylivra Agreement, Akcea has granted to us an exclusive right and license, with the right to grant certain sublicenses, under Akcea’s product-specific intellectual property to develop, manufacture and commercialize the Products in the PTC Territory. In addition, Akcea has granted to us a non-exclusive right and license, with the right to grant certain sublicenses, under Akcea’s core intellectual property and manufacturing intellectual property to develop, manufacture and commercialize the Products in the PTC Territory and to manufacture the Products worldwide in accordance with a supply agreement with Akcea. Akcea has in-licensed certain of the Akcea intellectual property from its parent company, Ionis. Each party has agreed not to, independently or with any third party, commercialize any competing oligonucleotide product in the PTC Territory for the same gene target as inotersen.

Payments and Contingent Payments. We paid to Akcea an upfront licensing fee of $18.0 million, consisting of an initial payment of $12.0 million paid in connection with entering into the Tegsedi-Waylivra Agreement in August 2018, and a second payment of $6.0 million that was paid after Waylivra received regulatory approval from the EMA in May 2019. In addition, Akcea was eligible to receive milestone payments, on a Product-by-Product basis, of $4.0 million upon receipt of regulatory approval for a Product from ANVISA, subject to a maximum aggregate amount of $8.0 million for all such Products. We paid Akcea $4.0 million upon our receipt of marketing authorization from ANVISA in October 2019 for the treatment of stage 1 or stage 2 polyneuropathy in adult patients with hATTR amyloidosis in Brazil with Tegsedi and an additional $4.0 million upon our receipt of marketing authorization from ANVISA in August 2021 for the treatment of FCS. Akcea is also entitled to receive royalty payments in the mid-twenty percent range of net sales on a country-by-country and Product-by-Product basis, commencing on the earlier to occur of (1) 12 months after the first commercial sale of such Product in Brazil or (2) the date when we, our affiliates or sublicensees have recognized revenue of $10.0 million or more in cumulative net sales for such Product in the PTC Territory. The royalty payments are subject to reduction in certain circumstances as set forth in the Tegsedi-Waylivra Agreement.

Termination. The Tegsedi-Waylivra Agreement will continue until the expiration of the last to expire royalty term with respect to all Products in all countries in the PTC Territory. Either party may terminate the Tegsedi-Waylivra Agreement on written notice to the other party if such other party is in material breach of its obligations thereunder and has not cured such breach within 30 days after notice in the case of a payment breach or 60 days after notice in the case of any other breach.

26

Table of Contents

Shiratori

Overview. In connection with our acquisition of Censa Pharmaceuticals, Inc., or Censa, in May 2020, we became a party to a license agreement dated as of February 8, 2015, as amended, between Shiratori and Censa, or the Shiratori License Agreement. Pursuant to the Shiratori License Agreement, Shiratori granted Censa the sole and exclusive worldwide right and license, with the right to sublicense, under certain licensed know-how, or the Licensed Know-How, and licensed patents, or the Licensed Patents, relating to manufacturing processes and technology for sepiapterin, to research, have researched, develop, have developed, use, import, export, market, have marketed, offer for sale, sell and have sold, and otherwise commercialize any final pharmaceutical product in finished form containing sepiapterin as an active pharmaceutical ingredient, including sepiapterin, collectively the Sepiapterin Products, covered by the Licensed Patents or using the Licensed Know-How in all countries and territories of the world outside of Japan, or the Sepiapterin Territory.

Payments and Contingent Payments. Under the Shiratori License Agreement, we are obligated to pay to Shiratori a low single digit percentage of annual net sales of the Sepiapterin Products in each country in the Sepiapterin Territory until the expiration of the last-to-expire Licensed Patent controlled by Shiratori covering the relevant country followed by an obligation to pay a reduced royalty rate for a specified period of time thereafter. We are also obligated to pay Shiratori certain regulatory and development milestones.

Termination. Unless earlier terminated, the Shiratori License Agreement will continue in full force and effect on a country-by-country and product-by-product basis until the obligation to pay royalties with respect to the sale of such Sepiapterin Product in such country expires. The parties may agree to mutually terminate the Shiratori License Agreement. Shiratori may elect to terminate the Shiratori License Agreement upon sixty days’ prior written notice to us in the event that we fail to (i) achieve regulatory approval for a Sepiapterin Product in either the United States or EU by February 8, 2026 or (ii) commercially launch a Sepiapterin Product in the United States or EU by February 8, 2027. We may elect to terminate the Shiratori License Agreement upon sixty days’ prior written notice to Shiratori.

Our Ongoing Acquisition-Related Obligations

From time to time, we have engaged in strategic transactions to expand and diversify our product pipeline, including through the acquisition of assets or businesses. In connection with these acquisitions, we have entered into agreements through which we have ongoing obligations, including obligations to make contingent payments upon the achievement of certain development, regulatory and net sales milestones or upon a percentage of net sales of certain products.

Complete Pharma Holdings, LLC

On April 20, 2017, we completed our acquisition of all rights to Emflaza, or the Emflaza Transaction. The Emflaza Transaction was completed pursuant to an asset purchase agreement, dated March 15, 2017, as amended on April 20, 2017, or the Emflaza Asset Purchase Agreement, by and between us and Marathon Pharmaceuticals, LLC (now known as Complete Pharma Holdings, LLC), or Marathon. The assets acquired by us in the Emflaza Transaction include intellectual property rights related to Emflaza, inventories of Emflaza, and certain contractual rights related to Emflaza. We assumed certain liabilities and obligations in the Emflaza Transaction arising out of, or relating to, the assets acquired in the Emflaza Transaction.

In addition to the upfront consideration paid to Marathon upon the closing of the Emflaza transaction, Marathon is entitled to receive contingent payments from us based on annual net sales of Emflaza, up to a specified aggregate maximum amount over the expected commercial life of the asset, subject to the terms and conditions of the Emflaza Asset Purchase Agreement. In 2022, we paid Marathon a single $50.0 million sales-based milestone in accordance with the Emflaza Asset Purchase Agreement.

Agilis Biotherapeutics, Inc.

On August 23, 2018, we completed our acquisition of Agilis pursuant to an Agreement and Plan of Merger, dated as of July 19, 2018, or the Agilis Merger Agreement, by and among us, Agility Merger Sub, Inc., a Delaware corporation and

27

Table of Contents

our wholly owned, indirect subsidiary, Agilis and, solely in its capacity as the representative, agent and attorney-in-fact of the equityholders of Agilis, Shareholder Representative Services LLC, or the Merger.

In addition to the upfront consideration paid to Agilis equityholders upon the closing of the Merger, Agilis equityholders may become entitled to receive contingent payments from us based on the achievement of certain development, regulatory and net sales milestones, as well as based upon a percentage of net sales of certain products.

On April 29, 2020, we, certain of the former equity holders of Agilis, or the Participating Rightholders, and, for the limited purposes set forth in the agreement, Shareholder Representative Services LLC, entered into a Rights Exchange Agreement, or the Rights Exchange Agreement. Pursuant to the Right Exchange Agreement, we issued 2,821,176 shares of our common stock and paid $36.9 million, in the aggregate, to the Participating Rightholders in exchange for the cancellation and forfeiture by the Participating Rightholders of their rights to receive certain milestone-based contingent payments under the Agilis Merger Agreement.

As of December 31, 2023, we have paid former equity holders of Agilis a total of $52.4 million in connection with the achievement of certain milestone-based contingent payments under the Agilis Merger Agreement. In May 2023, as part of our strategic portfolio prioritization, we decided to discontinue our preclinical and early research programs for our gene therapy platform, which included programs for Friedreich ataxia and Angelman syndrome. As a result, we do not expect the milestones under the Agilis Merger Agreement related to Friedreich ataxia and Angelman syndrome to be achieved. In addition, we do not expect to pay royalties on annual net sales related to Friedreich ataxia and Angelman syndrome. Our outstanding obligations under the Agilis Merger Agreement related to Upstaza include obligations to pay up to an aggregate maximum amount of $20.0 million upon the achievement of certain development milestones, up to an aggregate maximum amount of $11.1 million upon the achievement of certain regulatory milestones, and up to a maximum aggregate amount of $50.0 million upon the achievement of certain net sales milestones, pursuant to the terms of the Agilis Merger Agreement.

We expect to pay the former equity holders of Agilis $20.0 million in development milestone payments upon the acceptance for filing by the FDA of a BLA for Upstaza for the treatment of AADC deficiency, which we expect to occur in March 2024, and $4.5 million in regulatory milestone payments upon approval of the BLA from the FDA pursuant to the Agilis Merger Agreement.

BioElectron Technology Corporation

On October 25, 2019, we completed the acquisition of substantially all of the assets of BioElectron Technology Corporation, or BioElectron, pursuant to an Asset Purchase Agreement by and between the Company and BioElectron, dated October 1, 2019, or the BioElectron Asset Purchase Agreement.

In addition to the upfront consideration paid to BioElectron upon the closing of the asset acquisition, subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may become entitled to receive contingent milestone payments of up to $200.0 million (in cash or in shares of our common stock, as determined by us) from us based on the achievement of certain regulatory and net sales milestones. Subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may also become entitled to receive contingent payments based on a percentage of net sales of certain products.

Censa Pharmaceuticals, Inc.

On May 29, 2020, we acquired Censa pursuant to an Agreement and Plan of Merger, dated as of May 5, 2020, or the Censa Merger Agreement, by and among us, Hydro Merger Sub, Inc., our wholly owned, indirect subsidiary, and, solely in its capacity as the representative, agent and attorney-in-fact of the securityholders of Censa, Shareholder Representative Services LLC, or the Censa Merger.

In addition to the upfront consideration paid to the Censa securityholders upon the closing of the Censa Merger, pursuant to the Censa Merger Agreement, Censa securityholders will be entitled to receive contingent payments from us based on (i) the achievement of certain development and regulatory milestones up to an aggregate maximum amount of $217.5

28

Table of Contents

million for sepiapterin’s two most advanced programs and receipt of a priority review voucher from the FDA as set forth in the Censa Merger Agreement, (ii) $109 million in development and regulatory milestones for each additional indication of sepiapterin, (iii) the achievement of certain net sales milestones up to an aggregate maximum amount of $160.0 million, (iv) a percentage of annual net sales during specified terms, ranging from single to low double digits of the applicable net sales threshold amount, and (v) any sublicense fees paid to us in consideration of any sublicense of Censa’s intellectual property to commercialize sepiapterin, on a country-by-country basis, which contingent payment will equal to a mid-double digit percentage of any such sublicense fees. In February 2023, we completed enrollment of our Phase 3 placebo-controlled clinical trial for sepiapterin for PKU.  In connection with this event and pursuant to the Censa Merger Agreement, we paid a $30.0 million development milestone to the former Censa securityholders. We elected to pay this milestone in the form of shares of our common stock, less certain cash payments. Pursuant to such election, we issued 657,462 shares of our common stock and paid $0.4 million to former Censa securityholders. We expect to make payments to the former Censa securityholders of $65.0 million in the aggregate in cash upon the potential achievement in 2024 of regulatory milestones relating to sepiapterin pursuant to the Censa Merger Agreement.

Intellectual Property

Patents and trade secrets

Our success depends in part on our ability to obtain and maintain proprietary protection for our product candidates, technology and know-how, to operate without infringing the proprietary rights of others and to prevent others from infringing our proprietary rights. Our policy is to seek to protect our proprietary position by, among other methods, filing U.S. and certain ex-U.S. patent applications related to our proprietary technology, inventions and improvements that we believe are important to the development of our business, where patent protection is available. We also rely on trade secrets, know-how, continuing technological innovation and in-licensing opportunities to develop and maintain our proprietary position.

As of January 31, 2024, our patent portfolio included a total of 138 active U.S. patents and 61 pending U.S. non-provisional patent applications, including continuations and divisional applications, that are owned, co-owned, or exclusively in-licensed.  Our patent portfolio also includes numerous International and ex-U.S. patents and patent applications. The patent portfolio includes patents and patent applications with claims including composition of matter, pharmaceutical formulation and methods of use of our commercial products including ataluren, the active ingredient in the formulated product Translarna, and risdiplam, the active ingredient in the formulated product Evrysdi.

The patent rights relating to ataluren owned by us include 34 issued U.S. patents relating to composition of matter, methods of use, formulations, dosing regimens and methods of manufacture and multiple pending U.S. patent applications relating to methods of use, formulation, and dosing regimens. We do not license any material patent rights relating to ataluren to unaffiliated parties. The issued U.S. patents relating to composition of matter are currently scheduled to expire in April 2024 and all U.S. patents that issue from U.S. patent applications arising from the composition of matter would also be expected to expire in April 2024. Issued U.S. patents relating to therapeutic methods of use are currently scheduled to expire in 2026 and 2027, including patent term adjustment. Our patent rights relating to ataluren include granted patents or pending counterpart patent applications in a number of other jurisdictions, including Canada, certain South American countries, Europe, certain Middle Eastern countries, certain African countries, certain Asian countries and certain Eurasian countries. We own 13 European patents relating to composition of matter, uses, dosing regimens and methods of manufacture of ataluren, as well as multiple pending European patent applications relating to composition of matter, uses and formulations. Granted European patents will expire in April 2024 for those patents drawn to composition of matter, in 2026 and 2027 for those patents drawn to dosing regimen, and in 2027 for those patents drawn to the manufacturing process. Except as indicated above, the anticipated expiration dates referred to above are without regard to potential patent term extension, patent term adjustment or other marketing exclusivities that may be available to us.

The patent rights relating to risdiplam co-owned by us and Roche include 7 issued U.S. patents relating to composition of matter, methods of use, and methods of manufacture and pending U.S. patent applications. We do not license any material patent rights relating to risdiplam to unaffiliated parties. The issued U.S. patents relating to composition of matter are currently scheduled to expire in 2033, 2035 and 2042. Our patent rights include granted patents or pending counterpart patent applications in a number of other jurisdictions, including Canada, certain South American countries, Europe, certain

29

Table of Contents

Middle Eastern countries, certain African countries, certain Asian countries and certain Eurasian countries. We co-own 4 European patents relating to composition of matter, and uses of risdiplam. The expiration dates of the granted European patents relating to composition of matter are currently scheduled to expire in 2033 and 2035. Except as indicated above, these anticipated expiration dates are without regard to potential patent term extension, patent term adjustment or other marketing exclusivities that may be available to us.

The term of individual patents depends upon the legal term for patents in the countries in which they are obtained. In most countries, including the United States, the patent term is 20 years from the earliest filing date of a non-provisional patent application. In the United States, a patent’s term may, in certain cases, be lengthened by patent term adjustment, which compensates a patentee for administrative delays by the U.S. Patent and Trademark Office in examining and granting a patent, or may be shortened if a patent is terminally disclaimed over an earlier filed patent. The term of a U.S. patent that covers a drug, biological product or medical device approved pursuant to a pre-market approval, or PMA, may also be eligible for patent term extension when FDA approval is granted, provided statutory and regulatory requirements are met.

Analogous patent term extension provisions are available in Europe and certain other ex-U.S. jurisdictions to extend the term of a patent that covers an approved drug. One means of patent term extension in Europe after EMA approval is based on obtaining a Supplementary Protection Certificate, or SPC. We have applied for SPCs for ataluren in all applicable European countries in which we have a European patent and have obtained SPCs or expect to obtain SPCs in all applicable European countries. The maximum patent term extension provided by an SPC is a total of 5 years from the date of patent term expiration. For example, in jurisdictions where an SPC with maximum patent term extension has been granted, the ataluren composition of matter patent would be scheduled to expire in 2029. To the extent a marketing authorization in any particular jurisdiction is not or cannot be maintained, the granted patent may remain in force in that jurisdiction until its natural expiration date, although a granted SPC in that jurisdiction may be withdrawn.  To the extent an underlying granted patent may be invalidated in that jurisdiction prior to its natural expiration date, the associated SPC will be invalidated as well. In the future, if and when our product candidates receive approval by the FDA or other non-European ex-U.S. regulatory authorities, we expect to apply for patent term extensions on issued patents covering those products, depending upon the length of the clinical trials for each drug and other factors.

We have no patents covering Emflaza or the approved use of Emflaza. See “Item 1. Business-Government Regulation” for further information regarding the exclusivity periods that we expect to rely on.

We rely on orphan drug exclusivity in the EEA for Upstaza for the treatment of AADC deficiency. If Upstaza is approved in the United States, we expect to rely on the non-patent market exclusivity periods under the Orphan Drug Act and the BPCIA to commercialize Upstaza in the United States. If approved elsewhere, we expect to rely on orphan drug exclusivity in other countries or regions where such exclusivity is available. See “Item 1. Business-Government Regulation” for further information regarding the exclusivity periods that we expect to rely on.

We may rely, in some circumstances, on trade secrets to protect our technology. However, trade secrets can be difficult to protect. We seek to protect our proprietary technology and processes, in part, using confidentiality agreements with our employees, consultants, scientific advisors, contractors and collaborators. We also seek to preserve the integrity and confidentiality of our data and trade secrets by maintaining physical security of our premises and physical and electronic security of our information technology systems. While we have confidence in these individuals, organizations and systems, such agreements or security measures may be breached, and we may not have adequate remedies for any breach. In addition, our trade secrets may otherwise become known or be independently discovered by competitors. To the extent that our employees, former employees, consultants, scientific advisors, contractors or collaborators use intellectual property owned by us or licensed to us by others in their work for us, trade secret disputes may arise.  If such disputes arise in the U.S., we may protect our trade secrets and pursue remedies available under federal statute using either the Economic Espionage Act of 1996 and/or the Defend Trade Secrets Act of 2016 and, if necessary, under state law using either the Uniform Trade Secrets Act or other State law available in the applicable venue.  If such disputes arise ex-US, we may protect our trade secrets and pursue remedies available under local or international law.

30

Table of Contents

License agreements

We are a party to a number of license agreements under which we license patents, patent applications and other intellectual property from third parties. We enter into these agreements to augment our proprietary intellectual property portfolio. The licensed intellectual property covers some of the compounds that we are researching and developing, some post-transcriptional control targets and some of the scientific processes that we use. These licenses impose various diligence and financial payment obligations on us. We expect to continue to enter into these types of license agreements in the future.

We exclusively in-licensed know-how and materials related to the production and use of Upstaza.  For a further discussion of the material agreements relating to our in-licensing of Upstaza for the treatment of AADC deficiency, see “Item 1. Business-Our Collaborations, License Agreements and Funding Arrangements-National Taiwan University.”  We also exclusively in-license or jointly own patent applications with claims directed to composition of matter, formulation and methods of use of other gene therapy products candidates currently in development.

Manufacturing

We do not currently own or operate functional manufacturing or distribution facilities for the production of clinical or commercial quantities of our products or product candidates or compounds that we are testing in our preclinical programs. We currently rely, and expect to continue to rely, on third parties for the manufacture, packaging, labeling and distribution of clinical and commercial supplies of our products or product candidates that we may develop, other than small amounts of compounds that we may synthesize ourselves for preclinical testing. We have personnel with manufacturing and quality experience to oversee our contract manufacturers.

The active pharmaceutical ingredients in our products and product candidates are provided by third-parties. We currently rely on a single source for the production of some of our raw materials and we obtain our supply of the drug substance for Translarna from two third-party manufacturers.

We engage two separate manufacturers to provide bulk drug product for Translarna. We have a relationship with three manufacturers that are capable of providing fill and finish services for our finished commercial and clinical Translarna product.

We currently obtain our supplies of Translarna and most of our other products and product candidates from our third-party manufacturers pursuant to agreements that include specific supply timelines and volume expectations. If a manufacturer should become unavailable to us for any reason, we would seek to obtain supply from another manufacturer engaged by us for the applicable product or service. In the event that we were unable to procure the applicable supply from a validated manufacturer, we believe that there are a number of potential replacements for each of our outsourced services, however we likely would experience delays in our ability to supply Translarna to patients or in advancing our clinical trials while we identify and qualify replacement suppliers.

We obtain our supply of the drug substance for Emflaza through a third-party manufacturer that is currently the only third-party manufacturer qualified to provide Emflaza drug substance for use in the United States. All of our drug product manufacturing, processing and packaging needs for Emflaza tablet and suspension product are fulfilled pursuant to two different exclusive supply agreements assumed by us in connection with our acquisition of Emflaza. We expect to fulfill all of our requirements for Emflaza tablets as well as secondary packaging of pre-filled Emflaza oral suspension bottles pursuant to one of these agreements, which has an automatic renewal provision subject to the termination rights of each party. We expect to fulfill all of our requirements for Emflaza suspension product pursuant to the other agreement. We are obligated to pay to the manufacturer of the Emflaza suspension product royalty payments, on a quarterly basis, based on a percentage (ranging from low to middle-low double digits) of, or a fixed payment with respect to, our annual net sales of suspension product in the United States, subject to reduction in accordance with the terms of the agreement.

If our drug substance provider or either of our drug product manufacturers was to be unable to provide drug substance or manufacture Emflaza product in sufficient quantities to meet projected demand, future sales could be adversely affected, which in turn could have a detrimental impact on our ability to maintain our marketing authorization in the United States and on our ability to commercialize Emflaza, which in turn would have a material adverse effect on our business, financial

31

Table of Contents

results and results of operations. Further, Emflaza received a seven-year exclusive marketing period in the United States for its approved indications, commencing on the date of FDA approval, under the provisions of the Orphan Drug Act. Emflaza’s seven-year period of orphan drug exclusivity related to the treatment of DMD in patients five years and older expired in February 2024. Emflaza’s orphan drug exclusivity related to the treatment of DMD in patients two years of age to less than five expires in June 2026. As the holder of orphan exclusivity, we are required to assure the availability of sufficient quantities of Emflaza to meet the needs of patients. Failure to do so could result in loss of the drug’s remaining orphan exclusivity in the United States.

Translarna and Emflaza are manufactured in reliable and reproducible synthetic processes. Our raw materials are not scarce and are readily available subject to supply chain disruptions. We currently rely on a single source for the production of some raw materials and switching to an alternative source could, in some instances, take time and could lead to delays in manufacturing. We maintain inventories for such materials such that any delays with raw materials will not affect or delay our manufacturing. No material shortages or delays of raw materials were encountered in 2023 and no manufacturing delays are currently expected in 2024. The chemistry is amenable to scale up and does not require unusual equipment in the manufacturing process. We expect to continue to develop drug candidates that can be produced cost-effectively at contract manufacturing facilities or internally, in the case of our gene therapy platform.

We have agreements with third-party manufacturers for the long-term commercial supply of Translarna. In the event that we are unable to procure supply from a validated manufacturer, we would seek to identify and qualify replacement suppliers, however this process would likely delay our ability to supply Translarna to patients or advance our clinical trials. We may be unable to conclude agreements for commercial or clinical supply of Translarna with third-party manufacturers, or we may be unable to do so on acceptable terms.

We currently have contracts with multiple pharmacy and hospital distributors in the EU that distribute Translarna for limited commercial and EAP programs. We have engaged with third party logistic providers, or 3PLs, which distribute Translarna for the majority of our commercial and EAP programs on our behalf.

We utilize third parties for the commercial distribution of Emflaza, including a 3PL to warehouse Emflaza as well as specialty pharmacies to sell and distribute Emflaza to patients. The specialty pharmacies provide us with third-party call center services to provide patient support and financial services, prescription intake and distribution, reimbursement adjudication, and ongoing compliance support.

Pursuant to the Tegsedi-Waylivra Agreement, we have entered into a master supply agreement with Akcea whereby Akcea or its affiliates will manufacture and supply, or cause to be manufactured and supplied, Tegsedi and Waylivra in quantities sufficient to support the commercialization of Tegsedi and Waylivra in the PTC Territory. This is currently the only manufacturing and supply agreement that we have entered into for the drug substance of Tegsedi and Waylivra. If the master supply agreement is terminated and we are unable to find an alternative third party contractor, we may encounter delays in manufacturing Tegsedi and Waylivra.

We have a commercial manufacturing services agreement with MassBiologics of the University of Massachusetts Medical School, or MassBio, to provide sufficient quantities of our Upstaza program materials to meet anticipated clinical trial and commercial scale demands. If MassBio is unable to perform its obligations under the commercial manufacturing services agreement, identifying a replacement gene therapy manufacturer would likely be challenging and time-consuming. However, we believe that we have sufficient supply of Upstaza to meet our near term commercial needs in such an event.

We have manufacturing services related to the production of plasmid deoxyribonucleic acid, or DNA, and adeno-associated virus, or AAV, vectors for gene therapy applications for external customers at our leased biologics manufacturing and laboratory space located in Hopewell Township, New Jersey, or the Hopewell Facility. Performance obligations vary but may include manufacturing plasmid DNA and/or AAV vectors, material testing, stability studies, and other services related to material development. The transaction prices for these arrangements are fixed and include amounts stated in the contracts for each promised service. For the year ended December 31, 2023, we recognized $7.7 million of manufacturing revenue related to plasmid DNA and AAV vector production for external customers. No manufacturing revenue was recognized for the years ended December 31, 2022 and 2021. As of December 31, 2023, we had contract assets of $0.2 million and remaining performance obligations of $0.8 million related to the production of plasmid DNA

32

Table of Contents

and AAV vectors for gene therapy applications for external customers. For the period ended December 31, 2022, we had remaining performance obligations of $1.4 million and no contracts assets related to plasmid DNA and AAV production for external customers.

Manufacturers and suppliers of product candidates are subject to the FDA’s current Good Manufacturing Practices, or cGMP, requirements, and other rules and regulations prescribed by ex-U.S. regulatory authorities. We depend on our third-party suppliers and manufacturers for continued compliance with cGMP requirements and applicable ex-U.S. standards.

Commercial Matters

Sales and marketing team

Our product revenue has primarily been attributable to sales of Translarna for the treatment of nmDMD in territories outside of the United States and to sales of Emflaza for treatment of DMD in the United States. We have employees across the globe, with the largest concentrations being in the United States, Latin America and Europe.

In addition, in select territories, we have engaged full time consultants, marketing partners and distribution partners to assist us with our international commercialization efforts for our products. We continue to evaluate new territories to determine in which geographies we might, if approved, choose to commercialize our products ourselves and in which geographies we might choose to collaborate with third parties. We expect that our internal team and partnership network will continue to grow, as needed, to maximize access to patients.

Customers

During 2023, our product revenue was primarily attributable to Translarna for the treatment of nmDMD and to Emflaza for treatment of DMD. Translarna for the treatment of nmDMD was available on a commercial basis or via reimbursed EAP programs or similar styled programs in multiple territories outside of the United States. In some territories, orders for Translarna are placed directly with us and in other territories we have engaged with third-party distributors. As a result, orders for Translarna are generally received from hospital and retail pharmacies and, in some cases, one of our third-party partner distributors. Our third-party distributors act as intermediaries between us and end-users and do not typically stock significant quantities of Translarna. The ultimate payor for Translarna is typically a government authority or institution or a third-party health insurer. The payment terms are generally 30 to 90 days after receipt of products.

Emflaza for treatment of DMD is available on a commercial basis throughout the United States. We utilize five specialty pharmacies to sell and distribute Emflaza to patients. The specialty pharmacies receive prescription orders for Emflaza directly from physicians and ship Emflaza directly to the end-user upon fulfillment of the order. As such, there is very little inventory of Emflaza stocked. The ultimate payor for Emflaza is typically a state health insurance program or a third-party health insurer. The payment terms are generally 30 to 90 days after receipt of products.

During 2023, two of our distributors each accounted for over 10% of our net product sales. Financial information about our net product revenues and other revenues generated in the principal geographic regions in which we operate and our long-lived assets is set forth in our financial statements and in Note 15, “Geographic Information” to our consolidated financial statements included in this Annual Report on Form 10-K.

Translarna and Emflaza can generally only be returned if agreed upon in writing by us and the product is not opened nor in receipt by the final user, except in the case of quality issues associated with the product. Product is generally shipped when a specific patient is approved by the applicable government or insurer and an individual prescription has been written. The right of return is eliminated as a matter of course when the product is dispensed to patients. Other than in connection with our transition to a new third party distributor, we have never had a request for a return of a material amount of product for either Translarna or Emflaza.

In some countries, orders for named patient sales may be for multiple months of therapy, which can lead to an unevenness in orders which could result in significant fluctuations in quarterly net product sales. For example, almost all of our Brazilian product revenue for Translarna is attributable to centralized group purchase orders through the Brazilian Ministry

33

Table of Contents

of Health that are intended to cover multiple months of therapy. Similarly, Translarna orders placed through a distributor for the Ministry of Health of the Russian Federation are also intended to cover multiple months of therapy. Any fluctuations in quarterly net product sales in Brazil and Russia resulting from these centralized group purchase orders may also be exacerbated by any delays.

Market Access Considerations

Translarna for the treatment of nmDMD is currently available on a commercial basis in multiple countries outside of the United States. We consider our products to be commercially available when we are permitted to market treatment to patients.

Translarna for the treatment of nmDMD is also currently available through EAP or similar styled programs in select countries where funded named patient or cohort programs exist, both within the EEA and in other territories. These programs generally reference the EMA’s determinations with respect to our marketing authorization in the EEA. As of today, Translarna is available under EAP or similar styled programs in various countries outside of the United States. Generally, EAP programs allow for access to Translarna pursuant to a named patient program, under which a physician requests access to Translarna on behalf of the specific, or “named” patient or pursuant to a cohort program, which allows for a broader temporary authorization for use for nmDMD meeting the inclusion criteria. Our EAP programs are named patient or similar styled programs in all territories other than France, which is a cohort program.

Our ability to make Translarna available via commercial or EAP programs or through similar styled programs is largely dependent upon our ability to maintain our marketing authorization in the EEA for Translarna for the treatment of nmDMD in ambulatory patients aged two years and older. The marketing authorization is subject to annual review and renewal by the EC following reassessment by the EMA. In September 2022, we submitted a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization, which included a report on the placebo-controlled trial of Study 041 and data from the open-label extension as further described below. In February 2023, we also submitted an annual marketing authorization renewal request to the EMA. In September 2023, the Committee for Medicinal Products for Human Use, or CHMP, gave a negative opinion on the conversion of the conditional marketing authorization to full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of Translarna for the treatment of nmDMD. On January 25, 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In accordance with EMA regulations, the EC has 67 days to adopt the opinion. If the EC adopts the negative opinion, Translarna would no longer have marketing authorization in the member states of the EEA. See “Item 1. Business-Global commercial footprint-Global DMD franchise” and “Risk Factors-Risks Related to Regulatory Approval of our Product and our Product Candidates” for further information regarding the marketing authorization in the EEA and related risks.

Our future revenues from our products and any other product candidates we may develop, depends largely on our ability to obtain and maintain reimbursement from governments and third-party insurers. Each country in the EEA has its own pricing and reimbursement regulations and many countries in the EEA have other regulations related to the marketing and sale of pharmaceutical products in the applicable country. The pricing and reimbursement process varies from country to country and can take a substantial amount of time from initiation to completion. As a result, our commercial launches of products in the EEA has been and is expected to continue to be on a country-by-country basis and we generally will not be able to commence commercial sales of our products pursuant to our marketing authorizations in the EEA in any particular member state of the EEA until we conclude the applicable pricing and reimbursement negotiations and comply with any licensing, employment or related regulatory requirements in that country. The price that is approved by local governmental authorities pursuant to commercial pricing and reimbursement processes may be lower than the price for purchases of product in that country pursuant to a reimbursed early access program.

In some instances, reimbursement may be subject to challenge, reduction or denial by the government and other payers. For example, in France, EAP programs and commercial sales of a product can begin while pricing and reimbursement rates are under discussion with the applicable government health programs. In the event that the negotiated price of the product is lower than the amount reimbursed for sales made prior to the conclusion of price negotiations, we may become

34

Table of Contents

obligated to repay such excess amount to the applicable government health program. Such retroactive reimbursement would be made following the conclusion of price negotiations with the applicable government health authority.

For Emflaza, which is approved in the United States, we are engaged in pricing, coverage and reimbursement discussions with third-party payors, such as state and federal governments, including Medicare and Medicaid, managed care providers, private commercial insurance plans and pharmacy benefit management plans. Decisions regarding the extent of coverage and the amount of reimbursement to be provided for Emflaza are made on a plan-by-plan, and in some cases, on a patient-by-patient basis. Coverage and reimbursement decisions by third-party payors, including the processing and adjudication of prescriptions, may vary from weeks to several months. Certain third-party payors routinely impose additional requirements before approving reimbursement of a prescription, including prior authorization and the requirement to try another therapy first. The specialty pharmacies we utilize provide patient services programs to support product access and, when eligible, out-of-pocket assistance.

We have generated revenue from net sales of Upstaza for the treatment of AADC deficiency in the EEA since May 2022. Upstaza is approved for the treatment of AADC deficiency for patients 18 months and older within the EEA and the United Kingdom. Our future revenues from Upstaza depends largely on our ability to obtain and maintain reimbursement from governments and third-party insurers as described above.

Tegsedi for the treatment of hATTR amyloidosis and Waylivra for the treatment of FCS are currently available on a commercial basis in multiple countries outside of the United States and we have the right to commercialize these products in the PTC Territory. We have received marketing authorization from ANVISA for Tegsedi for the treatment of stage 1 or stage 2 polyneuropathy in adult patients with hATTR amyloidosis in Brazil and Waylivra for the treatment of FCS and FPL in Brazil. We make commercial sales of Tegsedi for the treatment of hATTR amyloidosis in Brazil and Waylivra for the treatment of FCS and FPL in Brazil. The marketing authorizations of Tegsedi and Waylivra in Brazil are subject to renewal every five years. We have also made both Tegsedi and Waylivra available in certain countries within the PTC Territory through EAP Programs. Our ability to make Tegsedi and Waylivra available within the PTC Territory is largely dependent upon the maintenance of the marketing authorizations in the EU and the United States by the licensor.

We record revenue net of estimated third party discounts and rebates. Allowances are recorded as a reduction of revenue at the time revenues from product sales are recognized. These allowances are adjusted to reflect known changes in factors and may impact such allowances in the quarter those changes are known.

For important information regarding market access and pricing and reimbursement considerations see “Item 1. Business-Government Regulation-Pharmaceutical Pricing and Reimbursement” and “Item 1A. Risk Factors-Risks Related to the Development and Commercialization of our Product and our Product Candidates” and “-Risks Related to Regulatory Approval of our Product and our Product Candidates”.

Competition

The biotechnology and pharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. While we believe that our technologies, knowledge, experience and scientific resources provide us with competitive advantages, we face potential competition from many different sources, including commercial pharmaceutical and biotechnology enterprises, academic institutions, government agencies and private and public research institutions. Any product candidates that we successfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

Many of our competitors may have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. These competitors also compete with us in recruiting and retaining qualified scientific and management personnel, as well as in acquiring technologies complementary to, or necessary for, our programs. Smaller or early stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies.

35

Table of Contents

Our commercial opportunity could be reduced or eliminated if our competitors develop and commercialize products that are safer, more effective, have fewer side effects, are more convenient or are less expensive than any products that we may develop. In addition, our ability to compete may be affected because in some cases insurers or other third-party payors seek to encourage the use of generic products. This may have the effect of making branded products less attractive, from a cost perspective, to buyers.

The key competitive factors affecting the success of our products and product candidates are likely to be its efficacy, safety, convenience, price and the availability of coverage and reimbursement from government and other third-party payors.

The competition for our products and product candidates includes the following:

36

Table of Contents

​

Government Regulation

Government authorities in the United States, at the federal, state and local level, and in other countries extensively regulate, among other things, the research, development, testing, quality control, approval, manufacturing, labeling, post-approval monitoring and reporting, recordkeeping, packaging, promotion, storage, advertising, distribution, marketing and sales and export and import of biopharmaceutical products such as those we are developing and marketing. In addition, sponsors of biopharmaceutical products and drug products participating in Medicaid and Medicare are required to comply with mandatory price reporting, discount, and rebate requirements. The process of obtaining regulatory approvals and the subsequent compliance with appropriate federal, state, local and ex-U.S. statutes and regulations require the expenditure of substantial time and financial resources. If we do not comply with applicable requirements, we may be subject to civil penalties, suspension or withdrawal of regulatory approvals, product recalls, seizure of products, fined, the government may refuse to approve our marketing applications, supplemental applications, or allow us to manufacture or market our products, we may be criminally prosecuted and we may be debarred or excluded from participation in government healthcare programs. These requirements are continually evolving. See “Item 1A. Risk Factors-Risks Related to Regulatory Approval of our Product and our Product Candidates” for important information regarding some of the risks to our business arising as a result of government regulation.

U.S. government regulation

In the United States, the FDA regulates drugs and biologic products, including gene therapy products, under the Federal Food, Drug, and Cosmetic Act, or the FDCA, the Public Health Service Act, or the PHSA, and regulations and guidance implementing these laws. The FDCA, PHSA and their corresponding regulations govern, among other things, the testing, manufacturing, safety, efficacy, labeling, packaging, storage, record keeping, distribution, reporting, advertising and other promotional practices involving drugs and biologic products. Failure to comply with the applicable FDA requirements at any time pre- or post-approval may result in a delay of approval or administrative or judicial sanctions.

37

Table of Contents

Regulatory requirements governing our business are also evolving. For example, the FDA has issued a growing body of guidance documents on CMC, clinical investigations and other areas of gene therapy development, all of which are intended to facilitate the industry’s development of gene therapy products. Moreover, the FDA also continually issues guidance documents that provide the FDA’s interpretation of its laws and regulations, as well as the FDA’s approach to scientific issues and questions.  While the FDA’s guidance is not binding, it does provide the FDA’s current interpretation and approach.

The new drug and biologic approval process

In the United States, an NDA is the vehicle through which the FDA approves a new pharmaceutical drug product for sale and marketing in the United States. A BLA is the vehicle through which the FDA approves a new biologic product for sale and marketing in the United States.

To market a new drug or biologic product in the United States, a sponsor generally must undertake the following:

​

Nonclinical Studies and IND Submission

Nonclinical tests include laboratory evaluations of product chemistry, pharmacology, stability, toxicity and product formulation, as well as animal or other nonclinical studies to assess potential safety and efficacy. In order to begin clinical testing, a sponsor must submit an IND to the FDA, which includes, among other things, the results of the nonclinical tests, manufacturing information, analytical data, proposed clinical protocols, and any available clinical data or literature on the product candidate. Some nonclinical testing may continue after the IND is submitted. The IND must become effective before human clinical trials may begin. An IND will automatically become effective 30 days after receipt by the FDA, unless before that time the FDA raises concerns or questions about issues such as the conduct of the trials as outlined in the IND. In that case, the IND sponsor and the FDA must resolve any outstanding FDA concerns or questions before clinical trials can proceed. Clinical holds also may be imposed by the FDA at any time before or during trials due to safety concerns or non-compliance.

38

Table of Contents

Clinical Trials

Clinical trials involve the administration of an investigational product to human subjects under the supervision of qualified investigators. Clinical trials are conducted in accordance with protocols detailing, among other things, the objectives of the study, the parameters to be used in monitoring safety, the effectiveness criteria to be evaluated, and a statistical analysis plan. A protocol for each clinical trial and subsequent protocol amendments must be filed with the FDA as part of the IND. Sponsors will also be required to provide FDA with diversity action plans.  In accordance with GCP requirements, all research subjects or their legally authorized representatives must provide their informed consent in writing prior to their participation in a clinical trial. Each clinical trial must be reviewed and approved by an IRB and is subject to ongoing IRB monitoring. The IRB must approve the protocol, protocol amendments, the informed consent form, and communications to study subjects before a study commences at the site. An IRB considers among other things, whether the risks to individuals participating in the trials are minimized and are reasonable in relation to anticipated benefits, and whether the planned human subject protections are adequate. The IRB must continue to oversee the clinical trial while it is being conducted. Special clinical trial ethical considerations also must be taken into account if a study involves children.  In the case of certain gene therapy studies, an IBC at the local level may also review and maintain oversight over the particular study, in addition to the IRB. If the product candidate is being investigated for multiple intended indications, separate INDs may also be required. Progress reports detailing the results of the clinical trials must be submitted at least annually to FDA and the IRB and more frequently if serious adverse events or other significant safety information is found. Certain reports may also be required to be submitted to the IBC.

Additionally, some clinical trials are overseen by an independent group of qualified experts organized by the clinical trial sponsor, known as a data safety monitoring board or committee. This group regularly reviews accumulated data and advises the study sponsor regarding the continuing safety of the trial. This group may also review interim data to assess the continuing validity and scientific merit of the clinical trial. The data safety monitoring board receives special access to unblinded data during the clinical trial and may advise the sponsor to halt the clinical trial if it determined there is an unacceptable safety risk for subjects or on other grounds, such as no demonstration of efficacy.

Information about certain clinical trials must be submitted within specific timeframes to the NIH to be publicly posted on the Clinicaltrials.gov website. Sponsors or distributors of investigational products for the diagnosis, monitoring, or treatment of one or more serious disease or conditions must also have a publicly available policy on evaluating and responding to requests for expanded access. Investigators must also provide certain information to clinical trial sponsors to allow the sponsors to make certain financial disclosures to the FDA.

The manufacture of investigational drugs and biologics for the conduct of human clinical trials is subject to cGMP requirements. Investigational drugs and biologics and active ingredients and therapeutic substances imported into the United States are also subject to regulation by the FDA. Further, the export of investigational products outside the United States is subject to regulatory requirements of the receiving country as well as U.S. export requirements under the FDCA.

In general, for the purposes of NDA and BLA approval, human clinical trials typically are conducted in three sequential phases, but the phases may overlap, be divided, or be combined. Phase 1 clinical trials may be conducted in patients or healthy volunteers to evaluate the product’s safety, dosage tolerance, structure-activity relationships, mechanism of action, absorption, metabolism distribution, excretion, and pharmacokinetics and, if possible, seek to gain an early indication of its effectiveness. Phase 2 clinical trials usually involve controlled trials in a larger but still relatively small number of subjects from the relevant patient population to evaluate dosage tolerance and appropriate dosage; identify possible short-term adverse effects and safety risks; and provide a preliminary evaluation of the efficacy of the drug or biologic product for specific indications.  Phase 3 clinical trials usually further evaluate clinical efficacy and test further for safety in an expanded patient population at geographically dispersed clinical trial sites, to generate enough data to provide statistically significant evidence of clinical efficacy and safety of the product candidate for approval. These trials are well-controlled and are intended to establish the overall risk- benefit profile of the product or product candidate and provide an adequate basis for physician labeling. Phase 3 clinical trials are usually larger, more time consuming, more complex and more costly than Phase 1 and Phase 2 clinical trials. The FDA typically requires that an NDA or BLA include data from two adequate and well-controlled clinical trials, but, in certain circumstances, approval may be based upon a single adequate and well-controlled clinical trial plus confirmatory evidence or a single large multicenter trial without confirmatory evidence. In some cases, the FDA may condition approval of an NDA or BLA on the applicant’s agreement to conduct additional

39

Table of Contents

clinical trials to further assess the product’s safety and effectiveness after NDA or BLA approval and trails to ensure that population representative data is collected. Such post-approval trials are typically referred to as Phase 4 studies. The results of Phase 4 studies can confirm or refute the effectiveness of a product candidate, and can provide important safety information.

Additional kinds of data may also help support a BLA or NDA, such as patient experience data and real world evidence. Real world evidence may also be used to assist in clinical trial design or support an NDA for already approved products. For genetically targeted populations and variant protein targeted products intended to address an unmet medical need in one or more patient subgroups with a serious or life threatening rare disease or condition, the FDA may allow a sponsor to rely upon data and information previously developed by the sponsor or for which the sponsor has a right of reference, that was submitted previously to support an approved application for a product that incorporates or utilizes the same or similar genetically targeted technology or a product that is the same or utilizes the same variant protein targeted drug as the product that is the subject of the application. More recently, a program was established whereby a platform technology that is incorporated within or utilized by an approved drug or biologic product may be designated as a platform technology, provided that certain conditions are met, in which case development and approval of subsequent products using such technology may be expedited.

Concurrent with clinical trials, companies usually complete additional nonclinical studies and must also develop additional information about the physical characteristics of the drug or biologic product candidate as well as finalize a process for manufacturing the product candidate in commercial quantities in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and, among other requirements, the sponsor must develop methods for testing the identity, strength, quality, potency and purity of the final biologic product. Additionally, appropriate packaging must be selected and tested and adequate stability studies must be conducted to demonstrate that the product candidate does not undergo unacceptable deterioration over its shelf life.

Additional FDA Expedited Review and Approval Programs

The FDA has various programs that are intended to expedite or simplify the process for the development and FDA review of certain products that are intended for the treatment of serious or life-threatening diseases or conditions, and demonstrate the potential to address unmet medical needs or present a significant improvement over existing therapy. The purpose of these programs is to provide important new therapeutics to patients earlier than under standard FDA review procedures.

To be eligible for a Fast Track designation, the FDA must determine, based on the request of a sponsor, that a product candidate is intended to treat a serious or life-threatening disease or condition and demonstrates the potential to address an unmet medical need. If Fast Track designation is obtained, sponsors may be eligible for more frequent development meetings and correspondence with the FDA. In addition, the FDA may potentially initiate a rolling review of sections of an application before the application is complete. This ‘‘rolling review’’ is available if the applicant provides and the FDA approves a schedule for the remaining information. Applicable user fees must also be paid before the FDA will commence its review. In some cases, a Fast Track product may be eligible for accelerated approval or priority review.

The FDA may give a priority review designation to product candidates that are intended to treat serious conditions and, if approved, would provide significant improvements in the safety or effectiveness of the treatment, diagnosis, or prevention of the serious condition. A priority review means that the goal for the FDA is to review an application within six months, rather than the standard review of ten months under current Prescription Drug User Fee Act, or PDUFA, guidelines.

The FDA’s accelerated approval process allows for potentially faster development and approval of certain drugs or biologic products intended to treat serious or life-threatening illnesses that provide meaningful therapeutic benefit to patients over existing treatments. Under the accelerated approval process, the adequate and well-controlled clinical trials conducted with the drug or biologic product establish that the drug or biologic product has an effect on a “surrogate” endpoint that is reasonably likely to predict clinical benefit or on the basis of an effect on a clinical endpoint other than survival or irreversible morbidity, that is reasonably likely to predict an effect on irreversible morbidity or mortality, taking into account the severity, rarity, or prevalence of the condition and availability or lack of alternative treatments. Drugs or biologic products approved through the accelerated approval process are subject to certain post-approval requirements, including completion of Phase 4 clinical trials to demonstrate clinical benefit.  By the date of approval of an accelerated

40

Table of Contents

approval product, FDA must specify the conditions for the required post approval studies, including enrollment targets, the study protocol, milestones, and target completion dates.  FDA may also require that the confirmatory Phase 4 studies be commenced prior to FDA granting a product accelerated approval.  Reports on the progress of the required Phase 4 confirmatory studies must be submitted to FDA every 180 days after approval. If the trials fail to verify the clinical benefit of the drug or biologics product, the FDA may withdraw approval of the application through a statutorily defined streamlined process. Failure to conduct the required Phase 4 confirmatory studies or to conduct such studies with due diligence, as well as failure to submit the required update reports can subject a sponsor to penalties.  Promotional materials for a drug or biologic approved under the accelerated approval pathway are subject to FDA prior review.

Sponsors can also request designation of a product candidate as a ‘‘breakthrough therapy.’’ A breakthrough therapy is defined as a product that is intended, alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. Products designated as breakthrough therapies are eligible for intensive guidance on an efficient development program beginning as early as Phase 1 trials, a commitment from the FDA to involve senior managers and experienced review staff in a proactive collaborative and cross-disciplinary review, rolling review, and the facilitation of cross-disciplinary review.

Another expedited pathway is the Regenerative Medicine Advanced Therapy, or RMAT, designation. Qualifying products must be a cell therapy, therapeutic tissue engineering product, human cell and tissue product, or a combination of such products, and not a product solely regulated as a human cell and tissue product. The product must be intended to treat, modify, reverse, or cure a serious or life-threatening disease or condition, and preliminary clinical evidence must indicate that the product has the potential to address an unmet need for such disease or condition. Advantages of the RMAT designation include all the benefits of the Fast Track and breakthrough therapy designation programs, including early interactions with the FDA. These early interactions may be used to discuss potential surrogate or intermediate endpoints to support accelerated approval.

Companion Diagnostics and Other Combination Products

A drug or biologic product may be regulated as combination product if it is intended for use in conjunction with a medical device, such as a drug delivery device or in vitro diagnostic device, as further discussed below. In such cases, the use of the two products together (i.e., the drug/biological product and the device) must be shown to be safe and effective for the proposed intended use and the labeling of the two products must reflect their combined use. In some cases, the device component may require a separate premarket submission; for example, when the device component is intended for use with multiple drug products. Sponsors of clinical studies using investigational devices are required to comply with FDA’s investigational device exemption regulations. Once approved or cleared, the sponsor of the device component submission (or the combination product submission, if both components are covered by one premarket submission) would need to comply with FDA’s post-market device requirements, including establishment registration, device listing, device labeling, unique device identifier, quality system regulation, medical device reporting, and reporting of corrections and removals requirements.

If the safety or effectiveness of a drug or biologic product candidate for its proposed indication is dependent on the measurement or detection of specified biomarkers, the FDA may require the contemporaneous approval or clearance of an in vitro companion diagnostic device that measures such biomarkers, and require the labeling of both the drug/biological product and the companion diagnostic to including instructions for use of the two products together.  The FDA has explained in guidance that in vitro companion diagnostic devices may be used for a number of purposes, including identifying appropriate subpopulations for treatment. The type of premarket submission required for a companion diagnostic device will depend on the FDA classification of the device. A premarket approval, or PMA, application is required for high risk devices classified as Class III; a 510(k) premarket notification is required for moderate risk devices classified as Class II; and a de novo request may be used for novel devices not previously classified by FDA that are low or moderate risk. The guidance states that the FDA generally will not approve a drug or biologic that is dependent upon the use of a companion diagnostic device if no such device is contemporaneously FDA-approved or -cleared for the relevant indication. According to the guidance, however, the FDA may approve such a drug/biologic product without an approved/cleared companion diagnostic when the drug/ biologic “is intended to treat a serious or life-threatening condition

41

Table of Contents

for which no satisfactory alternative treatment exists” and the FDA determines that the benefits from the use of the drug/biologic “are so pronounced as to outweigh the risks from the lack of an” approved/cleared companion diagnostic. Under these circumstances, the FDA expects that a companion diagnostic would be subsequently approved/cleared, and that the drug/biologic labeling would be revised “to stipulate the use of the” companion diagnostic device. The FDA would also consider whether additional protections, such as risk evaluation and mitigation strategies, or REMS, or post-approval requirements, are necessary.

In a separate guidance, specific to DMD and related dystrophinopathies, the FDA has stated that a sponsor should contemporaneously develop a companion diagnostic device in situations where (1) the safety or efficacy of the drug or biologic product “may be related to the patient’s specific dystrophin mutation or to another type of finding related to a biomarker,” and (2) a suitable companion diagnostic device is not currently available. However, given “the serious and life-threatening nature of dystrophinopathies and the lack of satisfactory alternative treatments that currently exist,” the guidance further states that the FDA may approve a drug/biologic “even if a companion diagnostic device is not yet approved or cleared, if the benefits are so pronounced as to outweigh the risks from the lack of an approved or cleared in vitro companion diagnostic device.”  During the review, the “FDA will determine the need for clearance or approval of the device.” The FDA guidance documents represent the FDA’s current thinking on a topic but do not establish legally enforceable responsibilities.

FDA Approval Process

Assuming successful completion of the required clinical testing, the results of the preclinical studies and of the clinical trials, together with other detailed information, including proposed labeling and information on the chemistry, manufacture and composition of the product, are submitted to the FDA in the form of an NDA or BLA requesting approval to market the product for one or more indications. In most cases, the NDA or BLA must be accompanied by a substantial user fee, though a waiver of such fees may be obtained under certain limited circumstances. Product candidates that are designated as orphan products are not subject to application user fees unless the application includes an indication other than the orphan indication. The user fees must be paid at the time of the first submission of the application, even if the application is being submitted on a rolling basis. The FDA has 60 days from its receipt of an NDA or BLA to determine whether the application will be accepted for filing based on the FDA’s threshold determination that it is sufficiently complete to permit a substantive review.

If the FDA determines that the NDA or BLA is incomplete, the FDA may refuse to file the application. If the FDA refuses to file an NDA or BLA, the applicant may refile the application with information addressing the FDA identified deficiencies, which refiling would be subject to FDA review before it is accepted for filing. After the NDA or BLA submission is accepted for filing, the FDA reviews the NDA or BLA to determine, among other things, whether a product meets FDA’s approval standard and whether the product is being manufactured in accordance with cGMP to assure and preserve the product’s identity, strength, quality and purity. Under the goals and policies agreed to by the FDA under the PDUFA, the FDA has set the review goal of completing its review of 90% of all standard applications for new molecular entities and original BLAs within ten months of the 60 day filing date. Under the FDA’s priority review program, however, the FDA set a review goal of completing its review of 90% of all applications within 6 months of the 60 day filing date. The FDA does not always meet its PDUFA goal dates. The review process and the PDUFA goal date may be extended by additional three-month review periods whenever the FDA requests or the NDA or BLA sponsor otherwise provides additional information or clarification regarding information already provided in the submission at any time during the review cycle.

NDAs or BLAs or supplements to NDAs or BLAs for a new active ingredient, dosage form, dosage regimen, or route of administration, unless subject to the below requirement for molecularly targeted cancer products, must contain data to assess the safety and effectiveness of the product for the claimed indications in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective. The FDA may, on its own initiative or at the request of the applicant, grant deferrals for submission of data or full or partial waivers. This requirement does not generally apply to products for an indication for which orphan designation has been granted. However, compliance may be required if approval is sought for other indications for which the product has not received orphan designation.

42

Table of Contents

Product candidates intended for the treatment of adult cancer which are directed at molecular targets that the FDA determines to be substantially relevant to the growth or progression of pediatric cancer, must submit, with the marketing application, reports from molecularly targeted pediatric cancer investigations designed to yield clinically meaningful pediatric study data, gathered using appropriate formulations for each applicable age group, to inform potential pediatric labeling. The FDA may, on its own initiative or at the request of the applicant, grant deferrals or waivers of some or all of this data, as above. Orphan products are not exempt from this requirement.

The FDA will typically inspect or conduct an inspection or remote regulatory assessment of one or more clinical sites to assure compliance with GCP before approving an NDA or BLA. The FDA also will inspect or conduct a remote regulatory assessment of the facility or the facilities at which the product is manufactured before the NDA or BLA is approved. The FDA will not approve the product unless cGMP compliance is satisfactory.  

The FDA may refer applications for novel drug products or biologic products to an advisory committee for recommendation as to whether the application should be approved and under what conditions. Specifically, for a product candidate for which no active ingredient (including any ester or salt of active ingredients) has previously been approved by the FDA, the FDA must either refer that product candidate to an advisory committee or provide in an action letter, a summary of the reasons why the FDA did not refer the product candidate to an advisory committee. The FDA may also refer other product candidates to an advisory committee if FDA believes that the advisory committee’s expertise would be beneficial. The FDA is not bound by the recommendation of an advisory committee, but it considers such recommendations carefully, particularly any negative recommendations or limitations, when making drug or biologic product approval decisions.

After evaluating the marketing application and all related information, including the advisory committee recommendation, if any, and inspection or remote regulatory assessment reports regarding the manufacturing facilities and clinical trial sites, the FDA may issue an approval letter, or, in some cases, a Complete Response Letter, or CRL. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications.  A CRL indicates that the review cycle of the application is complete and the application is not ready for approval and describes all of the specific deficiencies that the FDA identified. A CRL generally contains a statement of specific conditions that must be met in order to secure final approval of the marketing application, and may require additional clinical or preclinical testing in order for the FDA to reconsider the application. The deficiencies identified may be minor, for example, requiring labeling changes; or major, for example, requiring additional clinical trials. If a CRL is issued, the applicant may either: resubmit the marketing application, addressing all of the deficiencies identified in the letter; withdraw the application; or request an opportunity for a hearing. The FDA has the goal of reviewing 90% of application resubmissions in either two or six months of the resubmission date, depending on the kind of resubmission. Even with submission of additional information, the FDA ultimately may decide that the application does not satisfy the regulatory criteria for approval.

Additional regulation for gene therapy clinical trials

In addition to the regulations discussed above, there are a number of additional standards that apply to clinical trials involving the use of gene therapy. The FDA has issued, and continues to issue, various guidance documents regarding the development and commercialization of gene therapies, which outline additional factors that the FDA will consider at each of the above stages of development and relate to, among other things: the proper preclinical and nonclinical assessment of gene therapies; the design and conduct of clinical trials, the CMC information that should be included in an IND application; the proper design of tests to measure product potency in support of an IND or BLA application; and long term patient and clinical study subject follow up and regulatory reporting. The FDA also issued guidance documents that address guidance specific to the development of gene therapy products for neurodegenerative diseases.

​

Post-approval requirements

After FDA approval of a product is obtained, we are required to comply with a number of post-approval requirements, including, among other things, establishment registration and product listing, record-keeping requirements, reporting certain adverse reactions and production problems to the FDA, providing updated safety and efficacy information, and complying with requirements concerning advertising and promotional labeling. As a condition of approval of an NDA or BLA, the FDA may require the applicant to conduct additional clinical trials or other post market testing and surveillance

43

Table of Contents

to further monitor and assess the product’s safety and efficacy. There also are continuing annual program user fee requirements for approved products, though orphan products may receive exemptions if certain criteria are met.

The FDA also has the authority to require a specific REMS to ensure that a product’s benefits outweigh its risks.  A REMS may be required to include various elements, such as a medication guide or patient package insert, a communication plan to educate healthcare providers of the product’s risks, limitations on who may prescribe or dispense the product, or other measures that the FDA deems necessary to assure the safe use of the drug. The FDA may also impose a REMS requirement on an approved product if the FDA determines, based on new safety information, that a REMS is necessary to ensure that the product’s benefits outweigh its risks.

The FDA strictly regulates marketing, labeling, advertising and promotion of products that are placed on the market. Although physicians may prescribe a drug or biologic for off-label uses, manufacturers may only promote the product for the approved indications and in accordance with the approved labeling. All statements regarding products must be consistent with the FDA approved label, must be truthful and non-misleading, and must be adequately substantiated with a fair balance between product benefit claims and risks, among other requirements.  This means, for example, that a manufacturer cannot make claims about the use of its marketed products or their relative benefits compared to other treatments outside of their FDA approved indications and label and without adequate comparative studies, and it would not be able to discuss or provide information on off-label uses or safety benefits of such products in a promotional context.  In 2023, the FDA took a few actions in the advertising and promotional spaces, including issuing a final rule and a guidance on risk and efficacy disclosures in direct to consumer advertising, and a guidance on communication of off-label scientific information about approved products. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with the laws and regulations governing advertising and promotion can have negative consequences, including FDA and other governmental authority enforcement actions.  

In addition, the distribution of prescription pharmaceutical product samples is subject to the Prescription Drug Marketing Act, or PDMA, in addition to state requirements.  Reports must also be submitted to FDA on sample distribution. The Drug Supply Chain Security Act, or DSCSA, added sections in the FDCA that require manufacturers, repackagers, wholesale distributors, dispensers, and third-party logistics providers to take steps to identify and trace certain prescription drugs and biologics to protect against the threats of counterfeit, diverted, stolen, contaminated, or otherwise harmful products in the supply chain. The DSCSA regulates the distribution of prescription pharmaceutical drugs and biologics, requiring passage of documentation to track and trace each prescription product at the saleable unit level through the distribution system. This documentation must be transferred electronically and must enable interoperable electronic product tracing at the package level as of November 2023, though the FDA does not intend to take action to enforce requirements for the interoperable, electronic, package level product tracing until November 27, 2024.   Products subject to the DSCSA must only be transferred to appropriately licensed purchasers. The DSCSA also requires manufacturers and repackagers to affix or imprint a unique product identifier on product packages in both a human-readable and on a machine-readable data carrier. The DSCSA also establishes several requirements relating to the verification of product identifiers. Further, under this legislation, sponsors have product investigation, quarantine, disposition, and notification responsibilities related to counterfeit, diverted, stolen, and intentionally adulterated products that would result in serious adverse health consequences or death to humans, as well as products that are the subject of fraudulent transactions or which are otherwise unfit for distribution such that they would be reasonably likely to result in serious health consequences or death.

Also, quality control and manufacturing procedures must continue to conform to cGMPs after approval, including quality control and quality assurance and maintenance of records and documentation. Changes to the manufacturing process are strictly regulated and often require prior FDA approval or notification before being implemented. In 2023, the FDA issued a guidance specifically on demonstrating product comparability, and the management and reporting of manufacturing changes for investigational and licensed cellular and gene therapy products. FDA regulations also require investigation and correction of any deviations from cGMP and specifications, and impose reporting and documentation requirements upon the sponsor and any third-party manufacturers that the sponsor may decide to use.

Manufacturers and others involved in the manufacture and distribution of such products also must register their establishments with the FDA and certain state agencies, and provide information regarding the products that they manufacture.  The information that must be submitted to FDA regarding manufactured products was expanded through

44

Table of Contents

the Coronavirus Aid, Relief, and Economic Security, or CARES, Act to include the volume of drugs produced during the prior year.

Establishments may be subject to periodic, unannounced inspections or remote regulatory assessments by government authorities to ensure compliance with cGMP requirements and other laws. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance. The FDA may take into account results of inspections performed by certain counterpart ex-U.S. regulatory agencies in assessing compliance cGMPs. The FDA has entered into international agreements with ex-U.S. agencies, including in the EU, in order to facilitate this type of information sharing.

Sponsors are further subject to various requirements related to FDA drug shortage and manufacturing volume reporting, supply chain security, such as risk management plan requirements, and the promotion of supply chain redundancy.  Legislation and executive actions have also been issued to encourage domestic manufacturing.

Additional controls for biologics

To help reduce the risk of the introduction of adventitious agents or of causing other adverse events with the use of biologic products, the PHSA emphasizes the importance of manufacturing control for products whose attributes cannot be precisely defined. The PHSA also provides authority to the FDA to immediately suspend licenses in situations where there exists a danger to public health, to prepare or procure products in the event of shortages and critical public health needs, and to authorize the creation and enforcement of regulations to prevent the introduction or spread of communicable diseases in the United States and between states.

After a BLA is approved, the product may also be subject to official lot release as a condition of approval. As part of the manufacturing process, the manufacturer is required to perform certain tests on each lot of the product before it is released for distribution. If the product is subject to official release by the FDA, the manufacturer submits samples of each lot of product to the FDA together with a release protocol showing the results of all of the manufacturer’s tests performed on the lot. The FDA may also perform certain confirmatory tests on lots of some products before releasing the lots for distribution by the manufacturer.  In addition, the FDA conducts laboratory research related to the regulatory standards on the safety, purity, potency, and effectiveness of biological products.

Orphan drug designation.

We have received orphan drug designation from the FDA for Translarna for the treatment of nmDMD, Emflaza for the treatment of DMD, Upstaza for the treatment of AADC deficiency, Evrysdi for the treatment of SMA, vatiquinone for the treatment of Friedreich ataxia, utreloxastat for the treatment of ALS and sepiapterin for the treatment of hyperphenylalaninemia, including hyperphenylalaninemia caused by PKU. The FDA may grant orphan drug designation to drugs and biologics intended to treat a “rare disease or condition,” which is defined as a disease or condition that affects fewer than 200,000 individuals in the United States, or more than 200,000 individuals in the United States and for which there is no reasonable expectation that the cost of developing and making available in the United States a product for this type of disease or condition will be recovered from sales in the United States for that product. Additionally, sponsors must present a plausible hypothesis for clinical superiority to obtain orphan designation if there is a product already approved by the FDA that that is considered by the FDA to be the same as the already approved product and is intended for the same indication. This hypothesis must be demonstrated to obtain orphan exclusivity. Orphan drug designation must be requested before submitting an application for marketing approval. Orphan drug designation does not convey any advantage in, or shorten the duration of, the regulatory review and approval process. Orphan drug designation can provide opportunities for grant funding towards clinical trial costs, tax advantages and FDA user-fee benefits.

The FDA’s regulations provide flexibility in meeting approval standards for new therapies intended to treat persons with life-threatening and severely-debilitating illnesses, especially where no satisfactory alternative therapy exists, such that the FDA may exercise scientific judgment in determining the kind and quantity of data required for approval and during development programs.  Per guidance issued by the FDA in 2023 with respect to rare diseases, “[t]his flexibility extends from the early stages of development to the design of adequate and well-controlled clinical investigations required to demonstrate effectiveness to support marketing approval and to establish safety data needed for the intended use.” The

45

Table of Contents

FDA states that it “is committed to helping sponsors create successful drug development programs that address the particular challenges posed by each disease….”

If a product which has an orphan drug designation subsequently receives the first FDA approval for the indication for which it has such designation, the product is entitled to orphan drug exclusivity, which means the FDA may not approve any other application to market the same drug or biologic for the same indication for a period of seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan exclusivity or the same drug or biologic for different indications. However, competitors may receive approval of different drugs or biologics for the indications for which the orphan product has exclusivity.

Notably, the exact scope of orphan drug exclusivity may be an evolving space. A 2021 judicial decision, Catalyst Pharms., Inc. v. Becerra, challenged and reversed an FDA decision on the scope of orphan product exclusivity for the drug, Firdapse.  Under this decision, orphan drug exclusivity for Firdapse blocked approval of another company’s application for the same drug for the entire disease or condition for which orphan drug designation was granted, not just the disease or condition for which approval was received.  In a January 2023 Federal Register notice, however, the FDA stated that it intends to continue to apply its regulations tying the scope of orphan-drug exclusivity to the uses or indications for which a drug is approved.  The exact scope of orphan drug exclusivity will likely be an evolving area.

Orphan product sameness decisions are also an evolving space. The FDA issued a final guidance document on how the agency will determine the “sameness” of gene therapy products. Pursuant to the guidance, “sameness” will depend on the products’ transgene expression, viral vectors groups and variants, and other product features that may have a therapeutic effect. Generally, minor differences between gene therapy products will not result in a finding that two products are different. Any FDA sameness determinations could impact our ability to receive approval for our product candidates and to obtain or retain orphan drug exclusivity.

Rare Pediatric Disease Voucher Program

Under the FDCA, the FDA awards priority review vouchers to sponsors of rare pediatric disease products that meet certain criteria. To qualify, the rare disease must be serious or life-threatening in which the serious or life-threatening manifestations primarily affect individuals aged from birth to 18 years. Also, the product must contain no active ingredient (including any ester or salt of the active ingredient) that has been previously approved in any other application and the application must meet certain additional qualifying criteria, including eligibility for FDA priority review. If FDA determines that a product is for a rare pediatric disease and the qualifying application criteria are met, upon a sponsor’s request, FDA may award the sponsor a priority review voucher. This voucher may be redeemed to receive priority review (i.e., a review time of 6 months as compared to 10 months for standard review) of a subsequent marketing application for a different product. Use of a priority review voucher is subject to an FDA user fee. These vouchers are transferable. Accordingly, sponsors may sell these vouchers for substantial sums of money. Vouchers may also be revoked by FDA under certain circumstances and sponsors of approved rare pediatric disease products must submit certain reports to FDA.

Changes to the FDCA, however, have limited future pediatric priority review vouchers. Under the law’s sunset provision, the drug or biologic must be designated by FDA for a rare pediatric disease no later than September 30, 2024, and approved no later than September 30, 2026, unless the law is reauthorized by Congress. Accordingly, while Upstaza currently has a rare pediatric disease designation, if we cannot secure FDA BLA approval prior to September 30, 2026, we may not be able to receive the benefit of such designation.

Hatch-Waxman Act for Drugs.

Section 505 of the FDCA describes three types of drug marketing applications that may be submitted to the FDA to request marketing authorization for a new drug. A Section 505(b)(1) NDA is an application that contains full reports of investigations of safety and efficacy. A 505(b)(2) NDA is an application that contains full reports of investigations of safety and efficacy but where at least some of the information required for approval comes from investigations that were not conducted by or for the applicant and for which the applicant has not obtained the right of reference or use from the person by or for whom the investigations were conducted. This regulatory pathway enables the applicant to rely, in part, on the FDA’s prior findings of safety and efficacy for an existing product, or published literature, in support of its

46

Table of Contents

application. Section 505(j) establishes an abbreviated approval process for a generic version of approved drug products through the submission of an Abbreviated New Drug Application, or ANDA. An ANDA provides for marketing of a generic drug product that generally has the same active ingredients, dosage form, strength, route of administration, labeling, performance characteristics and intended use, among other things, to a previously approved product, called the reference listed drug. Certain differences, however, between the reference listed drug and ANDA product may be permitted pursuant to a suitability petition. Certain labeling differences may also be permitted if information in the reference listed drug’s label is protected by patent or exclusivities. ANDAs are termed “abbreviated” because they are generally not required to include nonclinical and clinical data to establish safety and efficacy. Instead, generic applications must scientifically demonstrate that their product is bioequivalent to, or performs in the same manner as, the innovator drug through in vitro, in vivo, or other testing. The generic version must deliver the same amount of active ingredients to the site of action in the same amount of time as the innovator drug and can often be substituted by pharmacists under prescriptions written for the reference listed drug. In seeking approval for a drug through an NDA, applicants are required to list with the FDA each patent with claims that cover the applicant’s drug or a method of using the drug. Upon approval of a drug, each of the patents listed in the application for the drug is then published in the FDA’s list of Approved Drug Products with Therapeutic Equivalence Evaluations, commonly known as the Orange Book. Drugs listed in the Orange Book can, in turn, be cited by potential competitors in support of approval of an ANDA or 505(b)(2) NDA.   In an effort to clarify which patents must be listed in the Orange Book, in January 2021, Congress passed the Orange Book Transparency Act of 2020, which largely codifies FDA’s existing practices into the FDCA. Listing patents in the Orange Book that do not qualify for listing can be considered to be anticompetitive conduct and, in 2023, the Federal Trade Commission sent letters to a number of companies with respect to certain patents that the agency asserted were improperly listed or inaccurate.

Upon submission of an ANDA or 505(b)(2) NDA, an applicant must certify to the FDA that (1) no patent information has been submitted to the FDA; (2) such patent has expired; (3) the date on which such patent expires; or (4) such patent is invalid or will not be infringed upon by the manufacturer, use or sale of the drug product for which the application is submitted. The applicant may also elect to submit a “section viii” statement certifying that its proposed label does not contain (or carves out) any language regarding the patented method-of-use rather than certify to a listed method-of-use patent. Generally, the ANDA or 505(b)(2) NDA approval cannot be made effective until all listed patents have expired, except where the ANDA or 505(b)(2) NDA applicant challenges a listed patent through the last type of certification, also known as a paragraph IV certification.

If the ANDA or 505(b)(2) NDA applicant has provided a paragraph IV certification to the FDA, the applicant must send notice of the certification to the NDA and patent holders. The NDA and patent holders may then initiate a patent infringement lawsuit in response to the notice of the paragraph IV certification, in which case the FDA may not make an approval effective until the earlier of 30 months from the patent or application owner’s receipt of the notice of the paragraph IV certification, the expiration of the patent, when the infringement case concerning each such patent is favorably decided in the applicant’s favor or settled, or such shorter or longer period as may be ordered by a court. This prohibition is generally referred to as the 30 month stay. In instances where an ANDA or 505(b)(2) NDA applicant files a paragraph IV certification, the NDA holder or patent owner(s) regularly take action to trigger the 30 month stay. Thus, approval of an ANDA or 505(b)(2) NDA could be delayed for a significant period of time depending on the patent certification the applicant makes and the reference drug sponsor’s decision to initiate patent litigation.

Exclusivity provisions under the FDCA can delay the submission or the approval of certain applications for competing products. The FDCA provides a five-year period of non-patent exclusivity within the United States to the first applicant to gain approval of an NDA for a new chemical entity. A drug is a new chemical entity if the FDA has not previously approved any other new drug containing the same active moiety, which is the molecule or ion responsible for the therapeutic activity of the drug substance. During the exclusivity period, the FDA generally may not accept for review an ANDA or a 505(b)(2) NDA submitted by another company that contains the new chemical entity. However, an ANDA or 505(b)(2) NDA may be submitted after four years if it contains a certification of patent invalidity or non-infringement.

The FDCA also provides a shorter three-year period of exclusivity for an NDA, 505(b)(2) NDA, or supplement to an existing NDA or 505(b)(2) NDA if new clinical investigations, other than bioavailability studies, that were conducted or sponsored by the applicant are deemed by the FDA to be essential to the approval of the application. Three-year exclusivity may be granted for example, for new indications, dosages, strengths or dosage forms of an existing drug. This three-year

47

Table of Contents

exclusivity covers only the conditions of use associated with the new clinical investigations and, as a general matter, does not prohibit the FDA from approving ANDAs or 505(b)(2) NDAs for generic versions of the original, unmodified drug product. Five-year and three-year exclusivity will not delay the submission or approval of a full NDA; however, an applicant submitting a full NDA would be required to conduct or obtain a right of reference to all of the preclinical studies and adequate and well-controlled clinical trials necessary to demonstrate safety and effectiveness.

BPCIA Exclusivity

The 2010 Patient Protection and Affordable Care Act included the BPCIA as a subtitle. The BPCIA established a regulatory scheme authorizing the FDA to approve biosimilars and interchangeable biosimilars. The FDA has issued a number of guidance documents outlining an approach to review and approval of biosimilars, including guidance documents on the demonstration of interchangeability and the licensure of biosimilar and interchangeable products for fewer than all of the reference product’s licensed conditions of use.

Under the BPCIA, a manufacturer may submit an application for licensure of a biologic product that is “biosimilar to” or “interchangeable with” a previously approved biological product or “reference product.” In order for the FDA to approve a biosimilar product, it must find that there is a high degree of similarity to the reference product, notwithstanding minor differences in clinically inactive components, and that there are no clinically meaningful differences between the reference product and proposed biosimilar product in terms of safety, purity and potency. Biosimilarity must be shown through analytical studies, animal studies, and at least one clinical trial, absent a waiver by the FDA. There must be no difference between the reference product and a biosimilar in mechanism of action, conditions of use, route of administration, dosage form, and strength. For the FDA to approve a biosimilar product as interchangeable with a reference product, the FDA must find that the biosimilar product can be expected to produce the same clinical results as the reference product, and (for products administered multiple times) that the biologic and the reference biologic may be switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date of approval of the reference product. The FDA may not approve a biosimilar product until 12 years from the date on which the reference product was approved. However, certain changes and supplements to an approved BLA, and subsequent applications filed by the same sponsor, manufacturer, licensor, predecessor in interest, or other related entity do not qualify for the 12 year exclusivity period. Even if a product is considered to be a reference product eligible for exclusivity, another company could market a competing version of that product if the FDA approves a full BLA for such product containing the sponsor’s own nonclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of their product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products.

The BPCIA also includes provisions to protect reference products that have patent protection. The biosimilar product sponsor and reference product sponsor may exchange certain patent and product information for the purpose of determining whether there should be a legal patent challenge. Based on the outcome of negotiations surrounding the exchanged information, the reference product sponsor may bring a patent infringement suit and injunction proceedings against the biosimilar product sponsor. The biosimilar applicant may also be able to bring an action for declaratory judgment concerning the patent.

The FDA maintains a publicly-available online database of licensed biological products, which is commonly referred to as the “Purple Book.”  The Purple Book lists product names, dates of licensure, and applicable periods of exclusivity.  Further, the reference product sponsor must provide patent information and patent expiry dates to FDA following the exchange of patent information between biosimilar and reference product sponsors. This information is then published in the Purple Book.

In an effort to increase competition in the drug and biologic product marketplace, Congress, the executive branch, and FDA have taken certain legislative and regulatory steps. For example, measures have been proposed and implemented to facilitate product importation. Moreover, the 2020 Further Consolidated Appropriations Act included provisions requiring that sponsors of approved drug and biologic products, including those subject to REMS, provide samples of the approved

48

Table of Contents

products to persons developing 505(b)(2) NDA or ANDA drug products, or biosimilar products within specified timeframes, in sufficient quantities, and on commercially reasonable market-based terms. Failure to do so can subject the approved product sponsor to civil actions, penalties, and responsibility for attorney’s fees and costs of the civil action. This same bill also includes provisions with respect to shared and separate REMS programs for reference and generic drug products.

Patent Term Restoration

If approved, drug and biologic products may also be eligible for periods of U.S. patent term restoration if an application is timely filed with the Patent and Trademark Office. If granted, patent term restoration extends the patent life of a single unexpired patent, that has not previously been extended, for a maximum of five years, and only those claims reading on the approved drug may be extended. The total patent life of the product with the extension also cannot exceed fourteen years from the product’s approval date. Subject to the prior limitations, the period of the extension is calculated by adding half of the time from the effective date of an IND to the initial submission of a complete marketing application, and all the time between the submission of the marketing application and its approval. This period may also be reduced by any time that the applicant did not act with due diligence.

Pediatric exclusivity

Pediatric exclusivity is another type of non-patent market exclusivity in the United States and, if granted, provides for the attachment of an additional six months of market protection to the term of any existing Orange Book- listed patents or regulatory exclusivity, including the non-patent exclusivity periods described above. This six-month exclusivity may be granted based on the voluntary completion of a pediatric study or studies in accordance with an FDA-issued “Written Request” for such a study or studies within a specified timeframe prior to the expiration of the underlying patent or market exclusivity period to be extended.

Regulation outside the United States

In order to market any product outside of the United States, we would need to comply with numerous and varying regulatory requirements of other countries regarding safety and efficacy and governing, among other things, clinical trials, marketing authorization, commercial sales and distribution of our products. Whether or not we obtain FDA approval for a product, we would need to obtain the necessary approvals by the comparable regulatory authorities of ex-U.S. countries before we can commence clinical trials or marketing of the product in those countries. The approval process varies from country to country and can involve additional product testing and additional administrative review periods. The time required to obtain approval in other countries might differ from and be longer than that required to obtain FDA approval. Regulatory approval in one country does not ensure regulatory approval in another, but a failure or delay in obtaining regulatory approval in one country may negatively impact the regulatory process in others. And, even if regulatory approval is granted, it may be withdrawn or limited under certain circumstances or post-approval requirements may be imposed by the applicable regulatory authority. Because biologically sourced raw materials are subject to unique contamination risks, their use may be restricted in some countries.

Regulation in the European Union

We have obtained an orphan medicinal product designation from the EC, following an evaluation by the EMA’s Committee for Orphan Medicinal Products, for Translarna for the treatment of nmDMD, Upstaza for the treatment of AADC deficiency, Evrysdi for the treatment of SMA, vatiquinone for the treatment of Friedreich ataxia, utreloxastat for the treatment of ALS and sepiapterin for the treatment of patients with hyperphenylalaninemia, including hyperphenylalaninemia caused by PKU. The EC can grant orphan medicinal product designation to products for which the sponsor can establish that it is intended for the diagnosis, prevention, or treatment of (1) a life-threatening or chronically debilitating condition affecting not more than five in 10,000 people in the EU, or (2) a life threatening, seriously debilitating or serious and chronic condition in the EU and that without incentives it is unlikely that sales of the drug in the EU would generate a sufficient return to justify the necessary investment. In addition, the sponsor must establish that there is no other satisfactory method approved in the EU of diagnosing, preventing or treating the condition, or if such a method exists, the proposed orphan drug will be of significant benefit to patients. Orphan drug designation is not a marketing authorization.

49

Table of Contents

It is a designation that provides a number of benefits, including fee reductions, regulatory assistance, and, in the event of a successful application for a centralized EU marketing authorization, 10 years of EU market exclusivity. During this market exclusivity period, neither the EMA, nor the EC nor any EU member states can accept an application or grant a marketing authorization for a “similar medicinal product.” A “similar medicinal product” is defined as a medicinal product containing a similar active substance or substances as contained in an authorized orphan medicinal product, and which is intended for the same therapeutic indication. The market exclusivity period for the authorized therapeutic indication may be reduced to six years if, at the end of the fifth year, it is established that the orphan designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity. In addition, a competing similar medicinal product may in limited circumstances be authorized prior to the expiration of the market exclusivity period, including if it is shown to be safer, more effective or otherwise clinically superior to our product. Our product candidates can lose orphan designation, and the related benefits, prior to us obtaining a marketing authorization if it is demonstrated that the orphan designation criteria are no longer met.

The EC has conducted a review of the Orphan Drug Regulation together with the Paediatric Regulation.  The outcome of this review is intended to guide future legislative changes and shape the EU’s pharmaceutical strategy.

Clinical Trial Developments. The structure and general regulation of clinical trials for both small molecule and biological medicines in the EU is similar to that in the United States. Separately, a new regulation, (EU) No.536/2014, regarding clinical trials of medicinal products for humans is included in the European regulatory framework and fills a series of regulatory gaps in the clinical trials regime through the creation of a uniform framework for the authorization of clinical trials by all interested EU member states with a single assessment of the results. The regulation (which came into effect on January 31, 2022) is thus intended to facilitate cross-border cooperation through streamlining of the rules on clinical trials across the EU, including by requiring the submission of clinical trial authorization applications via a new electronic EU portal.

Alongside the portal, a database is being created that will contain information on clinical trial data. The information on the database will be publicly accessible unless the trial data’s confidentiality can be justified on the basis of protection of commercially confidential information, protection of personal data, protection of confidential communication between EU countries, or ensuring effective supervision of the conduct of clinical trials by EU countries. A sponsor of a trial conducted in the EU under the new regulation will be required to submit a summary of the clinical trial results to the EU database within a year of the end of the trial. In addition, where the trial was intended to be used for obtaining a marketing authorization (whether through the centralized procedure or via the national authorities), the applicant must submit the clinical study report within 30 days after the marketing authorization has been granted (or refused or withdrawn).

Overview of application process.   To obtain regulatory approval of a drug under the EU’s regulatory systems and authorization procedures, an applicant may submit marketing authorization applications under a centralized, decentralized, or national procedure. The centralized procedure is compulsory for certain medicinal products, including orphan medicinal products, like Translarna for the treatment of nmDMD, and medicinal products produced by certain biotechnological processes, and optional for certain other innovative products. The centralized procedure enables applicants to obtain a marketing authorization that is valid in all EU member states based on a single application. Under the centralized procedure, the EMA’s Committee for Human Medicinal Products, or CHMP, is required to adopt an opinion on a valid application within 210 days, excluding clock stops, when additional written or oral information is to be provided by the applicant in response to questions.

More specifically, on day 120 of the procedure, once the CHMP has received the preliminary assessment reports and opinions from the rapporteur and co-rapporteur, it prepares a list of potential outstanding issues, referred to as “other concerns” or “major objections”. These are sent to the applicant together with CHMP’s recommendation. In addition, in relation to advanced therapy medicinal products, or ATMPs, which are medicines based on genes, cells or tissues, the Committee for Advanced Therapies, or CAT, EMA’s committee responsible for assessing the quality, safety and efficacy of ATMPs, prepares a draft opinion on the ATMP application that is submitted to EMA before the CHMP adopts a final opinion on the marketing authorization of the applicable medicine. The CHMP can make one of two recommendations: (1) the marketing authorization could be granted provided that satisfactory answers are given to the “other concerns” and/or “major objections” identified and that all conditions outlined in the list of outstanding issues are implemented and complied with; or (2) the product is not approvable since there are “major objections”.

50

Table of Contents

Applicants have three months from the date of receiving the potential outstanding issues to respond to the CHMP, and can request a three-month extension if necessary. The granting of a marketing authorization will depend on the recommendations and potential major objections identified by the CHMP as well as the ability of the applicant to adequately respond to these findings. An accelerated assessment can be granted by the CHMP in exceptional cases, when a medicinal product is expected to be of a major public health interest, in particular from the viewpoint of therapeutic innovation. In this circumstance, the EMA ensures that the opinion of the CHMP is given within 150 days. After the adoption of the CHMP opinion, a decision on the marketing authorization application must be adopted by the EC, after consulting the EU member states, which in total can take more than 60 days.

An applicant for a marketing authorization application may request a re-examination in the event of a negative opinion, in connection with which CHMP appoints new rapporteurs. Within 60 days of receipt of the negative opinion, the applicant must submit a document explaining the basis for its request for re-examination. The CHMP has 60 days to consider the applicant’s request for re-examination. The applicant may request an oral explanation before the CHMP, which is routinely granted, following which CHMP will adopt a final opinion. The final opinion, whether positive or negative, is published by the CHMP shortly following the CHMP meeting at which the oral explanation takes place. The EMA publishes a European Public Assessment Report, or EPAR, for every medicine granted a central marketing authorization by the EC following an assessment by the CHMP. EPARs are full scientific assessment reports of medicines authorized by the EMA.

Conditional marketing authorizations.   In specific circumstances, as with Translarna for the treatment of nmDMD, EU legislation enables applicants to obtain a marketing authorization on a conditional basis prior to obtaining the comprehensive clinical data required for an application for a full marketing authorization. Such conditional approvals may be granted for products designated as orphan medicinal products, if (1) the benefit-risk balance of the product is positive, (2) it is likely that the applicant will be in a position to provide the required comprehensive clinical trial data, (3) the product fulfills unmet medical needs, and (4) the benefit to public health of the immediate availability on the market of the medicinal product concerned outweighs the risk inherent in the fact that additional data are still required. A conditional marketing authorization may contain specific obligations to be fulfilled by the marketing authorization holder, including obligations with respect to the completion of ongoing or new studies, and with respect to the collection of pharmacovigilance data. Conditional marketing authorizations are valid for one year, and may be renewed annually, if the benefit-risk balance remains positive, and after an assessment of the need for additional or modified conditions and/or specific obligations. The timelines for the centralized procedure described above also apply with respect to the review by the CHMP of applications for a conditional marketing authorization. The granting of a conditional marketing authorization will depend on the applicant’s ability to fulfill the conditions imposed within the agreed upon deadline.

For important information about matters that may adversely affect our ability to renew our conditional marketing authorization for Translarna, see “Item 1A. Risk Factors-Risks Related to the Development and Commercialization of our Product and our Product Candidates.”

Variations to conditional marketing authorizations.   After the granting of a conditional marketing authorization, the marketing authorization holder may submit an application to vary the conditional marketing authorization under a variation procedure. In the case of the introduction of an additional therapeutic indication, the timeframe for the variation procedure for the initial assessment of the dossier is generally 90 days (plus up to 20 days for validation).

However, in the framework of a variation application assessment procedure, the EMA may send one or more requests for supplementary information to the marketing authorization holder, requiring that additional information be provided by the marketing authorization holder to support its variation application. Such supplementary requests will be sent together with a timetable stating the date by when the marketing authorization holder must submit the requested data and, where appropriate, the extended evaluation period to be applied to such variation procedure. The 90-day variation procedure may be suspended for up to three months for the marketing authorization holder to submit its responses to such supplementary requests. The marketing authorization holder will be notified of the outcome of the CHMP’s assessment of the variation procedure within 15 days from the adoption of the CHMP opinion. If unfavorable, the CHMP opinion may be subject to a re-examination procedure upon the marketing authorization holder’s request. This may imply an additional minimum two-month procedure. If the CHMP opinion is favorable, the EC will usually vary the marketing authorization to introduce the additional therapeutic indication within approximately two months from the receipt of the final CHMP opinion.

51

Table of Contents

Exceptional Circumstances. Similarly, certain of our product candidates may be eligible for a marketing authorization under exceptional circumstances. Such an authorization may be granted where the applicant can demonstrate in its application that it is unable to provide comprehensive data on efficacy and safety under normal conditions of use, because: 1) the indications for which the product in question is intended are encountered so rarely that the applicant cannot reasonably be expected to provide comprehensive evidence; 2) in the present state of scientific knowledge, comprehensive information cannot be provided; or 3) it would be contrary to generally accepted principles of medical ethics to collect such information. Authorizations under exceptional circumstances are annually reassessed and granted subject to a requirement for the applicant to implement certain procedures, in particular, competent authority notification in the event of any safety issue. After 5 years, the authorization is renewed under exceptional circumstances for an unlimited period, unless the EMA decides, on justified grounds relating to pharmacovigilance, to proceed with one additional five-year renewal.  A marketing authorization under exceptional circumstances will not be granted when a conditional marketing authorization is more appropriate.  Orphan products are further eligible for approval under exceptional circumstances only if the criteria considered for the approval under exceptional circumstances are fulfilled.

Additional requirements and considerations.   Prior to obtaining a marketing authorization in the EU, applicants have to demonstrate compliance with all measures included in an EMA-approved Pediatric Investigation Plan, or PIP, covering all subsets of the pediatric population, unless the EMA has granted (1) a product-specific waiver, (2) a class waiver, or (3) a deferral for one or more of the measures included in the PIP. In the case of orphan medicinal products, completion of an approved PIP can result in an extension of the aforementioned market exclusivity period from ten to twelve years.

In the EU there is also a procedure which allows member states to authorize the distribution of an unauthorized medicinal product in response to the spread of pathogens. The UK (but no EU countries) used this procedure with two COVID-19 vaccines during December 2020. Notwithstanding the UK’s subsequent full departure from the EU, the EU provision is mirrored in UK medicines legislation.

In the EU, for a period of eight years from the grant of a marketing authorization of an innovative product (the “reference medicinal product”), competent authorities may not accept marketing authorization applications from applicants seeking to market “generic medicinal products” where such applications rely on the data in the marketing authorization dossier of the reference product. Moreover, generic medicinal products that rely on the independently generated data of the reference product may not be placed on the market for 10 years from the granting of the initial marketing authorization for that reference medicinal product. This is extended to a maximum of 11 years if, during the first eight years of those 10 years, the marketing authorization holder obtains an authorization for one or more new therapeutic indications considered to offer a significant clinical benefit in comparison with existing therapies. These periods of data exclusivity do not prevent other companies from obtaining a marketing authorization based on their own independently generated data. The data exclusivity regime is currently under review. The EC intends to strike a balance between providing incentives for innovation and supporting timely patient access to medicinal products across the EU. To do so, the EC has published a proposal for a revised Directive on the Union Code Relating to Medicinal Products for Human Use, which proposes replacing the regulatory data protection system with a new regime that will offer innovators variable durations of data exclusivity.  Under the new rules, if implemented, new medicinal products will have a minimum period of regulatory protection of eight years, which includes six years of regulatory data protection and two years of market protection.  Such products may benefit from additional periods of regulatory data protection if they satisfy certain criteria, which may increase the total period of regulatory protection up to a maximum of 12 years (as compared to the current maximum of 11 years).

If a marketing authorization is granted in the EEA for a medicinal product, such as the marketing authorization granted for Translarna for the treatment of nmDMD by the EC, the marketing authorization holder is required to comply with a range of requirements applicable to the manufacturing, marketing, promotion and sale of the medicinal products that are in addition to the other conditions of the marketing authorization described above. The marketing authorization holder must, for example, comply with the EU’s stringent pharmacovigilance or safety reporting rules, pursuant to which post- authorization studies and additional monitoring obligations can be imposed. Other requirements relate to, for example, the manufacturing of products and active pharmaceutical ingredients in accordance with good manufacturing practice standards. Competent authorities of EU member states may conduct inspections to verify compliance with applicable requirements, and the marketing authorization holder will have to continue to expend time, money and effort to remain compliant. Non-compliance with EU requirements regarding safety monitoring or pharmacovigilance, and with requirements related to the development of products for the pediatric population, can also result in significant financial

52

Table of Contents

penalties in the EU Similarly, failure to comply with the EU’s requirements regarding the protection of individual personal data can also lead to significant penalties and sanctions. Individual EU member states may also impose various sanctions and penalties in case we do not comply with locally applicable requirements. The CAT is involved in any procedure regarding the provision of advice on the conduct of efficacy follow-up, pharmacovigilance and risk management systems of ATMPs as provided for in ATMP legislation.

Off-label promotion of medicinal products is prohibited in the EU. The applicable laws at EU level and in the individual EU member states also prohibit the direct-to-consumer advertising of prescription-only medicinal products. Violations of the rules governing the promotion of medicinal products in the EU could be penalized by administrative measures, fines and imprisonment. These laws may further limit or restrict our promotional activities with healthcare professionals. In addition, legislation adopted at the EU level and by individual EU member states require that promotional materials and advertising in relation to medicinal products comply with the product’s Summary of Product Characteristics, or SmPC, as approved by the competent authorities. The SmPC is the document that provides information to physicians concerning the safe and effective use of the medicinal product. Promotion of indications not covered by the SmPC is specifically prohibited. ATMP legislation lays down certain minor extra labelling requirements for ATMPs.

The EMA is responsible for coordinating inspections to verify compliance with the principles of GCP, good manufacturing practice, or GMP, GLP, and good pharmacovigilance practice. These inspections are also intended to verify compliance with other aspects of the supervision of authorized medicinal products in use in the EU. The EMA coordinates any inspection by the relevant member state regulatory authority as requested by the CHMP in connection with the assessment of marketing authorization applications or matters referred to these committees. Inspections may be routine or triggered by issues arising during the assessment of the dossier or by other information, such as previous inspection experience. Inspections usually are requested during the initial review of a marketing authorization application, but could arise post-authorization.

Inspectors are drawn from the regulatory authorities of member states of the EU and the EEA. Following an inspection, the inspectors provide a written inspection report to the inspected site or applicant and provide an opportunity for response. Some inspection reports require follow-up and may result in additional adverse consequences due to critical or major findings. The inspectors and the CHMP will comment on any response from an inspected site or applicant and may monitor future compliance with any proposed corrective action plan.

In the GCP area, inspectors grade their findings according to the following scale:

Possible consequences of critical and major findings include rejection of clinical trial data, causing significant delays in obtaining final marketing authorization, or other direct action by national regulatory authorities.

Falsified Medicines Directive – As of February 2019, new legislation required manufacturers of marketed prescription medicines to place safety features on all medicines and contribute financially to the establishment of a verification system allowing the authenticity of a medicine to be assessed at the time of supply to the patient. Under the legislation, all packages of prescription medicines placed on the market in Europe have to bear two safety features: a unique identifier in the form of a two-dimensional data matrix (barcode) and an anti-tamper device. In addition, ATMP legislation requires a procedure for tracing the product and its starting and raw materials from its source to the site where the product is used.

53

Table of Contents

Early access programs

Many jurisdictions allow the supply of unauthorized medicinal products in the context of strictly regulated and exceptional EAP programs, and some countries may provide reimbursement for drugs provided in the context of such programs. In the EU, the legal basis for EAP programs, also referred to as named-patient and compassionate use programs, is set out in the EU legislation regulating the authorization, manufacture, distribution and marketing of medicinal products. Detailed regulatory requirements applicable to EAP programs have been adopted and implemented by EU member states in their national laws. The promotion, advertising and marketing of unauthorized medicinal products is generally prohibited, and authorization for EAP programs must generally be obtained from national competent authorities, which might not grant such authorization. Obtaining authorization for an EAP program in one country does not ensure that authorization will be obtained in another country.

U.S. law permits “expanded access” (also known as compassionate use and treatment use) for certain patients with serious diseases who have no comparable alternative treatment options. The potential patient benefit must justify the potential risks of the treatment use and those potential risks must not be unreasonable in the context of the disease or condition to be treated. Moreover, providing the investigational drug or biologic for the requested use must not interfere with the initiation, conduct, or completion of clinical investigations that could support marketing approval of the expanded access use or otherwise compromise the potential development of the expanded access use. Additional requirements apply depending on the size of the expanded access population. To provide expanded access, sponsors, including individual physicians, must submit detailed regulatory information to the FDA and receive the agency’s approval for the use. However, if there is an emergency that requires that a patient be treated before a written submission can be made, the FDA may authorize the expanded access use by telephone. In such a case, a written expanded access submission must be submitted to the FDA within fifteen working days of the FDA’s authorization. Following approval for expanded access use, both the sponsor of the use and the investigator (i.e., physician) must comply with certain FDA requirements. Sponsors may not promote products as safe or effective for expanded-access uses.

Pharmaceutical Pricing and Reimbursement

The containment of healthcare costs has become a priority of federal, state and ex-U.S. governments, and the prices of pharmaceuticals have been a focus of this effort. Ex-U.S. governments, the U.S. government, and state legislatures have shown significant interest in implementing cost-containment programs to limit the growth of government-paid healthcare costs, including price controls, increases in rebates paid, restrictions on reimbursement and requirements for substitution of generic products for branded prescription drugs.

In some countries, particularly the countries of the EU, the pricing of prescription pharmaceuticals is subject to governmental control. In these countries, pricing and reimbursement negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product and there is only limited EU-level control over the decision-making autonomy of the government authorities including in relation to timing, justification and the ability to challenge such decisions. In addition, there can be considerable pressure by governments and other stakeholders on prices and reimbursement levels, including as part of cost containment measures. In some countries, governments can set conditions that must be satisfied for prices to be set at a certain value. Political, economic and regulatory developments may further complicate pricing and reimbursement negotiations, and pricing negotiations may continue after reimbursement has been obtained. Reference pricing used by various EU member states, and parallel distribution (arbitrage between low-priced and high- priced member states), can further reduce prices. In some countries we may be required to conduct a clinical trial or other studies that compare the cost-effectiveness of our product or product candidate to other available therapies in order to obtain reimbursement or pricing approval.

In the United States, federal price reporting laws require manufacturers to calculate and report complex pricing metrics used to determine prescription rebates paid under the Medicaid Drug Rebate Program and amounts reimbursed pharmacies and other providers by the Medicaid and Medicare programs. Various state healthcare programs similarly obligate us to report drug pricing information that is used as the basis for their reimbursement of pharmacies and other healthcare providers and the negotiation of supplemental rebates. Payment for a manufacturer’s drugs by these programs is conditioned on submission of this pricing information. Some government healthcare programs impose penalties if drug price increases exceed specified percentages or inflation rates, and these penalties can result in mandatory penny prices

54

Table of Contents

for certain federal and 340B program customers. States, such as California, have also enacted transparency laws that require manufacturers to report price increases and related information, and may cap price increases, or require negotiation of supplemental rebates for new drugs entering the market at price points determined to be high. Refusal to negotiate supplemental rebates can negatively affect market access and provider reimbursement. Failure to comply with the rules for calculating and submitting pricing information or otherwise overcharging the government or its beneficiaries may result in criminal, civil, or administrative sanctions or enforcement actions, and expose us to federal civil False Claims Act, or the False Claims Act, liability.

The Veterans Health Care Act of 1992 requires, as a condition of payment by certain federal agencies and the Medicaid program, that manufacturers of “covered drugs” (including all drugs approved under an NDA) enter into a Master Agreement and Federal Supply Schedule (FSS) contract with the Department of Veterans Affairs through which their covered drugs must be offered for sale at a mandatory calculated ceiling price to certain federal agencies, including the VA and Department of Defense. FSS contracts require compliance with applicable federal procurement laws and regulations, including disclosure of commercial prices during contract negotiations and maintenance of price relationships during the term of the contract, and subject manufacturers to contractual remedies as well as administrative, civil, and criminal sanctions. The Veterans Health Care Act also requires manufacturers to enter into pricing agreements with the Department of Health and Human Services to charge no more than a different ceiling price (derived from the Medicaid rebate percentage) to covered entities participating in the 340B drug discount program. Failure to accurately report drug pricing or to provide the mandatory discount may subject the manufacturer to specific civil monetary penalties. Termination of either of these agreements also jeopardizes payment by Medicaid and Medicare for the manufacturer’s drugs in an outpatient setting. Certain states have also enacted drug price transparency laws that require reporting of pricing information, including certain increases in a drug’s wholesale acquisition cost and the reasons causing the price increase.

Coverage policies, third-party reimbursement rates and drug pricing regulation may change at any time. For example, in the United States, healthcare reform measures under the Affordable Care Act, contain provisions that may affect the profitability of drug products. However, since its passage, Congress has repealed and amended certain provisions of the Affordable Care Act, repeal efforts may occur again, and legal challenges to the Affordable Care Act may contribute to the uncertainty of the ongoing implementation and impact of the Affordable Care Act and underscore the potential for additional reform going forward. Certain provisions of enacted or proposed legislative changes may negatively impact coverage and reimbursement of, or rebates paid by manufacturers for, healthcare items and services. We cannot assure that the Affordable Care Act, as currently enacted or as amended in the future, will not adversely affect our business and financial results and we cannot predict how future federal or state legislative or administrative changes relating to healthcare reform will affect our business.

Legislators and regulators at both the federal and state level are increasingly focused on containing the cost of drugs, and there has been increasing legislative and enforcement interest in the United States with respect to specialty drug pricing practices. Specifically, there have been recent U.S. Congressional inquiries and proposed bills designed to, among other things, bring more transparency to drug pricing, penalize companies that do not agree to cap prices paid for certain drugs, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. For example, in 2016, the Centers for Medicare and Medicaid Services, or CMS, issued a final rule regarding the Medicaid drug rebate program, which among other things, revises the manner in which the “average manufacturer price” or AMP is to be calculated by manufacturers participating in the program and implements certain amendments to the Medicaid rebate statute created under the Affordable Care Act, or ACA. More recently, Congress amended the Medicaid statute, effective October 1, 2019, to exclude prices paid by secondary manufacturers for an authorized generic drug (but not a product approved under the BLA process) from the NDA holder’s AMP for the brand, thereby increasing the rebate amount and the 340B price for the brand. This was implemented by CMS in a final rule issued December 31, 2020.  The rule also expanded the definition of products identified as “line extensions” and, in certain circumstances, required inclusion of patient copay assistance in Medicaid best price (effective January 1, 2023), thereby potentially increasing Medicaid rebates paid by manufacturers for such drugs. 340B program guidance regulations on civil monetary penalties for statutory violations, which had been finalized in early 2017 but deferred, also recently went into effect.

On November 27, 2020, CMS issued an interim final rule implementing a Most Favored Nation payment model under which reimbursement for certain Medicare Part B drugs and biologicals will be based on a price that reflects the lowest

55

Table of Contents

per capita Gross Domestic Product-adjusted (GDP-adjusted) price of any non-U.S. member country of the Organisation for Economic Co-operation and Development (OECD) with a GDP per capita that is at least sixty percent of the U.S. GDP per capita.  This rule now has been rescinded, but other efforts to address the costs of pharmaceuticals have been adopted, including the Inflation Reduction Act of 2022, or the IRA.  These and any additional healthcare reform measures could further constrain our business or limit the amounts that federal and state governments will pay for healthcare products and services, which could result in additional pricing pressures.

Any regulatory approval of a product is limited to specific diseases and indications for which such product has been deemed safe and effective by the FDA. Coverage by federal healthcare programs, however, may be more limited than the indications for which a drug is approved by the FDA or comparable ex-U.S. regulatory authorities’ coverage of the same products. Sales of any products for which we may receive regulatory approval for commercial sale will depend in part on the extent to which the costs of the products will be covered and reimbursed by third-party payors, including government healthcare programs (such as, in the United States, Medicare and Medicaid), private health insurers and other organizations. Obtaining reimbursement for orphan drugs may be particularly difficult because of the significant research and development challenges and costs and resulting pricing considerations typically associated with drugs developed to treat conditions that affect a small population of patients. In addition, third-party payors are likely to impose strict requirements for reimbursement in connection with drugs that are perceived as having high costs. Net prices for products may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors.

The process for determining whether a payor will provide coverage for a product may be separate from the process for setting the price or reimbursement rate that the payor will pay for the product once coverage is approved. Third- party payors may limit coverage to specific products on an approved list, or formulary, which might not include all of the approved products for a particular indication. Third-party payors are increasingly challenging the price and examining the cost-effectiveness of medical products and services. We may need to conduct expensive pharmacoeconomic studies in order to demonstrate the cost-effectiveness of our product or product candidates or conduct direct head-to-head studies to demonstrate clinical superiority and cost-effectiveness. Our products and product candidates may not be considered clinically superior and cost-effective to competitor products.

The marketability of any products for which we receive regulatory approval for commercial sale may suffer if the government and other third-party payors fail to provide adequate coverage and reimbursement.

Freedom of Information Requests and Affirmative Disclosures

We are also subject, in the U.S. and many other countries, to various regulatory schemes that require disclosure of clinical trial data or allow access to our data via freedom of information requests. We have been and may, from time to time, be notified by regulators, such as the EMA or the competent authorities of EU member states that they have received a freedom of information request for documents that they hold relating to our company, including information related to our product or our product candidates. For example, in 2015, we were notified by the EMA that it had received from another pharmaceutical company a request under Regulation (EC) No 1049/2001 seeking access to aspects of our marketing authorization application for Translarna for the treatment of nmDMD. Following the decision of the EMA to release such documentation with only minimal redactions we initiated litigation before the General Court of the EU to prevent disclosure of this information. In the first quarter of 2018, the Court ruled in favor of the EMA, allowing the EMA to release the documentation. We appealed the General Court’s decision to the Court of Justice of the EU, or CJEU, but the CJEU dismissed our appeal in January 2020 and released the information to the requester. In addition, under policies recently adopted in the EU, clinical trial data submitted to the EMA in MAAs that were traditionally regarded as confidential commercial information is now subject to automatic public disclosure. Further, under the Clinical Trials Regulation 536/2014, the sponsor of an EU trial must submit a summary of the results to an EU database within a year of the end of the trial. In addition, where the trial was intended to be used for obtaining a marketing authorization the applicant must submit the clinical study report 30 days after MA has been granted, refused or withdrawn. Subject to our limited ability to review and redact a narrow sub-set of confidential commercial information, these new EU policies will result in the EMA’s public disclosure of certain of our clinical study reports, clinical trial data summaries and clinical overviews for recently completed and future MAA submissions. The move toward public disclosure of development data could adversely affect our business in many ways, including, for example, resulting in the disclosure of our confidential methodologies for development of our products, preventing us from obtaining intellectual property right protection for

56

Table of Contents

innovations, requiring us to allocate significant resources to prevent other companies from violating our intellectual property rights, adding even more complexity to processing health data from clinical trials consistent with applicable data privacy regulations, and enabling competitors to use our data to gain approvals for their own products.

Fraud and Abuse Laws

Any present or future arrangements or interactions with third-party payors, healthcare professionals, healthcare organizations, patients and other customers may expose us to broadly applicable fraud and abuse and other healthcare laws and regulations that may restrict certain marketing and contracting practices. These laws include, and are not limited to, anti-kickback and false claims statutes.

Both the federal Foreign Corrupt Practices Act, or FCPA, and the UK Bribery Act of 2010, or Bribery Act are broad in scope and will require companies to make and keep books and records that accurately and fairly reflect the transactions of the company and to devise and maintain an adequate system of internal accounting controls. The FCPA prohibits the offering, promising, giving, or authorizing others to give anything of value, either directly or indirectly, to a non-U.S. government official, political party or candidate for public office in order to improperly influence any act or decision, secure any other improper advantage, or obtain or retain business. The FCPA also prohibits any U.S. person from corruptly acting outside the U.S. in furtherance of such offer, promise or payment. Under the UK Bribery Act, companies which carry on a business or part of a business in the United Kingdom may be held liable for bribes given, offered or promised to any person, including non-UK government officials and private persons, by employees and persons associated with the company in order to obtain or retain business or a business advantage for the company. Similar statutes have been adopted, or may be adopted in the future, by other countries in which we operate and with which we are or may be required to comply.

The federal Anti-Kickback Statute prohibits, among other things, knowingly and willfully offering, paying, soliciting or receiving remuneration, directly or indirectly, in cash or kind, to induce or reward either the referral of an individual for, or the purchase, or order or recommendation of, any good or service, for which payment may be made in whole or in part under federal and state healthcare programs such as Medicare and Medicaid. This statute imposes criminal penalties and has been broadly interpreted to apply to manufacturer arrangements with prescribers, purchasers and formulary managers, among others. Although a number of statutory exemptions and regulatory safe harbors exist to protect certain common activities from prosecution, the exemptions and safe harbors for this statute are narrow, and practices that involve compensation intended to induce prescriptions, purchases, or recommendations may be subject to scrutiny if they do not qualify for an exemption or safe harbor. HHS recently promulgated a regulation that is effective in two phases.  First, the regulation excludes from the definition of “remuneration” limited categories of (a) PBM rebates or other reductions in price to a plan sponsor under Medicare Part D or a Medicaid Managed Care Organization plan reflected in point-of sale reductions in price and (b) PBM service fees.  Second, the regulation expressly provides that rebates to plan sponsors under Medicare Part D either directly to the plan sponsor under Medicare Part D, or indirectly through a pharmacy benefit manager will not be protected under the anti-kickback statute discount safe harbor. The effective date of the two new safe harbors and the revision to the discount safe harbor was delayed by court order until January 1, 2023.  Recent legislation further delayed implementation of the new safe harbors and the revision to the discount safe harbor until January 1, 2032.  Our practices may not always meet all of the criteria for safe harbor protection. A person or entity need not have knowledge of the statutes or the specific intent to violate it in order to have committed a violation. In addition, the government may assert as a matter of law that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal civil False Claims Act. Federal enforcement agencies have shown increased interest under the federal Anti-Kickback Stature and the federal civil False Claims Act in pharmaceutical companies’ product and patient assistance programs, including reimbursement and co-pay support services and donations to independent charitable patient assistance programs. A number of investigations into these programs have resulted in significant civil and criminal settlements. Most states have adopted laws similar to the federal Anti-Kickback Statute, which apply to items and services reimbursed under Medicaid and other state programs; furthermore, in several states, these statutes and regulations apply regardless of the payor, including to commercial plans. Sanctions under these federal and state laws may include civil monetary penalties, exclusion of a manufacturer and its products from participation in federal healthcare programs, debarment from federal government procurement and non-procurement programs, criminal fines, and imprisonment. Several other countries, including the United Kingdom, have enacted similar anti-kickback, fraud and abuse laws and regulations.

57

Table of Contents

The federal civil False Claims Act imposes civil liability and penalties on individuals or entities for knowingly presenting, or causing to be presented, to the federal government, claims for payment that are false or fraudulent, knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim, or making a false statement to avoid, decrease or conceal an obligation to pay money to the federal government. Claims under the federal civil False Claims Act may be initiated by whistleblowers, who receive substantial financial incentives to come forward, through “qui tam” actions that can be pursued by the whistleblower even if the government declines to prosecute the case. Intent to deceive or actual knowledge of falsity is not necessary to establish civil liability, which may be predicated on deliberate indifference or reckless disregard for the truth. The federal government continues to use the False Claims Act, and the accompanying threat of significant liability, in investigations against pharmaceutical and healthcare companies. These investigations have involved, for example, allegations of improper financial relationships with referral sources, providing free product to customers with the expectation that the customers would bill federal programs for the free product, as well as the promotion of products for unapproved uses and reporting false pricing information. A violation of the federal Anti-Kickback Statute is a per se violation of civil False Claims Act. Potential liability under the federal civil False Claims Act includes treble damages and significant per claim penalties. The criminal federal False Claims Act imposes criminal fines or imprisonment against individuals or entities who make or present a claim to the government knowing such claim to be false, fictitious or fraudulent. Conviction or civil judgment for violation of the False Claims Act can also result in debarment from federal government procurement and non-procurement programs and exclusion from participation in federal healthcare programs. The majority of states also have statutes or regulations similar to the federal False Claims Act, which apply to items and services reimbursed under Medicaid and other state programs.

The Affordable Care Act included a provision requiring certain providers and suppliers of items and services to federal healthcare programs to report and return overpayments within sixty days after they are “identified” (the “Overpayment Statute”), after which the recipient of the overpayment incurs federal civil False Claims Act liability. The law prohibits a recipient of a payment from the government from keeping an overpayment when the government mistakenly pays more than the amount to which the recipient is entitled even if the overpayment is not caused by any conduct of the recipient. In 2014 and 2016, the CMS released regulatory guidance (in the form of final rules) to Medicare providers, suppliers and managed care and prescription drug plans regarding how to comply with the Overpayment Statute. Although these Medicare providers, suppliers and plans have faced federal False Claims Act liability since 2010 for failures to comply with the Overpayment Statute, these final rules interpreting the Overpayment Statute provide guidance regarding how to comply with applicable obligations, and guidance to government regulators and enforcement authorities regarding monitoring and prosecuting suspected violations. These final rules are not directly applicable to manufacturers, unless a manufacturer is a direct recipient of payment by an agency such as a research grant, but may impact a manufacturer’s customers and potential customers who are Medicare providers, suppliers, and plans.  In a proposed rule issued on December 27, 2022, CMS is proposing to revise the standard for “identification” which could significantly reduce the time to investigate and report any possible overpayment, thereby increasing the risk of incurring federal civil False Claims Act liability for healthcare providers and suppliers.

The federal Physician Payments Sunshine Act, enacted as part of the Affordable Care Act, and its implementing regulations, require manufacturers of drugs, devices, biologics and medical supplies for which payment is available under Medicare, Medicaid, or the Children’s Health Insurance Program (with certain exceptions) to report annually to CMS information related to certain payments and other transfers of value made to or at the request of covered recipients, such as, but not limited to, physicians, physician assistants, nurse practitioners, clinical nurse specialists, certified registered nurse anesthetists and certified nurse midwives licensed in the United States and to US teaching hospitals, as well as ownership and investment interests held by physicians and members of their immediate family. Payments made to physicians, other principal investigators and certain research institutions for research, including clinical trials, are included within the ambit of this law. Such information is made publicly available by CMS in a searchable format, with data collected in each calendar year published the following June. Failure to submit required information may result in civil monetary penalties, with increased penalties for “knowing failures,” for each payment, transfer of value or ownership or investment interest not timely and accurately reported in an annual submission. If not preempted by this federal law, several states currently require pharmaceutical companies to report expenses relating to the marketing and promotion of pharmaceutical products and to report gifts and payments to healthcare professionals in those states. Depending on the state, legislation may prohibit various marketing-related activities, such as gift bans, or require the posting of information relating to clinical studies and their outcomes. In addition, certain states, such as California, Nevada, Connecticut and Massachusetts, require pharmaceutical companies to implement compliance programs or marketing codes of conduct and

58

Table of Contents

several other states are considering similar proposals. Manufacturers that fail to comply with these state laws can face civil penalties.

Statutory requirements to disclose publicly payments made to healthcare professionals and healthcare organizations have also been enacted in certain European Union member states. In addition, self-regulatory bodies of the pharmaceuticals industry, such as the European Federation of Pharmaceutical Industries and Associations, or EFPIA, have published codes of conduct to which its members have agreed to abide, that require the public disclosure of payments made to healthcare professionals and healthcare organizations. In some countries (including France, Denmark and Portugal) such requirements are enforceable by law.

The federal Health Insurance Portability and Accountability Act of 1996, or HIPAA, created federal criminal statutes that prohibit, among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud or to obtain, by means of false or fraudulent pretenses, representations or promises, any of the money or property owned by, or under the custody or control of, a healthcare benefit program, regardless of whether the payor is public or private, in connection with the delivery of, or payment for, healthcare benefits, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense and knowingly and willfully falsifying, concealing, or covering up by any trick or device a material fact or making any materially false statements in connection with the delivery of, or payment for, healthcare benefits, items, or services relating to healthcare matters. Additionally, the Affordable Care Act amended the intent requirement of certain of these criminal statutes under HIPAA so that a person or entity no longer needs to have actual knowledge of the statute, or the specific intent to violate it, to have committed a violation.

HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, or HITECH Act, also imposes obligations on certain entities with respect to safeguarding the privacy, security and transmission of certain individually identifiable health information, known as protected health information. Among other things, the HITECH Act and its implementing regulations make HIPAA’s security and certain privacy standards directly applicable to “business associates,” defined as persons or organizations of covered entities, other than members of the covered entity’s workforce, that create, receive, maintain or transmit protected health information on behalf of a covered entity for a function or activity regulated by HIPAA. The HITECH Act also strengthened the civil and criminal penalties that may be imposed against covered entities, business associates and individuals, and gave state attorneys general new authority to file civil actions for damages or injunctions in federal courts to enforce the federal HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions. In addition, other federal and state laws, such as the California Consumer Privacy Act, or CCPA, may regulate the privacy and security of personal information that we maintain, many of which may differ from each other in significant ways. Since the CCPA was signed into law in 2018, several other states, including Virginia, Colorado, Utah and Connecticut, have enacted similar privacy laws that may apply to personal information that we collect or maintain.

Outside of the U.S., additional privacy and data protection laws may apply to our operations. For example, the European General Data Protection Regulation, or GDPR, United Kingdom’s implementation of the GDPR and equivalent Swiss legislation may apply to some or all of the clinical or other protected data obtained, transmitted, or stored from those territories. These laws require specific, freely given and fully informed consent to be obtained from patients or clinical study participants or other lawful bases for processing. There are also other requirements for lawful processing, including transparency obligations, data minimization requirements, data transfer restrictions and compliance obligations with individuals’ stringent rights to access their personal data and to otherwise control the processing of their personal data. There are data breach notification obligations, to supervisory authorities and to individuals, where there are potential risks to them arising from the data breach. These laws impose high regulatory fines in the event of breach of processing requirements of up to 4% of global annual turnover or EUR 20 million (whichever is the higher amount). The European, UK and Swiss legislation only permits transfer of personal data to countries where there is adequate protection as determined the EC or where other mechanisms are in place such as Standard Contractual Clauses or the EU-US Data Privacy Framework.

In addition, interactions between pharmaceutical companies and physicians are also governed by industry self-regulation codes of conduct and physicians’ codes of professional conduct. In the United States, some state laws require pharmaceutical companies to comply with these industry and physician codes and the relevant compliance guidance for

59

Table of Contents

pharmaceutical manufacturers promulgated by the federal government. The provision of benefits or advantages to physicians to induce or encourage the prescription, recommendation, endorsement, purchase, supply, order or use of medicinal products is prohibited in the EU. The provision of benefits or advantages to physicians is also governed by the national laws of the EU member states, as well as codes of conduct issued by self-regulatory industry bodies. Moreover, agreements with physicians must often be the subject of prior notification and approval by the physician’s employer, their competent professional organization, and the competent authorities of the individual EU member states. These requirements are provided in the national laws, industry codes, or professional codes of conduct, applicable in the EU member states.

Any continuing efforts to modify, repeal, or otherwise invalidate all, or certain provisions of, the Affordable Care Act, could have an impact on fraud and abuse provisions and other requirements, including the Physician Payments Sunshine Act, that were authorized and enacted under the Affordable Care Act.

Human Capital Resources

As of December 31, 2023, we had 995 employees, of whom 988 were employed full-time, and 70 consultants and contractors, of whom 67 were full-time. None of our U.S. based employees are represented by labor unions or covered by collective bargaining agreements, although certain international employees are covered by collective labor agreements established under local law. We consider our relationship with our employees to be good.

We believe that our growth and success is dependent on the contributions of our employees, as led by our executive officers. We focus significant attention on attracting, retaining, engaging, and further developing talented and experienced individuals to manage and support our operations. In particular, recruiting and retaining qualified scientific, clinical, manufacturing, commercial, marketing and support personnel is critical to our success. Competition for these skilled personnel is high. We believe that our strong culture of teamwork and desire to be ever better help us attract and retain employees. Our employees complete Gallup, Inc.’s Clifton Strengths talent assessment and attend related training sessions. These tools have been implemented to help our employees identify their core strengths and learn how to use these strengths to become more engaged and productive at work as well as to lead an overall more satisfying and healthier lifestyle. Our Brazilian office was recognized as a “great place to work” by the Great Place to Work Institute in 2021, 2022 and 2023.

Based on external benchmarks, we offer employees a number of additional resources and tools to help in their personal and professional development, including career coaching, targeted leadership development for identified current and emerging leaders, internal and external development programs, professional assessment tools, a paid subscription to a digital on-demand career and management learning solutions platform and a wellness website through which employees may access information regarding scheduled healthy lifestyle activities, articles and other beneficial resources. To help newly hired employees, our global onboarding team conducts monthly surveys and focus groups and each newly hired employee is paired with a “buddy” to assist in their transition. Also, we require specialized leadership training for all employees responsible for managing others within our organization.  In 2023, we established a center of excellence for coaching and mentoring, with 65 mentorships in place as of December 31, 2023. We have delivered more than 8,800 training hours, offered 140 learning sessions to all employees, and 95 customized training sessions to teams. We have also delivered more than 150 coaching hours with internal coaches. Our executive team routinely reviews employee turnover throughout the organization to monitor employee satisfaction.

We believe that we provide a competitive total reward offering to our employees, with market competitive cash compensation, equity, and industry competitive company-paid benefits, including subsidized medical, and dental insurance and retirement plans, as well as group vision insurance, tuition reimbursement, and benefits and policies to support parental leave, mental health and wellness, family planning and child bonding. In 2023, we implemented a program that offers financial support and access to high quality fertility care and family forming benefits to our employees. Total rewards offerings are established by employee positions, skill levels, experience, knowledge, and geographic location. We also provide flexible work arrangements for our employees, including remote work options when practicable. In addition, to assist our employees during times of personal disasters that impact them and their families, we have established an employee relief program that is funded by our employees with corporate matches.

60

Table of Contents

We are committed to hiring, developing, and supporting a diverse and inclusive workplace, and continue to focus on extending our equality, diversity, and inclusion initiatives across our workforce. All of our employees are required to adhere to our Code of Business Conduct and Ethics, and all relevant country regulations which sets forth the high level of integrity, legal compliance and patient-centric focus expected of all our employees. We have a team of professionals that oversees our culture and community program. The mission of our culture and community team is to collaborate with cross functional partners and create intentional efforts to connect and engage with employees who want to find community and apply their passion to make a difference. A core element of this mission is our equality, diversity and inclusion, or ED&I, program which is managed by an ED&I professional, who routinely meets with our executive committee. Our ED&I program seeks to enable all employees to feel a sense of purpose and belonging through their connections with our internal communities. This program is guided by a steering committee comprised of senior leaders, volunteer ED&I ambassadors and representatives from our seven Employee Resource Groups, or ERGs, each of which associates with a different underrepresented community. Our ERGs meet monthly and serve to offer a safe place for our employees to have conversations about social issues, celebrate cultural observances and to grow as individuals. We believe that our ERGs and our ED&I program help our employees to better understand and celebrate each other, resulting in a more cohesive work environment.

We continue to provide opportunities for talented individuals through our global Talent Pipeline Program, or the TPP. The TPP is a global fellowship program aimed at providing recent diverse graduates real-world experience in the biopharmaceutical industry and related professions, including research, clinical, finance, commercial, marketing, compliance, quality, legal, information technology, human resources, government affairs, and communications. Participants are recruited from a global diverse group of institutions and networks and are provided mentorship, job coaching, career counseling, and leadership training for one year. Participants from the TPP are often offered full-time positions based upon our workforce needs. The TPP was originally established in 2020 to benefit students that graduated during the COVID-19 pandemic.

Our Corporate Information

Our principal executive offices are located at 100 Corporate Court, South Plainfield, New Jersey 07080. Our telephone number is (908) 222-7000. We maintain a website at www.ptcbio.com.

Additional Information

We make available, free of charge on our website, www.ptcbio.com, our annual reports on Form 10-K, quarterly reports on Form 10-Q, current reports on Form 8-K, and all amendments to those reports filed or furnished pursuant to Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, as soon as reasonably practicable after we electronically file those reports with, or furnish them to, the Securities and Exchange Commission, or SEC. We also make available, free of charge on our website, the reports filed with the SEC by our executive officers, directors and 10% stockholders pursuant to Section 16 under the Exchange Act as soon as reasonably practicable after copies of those filings are provided to us by those persons. Such reports, proxy statements and other information may be obtained through the SEC’s website (www.sec.gov). The information contained on, or that can be accessed through, our website is not a part of or incorporated by reference in this Annual Report on Form 10-K.

Item 1A.   Risk Factors

The following risk factors and other information included in this Annual Report on Form 10-K should be carefully considered. The risks and uncertainties described below are not the only ones we face. Additional risks and uncertainties not presently known to us or that we presently deem less significant may also impair our business operations. Please see page 1 of this Annual Report on Form 10-K for a discussion of some of the forward-looking statements that are qualified by these risk factors. If any of the following risks occur, our business, financial condition, results of operations and future growth prospects could be materially and adversely affected.

61

Table of Contents

Risks Related to the Development and Commercialization of our Products and our Product Candidates

We may be unable to continue to commercialize Translarna for nmDMD in the EEA if the EC adopts the negative opinion issued by the CHMP for the renewal of the existing conditional authorization for Translarna.

Our marketing authorization for Translarna for the treatment of nonsense mutation Duchenne muscular dystrophy, or nmDMD, in ambulatory patients aged two years and older in the EEA is subject to annual review and renewal by the EC following reassessment by the EMA of the benefit-risk balance of the authorization. In September 2022, we submitted a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization, which included a report on the placebo-controlled trial of Study 041 and data from the open-label extension. In February 2023, we also submitted an annual marketing authorization renewal request to the EMA. In September 2023, the CHMP gave a negative opinion on the conversion of the conditional marketing authorization to full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of Translarna for the treatment of nmDMD. On January 25, 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In accordance with EMA regulations, the EC has 67 days to adopt the opinion. If the EC adopts the negative opinion, Translarna would no longer have marketing authorization in the member states of the EEA.

Given the negative opinion from the CHMP, we believe that it is likely that the EC will refuse to renew the marketing authorization for Translarna. While we are exploring other potential mechanisms in which we may provide Translarna to nmDMD patients in the EEA, we may be unable to identify processes that are both possible within the regulatory frameworks of individual EEA countries and commercially viable. As such, there is substantial risk to our ability to maintain our conditional marketing authorization in the EEA and our ability to commercialize Translarna for the treatment of nmDMD in the EEA. If we are unable to renew our conditional marketing authorization in the EEA or we are unable to identify other potential mechanisms in which we may provide Translarna to nmDMD patients in the EEA, we would lose all, or a significant portion of, our ability to generate revenue from sales of Translarna in the EEA, which would have a material adverse effect on our business, results of operations and financial condition.

Additionally, the CHMP’s negative opinion for Translarna and potential loss of the Translarna marketing authorization in the EEA may influence regulatory entities in other jurisdictions in which Translarna has been approved to reassess such approvals. For example, certain countries reference or depend on the determination by the EMA when considering the grant of a marketing authorization. There is substantial risk that we would be unable to maintain our marketing authorizations in these countries in the event the EC decides not to renew or otherwise varies, suspends or withdraws our marketing authorization in the EEA. Even in countries where our marketing authorization is maintained, there may be an impact on pricing and reimbursement of Translarna within those countries. Any potential reassessments or scheduled renewals of our marketing authorizations or impacts to pricing and reimbursement may lead to additional regulatory costs, requirements to complete additional clinical trials, restrictions on or removal of our marketing authorizations or loss of a significant portion of our revenue for Translarna in other jurisdictions, which could have a material adverse effect on our business, results of operations and financial condition.

​

If we are unable to continue to execute our commercial strategy for our products, fail to obtain renewal of, or satisfy the conditions of our marketing authorization for our products, or if we experience significant delays in accomplishing such goals, our business will be materially harmed.

We have invested a significant portion of our efforts and financial resources to bring our products to market through research and development, collaborations and acquisitions. Our ability to continue to generate product revenues will depend heavily on the successful commercialization of our products.

If we do not successfully maintain our marketing authorizations for our products and obtain new marketing authorizations for our product candidates and new uses of our approved products, our ability to generate additional revenue will be jeopardized and, consequently, our business will be materially harmed. Additionally, our ability to make our licensed

62

Table of Contents

products available within the relevant territories is largely dependent upon the maintenance of the marketing authorizations by the licensor. The success of our products will depend on a number of additional factors, including the following:

​

If we do not achieve one or more of these factors in a timely manner or at all, we could experience significant delays or an inability to continue to commercialize our products, either of which would have a material adverse effect on our business, results of operations and financial condition.

63

Table of Contents

Delays or failures in obtaining regulatory approval would prevent us from commercializing our product candidates in the applicable territory and our ability to generate revenue will be materially impaired. Moreover, should we need to conduct additional development work, other than those we have planned, we expect to incur significant costs, which may have a material adverse effect on our business and results of operations.

There is significant risk that we will be unable to obtain approval for our product candidates on a timely basis or at all, and we may be required to perform additional clinical trials, non-clinical studies or CMC assessments or analyses at significant cost. Product development is expensive, difficult to design and implement, can take many years to complete and is uncertain as to outcome. This is especially true for rare and/or complicated diseases. A failure of one or more clinical or preclinical trials, or manufacturing development can occur at any stage. Preclinical and clinical studies may also reveal unfavorable product candidate characteristics, including safety concerns, or may not demonstrate product candidate efficacy. There can be significant variability in results between different clinical trials of the same product candidate due to numerous factors. The outcome of preclinical testing and early clinical trials may not be predictive of the success of later clinical trials, and interim results of a clinical trial do not necessarily predict final results. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing authorization of their products.

The approval process is also subject to the substantial discretion of regulatory authorities and the approval procedures vary among countries, can involve additional testing, and the time for approval may materially differ and be subject to administrative delays that we cannot control. Approval by the FDA does not ensure approval by regulatory authorities in other countries or jurisdictions, and approval by one regulatory authority outside the United States does not ensure approval by regulatory authorities in other countries or jurisdictions or by the FDA. However, the failure to obtain approval in one jurisdiction may compromise our ability to obtain approval elsewhere.

In response to changes in the regulatory environment or requests from regulators, we may elect, or be obliged, to postpone a regulatory submission to include additional analyses, which could cause delays in getting our products to market and substantially increase our costs. Securing marketing authorization also requires the submission of information about the product manufacturing process to, and inspection or conduct of remote regulatory assessments of manufacturing facilities by, the regulatory authorities. Changes to manufacturers, product candidate formulation, manufacturing processes and other product candidate attributes, such as the method of delivery, during product candidate development may also require additional studies to demonstrate the comparability of the product candidate using prior processes, formulation, or manufacturers, or with the prior attributes, to the product candidate using new the processes, formulation, or manufacturers, or with the new attributes.

For example, we have been seeking FDA approval for Translarna for nmDMD with the FDA since 2010 and the FDA has repeatedly disagreed with our interpretation of our results. In October 2017, the Office of Drug Evaluation I of the FDA issued a Complete Response Letter for the NDA, stating that it was unable to approve the application in its current form. In response, we filed a formal dispute resolution request with the Office of New Drugs of the FDA. In February 2018, the Office of New Drugs of the FDA denied our appeal of the Complete Response Letter. In its response, the Office of New Drugs recommended a possible path forward for the ataluren NDA submission based on the accelerated approval pathway. This would involve a re-submission of an NDA containing the current data on effectiveness of ataluren with new data to be generated on dystrophin production in nmDMD patients’ muscles. We followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that we designed, such dystrophin data in a new study, Study 045, and announced the results of Study 045 in February 2021. Study 045 did not meet its pre-specified primary endpoint. In June 2022, we announced top-line results from the placebo-controlled trial of Study 041. Following this announcement, we submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential re-submission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support NDA re-submission. We held a Type C meeting with the FDA in the fourth quarter of 2023 to discuss the totality of Translarna data. Based on this discussion, the FDA suggested we request a pre-submission Type C meeting to discuss the specific contents of an NDA resubmission based on results from Study 041 and from our international drug registry study for nmDMD patients receiving Translarna. This meeting is scheduled for March 2024.

64

Table of Contents

With respect to Upstaza, in a late 2019 interaction with the FDA, the FDA requested additional information concerning the use of the commercial delivery system for Upstaza in young patients. In response to the FDA’s request, we provided additional information concerning the use of the commercial cannula for Upstaza in young patients. In October 2022, we held a Type C meeting with the FDA to discuss the details of a potential submission package for Upstaza. At that meeting, the FDA asked for additional bioanalytical data in support of comparability between the drug product used in the clinical studies and the commercial drug product. We completed these analyses and provided the results to the FDA for review. The FDA stated that the data that we provided were still not sufficient. However, the FDA also said that the available data from the ongoing clinical study in the United States assessing the safety of the drug delivery cannula for Upstaza could be used to support a BLA for accelerated approval based on biomarker data demonstrating a treatment-related increase in de novo dopamine production. At the FDA’s suggestion, we held a pre-BLA meeting in December 2023. We expect to submit a BLA to the FDA for Upstaza for the treatment of AADC deficiency in March 2024.

There is no guarantee that we will be able to achieve our milestones at all or within our anticipated timeframes, or that regulators may have additional questions to which we will need to respond.  There is also substantial risk that the results of our future or current studies will not ultimately support the approval of a product candidate. Regulators may also request additional studies, data and information, that we may need to develop and which were not originally planned for. Any delays in obtaining regulatory approval, or if we never obtain regulatory approval, could have a material adverse effect on our business, financial condition and results of operations.

We may use certain specialized pathways to develop our product candidates or to seek approval.  We may not qualify for these pathways or such pathways may not ultimately speed the time to approval or result in product candidate approval.

In the United States, we may pursue the accelerated approval pathway for certain of our product candidates, such as Translarna. However, the FDA may find that our product candidates do not qualify for accelerated approval. Moreover, even if we do ultimately receive accelerated approval, we would need to meet certain post approval requirements, such as completing a post-approval study confirming our product candidates’ clinical benefit that may require substantial time, effort, and funds.  The FDA must specify the conditions for the required post approval studies, including enrollment targets, the study protocol, milestones, and target completion dates, by the time of approval and the FDA may require that the post-approval studies be commenced before the date of approval.  If this study does not confirm the product’s clinical benefit or if the study is not conducted in accordance with the FDA’s requirements, it would be subject to the risk of expedited FDA withdrawal. Additional regulatory requirements also include the pre-submission of promotional materials to the FDA and potential restrictions, such as distribution restrictions, to assure the product’s safe use. In recent years, the accelerated approval pathway has come under significant FDA and public scrutiny.  Accordingly, depending on the results of our studies, the FDA may be more conservative in granting accelerated approval or, if granted, may be more apt to withdrawal approval if clinical benefit is not confirmed.  Due to these and other uncertainties, we are unable to estimate the timing or potential for product candidates for which we may use the accelerated approval pathway or the cost or effort required to receive FDA approval. Further, even if we receive accelerated approval, there is no guarantee that we would be able to maintain such approval.

If we or our collaborators experience any of a number of possible unforeseen events in connection with clinical trials related to our products or our product candidates, maintenance of our existing marketing authorization for our products and any additional potential marketing authorization or commercialization of our products or our product candidates could be delayed or prevented.

We or our collaborators may experience numerous unforeseen events during, or as a result of, clinical trials that could delay or prevent our ability to receive marketing authorization or commercialize our products or our product candidates, including:

65

Table of Contents

​

66

Table of Contents

These risks may be increased for product candidates intended for the treatment of diseases for which there is little clinical experience, where we are using new endpoints or methodologies, or where the product candidates are new or novel.  For example, there are no marketed therapies approved to treat the underlying cause of nmDMD and there is limited clinical trial experience with respect to drugs to treat nmDMD and other diseases that we are studying or have studied. As a result, the design and conduct of clinical trials for these diseases, particularly for drugs to address the underlying nonsense mutations causing these diseases in some subsets of patients, is subject to increased risk.  Furthermore, the regulatory requirements regarding gene therapies are continually evolving and regulatory authorities have only approved a limited number of gene therapies.  Moreover, because gene therapy products are a relatively new development, less is known about such products and product candidates and, accordingly there is an increased risk that such products may not perform as expected. Regulatory review agencies and the requirements and guidelines they promulgate may lengthen the regulatory review process, require us to perform additional or larger studies, increase our development costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and commercialization of our product candidates or lead to significant post-approval studies, limitations or restrictions.

We may also experience increased risks to the extent that product candidates require a specialized delivery device or method.  For example, Upstaza is administered directly to the putamen in the brain using stereotactic surgery, a brain surgery requiring significant skill and training. There is little experience with such surgeries being used to deliver drugs and for such surgeries being performed on children. We may need to train sufficient brain surgeons to perform the procedure properly, which may expose us to additional regulatory risks as our interactions with such healthcare providers must comply with all applicable laws and regulations. As a result, we will need to invest significant resources to ensure all personnel and contractors are adequately trained on these requirements and to monitor their conduct. Delivery of Upstaza to the putamen also requires certain medical devices, which may result in our product candidate being deemed to be a combination product by the FDA, requiring compliance with the FDA’s device regulations and collaboration with medical device manufacturers.

Our product development costs will increase if we experience delays in testing or marketing authorizations, and we may not have sufficient funding to complete the testing and approval process for any of our product candidates. We may be required to obtain additional funds to complete clinical trials and prepare for possible commercialization of our products and product candidates. We do not know whether any preclinical tests or clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. Significant preclinical or clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our products or our product candidates and allow our competitors to bring products to market before we do or impair our ability to successfully commercialize our products or our product candidates, and so may harm our business, results of operations and financial condition.

Subgroup, retrospective, post-hoc, and certain statistical analyses may not be reliable and typically will not form the basis for regulatory approval.

In the event that a study’s primary endpoint is not met, companies may undertake certain analyses to further understand the data and potential reasons for the study results, including retrospective, post-hoc, and subgroup analyses.  Because these analyses are not pre-planned and studies may not be adequately designed for these analyses, they may not be reliable and typically will not form the basis for regulatory approval.  For example, after determining that we did not achieve the primary efficacy endpoint with the pre-specified level of statistical significance in our completed ACT DMD and Phase 2b clinical trials of Translarna for the treatment of nmDMD, we performed subgroup, retrospective, and meta-analyses. We submitted these analyses to the FDA as part of our NDA, taking the position that the totality of clinical data from these trials support the clinical benefit of Translarna for the treatment of nmDMD. The FDA, however, did not agree that these analyses supported approval.

Some of our favorable statistical data from these trials also are based on nominal p-values.  Nominal p-values are subject to certain limitations, and which, because of these limitations, regulatory authorities typically give less weight to nominal p-values, compared to regular p-values. For example, the p-values in ACT DMD for change from baseline at week 48 in the 6-minute walk test, or 6MWT (which we also refer to as 6-minute walk distance, or 6MWD) and each secondary end point timed function test were nominal p-values.  The FDA found that certain post-hoc adjustments, our retrospective analyses and our reliance on nominal p-values for some of our statistical data did not support approval.

67

Table of Contents

An unfavorable view of our data and analyses by regulatory authorities has and could continue to negatively impact our ability to obtain or maintain marketing authorizations, which would have a material adverse effect on our revenue and would materially harm our business, financial results and results of operations.

If we experience delays or difficulties in the enrollment of patients in our clinical trials, our receipt of necessary regulatory approvals could be delayed or prevented.

We may not be able to initiate or continue clinical trials for our product candidates, including clinical trials due to the inability to enroll a sufficient number of patients.  Patient enrollment is affected a number of factors including:

For example, we previously experienced delays in 2021 and 2022 enrolling a Phase 2/3 trial of vatiquinone in children with mitochondrial disease associated seizures as some patients were unable or hesitant to travel to clinical trial sites due to the COVID-19 pandemic.

Enrollment delays in our clinical trials may result in increased development costs for our product candidates. Our inability to enroll, timely or at all, a sufficient number of patients in our clinical trials would result in significant delays or may require us to abandon one or more clinical trials altogether.

If serious adverse side effects are identified during the development of any product candidate or for any product for which we have or may obtain marketing approval, we may need to abandon or limit our development and/or marketing of that product or product candidate.

If our products or our product candidates are associated with undesirable side effects or have characteristics that are unexpected, regulatory authorities, institutional review boards, institutional biosafety committees, or independent ethics committees may place our studies on clinical hold, withdraw or suspend study approvals, or require that we modify our protocols. We may also need to abandon their development or limit development to certain uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a benefit-risk perspective. Adverse events or side effects may also result in study recruitment challenges, marketing authorization denial, limitations on the indicated use of a product, the inclusion of warnings, contraindications, or precautions on the label of any approved products, or significant conditions imposed on any approval, including the requirement of a risk evaluation and mitigation strategies, or REMS, costly post-marketing studies or clinical trials and surveillance to monitor the safety of the product.  Adverse effects may also prevent the adoption of a product, if it is approved. Many compounds that initially showed promise in clinical or earlier stage testing have later been found to cause side effects that prevented further development of the compound. Furthermore, we may be sued and held liable for harm caused by our products to patients as a result of the identification of undesirable side effects, which may cause reputational harm.

For example, although we did not observe a pattern of liver enzyme elevations in our Phase 2 or Phase 3 clinical trials of Translarna, we did observe modest elevations of liver enzymes in some subjects in one of our Phase 1 clinical trials. These elevated enzyme levels did not require cessation of Translarna administration, and enzyme levels typically normalized

68

Table of Contents

after completion of the treatment phase. We did not observe any increases in bilirubin, which can be associated with serious harm to the liver, in the Phase 1 clinical trial.

In addition, in Study 009, our first Phase 3 clinical trial of Translarna for the treatment of nmCF, five adverse events in the Translarna arm of the trial that involved the renal system led to discontinuation. As compared to the placebo group, the Translarna treatment arm also had a higher incidence of adverse events of creatinine elevations, which can be an indication of impaired kidney function. In the Translarna treatment arm, more severe clinically meaningful creatinine elevations were reported in conjunction with cystic fibrosis pulmonary exacerbations. These creatinine elevations were associated with concomitant treatment with antibiotics associated with impaired kidney functions, such as aminoglycosides or vancomycin. This led to the subsequent prohibition of concomitant use of Translarna and these antibiotics, which was successful in addressing this issue in the clinical trial.

The risk of finding adverse side effects may be particularly heightened in the case of gene therapies.  For instance, new gene copies may produce too much or too little of the desired protein or RNA, or the production of the desired protein or RNA may change over time. Because the treatment is irreversible, there may be challenges in managing side effects. Adverse effects would not be able to be reversed or relieved by stopping dosing and might require us to develop additional clinical safety procedures. Furthermore, new gene copies may disrupt other normal biological molecules and processes. Adverse side effects may also be experienced by patients as a result of the process for administering the therapy or related procedures.

There have been several significant adverse side effects in gene therapy treatments in the past, including reported cases of leukemia, immune- and complement-mediated responses, and death seen in other trials using other vectors. While new recombinant vectors have been developed to potentially reduce these side effects, gene therapy is still a relatively new approach to disease treatment and additional adverse side effects could develop. For instance, possible adverse side effects that could occur include an immunologic or complement-mediated reactions early after administration which, could substantially limit the effectiveness of the treatment. Depending on the vector, additional manufacturing, clinical, and preclinical testing may be required, as well as additional analyses, assessments, and potential long-term patient and clinical study subject monitoring and sample testing and associated regulatory reporting. Serious adverse events in our clinical trials, or other clinical trials involving gene therapy products or our competitors’ products, even if not ultimately attributable to the relevant product candidates, and the resulting publicity, could further adversely impact our product candidates in the form of increased government regulation, unfavorable public perception, potential regulatory delays, stricter labeling requirements, and a decrease in demand.

If, following approval, we or others identify previously unknown side effects, if such side-effects are severe, or if known side effects are more frequent or severe than in the past then our marketing authorizations may be restricted or withdrawn, changes may be required to the product’s label, sales may be adversely impacted, we may be required to undertake additional studies or trials, and government investigations or litigation, including product liability claims, may be brought against us. Additionally, if the safety warnings in our product labels are not followed, adverse medical situations in patients may arise, resulting in negative publicity and potential lawsuits. Any of these occurrences would limit or prevent us from commercializing our products, which would have a material adverse effect on our business, financial results and operations.

Certain of our products and product candidates may be difficult to produce, presenting manufacturing challenges that may delay product development and regulatory approval.

Manufacturers of pharmaceutical products must comply with strictly enforced manufacturing and quality requirements, including cGMP requirements, state and federal regulations, as well as ex-U.S. requirements when applicable.  These may be particularly difficult to meet for complex products such as biologic and gene therapy products.  Any failure to meet the applicable manufacturing and quality requirements could lead to a delay or interruption in development programs, delays in receiving regulatory approval, and consequences should we receive marketing approval.  

The manufacture of biologic and gene therapy products is technically complex, requires extreme precision to meet specification requirements and necessitates substantial expertise and capital investment. Production difficulties caused by unforeseen events, even if seemingly minimal, may delay the availability of material for clinical studies and commercial

69

Table of Contents

product. For example, given the nature of biologics manufacturing, there is a risk of contamination. Any contamination could materially adversely affect our ability to produce our gene therapy product candidates on schedule and could, therefore, harm our results of operations and cause reputational damage.

In addition, gene therapy products have only in limited cases been manufactured at scales sufficient for pivotal trials and commercialization. Few pharmaceutical contract manufacturers specialize in gene therapy products and those that do are still developing appropriate processes, controls and facilities for large-scale production. While we believe that there are alternative sources of supply that can satisfy our clinical and commercial requirements for Upstaza, we cannot be certain that we will be able to identify and establish relationships with such sources, if necessary, in a timely manner or at all, and what the terms and costs of such new arrangements would be, or that such alternative suppliers would be able to supply our potential commercial needs. To the extent that we decide to manufacture our own clinical and commercial supply of Upstaza as an alternative source of supply, there is no guarantee that we will be able to cost effectively produce sufficient quantities of our program material. Any switch from our current manufacturer would result in a significant delay, would require regulatory authority approval, and cause material additional costs.

Furthermore, some of the raw materials and other components required in our manufacturing process are derived from diverse biologic sources that may be difficult to procure and may be subject to contamination or recall. Any material shortage, supply chain disruption, contamination recall or restriction on the use of biologically derived substances in the manufacture of our product candidates could adversely impact or disrupt the production and commercialization of products.  

We have manufacturing services related to the production of plasmid DNA and AAV vectors for gene therapy applications for external customers at our Hopewell Facility. We have limited experience producing plasmid DNA and AAV vectors for third party customers. If we are unable to manufacture these product materials to the required specifications and regulatory requirements for the third parties we contract with, our business, financial condition, and results of operations could be materially adversely affected and we may become subject to regulatory or contractual actions, may need to expend significant time and costs to remedy issues, and we may forgo sales, incur liabilities or lose customers, which would materially adversely affect our business, financial condition and results of operations.

Finally, we and our third party manufacturers may experience any number of unforeseen issues, unforeseen delays, including equipment failure, labor shortages, natural disasters, power failures, transportation difficulties, quality control or other issues, including those resulting from compliance with regulatory requirements, as further described in these risks, that could prevent us from realizing the intended benefits of our manufacturing strategy.

​

Any of our products or any other product candidate that receives marketing authorization may fail to achieve the degree of market acceptance by physicians, patients, third-party payors and others in the medical community necessary for commercial success.

Even if we are successful in obtaining and maintaining marketing authorizations, our products may not gain sufficient market acceptance by physicians, patients, third-party payors and others in the medical community. Third-party payors may require prior authorizations or failure on another type of treatment before covering a particular drug, particularly with respect to higher-priced drugs. Decreases in third-party reimbursement for a product or a decision by a third-party payor to not cover a product could reduce physician usage of the product. If these products do not achieve an adequate level of acceptance, we may not generate significant product revenues or any profits from operations.

The degree of market acceptance of our products or product candidates, if approved for commercial sale, will depend on a number of factors, including:

70

Table of Contents

Obtaining coverage and reimbursement for a product from third-party payers is a time-consuming and costly process.  Failure to obtain adequate reimbursement may significantly impact the adoption and sale of products.  Market acceptance and obtaining reimbursement coverage may be particularly challenging in the case of gene therapies, where the cost of a single administration may be substantial and adequate coverage and reimbursement will be essential for patients to afford the treatment. Payors may require us to provide supporting scientific, clinical and cost-effectiveness data, which we may not be able to provide. Moreover, ethical, social and legal concerns about certain treatments, such as gene therapy, could result in additional regulations restricting or prohibiting sale of our products.

In the United States, third-party payers, including government payers such as the Medicare and Medicaid programs, play an important role in determining the extent to which new drugs and biologics will be covered and reimbursed. Expensive specialty drugs in particular are often subject to restriction. The Medicare and Medicaid programs increasingly are used as models for how private payers and government payers develop their coverage and reimbursement policies. We cannot be assured that Medicare or Medicaid will cover our product candidates that may be approved or provide reimbursement without restriction and at adequate levels to realize a sufficient return on our investment. Our rebate payments may increase or our prices be adjusted under value-based purchasing arrangements based on evidence-based measures or outcomes-based measures for a patient or beneficiary based on use of our drug. Moreover, reimbursement agencies in the EU may be more conservative than CMS. It is difficult to predict what third-party payers will decide with respect to the coverage and reimbursement for our products for which we obtain marketing approval. Additionally, within Europe, each country has its own reimbursement regime employing various health technology assessment approaches to assess the cost-effectiveness of the product (for example, in the United Kingdom a HTA assessment is conducted by NICE) which may significantly affect the effective access to the market.

Our ability to negotiate, secure and maintain third-party coverage and reimbursement may also be affected by political, economic and regulatory developments. Governments continue to impose cost containment measures, and third-party payors are increasingly challenging prices charged for medicines and examining their cost effectiveness, in addition to their safety and efficacy. These and other similar developments could significantly limit the degree of market acceptance of our products or any of our other product candidates that receive marketing authorization.

If we are unable to establish or maintain sales, marketing and distribution capabilities or enter into agreements with third parties to market, sell and distribute our products or product candidates, we may not be successful in our continuing efforts to commercialize our products or any other product candidate if and when they are approved.

Our ongoing commercial strategy for our products and any other product candidate that may receive marketing authorization involves the development of a commercial infrastructure that spans multiple jurisdictions and is heavily dependent upon our ability to continue to build an infrastructure that is capable of implementing our global commercial strategy. The establishment and development of our commercial infrastructure will continue to be expensive and time consuming, and we may not be able to develop our commercial organizations in all intended territories, including in the United States, in a timely manner or at all. Doing so will require a high degree of coordination and compliance with laws and regulations in numerous territories, including restrictions on advertising practices, enforcement of intellectual property

71

Table of Contents

rights, restrictions on pricing or discounts, transparency laws and regulations, and unexpected changes in regulatory requirements and tariffs. If we are unable to effectively coordinate such activities or comply with such laws and regulations, our ability to commercialize our products or any other product candidates that may receive marketing authorization will be adversely affected. If we are unable to establish and maintain adequate sales, marketing and distribution capabilities, whether independently or with third parties, we may not be able to generate product revenue consistent with our expectations and may not become profitable.

There are risks involved with establishing our own sales and marketing capabilities and entering into arrangements with third parties to perform these services. For example, recruiting and training an internal commercial team is expensive and time consuming and could delay commercialization efforts. If a commercial launch for any product or product candidate for which we recruit a commercial team and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition such personnel.

The arrangements that we have entered into, or may enter into, with third parties to perform sales and marketing services will generate lower product revenues or profitability of product revenues to us than if we were to market and sell any products that we develop ourselves. In addition, we may not be successful in entering into arrangements with third parties to sell and market our product candidates or may be unable to do so on terms that are favorable to us. We have little control over such third parties, and any of them may fail to devote the necessary resources and attention to sell and market our products effectively.

If we do not establish sales and marketing capabilities successfully, either on our own or in collaboration with third parties, we will not be successful in commercializing our products or product candidates.  Factors that may materially affect our efforts to commercialize our products include:

Any of these factors, individually or as a group, if not resolved in a favorable manner may have a material adverse effect on our business and results of operations. Similar risks apply in those territories where any of our products are available on a reimbursed basis under an EAP program.

72

Table of Contents

A substantial portion of our commercial sales currently occurs in territories outside of the United States which subjects us to additional business risks that could adversely affect our revenue and results of operations.

We commercialize Translarna, Upstaza, Tegsedi and Waylivra outside of the United States. We have operations in multiple European countries, Latin America and other territories. We expect that we will continue to expand our international operations in the future, including in emerging growth markets, pending successful completion of the applicable regulatory processes. International operations inherently subject us to a number of risks and uncertainties, including:

For example, the Brazilian Ministry of Health has previously experienced significant administrative delays processing centralized group purchase orders. Almost all of our product revenue for Translarna in Brazil is attributable to such purchase orders. These centralized group purchase order delays have caused, and may continue to cause, fluctuations in our ability to generate revenue in Brazil.

In addition, some countries in which a product candidate is not approved allow patients access to the product candidate through other legal mechanisms, including court intervention or EAP programs, if the product is approved in another jurisdiction. The price that is ultimately approved by governmental authorities in any country pursuant to commercial pricing and reimbursement processes may be significantly lower than the price we are able to charge for sales under such legal mechanisms and we may become obligated to repay such excess amount.

Some of the countries in which our products are available for sale are in emerging markets. Some countries within emerging markets, including those in Latin America, may be especially vulnerable to periods of global or regional financial instability or may have very limited resources to spend on. We also may be required to increase our reliance on third-party agents within less developed markets. In addition, many emerging market countries have currencies that fluctuate substantially and if such currencies devalue and we cannot offset the devaluations, our financial performance within such countries could be adversely affected.

Furthermore, in some countries, including Brazil and Russia, orders for named patient sales may be for multiple months of therapy, which can lead to an unevenness in orders which could result in significant fluctuations in quarterly net product sales. Other factors may also contribute to fluctuations in quarterly net product sales including a product’s availability in any particular territory, government actions, economic pressures, political unrest and other factors. Net product sales are impacted by factors such as the timing of decisions by regulatory authorities and our ability to successfully negotiate favorable pricing and reimbursement processes on a timely basis in the countries in which we have or may obtain regulatory approval, including the United States, EEA and other territories.

73

Table of Contents

Any of these factors may, individually or as a group, have a material adverse effect on our business and results of operations. As we continue to expand our existing international operations, we may encounter new risks.

Laws and regulations governing export restrictions and economic sanctions may preclude us from developing and selling certain products, generating revenue from such products, and manufacturing certain materials outside of the United States.

Many countries, including the United States, restrict the export or import of products to or from certain countries through, for example, bans, sanction programs, and boycotts. Such restrictions may preclude us from supplying products or generating revenue in certain countries or may require an export license prior to the export of the controlled item. Various laws, regulations and executive orders also restrict the use and dissemination outside of the United States, or the sharing with certain non-U.S. nationals, of information classified for national security purposes, as well as certain products and technical data relating to those products. Furthermore, if we, or third parties acting on our behalf, do not comply with these restrictions, we may be subject to substantial civil and criminal penalties and suspension or debarment from government contracting.

Our activities outside of the United States, require that we dedicate resources to comply with these laws. Many of our customers and suppliers are ex-U.S. entities or have significant ex-U.S. operations. Although these restrictions have not affected our operations in the past, there is a risk that they could do so in the future as additional geographic regions and entities may become subject to such restrictions. The imposition of new or additional economic and trade sanctions against our major customers or suppliers or financial counterparties or intermediaries could result in our inability to sell to, and generate revenue from such customers or purchase materials from such suppliers. For example, we make sales of Translarna through a distributor to the Ministry of Health of the Russian Federation to access Russian nmDMD patients. Our ability to generate and realize revenue in Russia may be materially and adversely impacted as many countries, including the United States, have imposed and may continue to consider imposing additional enhanced export controls on certain products and sanctions on certain industry sectors and parties in Russia in connection with the Russia-Ukraine conflict. We also contract with government-owned hospitals and third-party manufacturers located in China, which has recently been involved in political conflict with the United States. This conflict has increased the likelihood of restrictions that could materially and adversely affect our clinical trial sites located in China, our ability to obtain certain supplies, our ability to manufacture certain product candidates and our ability to potentially commercialize products in China. If our activities are affected because of these or other such restrictions, sanctions, or controls, our business, financial condition and results of operations could be materially and adversely affected. As a result of restrictive export laws, our customers may also seek to obtain a greater supply of similar or substitute products from our competitors that are not subject to these restrictions, which could materially and adversely affect our business, financial condition and results of operations.

We face substantial competition, which may result in others discovering, developing or commercializing products before or more successfully than we do.

The development and commercialization of new drug products is highly competitive. We face competition with respect to our current products and product candidates and any products we may seek to develop or commercialize in the future from major pharmaceutical companies, specialty pharmaceutical companies, and biotechnology companies worldwide. Other gene therapy companies may in the future decide to utilize existing technologies to address unmet needs that could potentially compete with our product candidates.

There is currently no marketed therapy for nmDMD, other than Translarna in the EEA. Santhera Pharmaceuticals has received approval of Agramee (vamorolone) in the United States for DMD patients ages 2 and up and in the EU and United Kingdom for patients ages 4 years and older. Sarepta Therapeutics has received approval of Elevidys for DMD patients 4 to 5 years of age with a confirmed mutation in the “DMD gene” in the United States (Accelerated Approval granted with Full Approval pending) and United Arab Emirates and Qatar. Sarepta Therapeutics has also received approval in the United States for two treatments (Exondys 51 (eteplirsen) and Vyondys 53 (golodirsen)) addressing the underlying cause of disease for different mutations in the DMD gene. Additionally, the FDA granted accelerated approval to Viltepso (viltolarsen) from NS Pharma for the treatment of DMD in patients with exon 53 skipping and Sarepta (Casimersen (SRP 4045) for the treatment of DMD in patients with exon 45 skipping. Viltepso (viltolarsen) from NS Pharma is also approved in Japan. Other biopharmaceutical companies are developing treatments addressing the underlying cause of disease for

74

Table of Contents

different mutations in the DMD gene, including, Dyne Therapeutics (DYNE-251), Wave Life Sciences (WVE-N53), Daiichi Sankyo (DS 5141)), Nippon Shinyaku (Viltolarsen (NS 065/NCNP 01) and NS 089/NCNP 02)), and Astellas (AT 702). Additionally, other pharmaceutical companies are developing micro dystrophin gene therapies for patients with DMD regardless of genotype, including Pfizer (PF 06939926) and Solid Biosciences (SGT 001).

Although the FDA has not approved a corticosteroid specifically for DMD in the United States other than Emflaza, we face competition in the United States in the DMD market from prednisone/prednisolone, which, while not approved for DMD in the United States, is generically available and has been prescribed off label for DMD patients. Santhera has received approval of Agramee (vamorolone), in the United States for DMD patients ages 2 and up and in the European Union and United Kingdom for patients ages 4 years and older. With the expiration of Emflaza’s orphan exclusivity for treatment of DMD in patients five years and older in February 2024, we expect to face competition from generic versions of Emflaza for this indication.

Currently, no other treatment options are available for the underlying cause of AADC deficiency. Additionally, we are not aware of any late-stage development product candidates for AADC deficiency.

There are several pharmaceutical and biotechnology companies engaged in the development or commercialization of products against targets that are also targets of Tegsedi and Waylivra. For example, Ionis is developing Olezarsen for the treatment of FCS. Additionally, Waylivra faces competition from Myalept (metreleptin) produced by Chesi Farmaceutica, Inc., which is currently approved in Brazil for use in generalized lipodystrophy patients. Tegsedi faces competition from drugs like Onpattro (patisiran) which was launched by Alnylam Pharmaceuticals in the United States in 2018 and received approval in Brazil for the treatment of hATTR amyloidosis in 2020 as was well as AMVUTTRA (vutrisiran) which Alnylam Pharmaceuticals received approval for in the United States and Brazil in 2022 for the treatment of the polyneuropathy of hATTR amyloidosis in adults. Vyndaqel (tafamids meglumine) and Vyndamax (tafamidis) are commercialized in the United States, EU and some countries in Latin America by Pfizer. Other companies are also pursuing product candidates for the treatment of ATTR Amyloidosis with polyneuropathy including BridgeBio Pharma (AG 10), Intellia Therapeutics (NTLA2001), Proclara Biosciences (NPT 189) and SOM Biotech (tolcapone). For Waylivra, Ionis is developing Olezarsen for the treatment of FCS. Waylivra also faces competition from Myalept, (metreleptin) produced by Cheisi Farmaceutica, Inc., currently approved in Brazil for use in generalized lipodystrophy patients.

Evrysdi, an orally bioavailable treatment, faces competition from treatments that are not orally bioavailable, including Spinraza (nusinersen), a drug developed by Ionis and marketed by Biogen, which is approved to treat SMA and Zolgensma (onasemnogene abeparvovec), a gene therapy drug developed by AveXis, Inc., (acquired by Novartis in 2018), which is approved in the United States and Japan for the treatment of SMA in patients under 2 years of age and in Europe for babies and young children who weigh up to 21 kilograms. Novartis is also developing OAV-101, an intrathecal administration of Zolgensma, for SMA patients ages ≥ 2 to < 18 years of age. Biogen is developing a higher dose regimen of nusinersen with potential for improved efficacy and evaluating an implantable medical device to enable subcutaneous delivery of nusinersen. Other companies are also pursuing product candidates for the treatment of SMA, including Scholar Rock (apitegromab, SRK-015), Biohaven (Taldefgrobep alfa), Roche Pharmaceuticals (RO-7204239/GYM-329), Biogen / Ionis (BIIB-115/ION-306) and NMD Pharma (NMD-670).

For additional discussion regarding the competition we face with respect to our current product candidates, see “Item 1. Business-Competition.”

Our competitors may develop products that are more effective, safer, more convenient or less costly than any that we are marketing or developing or that would render our products or product candidates obsolete or non-competitive. Our competitors may also obtain marketing authorization for their products more rapidly than we may obtain approval for our products and product candidates, which could result in our competitors establishing a strong market position before we are able to enter the market.

We believe that many competitors are attempting to develop therapeutics for the target indications of our products and product candidates, including academic institutions, government agencies, public and private research organizations, large pharmaceutical companies and smaller more focused companies.

75

Table of Contents

Many of our competitors may have significantly greater financial resources and expertise in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approvals and marketing approved products than we do. Mergers and acquisitions in the pharmaceutical and biotechnology industries may result in even more resources being concentrated among a smaller number of our competitors. Smaller and other early stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. These third parties compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical trial sites and patient registration for clinical trials, as well as in acquiring technologies complementary to or necessary for our programs.

Our products or product candidates may become subject to unfavorable pricing regulations, third-party reimbursement practices or healthcare reform initiatives, which would harm our business.

We may not obtain adequate coverage or reimbursement for our products, or we may be required to sell our products at an unsatisfactory price. In addition, obtaining pricing, coverage and reimbursement approvals can be a time consuming and expensive process. Our business would be materially adversely affected if we do not receive these approvals on a timely basis.

The regulations and practices that govern marketing authorizations, pricing, coverage and reimbursement for new drug products vary widely from country to country. Current and future legislation may significantly change the approval requirements in ways that could involve additional costs and cause delays in obtaining approvals. Some countries, including almost all of the member states of the EEA, require approval of the sale (list) price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In some ex-U.S. markets, including the European market, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we might obtain marketing authorization for a product in a particular country, but then be subject to price regulations, in some countries at national as well as regional levels, that delay our commercial launch of the product, possibly for lengthy time periods, and negatively impact the revenues we are able to generate from the sale of the product in that country. Adverse pricing limitations may hinder our ability to recoup our investment in one or more products or other product candidates, even following marketing authorization.

Our ability to successfully commercialize our products or product candidates that may receive marketing authorization will depend in large part on the extent to which coverage and reimbursement for these products and related treatments will be available from government health administration authorities, private health insurers, managed healthcare organizations and other third-party payors and organizations. Government authorities and other third-party payors, such as private health insurers and managed healthcare organizations, decide which medications they will pay for and establish reimbursement conditions and rates. A primary trend in the EU and U.S. healthcare industries and elsewhere is cost containment. Government authorities, including the United States government and state legislatures, and other third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. Prices at which our products are reimbursed can be subject to challenge, reduction or denial by the government and other payers. Increasingly, third-party payors are requiring that drug companies provide them with discounts off the products’ sale (list) prices and are challenging the prices manufacturers charge for medical products. We cannot be sure that coverage will be available for any product or product candidate that we may commercialize and, if coverage is available, the level of reimbursement is also uncertain.

Reimbursement levels may impact the demand for, or the price of, any product or product candidate for which we obtain marketing authorization. Obtaining reimbursement for our products has been and is expected to continue to be, particularly difficult due to price considerations typically associated with drugs that are developed to treat conditions that affect a small population of patients. In addition, third-party payors are likely to impose strict requirements for reimbursement of a higher priced drug, such as prior authorization and the requirement to try other therapies first, or high co-payments which can result in patient rejection. Decreases in third-party reimbursement for a product or a decision by a third-party payor to not cover a product could reduce physician usage of the product. If reimbursement is not available or is available only on a limited basis, we may not be able to successfully commercialize any product or product candidate for which we have obtained or may obtain marketing authorization.

76

Table of Contents

There may be significant delays in obtaining coverage for newly approved drugs, and coverage may be more limited than the drug’s approved indications as determined by the applicable regulatory authority. Moreover, eligibility for reimbursement does not imply that any drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution. Interim reimbursement levels for new drugs, if applicable, may also not be sufficient to cover our costs and may not be made permanent, and programs intended to provide patient assistance until coverage is established can be very costly and limited in duration by law. Reimbursement rates may vary according to the use of the drug and the clinical setting in which it is used, may be based on reimbursement levels already set for lower cost drugs, and may be incorporated into existing payments for other services. Further, coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for one or more products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Net prices for drugs may be reduced by mandatory discounts or rebates required by government healthcare programs or private payors and by any future relaxation of laws, enforcement policies or administrative determinations with respect to the importation of drugs into the United States from other countries where they may be sold at lower prices.

In the United States, third-party payors include federal healthcare programs, such as Medicare, Medicaid, TRICARE, and Veterans Health Administration programs; managed care providers, private health insurers and other organizations. Several of the U.S. federal healthcare programs establish ceiling prices or require that drug manufacturers extend discounts or pay rebates to certain programs in order for their products to be covered and reimbursed. For example, the Medicaid Drug Rebate Program requires pharmaceutical manufacturers of covered outpatient drugs to enter into and have in effect a national rebate agreement with the federal government as a condition for coverage of the manufacturer’s covered outpatient drug(s) by state Medicaid programs. The amount of the rebate for each product is based on a statutory formula and may be subject to an additional discount if certain pricing increases more than inflation. State Medicaid programs and Medicaid managed care plans can seek additional “supplemental” rebates from manufacturers in connection with states’ establishment of preferred drug lists. A further requirement for Medicaid coverage is that manufacturers of single source and innovator multiple source drugs enter into a Master agreement and Federal Supply Schedule, or FSS, agreement with the Secretary for Veterans Affairs and charge no more than statutory ceiling prices to the Department of Veteran Affairs, the Department of Defense and certain other federal agencies.

Similarly, in order for a covered outpatient drug to receive federal reimbursement under the Medicare Part B and Medicaid programs, the manufacturer must extend discounts on the covered outpatient drug to entities that are enrolled and participating in the 340B drug pricing program, which is a federal program that requires manufacturers to provide discounts to certain statutorily-defined safety-net providers. The 340B discount for each product is calculated based on certain Medicaid Drug Rebate Program metrics that manufacturers are required to report to CMS.

Emflaza is also eligible for reimbursement under the Medicare Part D program. Under Part D, Medicare beneficiaries may enroll in prescription drug plans offered by private entities, which will provide coverage of outpatient prescription drugs. Part D prescription drug formularies are required to include drugs within each therapeutic category and class of covered Part D drugs, though not necessarily all the drugs in each category or class. Any negotiated prices for our products covered by a Part D prescription drug plan likely will be lower than the prices we might otherwise obtain, and payment of Medicare Coverage Gap discounts may further reduce realization on Part D drugs. Further, CMS is proposing to relax Part D coverage requirements to give plans more leverage in negotiating their formularies.

With respect to drugs eligible for reimbursement under Medicare Part B, on November 27, 2020, CMS issued an interim final rule implementing a Most Favored Nations payment model under which reimbursement for certain Medicare Part B drugs and biologicals will be based on a price that reflects the lowest per capita Gross Domestic Product-adjusted (GDP-adjusted) price of any non-U.S. member country of the Organisation for Economic Co-operation and Development (OECD) with a GDP per capita that is at least sixty percent of the U.S. GDP per capita.  This rule now has been rescinded but other measures, including the Inflation Reduction Act of 2022, or IRA, have been enacted to address the costs of pharmaceuticals. Such rules and any additional healthcare reform measures could further constrain our business or limit the amounts that federal and state governments will pay for healthcare products and services, which could result in additional pricing pressures.

77

Table of Contents

In addition, U.S. private health insurers often rely upon Medicare coverage policies and payment limitations in setting their own coverage and reimbursement policies. Any such coverage or payment limitations may result in a similar reduction in payments from non-governmental payors. Payment by private payors is also subject to payor-determined coverage and reimbursement policies that vary considerably and are subject to change without notice. We expect that coverage and reimbursement of Emflaza in the United States will vary from commercial payor to commercial payor. Many commercial payors, such as managed care plans, manage access to prescription drugs partly to control costs to their plans, and may use drug formularies and medical policies to limit their exposure. Exclusion from policies can directly reduce product usage in the payor’s patient population and may negatively impact utilization in other payor plans, as well.

There has been recent negative publicity and increasing legislative and public scrutiny around pharmaceutical drug pricing in the U.S., in particular with respect to orphan drugs and specifically with respect to Emflaza. Moreover, U.S. government authorities and third-party payors are increasingly attempting to limit or regulate drug prices and reimbursement, often with particular focus on orphan drugs. These dynamics may give rise to heightened attention and potential negative reactions to pricing decisions for Emflaza and products for which we may receive regulatory approval in the future, possibly limiting our ability to generate revenue and attain profitability.

Moreover, in 2017, the U.S. Congress modified and amended certain provisions of the 2010 U.S. healthcare reform legislation (the Patient Protection and Affordable Care Act of 2010, as amended by the Health Care and Education Reconciliation Act of 2010, known collectively as the Affordable Care Act), which could have an impact on coverage and reimbursement for healthcare items and services covered by the federal and state healthcare programs as well as plans in the private health insurance market. The so-called “individual mandate” was repealed as part of tax reform legislation adopted in December 2017. Legal challenges to the Affordable Care Act continue to arise and there may be future efforts to modify, repeal, or otherwise invalidate all, or certain provisions of the Affordable Care Act. The Biden administration is expected to continue to take measures to further facilitate the implementation of the Affordable Care Act. We cannot assure that the Affordable Care Act, as currently enacted or as amended in the future, will not adversely affect our business and financial results and we cannot predict how future federal or state legislative or administrative changes relating to healthcare reform will affect our business.

Additionally, the Budget Control Act of 2011, among other things, created measures for spending reductions by Congress. Failure of the Joint Select Committee on Deficit Reduction to reach required deficit reduction goals triggered the legislation’s automatic reduction to several government programs. This legislation resulted in aggregate reductions to Medicare payments to providers of up to 2% per fiscal year, which went into effect in April 2013 and will remain in effect through 2031. However, pursuant to the CARES Act and subsequent legislation, these Medicare sequester reductions were suspended through the end of March 2022 and from April 2022 through June 2022, a 1% cut was in effect, with the full 2% cut remaining thereafter. The American Taxpayer Relief Act of 2012, among other things, reduced Medicare payments to several providers and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. These new laws may result in additional reductions in Medicare and other healthcare funding and otherwise affect the prices we may obtain for any of our product candidates for which we may obtain regulatory approval or the frequency with which any such product candidates is prescribed or used.

In the EU, reference pricing systems and other measures may lead to cost containment and reduced prices with respect to Translarna for the treatment of nmDMD, Upstaza for the treatment of AADC deficiency and other product candidates that might receive marketing authorization in the future. Our inability to promptly obtain coverage and profitable payment rates from both government-funded and private payors for our product or any of our product candidates that may receive marketing authorization, or a reduction in coverage for payment rates for our product or any such product candidates, could have a material adverse effect on our business, results of operations and financial condition. In addition, in the EU, an authorized trader, such as a wholesaler, can purchase a medicine in one EU member state and obtain a license to import the product into another EU member state. This process is called “parallel distribution”. As a result, a purchaser in one EU member state may seek to import Translarna from another EU member state where Translarna is sold at a lower price. This could have a negative impact on our business, financial condition, results of operations and growth.

Similarly, sales of Emflaza in the United States could also be reduced if deflazacort is imported into the United States from lower-priced markets, whether legally or illegally. For example, in the United States, prices for pharmaceuticals are generally higher than in the bordering nations of Mexico and Canada. In October 2020, the Department of Health and

78

Table of Contents

Human Services, or HHS, and the FDA published a final rule allowing states and other entities to develop a Section 804 Importation Program, or SIP, to import certain prescription drugs from Canada into the United States. Certain states have passed laws allowing for the importation of drugs from Canada with the intent of developing SIPs for review and approval by the FDA.  Florida recently received approval for its SIP from the FDA. Further, on November 20, 2020, HHS finalized a regulation removing safe harbor protection for price reductions from pharmaceutical manufacturers to plan sponsors under Part D, either directly or through pharmacy benefit managers, unless the price reduction is required by law.. The rule also creates a safe harbor for price reductions reflected at the point-of-sale, as well as a new safe harbor for certain fixed fee arrangements between pharmacy benefit managers and manufacturers.  The effective date of the new safe harbors and the revision to the discount safe harbor was delayed by court order until January 1, 2023. Recent legislation further delayed implementation of the new safe harbors and the revision to the discount safe harbor until January 1, 2032.

Risks Related to Our Financial Position and Need for Additional Capital

We have incurred significant losses since our inception and based on our current commercial, research and development plans, we expect to continue to incur significant operating expenses for the foreseeable future. We may never generate profits from operations or maintain profitability.

Since inception, we have incurred significant operating losses. As of December 31, 2023, we had an accumulated deficit of $3,283.6 million. We have financed our operations to date primarily through the private offerings of convertible senior notes, public and “at the market offerings” of common stock, proceeds from royalty purchase agreements, net proceeds from our borrowings under our credit agreement with Blackstone, private placements of our convertible preferred stock and common stock, collaborations, bank and institutional lender debt, other convertible debt, grant funding and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease area addressed by our product candidates. We have relied on revenue generated from net sales of Translarna for the treatment of nmDMD in territories outside of the United States since 2014, Emflaza for the treatment of DMD in the United States since 2017, and Upstaza for the treatment of AADC deficiency in the EEA since May 2022. We have also relied on revenue associated with milestone and royalty payments from Roche pursuant to the SMA License Agreement under our SMA program and revenue generated from net sales of Tegsedi and Waylivra in Latin America and the Caribbean. Based on our current commercial, research and development plans, we expect to continue to incur significant operating expenses for the foreseeable future, which we anticipate will be partially offset by revenues generated from the sale of our products and our collaboration and royalty revenues. We expect to continue to generate operating losses through 2024 and, while we anticipate that operating losses generated in future periods should decline versus prior periods, we may never generate profits from operations or maintain profitability. The net losses we incur may fluctuate significantly from period to period.

From time to time, we have engaged in strategic transactions to expand and diversify our product pipeline, including through the acquisition of assets or businesses. In connection with these acquisitions, we have entered into agreements through which we have ongoing obligations, including obligations to make contingent payments upon the achievement of certain development, regulatory and net sales milestones or upon a percentage of net sales of certain products. See “Item 1. Business-Our Ongoing Acquisition-Related Obligations” for further information regarding our acquisitions and our ongoing obligations. We may engage in additional strategic transactions to expand and diversify our product pipeline, including through the acquisition of assets, businesses, or rights to products, product candidates or technologies or through strategic alliances or collaborations and we may incur expenses, including with respect to transaction costs, subsequent development costs or any upfront, milestone or other payments or other financial obligations associated with any such transaction.

Our current ability to generate revenue from sales of Translarna is dependent upon our ability to maintain our marketing authorizations in the EEA for Translarna for the treatment of nmDMD in ambulatory patients aged two years and older, in Russia for the treatment of nmDMD in patients aged two years and older and in Brazil for the treatment of nmDMD in ambulatory patients two years and older and for continued treatment of patients that become non-ambulatory, as well as in various other countries. The marketing authorization in the EEA is subject to annual review and renewal by the EC following reassessment by the EMA of the benefit-risk balance of the authorization. For example, in February 2023, we submitted an annual marketing authorization request to the EMA. In September 2023, the CHMP gave a negative opinion on the conversion of the conditional marketing authorization to the full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of

79

Table of Contents

Translarna. On January 25, 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In accordance with EMA regulations, the EC has 67 days to adopt the opinion from the date of its issuance. If the EC adopts the negative opinion, Translarna would no longer have marketing authorization in the EEA. For more information regarding the risks associated with the a potential EC adoption of the CHMP’s negative opinion on Translarna’s marketing authorization, see Item 1A. Risk Factors, “We may be unable to continue to commercialize Translarna for nonsense mutation Duchenne muscular dystrophy in the European Economic Area if the European Commission adopts the negative opinion issued by the Committee for Medicinal Products for Human Use of the European Medicines Agency for the renewal of the existing conditional authorization for Translarna.” We also expect that our efforts to advance Translarna for the treatment of nmDMD in the United States will be time-consuming and may be expensive.

We anticipate that we will continue to incur significant expenses in connection with our commercialization efforts in the United States, the EEA, Latin America and other territories, including expenses related to our commercial infrastructure and corresponding sales and marketing, legal and regulatory, and distribution and manufacturing undertakings as well as administrative and employee-based expenses. In addition to the foregoing, we expect to continue to incur significant costs in connection with ongoing, planned and potential future clinical trials and studies for sepiapterin and our splicing and ferroptosis and inflammation programs as well as studies in our products for maintaining authorizations, label extensions and additional indications. We continue to seek marketing authorization for Translarna for the treatment of nmDMD in territories that we do not currently have marketing authorization in and we are exploring other potential mechanisms in which we may provide Translarna to nmDMD patients in the EEA if the EC adopts the CHMP’s negative opinion for Translarna. We anticipate submitting a BLA to the FDA for Upstaza for the treatment of AADC deficiency in the United States in March 2024. We also expect to submit an MAA to the EMA for sepiapterin for the treatment of PKU in March 2024 and we expect to submit an NDA to the FDA for sepiapterin for the treatment of PKU no later than the third quarter of 2024. These efforts may significantly impact the timing and extent of our commercialization and manufacturing expenses.

In addition, the clinical and regulatory developments noted in this risk factor may exacerbate the risks related to our commercialization efforts set forth under the heading “Risks Related to the Development and Commercialization of our Products and our Product Candidates,” which could increase the costs associated with our commercial activities or have a negative impact on our revenues.

We may seek to continue to expand and diversify our product pipeline through opportunistically in-licensing or acquiring the rights to products, product candidates or technologies and we may incur expenses, including with respect to transaction costs, subsequent development costs or any upfront, milestone or other payments or other financial obligations associated with any such transaction, which would increase our future capital requirements.

With respect to our outstanding 1.50% convertible senior notes due September 15, 2026, or the 2026 Convertible Notes, cash interest payments are payable on a semi-annual basis in arrears, which will require total funding of $4.3 million annually.

We expect to pay the former equityholders of Agilis $20.0 million in development milestone payments upon the acceptance for filing by the FDA of a BLA for Upstaza for the treatment of AADC deficiency and $4.5 million in regulatory milestones for the approval of the BLA from the FDA pursuant to the Agilis Merger Agreement. We anticipate submitting a BLA to the FDA for Upstaza for the treatment of AADC deficiency in the United States in March 2024. We also expect to make payments to the former Censa securityholders of $65.0 million in the aggregate in cash upon the potential achievement in 2024 of regulatory milestones relating to sepiapterin pursuant to the Censa Merger Agreement.

In addition, our expenses will increase if and as we:

80

Table of Contents

Our expenses may also increase as a result of economic conditions, such as potentially high inflation rates within the jurisdictions that we operate, sustained high interest rates, or unfavorable fluctuations in foreign currency exchange rates.

Our ability to generate profits from operations and become and remain profitable depends on our ability to successfully develop and commercialize drugs that generate significant revenue. This will require us to be successful in a range of challenging activities, including:

We may never succeed in these activities and, even if we do, may never generate revenues that are significant enough to generate profits from operations. Even if we do generate profits from operations, we may not be able to sustain or increase profitability on a quarterly or annual basis. Our failure to generate profits from operations and remain profitable would decrease the value of our company and could impair our ability to raise capital, expand our business, maintain our research and development efforts, diversify our product offerings or continue our operations. A decline in the value of our company could also cause our stockholders to lose all or part of their investment in our company.

81

Table of Contents

We may need additional funding. If we are unable to raise capital when needed, we could be forced to delay, reduce or eliminate our product development programs or commercialization efforts.

As noted in the prior risk factor, we expect to incur significant expenses related to our clinical, regulatory, commercial, legal, research and development, and other business efforts. We believe that our cash flows from product sales, together with existing cash and cash equivalents, and marketable securities will be sufficient to fund our operating expenses and capital expenditure requirements for at least the next twelve months. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect.

Our future capital requirements will depend on many factors, including:

82

Table of Contents

​

Conducting preclinical testing and clinical trials is a time-consuming, expensive and uncertain process that takes years to complete, and we may never generate the necessary data or results required to obtain regulatory approval and achieve product sales for certain product candidates or indications. In addition, our products and product candidates, if approved, may not achieve sustained commercial success. Likewise, if we fail to maintain our marketing authorization or lose non-patent market exclusivity for our products and product candidates, we will be unable to commercialize and generate revenue from the sales of those products.

Accordingly, we may need to continue to rely on additional financing in connection with our continuing operations and to achieve our business objectives. In addition, we may seek additional capital due to favorable market conditions or based on strategic considerations, even if we believe that we have sufficient funds for our current or future operating plans. Additional financing may not be available to us on acceptable terms or at all. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or our commercialization efforts.

We may engage in strategic transactions to acquire assets, businesses, or rights to products, product candidates or technologies or form collaborations or make investments in other companies or technologies that could harm our operating results, dilute our stockholders’ ownership, increase our debt, or cause us to incur significant expense.

As part of our business strategy, we may engage in additional strategic transactions to expand and diversify our product pipeline, including through the acquisition of assets, businesses, or rights to products, product candidates or technologies or through strategic alliances or collaborations, similar to our acquisitions of Emflaza, Agilis, Censa and BioElectron’s assets and the Tegsedi-Waylivra Agreement. We may not identify suitable strategic transactions, or complete such transactions in a timely manner, on a cost-effective basis, or at all. Moreover, we may devote resources to potential opportunities that are never completed, or we may incorrectly judge the value or worth of such opportunities. Even if we successfully execute a strategic transaction, we may not be able to realize the anticipated benefits of such transaction, may incur additional debt or assume unknown or contingent liabilities in connection therewith, and may experience losses related to our investments in such transactions. Integration of an acquired company or assets into our existing business may not be successful and may disrupt ongoing operations, require the hiring of additional personnel and the implementation of additional internal systems and infrastructure, and require management resources that would otherwise focus on developing our existing business. Even if we are able to achieve the long-term benefits of a strategic transaction, our expenses and short-term costs may increase materially and adversely affect our liquidity. Any of the foregoing could have a detrimental effect on our business, results of operations and financial condition.

In addition, future strategic transactions may entail numerous operational, financial and legal risks, including:

83

Table of Contents

If we are unable to successfully manage any strategic transaction in which we may engage, our ability to develop new products and continue to expand and diversify our product pipeline may be limited.

Raising additional capital may cause dilution to our stockholders, restrict our operations or require us to relinquish rights to our technologies or product candidates.

Until such time, if ever, as we can generate enough product revenues to cover our expenses, we expect to supplement our cash needs through a combination of equity offerings, debt financings, royalty sales, collaborations, strategic alliances, grants and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease areas addressed by our product candidates; marketing, distribution, licensing or other arrangements.

To the extent that we raise additional capital through the sale of equity or convertible debt securities, our stockholders’ ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Any debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, entering into agreements involving licenses to our intellectual property, making capital expenditures or declaring dividends.

If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates; or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our product development or future commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Our ability to use our net operating losses and certain other tax attributes to offset potential taxable income and related income taxes that would otherwise be due is subject to limitation under the provisions of Sections 382 and 383 of the Internal Revenue Code as a result of ownership changes of the Company and could be subject to further annual limitations under such provisions. In addition, we may not generate sufficient future taxable income to use our net operating losses and certain other tax attributes.

If a corporation undergoes an “ownership change” within the meaning of Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, or Sections 382 and 383, the corporation’s ability to utilize any net operating losses, or NOLs, and certain tax credits and other tax attributes generated before such an ownership change, is limited. We believe that we have in the past experienced ownership changes within the meaning of Sections 382 and 383 that have resulted in limitations under Sections 382 and 383 (and similar state provisions) on the use of our NOLs and other tax attributes.

Sections 382 and 383 are extremely complex provisions with respect to which there are many uncertainties, and we have not requested a ruling from the United States Internal Revenue Service, or IRS, to confirm our analysis of the ownership change limitations related to the NOLs and other tax attributes generated by us. Therefore, we have not established whether the IRS would agree with our analysis regarding the application of Sections 382 and 383. We continue to fully evaluate the impact of a limitation on the use of our NOLs and other tax attributes under Sections 382 and 383.

84

Table of Contents

Moreover, our ability to use these NOLs to offset potential future taxable income and related income taxes that would otherwise be due is dependent upon our generation of future taxable income. We generated taxable income that is subject to income tax in 2023, but continue to maintain NOLs from previous years that will be carried forward.

Changes in our effective income tax rates and future changes to U.S. and non-U.S. tax laws could adversely affect our results of operations.

We are subject to income taxes in the Unites States and various ex-U.S. jurisdictions. Taxes will be incurred as income is earned in these different jurisdictions. Various factors may have favorable or unfavorable effects on our effective income tax rate. These factors include, but are not limited to, interpretations of existing tax laws, changes in tax laws and rates, the accounting for stock options and other share-based compensation, changes in accounting standards, future levels of research and development spending, changes in the mix and level of pre-tax earnings by taxing jurisdiction, the outcome of examinations by the IRS and other jurisdictions, the accuracy of our estimates for unrecognized tax benefits, the realization of deferred tax assets, or by changes to our ownership or capital structure. The impact on our income tax provision resulting from the above-mentioned factors and others may be significant and could adversely affect our results of operations.

Changes in tax laws or regulations, including further regulatory developments arising from U.S. tax reform legislation as well as multi-jurisdictional changes enacted in response to the action items provided by the Organization for Economic Cooperation and Development (OECD), may increase tax uncertainty and the amount of tax we pay.

On December 22, 2017, the United States government enacted the 2017 Tax Act, which significantly reformed the U.S. Internal Revenue Code of 1986, as amended, or the Code. The Tax Act, among other things, contained significant changes to corporate taxation. As part of Congress’s response to the COVID-19 pandemic, economic relief legislation was enacted in 2020 and 2021. Such legislation contains numerous tax provisions. In addition, the IRA was signed into law in August 2022.  The IRA introduced new tax provisions, including a 1% excise tax imposed on certain stock repurchases by publicly traded corporations. The 1% excise tax generally applies to any acquisition by the publicly traded corporation (or certain of its affiliates) of stock of the publicly traded corporation in exchange for money or other property (other than stock of the corporation itself), subject to a de minimis exception. Thus, the excise tax could apply to certain transactions that are not traditional stock repurchases.

Regulatory guidance under the 2017 Tax Act, the IRA, and such additional legislation is and continues to be forthcoming, and such guidance could ultimately increase or lessen the impact of these laws on our business and financial condition. In addition, it is uncertain if and to what extent various states will conform the 2017 Tax Act, IRA, and additional tax legislation.

Although we monitor actual and potential changes to the tax laws in the United States and other jurisdictions, it is very difficult to assess to what extent these changes may impact the way in which we conduct our business or our effective tax rate due to the unpredictability and interdependency of these changes. Changes in tax laws and related regulations and practices could have a material adverse effect on our business operations, cash flows, effective tax rate, financial position and results of operations.

Risks Related to Regulatory Approval of our Products and our Product Candidates

We may not be able to obtain orphan drug exclusivity for our products or product candidates in either the United States or the EU.

Regulatory authorities in some jurisdictions, including the EU and the United States, may designate drugs for relatively small patient populations as orphan drugs. We have obtained orphan drug designations from the EMA and from the FDA for Translarna for the treatment of nmDMD, Upstaza for the treatment of AADC, Evrysdi for the treatment of SMA, sepiapterin for the treatment of patients with hyperphenylalaninemia, including hyperphenylalaninemia caused by PKU, vatiquinone for the treatment of Friedreich ataxia and utreloxastat for the treatment of ALS. The FDA has also granted an orphan drug designation to Emflaza for the treatment of DMD. We may also seek orphan drug designation and exclusivity for other product candidates, if we believe that the product candidate may qualify. We, however, may not be able to obtain

85