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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 20-F
(Mark One)
REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934
OR
ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the fiscal year ended December 31, 2022
OR
TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
OR
SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
Commission file number: 001-39071
ADC Therapeutics SA
(Exact name of Registrant as specified in its charter)
Switzerland
(Jurisdiction of incorporation or organization)
Biopôle
Route de la Corniche 3B 
1066 Epalinges 
Switzerland
(Address of principal executive offices)
Jose “Pepe” Carmona
ADC Therapeutics America, Inc.
430 Mountain Avenue, 4th Floor
Murray Hill, NJ 07974
(908) 546-5556
(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)

Securities registered or to be registered pursuant to Section 12(b) of the Act:
Title of each classTrading SymbolName of each exchange on which registered
Common Shares, par value CHF 0.08 per shareADCTNew York Stock Exchange
Securities registered or to be registered pursuant to Section 12(g) of the Act:
None
Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act:
None
Indicate the number of outstanding shares of each of the issuer’s classes of capital stock or common stock as of the close of the period covered by the annual report.
Common shares: 80,642,527
Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.
o Yes x No
If this report is an annual or transition report, indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934.
o Yes x 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.
x Yes o No
Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted 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).
x Yes o No
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or an emerging growth company. See definition of “large accelerated filer,” “accelerated filer,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.
Large accelerated filer
Accelerated filer
Non-accelerated filer
Emerging growth company
If an emerging growth company that prepares its financial statements in accordance with U.S. GAAP, 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.

† The term “new or revised financial accounting standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification after April 5, 2012.
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.

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). ☐

Indicate by check mark which basis of accounting the registrant has used to prepare the financial statements included in this filing:
US GAAP
International Financial Reporting Standards
Other
as issued by the International Accounting Standards Board
If “Other” has been checked in response to the previous question indicate by check mark which financial statement item the registrant has elected to follow.
o Item 17 o Item 18
If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).
Yes x No


TABLE OF CONTENTS
D. Risk Factors
i

ii

PRESENTATION OF FINANCIAL AND OTHER INFORMATION

Unless otherwise indicated or the context otherwise requires, all references in this Annual Report to “ADC Therapeutics,” “ADCT,” the “Company,” “we,” “our,” “ours,” “us” or similar terms refer to ADC Therapeutics SA and its consolidated subsidiaries.

Trademarks

We own various trademark registrations and applications, and unregistered trademarks, including ADC Therapeutics, ADCT, ZYNLONTA and our corporate logo. All other trade names, trademarks and service marks of other companies appearing in this Annual Report are the property of their respective owners. Solely for convenience, the trademarks and trade names in this Annual Report may be referred to without the ® and ™ symbols, but such references should not be construed as any indicator that their respective owners will not assert, to the fullest extent under applicable law, their rights thereto. We do not intend to use or display other companies’ trademarks and trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

Financial Statements

Our consolidated financial statements are presented in U.S. dollars and have been prepared in accordance with International Financial Reporting Standards as issued by the International Accounting Standards Board (“IFRS”). None of the consolidated financial statements were prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”). The terms “dollar,” “USD” or “$” refer to U.S. dollars and the term “Swiss franc” and “CHF” refer to the legal currency of Switzerland, unless otherwise indicated. We have made rounding adjustments to some of the figures included in this Annual Report. Accordingly, any numerical discrepancies in any table between totals and sums of the amounts listed are due to rounding.

Market and Industry Data

This Annual Report contains industry, market and competitive position data that are based on general and industry publications, surveys and studies conducted by third parties, some of which may not be publicly available, and our own internal estimates and research. Third-party publications, surveys and studies generally state that they have obtained information from sources believed to be reliable, but do not guarantee the accuracy and completeness of such information. These data involve a number of assumptions and limitations and contain projections and estimates of the future performance of the industries in which we operate that are subject to a high degree of uncertainty.

FORWARD-LOOKING STATEMENTS

This Annual Report contains statements that constitute forward-looking statements. All statements other than statements of historical facts contained in this Annual Report, including statements regarding our future catalysts, results of operations and financial position, business and commercial strategy, market opportunities, products and product candidates, research pipeline, ongoing and planned preclinical studies and clinical trials, regulatory submissions and approvals, research and development costs, projected revenues and expenses and the timing of revenues and expenses, timing and likelihood of success, as well as plans and objectives of management for future operations are forward-looking statements. Many of the forward-looking statements contained in this Annual Report can be identified by the use of forward-looking words such as “anticipate,” “believe,” “could,” “expect,” “should,” “plan,” “intend,” “estimate,” “will” and “potential,” among others.

Forward-looking statements are based on our management’s beliefs and assumptions and on information available to our management at the time such statements are made. Such statements are subject to known and unknown risks and uncertainties, and actual results may differ materially from those expressed or implied in the forward-looking statements due to various factors, including, but not limited to, those identified in the “Item 3. Key Information — D. Risk Factors” section of this Annual Report. Factors that may cause such differences include, but are not limited to: the Company’s ability to achieve its financial guidance including the 2023 net product revenue guidance for Zynlonta and the decrease in operating expenses for 2023 and 2024, the Company’s ability to continue to commercialize ZYNLONTA in the United States and future revenue from the same; Swedish Orphan Biovitrum AB (Sobi)’s ability to successfully commercialize ZYNLONTA in the European Economic Area and market acceptance, adequate reimbursement coverage, and future revenue from the same; our strategic partners’, including Mitsubishi Tanabe Pharma Corporation and Overland Pharmaceuticals, ability to obtain regulatory approval for ZYNLONTA in foreign jurisdictions, and the timing and amount of future revenue and payments to us from such partnerships; the Company’s ability to market its products in compliance with applicable laws and regulations; the timing and results of the Company’s or its partners’ research projects or clinical trials including LOTIS 2, 5, 7 and 9, ADCT 901, 701, 601, 602 and 212, the timing and outcome of regulatory submissions and actions by the U.S. Food and Drug Administration or other regulatory agencies with respect to the Company’s products or product candidates; projected revenue and expenses; our indebtedness and the restrictions imposed on the Company’s activities by such indebtedness, the ability to repay such indebtedness and the significant cash required to service such indebtedness; the Company’s ability to obtain financial and other resources for its research, development, clinical, and commercial activities; the manufacture and supply of our products and product candidates; our expectations regarding the size of the patient populations amenable to treatment with our products and, if approved, product candidates, as well as the treatment landscape of the indications that we are targeting with our products and product candidates; our ability to identify and develop additional product candidates; the ability of our competitors to discover, develop or commercialize competing products before or more successfully than we do; our competitive position and the development of and projections relating to our competitors or our industry; our
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estimates of our expenses, revenues, capital requirements, estimated cash runway and need for or ability to obtain additional financing; our ability to identify and successfully enter into strategic collaborations or licensing opportunities in the future, and our assumptions regarding any potential revenue that we may generate under current or future collaborations or licensing arrangements; our ability to obtain, maintain, protect and enforce intellectual property protection for our products and product candidates, and the scope of such protection; our ability to operate our business without infringing, misappropriating or otherwise violating the intellectual property rights of third parties; our expectations regarding the impact of the COVID-19 pandemic; our expectations regarding the impact of the current conflict between Russia and Ukraine, including resulting sanctions and changes in commodities prices, on our business and industry and the financial markets; our expectations regarding the impact of inflation and other market risks; our ability to attract and retain qualified key management and technical personnel; our expectations regarding the effectiveness of our internal controls over financial reporting; and our expectations regarding the time during which we will be a foreign private issuer.

Because forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified and some of which are beyond our control, you should not rely on these forward-looking statements as predictions of future events. Moreover, we operate in an evolving environment. New risk factors and uncertainties may emerge from time to time, and it is not possible for management to predict all risk factors and uncertainties. Except as required by applicable law, we do not plan to publicly update or revise any forward-looking statements, whether as a result of any new information, future events, changed circumstances or otherwise.

In addition, statements that “we believe” and similar statements reflect our beliefs and opinions on the relevant subject. These statements are based upon information available to us as of the date of this Annual Report, and while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. These statements are inherently uncertain and investors are cautioned not to unduly rely upon these statements.

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PART I
ITEM 3.    KEY INFORMATION
D. Risk Factors
Our business faces significant risks and uncertainties. You should carefully consider all of the information set forth in this Annual Report and in other documents we file with or furnish to the Securities and Exchange Commission (the “SEC”), including the following risk factors, before deciding to invest in or to maintain an investment in our securities. Our business, as well as our reputation, financial condition, results of operations, and share price, could be materially adversely affected by any of these risks, as well as other risks and uncertainties not currently known to us or not currently considered material.
Risk Factors Summary
Our ability to implement our business strategy is subject to numerous risks, as more fully described in this Annual Report and our other documents filed with the SEC. These risks include, among others:

We have incurred substantial net losses since our inception, expect to continue to incur losses for the foreseeable future and may never achieve or sustain profitability. We may need to raise additional capital to fund our operations and execute our business plan.

Our indebtedness under the loan agreement and guaranty (the “Loan Agreement”) with certain affiliates and/or funds managed by each of Oaktree Capital Management, L.P. and Owl Rock Capital Advisors LLC, as lenders, and Owl Rock Opportunistic Master Fund I, L.P., as administrative agent and collateral agent, and the associated restrictive covenants thereunder could adversely affect our financial condition.

Our purchase and sale agreement with certain entities managed by HealthCare Royalty Management, LLC (“HCR”) reduces the amount of cash we are able to generate from sales of, and licensing agreements involving, ZYNLONTA and Cami and could make us a less attractive acquisition target.

We may be unable to complete clinical trials on our expected timelines, if at all.

Our products and product candidates may cause undesirable side effects or have other properties.

We may be unable to obtain, or experience delays in obtaining, regulatory approval for our product candidates. We may be unable to maintain regulatory approval for any approved products.

We or our partners may not be able to successfully commercialize our products.

There can be no assurance regarding the outcome of ongoing or planned clinical trials or the sufficiency of results from such clinical trials.

Coverage and reimbursement may be limited or unavailable for our products.

Our products and product candidates are complex and difficult to manufacture.

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

We rely on third parties to conduct preclinical studies and clinical trials and for the manufacture, production, storage and distribution of our products and product candidates and certain commercialization activities for our products.

If we are unable to obtain, maintain or protect our intellectual property rights in any products or technologies we develop, or if the scope of the intellectual property protection obtained is not sufficiently broad, third parties could develop and commercialize products and technology similar or identical to ours, and we may not be able to compete effectively in our market.

We may become involved in lawsuits to protect or enforce our patents or other intellectual property, which could be expensive, time-consuming and unsuccessful, and our issued patents covering one or more of our products, product candidates or technologies, including ZYNLONTA or the technology we use in our products and product candidates, could be found invalid or unenforceable if challenged in court.
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We may be subject to claims by third parties asserting that our products infringe their intellectual property or that we or our employees, consultants or advisors have misappropriated their intellectual property, or claiming ownership of what we regard as our own intellectual property.

Product liability lawsuits and product recalls could cause us to incur substantial liabilities and to limit development and commercialization of our products.

Risks Related to Our Financial Position and Capital Requirements
We have incurred substantial net losses since our inception, expect to continue to incur losses for the foreseeable future and may never achieve or sustain profitability. We may need to raise additional capital to fund our operations and execute our business plan and such additional capital could be dilutive, limit our ability to operate our business and adversely impact the price of our stock.

We have incurred substantial net losses since our inception and expect to continue to incur losses for the foreseeable future. As of December 31, 2022, we had accumulated losses of USD 1,080.7 million. We expect to continue to incur net losses for the foreseeable future as we continue to devote substantial resources to research and development and marketing and commercialization efforts, in particular to establish ZYNLONTA as the 3L+ diffuse large B cell lymphoma (“DLBCL”) standard of care, continue to study and advance ZYNLONTA in earlier lines of therapy and in combinations to potentially expand our market opportunity and further develop our clinical-stage PBD-based pipeline and our ADC platform. We are unable to accurately predict whether and when we will achieve profitability. Even if we achieve profitability, we may not be able to sustain profitability in subsequent periods. This risk is heightened as we only have one approved product, ZYNLONTA, at the present time and thus are heavily dependent on its commercial performance and its continued research and development.
As a result, we may need to raise additional capital to fund our operations and execute our business plan. We do not have any committed external source of funds, and additional funds may not be available when we need them or on terms that are acceptable to us. Our ability to raise additional funds will depend on financial, economic and market conditions and other factors, over which we may have no or limited control. Further, as a Swiss company, we have less flexibility to raise capital, particularly in a quick and efficient manner, as compared to U.S. companies. See “—Risks Related to Our Common Shares—Our shareholders enjoy certain rights that may limit our flexibility to raise capital, issue dividends and otherwise manage ongoing capital needs.” The restrictions contained in our contractual agreements may also limit our ability to raise certain forms of capital. For example, subject to certain exceptions, the Loan Agreement restricts our ability to incur indebtedness and our purchase and sale agreement with HCR restricts our ability to sell, finance or loan any additional royalties on ZYNLONTA outside of China, Hong Kong, Macau, Taiwan, Singapore and South Korea or on Cami, and to incur indebtedness exceeding 20% of our market capitalization. If adequate funds are not available to us on a timely basis or on terms acceptable to us, we may be required to delay, limit, reduce or terminate our research and development, commercialization or growth efforts.

We may seek additional capital through a variety of means. If we raise additional capital through the sale of equity or convertible debt securities, your ownership interest will be diluted, and the terms of such equity or convertible debt securities may include liquidation or other preferences that are senior to or otherwise adversely affect your rights as a shareholder. If we raise additional capital through the sale of debt securities or through entering into credit or loan facilities, we may be restricted in our ability to take certain actions, such as incurring additional debt, making capital expenditures, acquiring or licensing intellectual property rights, declaring dividends or encumbering our assets to secure future indebtedness. If we raise additional capital through collaborations with third parties, we may be required to relinquish valuable rights to our intellectual property, products or product candidates or we may be required to grant licenses for our intellectual property, products or product candidates on unfavorable terms.

Our indebtedness under the Loan Agreement and the associated restrictive covenants thereunder could adversely affect our financial condition.

We have significant indebtedness outstanding under the Loan Agreement. Such indebtedness requires us to dedicate a substantial portion of our cash and cash equivalents to the payment of interest on, and principal of, the indebtedness, thereby reducing the amounts available to fund working capital, capital expenditures, research and development efforts, commercialization efforts and other general corporate purposes. Indebtedness under the Loan Agreement bear variable rates of interest based on the prevailing SOFR, thereby making us more vulnerable to rising interest rates.

The Loan Agreement contains certain restrictions on our activities and customary covenants, including a covenant to maintain qualified cash of at least USD 60.0 million plus an amount equal to any accounts payable of the Company or its subsidiaries that remain unpaid more than ninety (90) days after the date of the original invoice therefor, and negative covenants including limitations on indebtedness, liens, fundamental changes, asset sales, investments, dividends and other restricted payments and other matters customarily restricted in such agreements. The obligations under the Loan Agreement are secured by substantially all assets of the Company and certain of its subsidiaries and are guaranteed initially by the Company’s subsidiaries in the United States and the United Kingdom. Such covenants could limit our flexibility in planning for, or reacting to, changes in our business and our industry; place us at a competitive disadvantage compared to our competitors who have less debt or competitors with comparable debt on more favorable terms; and limit our ability to borrow additional amounts.

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Our ability to maintain compliance with the covenants imposed by our indebtedness and to repay the principal of, pay interest on and refinance, our indebtedness depends on our future performance, which is subject to economic, financial, competitive and other factors, many of which are beyond our control. If we are unable to comply with the covenants imposed by our indebtedness or to generate sufficient cash flow to service or repay our indebtedness, we may be in default of the Loan Agreement and be required to adopt one or more alternatives, such as restructuring debt or obtaining additional financing on terms that may be unfavorable to us or highly dilutive.

Our purchase and sale agreement with HCR reduces the amount of cash we are able to generate from sales of, and licensing agreements involving, ZYNLONTA and Cami and could make us a less attractive acquisition target.

Under our purchase and sale agreement with HCR, we are obligated to pay to HCR royalties presenting a percentage of net sales of ZYNLONTA in certain jurisdictions, a percentage of any upfront or milestone payments we receive from licenses that we grant to commercialize ZYNLONTA in certain jurisdictions, and a percentage of any upfront or milestone payments (or on royalties) we receive from licenses that we grant to commercialize Cami. See “Item 10. Additional Information—C. Material Contracts.” As a result, our ability to generate from sales of, and licensing agreements involving, ZYNLONTA and Cami is reduced, which could adversely affect our financial condition.

In addition, upon the occurrence of a change in control event, we are obligated to pay HCR an amount equal to 2.50 times the amount paid by HCR under the agreement, or at 2.25 times the amount paid by HCR under the agreement if HCR receives royalty payments exceeding a mid-nine-digit amount on or prior to March 31, 2029, less any amounts we previously paid to HCR. If the change in control event occurs prior to the 36-month anniversary of the closing of the royalty purchase agreement, we are obligated to pay HCR an amount equal to 2.0 times the amount paid by HCR, less any amounts we previously paid to HCR pursuant to the agreement. The foregoing may make us a less attractive acquisition target by reducing the benefit accruing to our shareholders in any change-of-control transaction.

Our statement of operations is subject to considerable non-cash charges and volatility due to factors that may be beyond our control.

Our warrants are presented in the audited consolidated balance sheet as a liability, which is remeasured to fair value at each reporting date. The fair value changes based on our share price and its expected volatility. Our purchase and sale agreement with HCR is accounted for as a short-term and long-term debt obligation. To determine the accretion of the liability, we are required to estimate the total amount of future royalty payments and estimated timing of such payment to HCR based on the Company's revenue projections as well as the achievement of the certain milestones. Based on our periodic review, the amount and timing of repayment is likely to be different at each reporting period. To the extent the amount or timing of such payments is materially different than our initial estimates, we will record a cumulative catch-up adjustment. As a result, our warrants and the purchase and sale agreement with HCR could result in considerable non-cash charges to, and significant volatility in, our statement of operations.

Our ability to use tax loss carryforwards and deferred tax assets may be limited.

As of December 31, 2022, we reported USD 926.4 million in tax loss carryforwards for Swiss corporate income tax purposes. In addition, as of December 31, 2022, we reported USD 26.8 million in deferred tax assets, consisting primarily of U.S. federal and state R&D and Orphan Drug tax credit carryforwards. Such tax loss carryforwards and tax credits could, with certain limitations, be used to offset future taxable income. Swiss tax loss carryforwards generally expire seven years after the tax year in which they were incurred; U.S. federal and state tax credits generally expire after 20 years, although some state tax credits expire as quickly as seven years after the tax year in which they were incurred, and others do not expire. There can be no assurance that we will be able to generate sufficient income that allows us to use such tax loss carryforwards or tax credits before their expiration. We recognize deferred tax assets in our financial statements based on our assessment of the value of U.S. federal and state tax credits that we will be able to realize; however, such assessments are based on our projections of our future taxable income, which are subject to uncertainty and change based on numerous factors, including those described in this “Risk Factors” section. There can be no assurance that we will realize the value of the deferred tax assets recognized on our financial statements. In addition, relevant tax authorities may not accept our claims of tax loss carryforwards or tax credits. Furthermore, changes in tax law, as well as interpretation of such tax laws, could reduce, eliminate, or otherwise impair our ability to use our tax loss carryforwards and tax assets.

Exchange rate fluctuations may materially affect our results of operations and financial condition.

We operate internationally and are exposed to fluctuations in foreign exchange rates between the U.S. dollar and other currencies, particularly the British pound, the Euro and the Swiss franc. Our reporting currency is the U.S. dollar and, as a result, financial line items are converted into U.S. dollars at the applicable foreign exchange rates. As our business grows, we expect that at least some of our revenues and expenses will be denominated in currencies other than the U.S. dollar. Therefore, unfavorable developments in the value of the U.S. dollar relative to other relevant currencies could adversely affect our business and financial condition.

Risks Related to Research and Development

We may expend our resources to pursue particular products or product candidates and fail to capitalize on those that may be more profitable or for which there is a greater likelihood of success.

Because we have limited financial resources and personnel, we may prioritize the research, development and commercialization of select products or product candidates and of products and product candidates in select indications or markets. As a result, we may forgo or delay the
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pursuit of other products and product candidates or of other indications and markets that later prove to have greater commercial potential. Decision-making about development and commercialization priorities involves inherent subjectivity and uncertainty, and there can be no assurance that we will pursue product candidates with the greatest likelihood of obtaining regulatory approval or products and product candidates with the greatest market potential. In addition, we may relinquish valuable rights to products or product candidates through partnering, licensing or other arrangements in cases in which it would have been more advantageous for us to retain sole development and commercialization rights to such products or product candidates.

We may be unable to complete clinical trials on our expected timelines, if at all.

Clinical trials are subject to the numerous risks described in this “Risk Factors” section and in our other filings with the SEC, and a failure, delay or termination of one or more clinical trials can occur at any stage of the clinical trial process. Events that could impede our ability to complete clinical trials on a timely basis include but are not limited to:

delays in the timely commencement of clinical trials due to negative preclinical data, delays in receiving the required regulatory clearance from the appropriate regulatory authorities, delays in reaching an agreement on acceptable terms with prospective clinical research organizations (“CROs”) and clinical trial sites and difficulties in obtaining required Institutional Review Board (“IRB”) or ethics committee approval at each clinical trial site;

challenges in recruiting and enrolling suitable patients that meet the study criteria to participate in clinical trials, which challenges may be heightened for clinical trials that seek to enroll patients with characteristics that are found in a small population and by the novel nature of our products and product candidates;

Third party competition from alternative clinical trials in a similar space or new treatments in similar indications which may limit or ability to enroll new subjects;

difficulties in retaining and following up with subjects;

any failure by us or CROs, CMOs, and other third parties to adhere to applicable requirements, which risk may be heightened by our reliance on third parties;

safety issues, including occurrence of treatment emergent adverse events (“TEAEs”), which may result in trial suspension or the imposition of clinical holds such as those that were imposed and subsequently lifted by the FDA on our clinical trials for Cami due to the occurrence of Guillain–Barré syndrome;

the inability to manufacture adequate quantities of a product or a product candidate or other materials necessary in accordance with current Good Manufacturing Practices (“cGMPs”) to conduct clinical trials, including, for example, quality issues and delays in the testing, validation, manufacturing delays or failures at our CROs and delivery of the product or product candidate to the clinical trial sites;

changes in regulatory requirements and guidance;

changes in the treatment landscape, such as new therapies or the withdrawal of a competing product; and

lack of adequate funding to continue the clinical trial.

Any delays in the completion of clinical trials could increase costs, delay or prevent regulatory approval of our product candidates and impair our ability to maintain regulatory approval of and to commercialize any approved products.

There can be no assurance regarding the outcome of ongoing or planned clinical trials or the sufficiency of results from such clinical trials.

Drug research and clinical trials are inherently uncertain. There can be no assurance regarding the outcome of any ongoing or planned clinical trials, including whether such trials will meet their respective endpoint, whether severe adverse events will occur during the trials and whether the final results will ultimately be sufficient to support regulatory approval. For example, we are conducting a Phase 3 confirmatory trial of ZYNLONTA in combination with rituximab for the treatment of relapsed or refractory DLBCL. Despite ZYNLONTA having received accelerated approval from the FDA and conditional approval from the EMA and UK MHRA, it is possible that ZYNLONTA will fail to achieve its endpoints in this clinical trial, which could result in our inability to maintain regulatory approval. Results from earlier-stage clinical trials are even more unpredictable due to the size of the clinical trials and number of unknown factors at such early stages.

Results from preclinical studies and early-stage clinical trials of a product candidate may not be predictive of results from late-stage clinical trials of that product candidate or of any other product or product candidate. In addition, positive and promising results from preclinical studies and clinical trials of a product or product candidate in one indication may not be predictive of results from clinical trials of that product or product candidate in other indications. There may be significant differences between clinical trials, including differences in inclusion and
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exclusion criteria, efficacy endpoints, dosing regimen and statistical design. Our product ZYNLONTA has received accelerated approval from the FDA and conditional approval from the EMA and UK on the basis of overall response rate (“ORR”) from our pivotal Phase 2 clinical trial for the treatment of relapsed or refractory DLBCL. However, there can be no assurance that our confirmatory clinical trial of ZYNLONTA in combination with rituximab for the treatment of relapsed or refractory DLBCL, or any clinical trial of ZYNLONTA in other indications, will produce similar results. If the results of our confirmatory trial for ZYNLONTA or the additional trials for ZYNLONTA in other indications do not meet their primary endpoints, then we may be unable to maintain regulatory approval for ZYNLONTA or obtain regulatory approval for expanded or new indications for ZYNLONTA. Failure to maintain or obtain regulatory approval for ZYNLONTA could have an adverse impact on our ability to continue to generate and grow our revenue in the future.

From time to time, we may announce or publish preliminary data but such data are subject to the risk that one or more of the outcomes may materially change as more data become available. We also make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully evaluate all data. Therefore, positive preliminary results in any ongoing clinical trial may not be predictive of results in the completed trial. Preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, preliminary data should be viewed with caution until the final data are available.

Our products and product candidates may cause undesirable side effects or have other properties.

Undesirable side effects caused by our products or product candidates could cause us or regulatory authorities to interrupt, delay or halt clinical trials, result in more restrictive labeling, boxed warnings, REMS or the denial or withdrawal of regulatory approval by the FDA, the EMA or other regulatory authorities, subject us to product liability claims or require us to issue product recalls. In addition, undesirable side effects could impair our ability to market our products, limit patients’ and physicians’ willingness to use our products and make it more difficult for us to obtain adequate coverage and reimbursement for our products.

In our clinical trials, we have observed certain class toxicities associated with our warheads, including elevated liver enzymes, skin rash, and effusions and edema. The prescribing information for ZYNLONTA contains warnings and precautions for effusion and edema, myelosuppression, infections, cutaneous reactions and embryo-fetal toxicity. Such information is based on adverse events observed in our clinical trials. However, clinical trials by their nature utilize a sample of the potential patient population. With a limited number of subjects and limited duration of exposure, rare and severe side effects of our products or product candidates may only be uncovered with a significantly larger number of patients exposed to the drug. Therefore, there can be no assurance that ZYNLONTA will not cause side effects that are different or more severe in a greater proportion of patients when used by more patients as we commercialize the product. Similarly, as our other product candidates advance through late-stage clinical trials that involve more patients than earlier-stage clinical trials, these product candidates may cause side effects that are different in nature, severity and frequency than observed in earlier-stage clinical trials.

In addition, we are developing ZYNLONTA and certain of our product candidates in combination with other therapies, such as rituximab and checkpoint inhibitors. Combining therapies may cause additional, different or more severe side effects than when a drug is used as a monotherapy. In addition, therapies used in combination may have common toxicities. When used in combination, the severity and frequency of such undesirable side effects may be greater than the cumulative severity and frequency of such side effects when the therapies are used as monotherapies.

We may not be successful in our efforts to expand the market opportunity of ZYNLONTA, develop additional product candidates or build up our research pipeline.

ZYNLONTA is currently approved for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including DLBCL not otherwise specified, DLBCL arising from low-grade lymphoma, and also high-grade B-cell lymphoma. We are undertaking clinical trials to potentially expand ZYNLONTA into other indications and into earlier lines of therapy. However, clinical development and regulatory review is inherently unpredictable and are subject to numerous risks and uncertainties described in this “Risk Factors” section. Failure to expand the indication(s) for ZYNLONTA, could limit the market opportunity for ZYNLONTA and our potential future revenue which could have an adverse effect on our business and operations. There can be no assurance that we will succeed in expanding the market opportunity of ZYNLONTA.

A key element of our development strategy is to build a robust pipeline of PBD-based ADCs targeting both novel and clinically validated cancer targets for the treatment of hematological malignancies and solid tumors. Our license and collaboration agreement with MedImmune Limited (“MedImmune”) allows us to develop PBD-based ADCs against 11 targets. See “Item 10. Additional Information—C. Material Contracts.” We have selected all 11 targets under this agreement. There can be no assurance that these targets will yield safe, effective and commercially viable product candidates. If we wish to develop ADCs for additional targets, we must secure additional licenses from MedImmune, which we may not be able to obtain at a reasonable cost or on reasonable terms, if at all. We may not be successful in developing additional PBD-based ADC’s against the 11 targets selected under our Medimmune license or additional targets. If we are not successful in developing these new drugs, our future market opportunity and potential revenue may be negatively impacted which could adversely impact our business and operations.

We also pursue research programs involving non-ADC product candidates. However, we may be unable to identify suitable additional product candidates for clinical development, which would limit our ability to develop product candidates and our ability to obtain revenues
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from commercializing any such product candidates. Even if we are successful in continuing to build our research pipeline, the potential product candidates that we identify may fail in clinical development or commercialization.

Risks Related to Regulatory Approval and Government Regulation

We may be unable to obtain, or experience delays in obtaining, regulatory approval for our product candidates. We may be unable to maintain regulatory approval for any approved products.

Our product candidates must be approved by the FDA in the United States, by the EMA in the European Union and by comparable regulatory authorities in other jurisdictions prior to commercialization. In order to obtain regulatory approval for the commercial sale of any product candidates, we must demonstrate through extensive preclinical studies and clinical trials that the product candidate is safe and effective for use in each target indication and that manufacturing of the product candidate is robust and reproducible. The time required to obtain regulatory approval is unpredictable, typically takes many years following the commencement of clinical trials and depends upon numerous factors.

Regulatory authorities have substantial discretion in the approval process. They may refuse to accept any application or may decide that our data are insufficient for approval and require additional clinical trials or other studies. In this Annual Report and elsewhere in our public communications, we designate certain of our clinical trials as “pivotal,” if we believe that these clinical trials, if successful, will support biologics license application (“BLA”) submissions; however, there can be no assurance that any clinical trial that we designate as “pivotal” will be viewed as sufficient by the FDA, the EMA and other comparable regulatory authorities in other jurisdictions to support regulatory approval. If we are required to conduct additional clinical trials or other testing of any of our products and product candidates beyond those that are contemplated, we may incur significant additional costs and regulatory approval may be delayed or prevented.

Various regulatory programs in the United States, such as Breakthrough Therapy Designation, Fast Track Designation or Priority Review Designation, are designed to expedite the development and review of therapies to treat certain diseases. We may seek such designations, and comparable designations by foreign regulatory authorities, for one or more of our product candidates for the treatment of certain indications. However, regulatory authorities have broad discretion whether or not to grant such designations, and the receipt of such designations may not result in faster development, review or approval and does not guarantee regulatory approval.

We are developing certain of our products and product candidates in combination with other therapies. If we choose to develop a product or product candidate for use in combination with an approved therapy, we are subject to the risk that the FDA, the EMA or comparable regulatory authorities in other jurisdictions could revoke approval of, or that safety, efficacy, manufacturing or supply issues could arise with, the therapy used in combination with our product or product candidate. If the therapies we use in combination with our products and product candidates are replaced as the standard of care, the FDA, the EMA or comparable regulatory authorities in other jurisdictions may require us to conduct additional clinical trials. The occurrence of any of these risks could result in our products, if approved only for use in combination with another approved therapy, being removed from the market or being less successful commercially. Where we develop a product or product candidate for use in combination with a therapy that has not been approved by the FDA, the EMA or comparable regulatory authorities in other jurisdictions, we may not be able to market our product or product candidate for use in combination with such an unapproved therapy, unless and until the unapproved therapy receives regulatory approval. Unapproved therapies face the same risks described with respect to our product candidates currently in development. In addition, other companies may also develop their products or product candidates in combination with the unapproved therapies with which we are developing our products and product candidates for use in combination. Any setbacks in these companies’ clinical trials, including the emergence of serious adverse effects, may delay or prevent the development and approval of our products and product candidates for use in combination with an approved therapy.

In addition, the approval policies or regulations of the FDA, the EMA or comparable regulatory authorities in other jurisdictions may change in a manner rendering our clinical data insufficient for approval. Recently, the accelerated approval pathway has come under scrutiny within the FDA and by Congress. The FDA has put increased focus on ensuring that confirmatory studies are conducted with diligence and, ultimately, that such studies confirm the benefit. For example, FDA has convened its Oncologic Drugs Advisory Committee to review what the FDA has called dangling or delinquent accelerated approvals where confirmatory studies have not been completed or where results did not confirm benefit. In addition, Congress recently enacted the Food and Drug Omnibus Reform Act (“FDORA”), which included provisions related to the accelerated approval pathway and authorizes the FDA to require a post-approval study to be underway prior to approval or within a specified time period following approval. In addition, the Oncology Center of Excellence within the FDA is advancing Project Optimus, which is an initiative to reform the dose optimization and dose selection paradigm in oncology drug development to emphasize selection of an optimal dose, which is a dose or doses that maximizes not only the efficacy of a drug but the safety and tolerability as well. This shift from the prior approach, which generally determined the maximum tolerated dose, may require sponsors to spend additional time and resources to further explore a product candidate’s dose-response relationship to facilitate optimum dose selection in a target population. Other recent Oncology Center of Excellence initiatives have included Project FrontRunner, a new initiative with a goal of developing a framework for identifying candidate drugs for initial clinical development in the earlier advanced setting rather than for treatment of patients who have received numerous prior lines of therapies or have exhausted available treatment options, and Project Equity, which is an initiative to ensure that the data submitted to the FDA for approval of oncology medical products adequately reflects the demographic representation of patients for whom the medical products are intended.

Furthermore, the process and time required to obtain regulatory approval differ by jurisdiction. Approval by one regulatory authority does not ensure approval by regulatory authorities in other jurisdictions. In particular, prior to regulatory approval, regulatory authorities may require
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additional clinical trials to be conducted with a local population. Moreover, in many countries outside the United States, a drug must be approved for reimbursement before it can be approved for sale in that country, which can take considerable time and be heavily impacted by political, economic and regulatory developments.

As part of regulatory approval, we may be subject to a number of post-marketing requirements and commitments, such as post-marketing studies or clinical trials, surveillance to monitor the safety or efficacy of any approved product and risk evaluation and mitigation strategies. For example, our post-marketing obligations with respect to ZYNLONTA include a deferred pediatric trial and a trial in patients with hepatic impairment. In particular, for any products for which we receive accelerated approval from the FDA or conditional approval from the EMA or comparable regulatory authorities in other jurisdictions, we are required to complete confirmatory clinical trials. The FDA may withdraw approval of our products approved under the accelerated approval pathway if, for example, the clinical trial(s) required to verify the predicted clinical benefit of a product fails to verify such benefit or does not demonstrate sufficient clinical benefit to justify the risks associated with the product, other evidence demonstrates that a product is not shown to be safe or effective under the conditions of use, we fail to conduct any required post-marketing confirmatory clinical trial with due diligence or we disseminate false or misleading promotional materials relating to the relevant product. There can be no assurance that we will receive full approval or maintain the current accelerated approval for ZYNLONTA for the treatment of relapsed or refractory DLBCL or that we will receive full approval for ZYNLONTA in other indications or for any of product candidates for which we receive accelerated approval. In addition, any products for which we receive regulatory approval in a particular jurisdiction and the activities associated with their commercialization, including testing, manufacture, recordkeeping, labeling, storage, approval, advertising, promotion, sale and distribution, will be subject to comprehensive regulation by the FDA, the EMA or comparable regulatory authorities in other jurisdictions. These requirements include, without limitation, submissions of safety and other post-marketing information and reports, registration and listing requirements, the FDA’s cGMP requirements or comparable requirements in foreign jurisdictions, requirements relating to manufacturing, quality control, quality assurance and corresponding maintenance of records and documents, including periodic inspections by the FDA, the EMA or comparable regulatory authorities in other jurisdictions, requirements regarding the distribution of samples to physicians, tracking and reporting of payments to physicians and other healthcare providers and recordkeeping. If we are unable to complete the required confirmatory or post-marketing studies, if such studies fail to meet their safety and efficacy endpoints or if we otherwise fail to comply with post-marketing requirements and regulations, we may be unable to maintain regulatory approval for any approved products.

The policies of the FDA, the EMA and comparable regulatory authorities in other jurisdictions may change and additional regulations may be enacted. If we are slow or unable to adapt to changes in existing requirements or to the adoption of new requirements, or not able to maintain regulatory compliance, we may lose any regulatory approval that may have been obtained. We cannot predict the likelihood, nature or extent of government regulation that may arise from future legislation or administrative action, either in the United States or abroad, as the regulatory environment changes rapidly.

We may not receive Orphan Drug Designation for our product candidates.

Regulatory authorities in some jurisdictions, including the United States and the European Union, may designate drugs for relatively small patient populations as orphan drugs. In the United States, orphan drug designation entitles a party to financial incentives such as tax advantages and user fee waivers. In addition, if a product receives the first FDA approval for the indication for which it has orphan designation, the product is entitled to orphan drug exclusivity, which means the FDA may not approve any other application to market the same drug for the same indication for a period of seven years, except in limited circumstances, such as a showing of clinical superiority over the product with orphan exclusivity or where the manufacturer is unable to assure sufficient product quantity. In the European Union, orphan drug designation entitles a party to financial incentives such as reduction of fees or fee waivers and ten years of market exclusivity for the orphan indication following drug or biological product approval, provided that the criteria for orphan designation are still applicable at the time of the granting of the marketing authorization. This period may be reduced to six years if, at the end of the fifth year, the orphan drug designation criteria are no longer met, including where it is shown that the product is sufficiently profitable not to justify maintenance of market exclusivity. The respective orphan drug designation and exclusivity frameworks in the United States and in the European Union are subject to change, and any such changes may affect our ability to obtain, or the impact of obtaining, European Union or U.S. orphan designations in the future.

We may pursue orphan drug designation for one or more of our other product candidates. However, obtaining an orphan drug designation can be difficult, and we may not be successful in doing so. Even if we obtain orphan drug designation, we may not be able to maintain such designation. For example, in the process of seeking marketing authorization in the European Union, the Committee for Orphan Medicinal Products recommended to not uphold ZYNLONTA’s previously granted orphan drug designation. Even if we obtain orphan drug designation for our product candidates in specific indications, we may not be the first to obtain regulatory approval of these product candidates for the orphan-designated indication. Orphan drug designation neither shortens the development time or regulatory review time of a product candidate nor gives the product candidate any advantage in the regulatory review or approval process. In addition, exclusive marketing rights in the United States may be limited if we seek approval for an indication broader than the orphan-designated indication or may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition. Furthermore, even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different ADCs with different monoclonal antibody elements or functional elements of the conjugated molecule can be approved for the same condition. Even after an orphan product is approved, the FDA can subsequently approve the same ADC with the same monoclonal antibody element and functional element of the conjugated molecule for the same condition if the FDA concludes that the later ADC is safer, more effective or makes a major contribution to patient care. Our inability to obtain orphan drug designation for any product candidates for the treatment of rare cancers and/or our inability to maintain that designation
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for the duration of the applicable exclusivity period, could reduce our ability to make sufficient sales of the applicable product candidate to balance our expenses incurred to develop it.

We may not receive the 12 years of data exclusivity from our anticipated Reference Product Exclusivity.

We believe ZYNLONTA is the first loncastuximab tesirine product to have been licensed by the FDA and should be entitled to a period of 12 years of Reference Product Exclusivity (“RPE”). However, the FDA has not yet awarded ZYNLONTA such RPE, and the FDA may not do so for unknown reasons. The Biologics Price Competition and Innovation Act of 2009 (the “BPCIA”) established an abbreviated pathway to licensure for follow-on biologics called biosimilars. Biosimilars are biological products approved under section 351(k) of the Public Health Act Service Act (“PHS Act”) relying on the FDA’s findings of safety, purity, and potency for a licensed biologic (“Reference Product”) submitted pursuant to section 351(k) of the PHS Act. A biosimilar is highly similar to its Reference Product, excluding minor differences in clinically inactive components for which there are no clinically meaningful differences between the proposed biological product and the Reference Product in safety, purity, or potency.

The BPCIA provides a 12-year period of RPE during which an applicant may not submit, and/or the FDA may not license, a biosimilar application relying on the Reference Product. That RPE runs from the “date of first licensure,” which is the date that the FDA first licensed the Reference Product, and when such a period of RPE is awarded to a given Reference Product, it is listed in the FDA’s Database of Licensed Biological Products (the “Purple Book”) as a “Date of First Licensure.” When there is a “Date of First Licensure” listed in the Purple Book for a Reference Product, it signifies that the FDA has made a determination on the product’s eligibility for RPE and has awarded that product 12 years of RPE during which the product may not serve as a Reference Product for any proposed biosimilar. The FDA historically has been slow to make these determinations and often does not do so until there is a biosimilar application pending. There is no “Date of First Licensure” listed in the Purple Book for ZYNLONTA.

RPE is available unless the putative Reference Product falls under one of several exclusions. Specifically, RPE is not available where licensure is for a supplement for the putative Reference Product or where the licensure is for a subsequent application filed by the same sponsor or manufacturer of the biological product for a change other than a modification to the structure of the biological product that results in a change in safety, purity, and potency. The “same sponsor” includes any licensor, predecessor in interest, or other related entity. For each putative Reference Product, the FDA assesses whether an application is considered a subsequent application filed by the same sponsor or manufacturer of the biological product and whether there is a modification to the structure of the biological product previously licensed by such an entity. If there is a structural modification, the FDA then determines whether such modification would result in a change in safety, purity, or potency.

ZYNLONTA is listed in the Purple Book, but the FDA has not yet listed a Date of First Licensure. Accordingly, it is unclear whether the FDA will award ZYNLONTA its 12 years of RPE. While we are not aware of any disqualifying factors, the FDA could determine that ZYNLONTA is not entitled to RPE if it determines that an entity related to us received licensure of a similar molecule in the past.

Even if ZYNLONTA does receive its 12 years of exclusivity, the value of RPE is limited. As data exclusivity, RPE would not preclude subsequent licensure of a similar or related product unless the application sought to rely on the FDA’s findings of safety, purity, and potency for ZYNLONTA in a biosimilar application filed pursuant to section 351(k) of the PHS Act. Accordingly, the FDA could approve an identical loncastuximab tesirine product with full studies demonstrating safety, purity, and potency submitted under section 351(k) of the PHS Act. The FDA could also approve loncastuximab tesirine for a different indication or with a different route of administration or formulation despite any RPE for ZYNLONTA.

If we are found to have improperly promoted off-label use of our products, we may become subject to significant liability.

The FDA, the EMA and comparable regulatory authorities in other jurisdictions strictly regulate the promotional claims that may be made about prescription drug products, such as our products. While physicians, in the practice of medicine, may prescribe approved drugs for unapproved indications, a product may not be promoted for uses that are not approved by the applicable regulatory authority as reflected in the product’s approved labeling or for uses inconsistent with the product’s approved labeling. For example, despite ZYNLONTA being approved for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including DLBCL not otherwise specified, DLBCL arising from low grade lymphoma and high-grade B-cell lymphoma, physicians, in their professional medical judgment, may nevertheless prescribe the drug product to their patients in a manner that is inconsistent with the approved labeling. In addition, although we believe our warhead may provide for superior efficacy as compared to marketed ADCs, without head-to-head data, we will be unable to make comparative claims for our products. If we are found to have promoted such off-label use or made such unsubstantiated comparative claims, we may become subject to significant liability under the Federal Food, Drug, and Cosmetic Act (the “FDCA”) and other statutory authorities, such as laws prohibiting false claims for reimbursement.




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Failure to comply with health and data protection laws and regulations could lead to government enforcement actions, private litigation and adverse publicity and could negatively affect our operating results and business.

We receive, generate and store significant and increasing volumes of sensitive information, such as employee and patient data. In addition, we actively seek access to medical information, including patient data, through research and development collaborations or otherwise. We and any potential collaborators may be subject to federal, state, local and foreign laws and regulations that apply to the collection, use, retention, protection, disclosure, transfer and other processing of personal data, including the Health Insurance Portability and Accountability Act of 1996 (“HIPAA”), as amended by the Health Information Technology for Economic and Clinical Health Act of 2009 (“HITECH”), the Regulation 2016/679, known as the General Data Protection Regulation (the “GDPR”), as well as European Union member state implementing legislations, and the UK General Data Protection Regulation (“UK GDPR”). These laws and regulations are complex and change frequently, at times due to changes in political climate, and existing laws and regulations are subject to different and conflicting interpretations, which adds to the complexity of processing personal data from these jurisdictions. Compliance with U.S. and international data protection laws and regulations could require us to take on more onerous obligations in our contracts, restrict our ability to collect, use and disclose data, or in some cases, impact our ability to operate in certain jurisdictions. Failure to comply with these laws and regulations could result in government enforcement actions, which could include civil, criminal and administrative penalties, private litigation, and adverse publicity and could negatively affect our operating results and business. Moreover, clinical trial subjects, employees and other individuals about whom we or our potential collaborators obtain personal information, as well as the providers who share this information with us, may limit our ability to collect, use and disclose the information. Claims that we have violated individuals’ privacy rights, failed to comply with data protection laws, or breached our contractual obligations, even if we are not found liable, could be expensive and time-consuming to defend and could result in adverse publicity that could harm our business.

If we are unable to comply, or do not fully comply, with applicable fraud and abuse, transparency, government price reporting, privacy and security, and other healthcare laws, we could face substantial penalties.

Healthcare providers, physicians and third-party payors will play a primary role in the recommendation and prescription of our products for which we obtain marketing approval. Our operations, including any arrangements with healthcare providers, physicians, third-party payors and customers may expose us to broadly applicable fraud and abuse and other healthcare laws that may affect the business or financial arrangements and relationships through which we would market, sell and distribute our products. The healthcare laws that may affect our ability to operate include, but are not limited to:

The federal Anti-Kickback Statute, which prohibits any person or entity from, among other things, knowingly and willfully soliciting, receiving, offering or paying any remuneration, directly or indirectly, overtly or covertly, in cash or in kind, to induce or reward either the referral of an individual for, or the purchase, order or recommendation of an item or service reimbursable, in whole or in part, under a federal healthcare program, such as the Medicare and Medicaid programs. The term “remuneration” has been broadly interpreted to include anything of value. The federal Anti-Kickback Statute has also been interpreted to apply to arrangements between pharmaceutical manufacturers, on the one hand, and prescribers, purchasers, and formulary managers, on the other hand. There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from prosecution, but the exceptions and safe harbors are drawn narrowly and require strict compliance in order to offer protection.

Federal civil and criminal false claims laws, such as the FCA, which can be enforced by private citizens through civil qui tam actions, and the Civil Monetary Penalties Law prohibit individuals or entities from, among other things, knowingly presenting, or causing to be presented, false, fictitious or fraudulent claims for payment of federal funds, and knowingly making, using or causing to be made or used a false record or statement material to a false or fraudulent claim to avoid, decrease or conceal an obligation to pay money to the federal government. For example, pharmaceutical companies have been prosecuted under the FCA in connection with their alleged off-label promotion of drugs, purportedly concealing price concessions in the pricing information submitted to the government for government price reporting purposes, and allegedly providing free product to customers with the expectation that the customers would bill federal healthcare programs for the product. In addition, 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 FCA. As a result of a modification made by the Fraud Enforcement and Recovery Act of 2009, a claim includes “any request or demand” for money or property presented to the U.S. government. In addition, manufacturers can be held liable under the FCA even when they do not submit claims directly to government payors if they are deemed to “cause” the submission of false or fraudulent claims.

HIPAA, which, among other things, imposes criminal liability for executing or attempting to execute a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, or willfully obstructing a criminal investigation of a healthcare offense, and creates federal criminal laws that prohibit knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement or representation, or making or using any false writing or document knowing the same to contain any materially false, fictitious or fraudulent statement or entry in connection with the delivery of or payment for healthcare benefits, items or services.

HIPAA, as amended by HITECH, and its implementing regulations, which impose privacy, security and breach reporting obligations with respect to individually identifiable health information upon entities subject to the law, such as health plans, healthcare clearinghouses and certain healthcare providers, known as covered entities, and their respective business associates and covered subcontractors that perform services for them that involve individually identifiable health information. HITECH also created new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave
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state attorneys general new authority to file civil actions for damages or injunctions in U.S. federal courts to enforce HIPAA laws and seek attorneys’ fees and costs associated with pursuing federal civil actions.

Federal and state consumer protection and unfair competition laws, which broadly regulate marketplace activities and activities that potentially harm consumers.

The federal transparency requirements under the Physician Payments Sunshine Act, created under the Health Care Reform Act, which requires, among other things, certain manufacturers of drugs, devices, biologics and medical supplies reimbursed under Medicare, Medicaid, or the Children’s Health Insurance Program to report annually to the CMS information related to payments and other transfers of value provided to physicians, as defined by such law, certain other healthcare professionals, and teaching hospitals and physician ownership and investment interests, including such ownership and investment interests held by a physician’s immediate family members.

State and foreign laws that are analogous to each of the above federal laws, such as anti-kickback and false claims laws, that may impose similar or more prohibitive restrictions, and may apply to items or services reimbursed by non-governmental third-party payors, including private insurers.

State and foreign laws that require pharmaceutical companies to implement compliance programs, comply with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government, or to track and report gifts, compensation and other remuneration provided to physicians and other healthcare providers; state laws that require the reporting of marketing expenditures or drug pricing, including information pertaining to and justifying price increases; state and local laws that require the registration of pharmaceutical sales representatives; state laws that prohibit various marketing-related activities, such as the provision of certain kinds of gifts or meals; state laws that require the posting of information relating to clinical trials and their outcomes; and other federal, state and foreign laws that govern the privacy and security of health information or personally identifiable information in certain circumstances, including state health information privacy and data breach notification laws which govern the collection, use, disclosure, and protection of health-related and other personal information, many of which differ from each other in significant ways and often are not pre-empted by HIPAA, thus requiring additional compliance efforts.

Ensuring that our business arrangements with third parties comply with applicable healthcare laws and regulations is costly. If our operations are found to be in violation of any of these laws or any other current or future healthcare laws that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, disgorgement, imprisonment, exclusion from government funded healthcare programs, such as Medicare and Medicaid, contractual damages, reputational harm, diminished profits and future earnings, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations, any of which could substantially disrupt our operations. Although effective compliance programs can mitigate the risk of investigation and prosecution for violations of these laws, these risks cannot be entirely eliminated. Any action against us for an alleged or suspected violation could cause us to incur significant legal expenses and could divert our management’s attention from the operation of our business, even if our defense is successful.

Healthcare reform legislation and other changes in the healthcare industry and in healthcare spending may adversely affect our business model.

Our revenues and revenue prospects could be affected by changes in healthcare spending and policies in the United States, the European Union and any other potential jurisdictions in which we or our collaborators may seek to commercialize our products. We operate in a highly regulated industry, and new laws, regulations and judicial decisions, or new interpretations of existing laws, regulations and decisions, related to healthcare availability, the method of delivery and payment for healthcare products and services could negatively affect our business, financial condition and prospects. There is significant interest in promoting healthcare reforms, and it is likely that federal and state legislatures within the United States and the governments of other countries will continue to consider changes to existing healthcare legislation. For example, there have been and continue to be a number of initiatives at the United States federal and state levels that seek to reduce healthcare costs, including the Budget Control Act (which, subject to certain sequestration periods, imposed 2% reductions in Medicare payments to providers per fiscal year), the Infrastructure Investment and Jobs Act (which added a requirement for manufacturers of certain single-source drugs (including biologics and biosimilars) separately paid for under Medicare Part B for at least 18 months and marketed in single-dose containers or packages (known as refundable single-dose container or single-use package drugs) to provide annual refunds if those portions of the dispensed drug that are unused and discarded exceed an applicable percentage defined by statute or regulation), and the Inflation Reduction Act (which will, among other things, allow U.S. Department of Health and Human Services (“HHS”) to negotiate the selling price of certain drugs and biologics that CMS reimburses under Medicare Part B and Part D and penalize drug manufacturers that increase prices of Medicare Part B and Part D drugs at a rate greater than the rate of inflation). Individual states in the United States have also become increasingly active in passing legislation and implementing regulations designed to control pharmaceutical product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing. In addition, regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other healthcare programs. We expect that additional state and federal healthcare reform measures will be adopted in the future. Any adopted health reform measure could reduce the ultimate demand for our products or put pressure on our product pricing. We expect that the Infrastructure Investment and Jobs Act’s requirement will apply to ZYNLONTA and that we will owe refunds to CMS. It is likely that federal and state legislatures within the United States and foreign governments will continue to consider changes to existing
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healthcare legislation. We cannot predict the reform initiatives that may be adopted in the future or whether initiatives that have been adopted will be repealed or modified.

Risks Related to Commercialization and Manufacturing

We or our foreign commercialization partners may not be able to successfully commercialize our products.

To successfully commercialize our products, we must attract and retain qualified sales and marketing personnel and attain significant market acceptance of our products. We face significant competition for qualified personnel. See “—We face substantial competition, which may result in others discovering, developing or commercializing products, treatment methods or technologies before or more successfully than we do.” Establishing market acceptance of our products among physicians, patients, patient advocacy groups, third-party payors and the medical community is complex and resource intensive. The risk of our inability to establish market acceptance may be heightened as our products represent novel treatment methods and be influenced by factors beyond our control, including perceptions of ADC products generally or those of our competitors and coverage and reimbursement for our products. If we do not successfully commercialize our products, we may not generate significant product revenues and may not receive a satisfactory return on our investment into the research and development of those products.

Alternatively, we have established collaborations with third parties to commercialize our product. See “Item 10. Additional Information—C. Material Contracts.” In such collaborations, we depend on the performance of the contractual counterparty, over which we have limited control. Therefore, such collaborations may generate lower product revenues or profit than if we were to commercialize our products ourselves. We may wish to establish additional collaborations with third parties to commercialize our product. We may not be successful in entering into such marketing and distribution arrangements with third parties or in entering in such marketing and distribution arrangements with third parties on favorable terms. Moreover, such arrangements are complex and time-consuming to negotiate, document and implement and they may require substantial resources to maintain.

Coverage and reimbursement may be limited or unavailable for our products.

In both domestic and foreign markets, sales of our products will depend substantially on the extent to which the costs of our products will be covered by third-party payors, such as government health programs, commercial insurance and managed healthcare organizations. These third-party payors decide which products will be covered and establish reimbursement levels for those products. If coverage and adequate reimbursement are not available, or are available only to limited levels, we may not be able to successfully commercialize our products.

Obtaining coverage approval and reimbursement from a government or other third-party payor is a time-consuming and costly process that could require us to provide supporting scientific, clinical and cost-effectiveness data for the use of our products to the payor, which we may be unable to provide. In particular, there is significant uncertainty related to the insurance coverage and reimbursement of newly approved products. In the United States, there is no uniform policy for coverage and reimbursement and, as a result, coverage and reimbursement can differ significantly from payor to payor. The principal decisions about reimbursement for new medicines are typically made by the Centers for Medicare & Medicaid Services (the “CMS”), which decides whether and to what extent a new medicine will be covered and reimbursed under Medicare. Private payors often, but not always, follow the CMS’s decisions regarding coverage and reimbursement. Further, coverage policies and third-party payor reimbursement rates may change at any time. It is difficult to predict what third-party payors will decide with respect to coverage and reimbursement for fundamentally novel products such as ours, as there is no body of established practices and precedents for these new products. Further, one payor’s determination to provide coverage and adequate reimbursement for a product does not assure that other payors will also provide coverage and adequate reimbursement for that product. In Europe, pricing and reimbursement schemes may be more restrictive than those in the United States and vary widely from country to country and may require additional clinical trials and additional cost-effectiveness assessments. In addition, countries may restrict the price of products through the use of nationalized tender processes, controls on the profitability of drug companies, guidance to physicians to limit prescriptions, reference pricing and parallel distribution. Furthermore, many countries have increased the amount of discounts required on pharmaceutical products. This risk may be heightened by our collaboration with Sobi, pursuant to which we do not control the commercialization of, including obtaining coverage and reimbursement for, ZYNLONTA. The downward pressure on healthcare costs in general, and prescription products in particular, has become increasingly intense.

Furthermore, the containment of healthcare costs has become a priority of governments and private third-party payors. Governments and private third-party payors have attempted to control costs by limiting coverage and the amount of reimbursement for particular medications. We also expect to experience pricing pressures due to the trend towards managed healthcare, the increasing influence of health maintenance organizations and additional legislative changes. In particular, we contract with group purchasing organizations, which increases our gross-to-net deductions. These and other cost-control initiatives could cause us to decrease the price we might establish for products, which could result in lower-than-anticipated product revenues. In addition, the publication of discounts by third-party payors or authorities may lead to further pressure on the prices or reimbursement levels within the country of publication and other countries. If pricing is set at unsatisfactory levels or if coverage and adequate reimbursement of our products is unavailable or limited in scope or amount, our revenues and the potential profitability of our products in those countries would be negatively affected.

Our products and product candidates are complex and difficult to manufacture.

Our products and product candidates are complex and difficult to manufacture. Problems with the manufacturing process, including even minor deviations from the normal process, could result in product defects or manufacturing failures that result in lot failures, product recalls,
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product liability claims, insufficient inventory and make us a less attractive collaborator for potential partners. We may encounter problems achieving adequate quantities and quality of clinical-grade materials that meet FDA, EMA or other applicable standards or specifications with consistent and acceptable production yields and costs. In the past, we have received batches of certain of ZYNLONTA and our product candidates that did not meet our specifications. There can be no assurance that manufacturing issues will not occur in the future. We currently rely on third parties to manufacture all our raw materials, components and finished products and this risk may be heighted by our reliance on contract manufacturing organizations (“CMOs”) to produce our products and product candidates. See “Risks Related to Our Relationship with Third Parties.” In particular, our products, product candidates and research pipeline use PBDs, which are highly potent cytotoxins that require special handling, which may subject us to liability for any contamination or injury, or failure to comply with environmental, health and safety laws and regulations.

Increases in the costs and expenses of components or raw materials may also adversely influence our business, results of operations and financial condition. Supply sources could be interrupted from time to time and, if interrupted, it is not certain that supplies could be resumed, whether in part or in whole, within a reasonable timeframe and at an acceptable cost, or at all. The cost to manufacture our products could be significantly greater than we expect, which could limit the market acceptance of our products or reduce our potential profit on such product sales.

Furthermore, given the nature of biologics manufacturing, there is a risk of contamination during manufacturing. Any contamination could materially harm our ability to produce products and product candidates on schedule and could cause reputational damage. Some of the raw materials required in our manufacturing process are derived from biologic sources, which are difficult to procure and may be subject to contamination or recall. A material shortage, contamination, recall or restriction on the use of biologically derived substances in the manufacture of any products or product candidates could adversely impact or disrupt the commercial manufacturing or the production of clinical material, which could materially harm our development timelines and our business, financial condition, results of operations and prospects.

The market opportunities for our products and product candidates may be smaller than we estimate and any approval that we obtain may be based on a narrower definition of the patient population.

Our projections of the number of people who have the cancers we are targeting, as well as the subset of people with these cancers in a position to receive a certain line of therapy and who have the potential to benefit from treatment with our products and product candidates, are based on estimates derived from a variety of sources, including scientific literature, surveys of clinicians and healthcare professionals and other forms of market research. These estimates may be inaccurate or based on imprecise data and are based on assumptions such as labeling, acceptance, patient access and pricing and reimbursement. The number of patients in the addressable markets may turn out to be lower than expected, new treatments may be approved in the future which may reduce our potential patient population, patients may not be otherwise amenable to treatment with our products and product candidates or new patients may become increasingly difficult to identify or gain access to, all of which could negatively impact our market opportunity estimate and materially adversely affect our business, financial condition, results of operations and prospects.

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

The biotechnology industry is characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. We face competition with respect to our current products and product candidates and will face competition with respect to any products and product candidates that we may seek to develop or commercialize in the future. Our competitors include large pharmaceutical and biotechnology companies, academic institutions, government agencies and other public and private research organizations that conduct research, seek patent protection and establish collaborative arrangements for research, development, manufacturing and commercialization. Many of our competitors have significantly greater financial resources and capabilities in research and development, manufacturing, preclinical testing, conducting clinical trials, obtaining regulatory approval and marketing than we do. Furthermore, mergers and acquisitions in the biotechnology industry may result in even more resources being concentrated among a smaller number of our competitors.

Many companies are active in the oncology market and are developing or marketing products for the specific therapeutic markets that we target, including both antibody- and non-antibody-based therapies. Similarly, we also face competition from other companies and institutions that continue to invest in innovation in the ADC field including new payload classes, new conjugation approaches and new targeting moieties. Specifically, we are aware of multiple companies with ADC technologies that may be competitive with our products and product candidates, including, but not limited to, AbbVie, Inc., Daiichi Sankyo Company, GlaxoSmithKline plc, Gilead Sciences, Inc., Mersana Therapeutics Inc., Sanofi S.A., Roche Holding AG and Seagen, Inc. There are hundreds of ADCs in development, the vast majority of which were being developed for the treatment of cancer.

In the relapsed or refractory DLBCL setting, for which we are commercializing ZYNLONTA, current third-line treatment options include CAR-T, allogeneic stem cell transplant, polatuzumab in combination with bendamustine and a rituximab product, selinexor, tafasitamab in combination with lenalidomide and chemotherapy using small molecules. If Zynlonta is approved for use as a second-line treatment for DLBCL patients, we will continue to compete with CAR-T, rituximab in combination with chemotherapies, polatuzumab in combination with bendamustine and a rituximab product, and tafasitamab in combination with lenalidomide. If Zynlonta is approved for use in the frontline for frail or unfit DLBCL patients we will compete with a rituximab product in combination with mini-CHOP. In addition, we expect changes to the treatment paradigm, including potential new entrants such as bispecific antibodies. New technologies, procedures or treatments could render
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our products and product candidates obsolete and there can be no assurance that our products and product candidates would be able to compete effectively. If we are unable to compete with these new treatment options, physicians may not utilize our products and our future revenues and estimates may be negatively impacted.

Risks Related to Our Relationship with Third Parties

We rely on third parties to conduct preclinical studies and clinical trials and for the manufacture, production, storage and distribution of our products and product candidates and certain commercialization activities for our products.

We rely, and we expect that we will continue to rely, on CROs and other third parties to assist in managing, monitoring and otherwise carrying out preclinical studies and clinical trials of our products and product candidates and CMOs and other third parties for the manufacture, production, storage and distribution of our products and product candidates and certain commercialization activities for our products, including government pricing, reporting and chargeback and rebate processing, pharmacovigilance and adverse event reporting. We have less control over the activities of third parties than we would otherwise have if we relied entirely upon our own staff and we are exposed to different risks, including all the risks associated with such third parties’ businesses and financial condition, than if we performed such functions ourselves. There can be no assurance that these third parties will perform services for us in accordance with our timelines, standards and expectations. If these third parties do not successfully carry out their duties under their agreements or otherwise fail to comply with regulatory requirements, we may experience delays in our research and development activities, be unable to obtain and maintain regulatory approval, be unable to commercialize our products and be required to issue product recalls. In addition, if any of our relationships with these third parties terminate, we may not be able to enter into alternative arrangements on a timely basis or on commercially reasonable terms, and even if successful in entering into alternative arrangements, we may experience significant delays during the transition. This risk may be heightened by our use of single-source supplier arrangements. Furthermore, if a CMO or other third-party manufacturer cannot maintain a compliance status acceptable to the FDA, or if the EMA or a comparable regulatory authority in another jurisdiction does not approve these facilities for the manufacture of our products and product candidates or if it withdraws any such approval in the future, we may need to find alternative manufacturing facilities, which would be time consuming, costly and uncertain and significantly impact our ability to develop, obtain regulatory approval for, source adequate supply of or market our products and product candidates.

Our collaborators may not perform as expected, and we may be unable to maintain existing or establish additional collaborations for the development and commercialization of our products and product candidates.

We have entered into, and may in the future may enter into, collaboration agreements with third parties for the development and commercialization for products, product candidates and/or research programs. See “Item 10. Additional Information—C. Material Contracts” for a description of such agreements that are material to us. There can be no assurance that we will be able to enter into additional collaboration agreements on favorable terms, or at all. Even if we are successful in our efforts to establish collaborations, we may not be able to maintain such collaborations if, for example, development or approval of a product or product candidate is delayed or sales of an approved product are disappointing. If we fail to establish and maintain collaborations, we could bear all of the risk and costs related to the development and commercialization of any such product or product candidate, which may require us to seek additional financing, hire additional employees and otherwise develop expertise for which we have not budgeted, and may have a detrimental effect on our financial position by reducing or eliminating the potential for us to receive technology access and license fees, milestones and royalties, and/or reimbursement of development costs.

In such collaborations, we will depend on the performance of our collaborators. Our collaborators may fail to perform their obligations under the collaboration agreements or may not perform their obligations in a timely manner. If conflicts arise between our collaborators and us, the other party may act in a manner adverse to us and could limit our ability to implement our strategies. Furthermore, our collaborators may not properly obtain, maintain, enforce or defend our intellectual property or proprietary rights or may use our proprietary information in such a way as to invite litigation that could jeopardize or invalidate our proprietary information or expose us to potential litigation. In addition, we cannot control the amount and timing of resources our collaborators may devote to our products and product candidates. They may separately pursue competing products, therapeutic approaches or technologies to develop treatments for the diseases targeted by us. Competing products, either developed by the collaborators or to which the collaborators have rights, may result in the withdrawal of support for our products and product candidates. Even if our collaborators continue their contributions to the strategic collaborations, they may nevertheless determine not to actively pursue the development or commercialization of any resulting products. Additionally, if our collaborators pursue different clinical or regulatory strategies with their product candidates based on similar technology as is used in our products and product candidates, adverse events with their product candidates could negatively affect our products and product candidates. Any of these developments could harm our development and commercialization efforts which adversely impact our business and operations.

Risks Related to Intellectual Property

If we are unable to obtain, maintain or protect our intellectual property rights in any products or technologies we develop, or if the scope of the intellectual property protection obtained is not sufficiently broad, third parties could develop and commercialize products and technology similar or identical to ours, and we may not be able to compete effectively in our market.

Our success depends in significant part on our own and any of our licensors’ ability to obtain, maintain and protect patents and other intellectual property rights and operate without infringing, misappropriating, or otherwise violating the intellectual property rights of others. To protect our proprietary position, we have filed numerous patent applications both in the United States and in foreign jurisdictions to obtain
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patent rights to inventions we have developed that are important to our business, including ZYNLONTA. We have also licensed from third parties rights to patents and other intellectual property, including from MedImmune with respect to the PBD technology we use for our PBD-based ADCs, from Synaffix B.V. (“Synaffix”) for site-specific conjugation technology we use in ADCT-601 and ADCT-701, and from other parties for some of our other product candidates and related technology. If we or our current or future licensors are unable to obtain or maintain patent protection with respect to such inventions and technology, our business, financial condition, results of operations and prospects could be materially harmed.

The patent prosecution process is expensive, time-consuming and complex and uncertain, and we and our current or future licensors may not be able to prepare, file, prosecute, maintain and enforce all necessary or desirable patent applications at a reasonable cost or in a timely manner. Patents may be invalidated and patent applications may not be granted for a number of reasons, including known and unknown prior art (including our own prior art), deficiencies in the patent applications or the lack of novelty of the underlying inventions or technology. It is also possible that we or our current and future licensors will fail to identify patentable aspects of inventions made in the course of research, development and commercialization activities in time to obtain patent protection. Although we enter into non-disclosure and confidentiality agreements with parties who have access to confidential or patentable aspects of our research, development and commercialization activities, such as our employees, corporate collaborators, outside scientific collaborators, CROs, consultants, advisors and other third parties, any of these parties may breach the agreements and disclose such activities before a patent application is filed, thereby jeopardizing our ability to seek patent protection. In addition, publications of discoveries in the scientific literature often lag behind actual discoveries, and patent applications in the United States and other jurisdictions are typically not published until eighteen months after filing, or in some cases not at all. Therefore, we cannot be certain that we or our current or future licensors were the first to make the inventions claimed in our owned or licensed patents or patent applications, or that we or our current or future licensors were the first to file for patent protection of such inventions.

Moreover, in some circumstances, we may not have the right to control the preparation, filing, prosecution, maintenance, enforcement and defense of patents and patent applications covering technology that we license from third parties, and are reliant on our licensors. For example, pursuant to our agreements with MedImmune, MedImmune retains control of the preparation, filing, prosecution, maintenance, enforcement and defense of certain of the patents and patent applications licensed to us. Therefore, these patents and applications may not be prepared, filed, prosecuted, maintained, enforced and defended in a manner consistent with the best interests of our business. If our current or future licensors fail to prosecute, maintain, enforce or defend such patents and other intellectual property rights, are not fully cooperative or disagree with us as to the prosecution, maintenance or enforcement of any patent rights, or lose rights to those patents or patent applications, the rights that we have licensed may be reduced or eliminated, and our right to develop and commercialize any of our products and product candidates that are the subject of such licensed rights could be adversely affected.

The patent position of biotechnology companies generally is highly uncertain, involves complex legal and factual questions and has, in recent years, been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our and our current or future licensors’ patent rights are highly uncertain. Our owned and licensed pending and future patent applications may not result in patents being issued which protect the products or technologies we develop, in whole or in part, or which effectively prevent others from commercializing competitive technologies and products. Moreover, the patent examination process may require us or our current and future licensors to narrow the scope of the claims of our owned or licensed pending and future patent applications, which may limit the scope of patent protection that may be obtained. Additionally, the scope of patent protection can be reinterpreted after issuance. Even if our owned or licensed pending and future patent applications issue as patents, they may not issue in a form that will provide us with any meaningful protection, prevent competitors or other third parties from competing with us, or otherwise provide us with any competitive advantage. Any patents that we hold or in-license may be challenged, narrowed, circumvented or invalidated by third parties in court or in patent offices in the United States and abroad. Our owned or licensed patent applications cannot be enforced against third parties practicing the technology claimed in such applications unless and until a patent issues from such applications, and then, only to the extent the issued claims cover the technology. Our competitors or other third parties may also be able to circumvent our patents by developing similar or alternative technologies or products in a non-infringing manner.

We may be subject to a third-party pre-issuance submission of prior art to the United States Patent and Trademark Office (“USPTO”). We cannot assure you that all of the potentially relevant prior art relating to our patents and patent applications has been found. If such prior art exists, it can invalidate a patent or prevent a patent from issuing from a pending patent application. Even if patents do successfully issue and even if such patents cover our products and product candidates, third parties may initiate an opposition, interference, reexamination, post-grant review, inter partes review, nullification or derivation action in court or before patent offices, or other proceedings challenging the inventorship, validity, enforceability or scope of such patents, which may result in the patent claims being narrowed or invalidated. An adverse determination in any such proceeding or litigation could reduce the scope of, or invalidate, the patent rights we own or license, allow third parties to commercialize the products or technologies we develop and compete directly with us, without payment to us, or result in our inability to manufacture or commercialize products without infringing third-party patent rights. Such proceedings also may result in substantial cost and require significant time and attention from our scientific and management personnel, even if the eventual outcome is favorable to us. Consequently, there can be no assurance that any product, product candidate or technology we develop will be protectable or remain protected by valid and enforceable patents. In addition, if the breadth or strength of protection provided by our patents or patent applications is threatened, regardless of the outcome, it could dissuade companies from collaborating with us to license, develop or commercialize current or future products and product candidates.

Because patent applications in the United States and most other countries are confidential for a period of time after filing, and some remain so until issued, we cannot be certain that we or our current and future licensors were the first to file any patent application related to a product or product candidate. Furthermore, if third parties have filed such patent applications on or before March 15, 2013, an interference proceeding
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in the United States can be initiated by such third parties to determine who was the first to invent any of the subject matter covered by the patent claims of our applications. If third parties have filed such applications after March 15, 2013, a derivation proceeding in the United States can be initiated by such third parties to determine whether our invention was derived from theirs. Even where we have a valid and enforceable patent, we may not be able to exclude others from practicing our invention where the other party can show that they used the invention in commerce before our filing date or the other party benefits from a compulsory license. Any of the foregoing could have a material adverse effect on our business, results of operations, financial condition and prospects.

We may become involved in lawsuits to protect or enforce our patents or other intellectual property, which could be expensive, time-consuming and unsuccessful, and our issued patents covering one or more of our products, product candidates or technologies, including ZYNLONTA or the technology we use in our products and product candidates, could be found invalid or unenforceable if challenged in court.

Competitors and other third parties may infringe, misappropriate or otherwise violate our issued patents or other intellectual property or the patents or other intellectual property of our licensors. To protect our competitive position, we or our licensors may, from time to time, resort to litigation in order to enforce or defend any patents or other intellectual property rights owned by or licensed to us, or to determine or challenge the scope or validity of patents or other intellectual property rights of third parties. Enforcement of intellectual property rights is difficult, unpredictable and expensive, and many of our or our licensors’ or collaboration partners’ adversaries in these proceedings may have the ability to dedicate substantially greater resources to prosecuting these legal actions than we or our licensors or collaboration partners can. Accordingly, despite our or our licensors’ or collaboration partners’ efforts, we or our licensors or collaboration partners may not prevent third parties from infringing upon, misappropriating or otherwise violating intellectual property rights we own or control, particularly in countries where the laws may not protect those rights as fully as in the United States and the European Union. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. We may fail in enforcing our rights, in which case third parties, including our competitors, may be permitted to use our technology without being required to pay us any license fees.

If we or one of our current or future licensors were to initiate legal proceedings against a third party to enforce a patent covering one of our products or product candidates, the defendant could counterclaim that such patent is invalid or unenforceable. In patent litigation in the United States and in Europe, defendant counterclaims alleging invalidity or unenforceability are commonplace. A claim for a validity challenge may be based on failure to meet any of several statutory requirements, for example, lack of novelty, obviousness or non-enablement. A claim for unenforceability could involve an allegation that someone connected with prosecution of the patent withheld relevant information from the USPTO or the European Patent Office or made a misleading statement during prosecution. Third parties may also raise similar claims before the USPTO or an equivalent foreign body, even outside the context of litigation. Potential proceedings include reexamination, post-grant review, inter partes review, interference proceedings, derivation proceedings and equivalent proceedings in foreign jurisdictions (e.g., opposition proceedings). Such proceedings could result in the revocation of, cancellation of, or amendment to our patents in such a way that they no longer cover our technology or any products or product candidates that we may develop. The outcome following legal assertions of invalidity and unenforceability during patent litigation is unpredictable. If a defendant were to prevail on a legal assertion of invalidity or unenforceability, we would lose at least part, and perhaps all, of the patent protection on one or more of our products or product candidates or certain aspects of the PBD technology we use in our products and product candidates, and third parties, including our competitors, could compete directly with us, without payment to us. Such a loss of patent protection could have a material adverse impact on our business, financial condition, results of operations and prospects. Further, litigation could result in substantial costs and diversion of management resources, regardless of the outcome, and this could harm our business and financial results. Patents and other intellectual property rights also will not protect our technology if competitors design around our protected technology without infringing our patents or other intellectual property rights.

In addition, our patents or the patents of our licensors may become involved in inventorship or priority disputes. Interference proceedings provoked by third parties or brought by us or declared by the USPTO may be necessary to determine the priority of inventions with respect to our or our licensors’ patents or patent applications. If we or our licensors are unsuccessful in any interference proceedings to which we or they are subject, we may lose valuable intellectual property rights through the loss of one or more patents owned or licensed or our owned or licensed patent claims may be narrowed, invalidated or held unenforceable. If we or our licensors are unsuccessful in any interference proceeding or other priority or inventorship dispute, we may be required to obtain and maintain licenses from third parties, including parties involved in any such interference proceedings or other priority of inventorship disputes. Such licenses may not be available on commercially reasonable terms or at all, or may be non-exclusive. If we are unable to obtain and maintain such licenses, we may need to cease the development, manufacture and commercialization of one or more of the products and product candidates we may develop. The loss of exclusivity or narrowing of our owned or licensed patent claims could limit our ability to stop others from using or commercializing similar or identical technology and products. Any of the foregoing could have a material adverse effect on our business, results of operations, financial condition and prospects.

If we fail to comply with our obligations in the agreements under which we license intellectual property rights from third parties or otherwise experience disruptions to our business relationships with our licensors, we could lose the ability to continue the development and commercialization of our products and product candidates.

We are party to a number of intellectual property and technology licenses that are important to our business. For example, the PBD technology we use to generate our PBD-based ADCs was developed by, and is licensed on a target-exclusive basis from, MedImmune. All of our ADC products, product candidates and research programs utilize a PBD-based warhead. For more information regarding these agreements,
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see “Item 10. Additional Information—C. Material Contracts.” If we fail to comply with our obligations under these or our other agreements, including payment and diligence terms, our current and future licensors may have the right to terminate these agreements, in which event we may not be able to develop, manufacture, market or sell any product that is covered by these agreements or may face other penalties under these agreements. Such an occurrence could adversely affect the value of the products and product candidates being developed under any such agreement. Termination of these agreements or reduction or elimination of our rights under these agreements may result in our having to negotiate new or reinstated agreements, which may not be available to us on equally favorable terms, or at all, or cause us to lose our rights under these agreements, including our rights to intellectual property or technology important to our development programs. Accordingly, termination of these agreements may require us to cease the development of our products and product candidates, including ZYNLONTA.

In addition, the agreements under which we license intellectual property or technology from third parties are generally complex, and certain provisions in such agreements may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, or increase what we believe to be our financial or other obligations under the relevant agreements. Moreover, if disputes over intellectual property that we have licensed prevent or impair our ability to maintain our current licensing arrangements on commercially acceptable terms, we may be unable to successfully develop and commercialize the affected products and product candidates. Any of the foregoing could have a material adverse effect on our business, financial condition, results of operations and prospects.

We may not be successful in obtaining additional intellectual property rights necessary or required to further develop our products and product candidates.

A third party may hold intellectual property, including patent rights, that is important or necessary to the development of our products and product candidates. In order to avoid infringing these third-party patents, we may find it necessary or prudent to obtain licenses from such third-party intellectual property holders. Moreover, we may need to obtain additional licenses from our existing licensors and others to advance our research or allow commercialization of products and product candidates we may develop. In addition, many of our patents are co-owned with MedImmune, which licenses its interest in such patents to us. With respect to any patents we co-own with third parties, we may require licenses to such co-owners’ interest to such patents. In addition, we may need the cooperation of any co-owners of our patents in order to enforce such patents against third parties, and such cooperation may not be provided to us. We may be unable to secure such licenses or otherwise acquire or in-license any compositions, methods of use, processes or other intellectual property rights from third parties that we identify as necessary for products and product candidates we develop, including ZYNLONTA. The licensing or acquisition of third-party intellectual property rights is a competitive area, and more established companies may pursue strategies to license or acquire third-party intellectual property rights that we may consider attractive or necessary. These established companies may have a competitive advantage over us due to their size, capital resources and greater clinical development or commercialization capabilities. In addition, companies that perceive us to be a competitor may be unwilling to assign or license rights to us. As a result, we may be unable to obtain any such licenses at a reasonable cost or on reasonable terms, if at all. In that event, we may be required to expend significant time and resources to redesign our technology, products, product candidates or the methods for manufacturing them or to develop or license replacement technology, all of which may not be feasible on a technical or commercial basis. If we are unable to do so, we may be unable to develop or commercialize the affected products and product candidates, including ZYNLONTA, which could significantly harm our business, financial condition, results of operations and prospects. In addition, even if we obtain a license, it may be non-exclusive, thereby giving third parties, including our competitors, access to the same technologies licensed to us. In addition, any license we obtain could require us to make substantial licensing and royalty payments. If we are unable to obtain an exclusive license to any third-party or co-owned patents or patent applications, such parties may be able to license their rights to other third parties, including our competitors, and such third parties could market competing products and technology. Any of the foregoing could have a material adverse effect on our business, results of operations, financial condition and prospects.

Third parties may initiate legal proceedings against us alleging that we infringe, misappropriate, or otherwise violate their intellectual property rights or we may initiate legal proceedings against third parties to challenge the validity or scope of intellectual property rights controlled by third parties, the outcome of which would be uncertain and could have an adverse effect on the success of our business.

Our commercial success depends upon our ability to develop, manufacture, market and sell our products and product candidates and use our and our current or future licensors’ proprietary technologies without infringing, misappropriating or otherwise violating the intellectual property rights of third parties. Third parties may initiate legal proceedings against us or our current and future licensors alleging that we or our current and future licensors infringe, misappropriate or otherwise violate their intellectual property rights. In addition, we and our licensors have initiated, and we and our current and future licensors may in the future initiate, legal proceedings against third parties to challenge the validity or scope of intellectual property rights controlled by third parties, including in oppositions, interferences, reexaminations, inter partes reviews or derivation proceedings in the United States or other jurisdictions. These proceedings can be expensive and time-consuming, and many of our or our current and future licensors’ adversaries in these proceedings may have the ability to dedicate substantially greater resources to prosecuting these legal actions than we or our current and future licensors. Numerous U.S.- and foreign-issued patents and pending patent applications which are owned by third parties exist in the fields in which we are pursuing our products and product candidates. We are aware of a patent family with issued claims that could be construed to cover the linker in ADCT-601, ADCT-701 and ADCT-212. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that we may be subject to claims of infringement of the patent rights of third parties.

There are, and in the future, we may identify, other third-party patents or patent applications with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of one or more of our products and product candidates. Because patent applications can take many years to issue, there may be currently pending patent applications that may later result in issued
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patents that our products and product candidates may infringe. In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents. Parties making infringement, misappropriation or other intellectual property claims against us may obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize one or more of our products and product candidates, including ZYNLONTA. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of management and employee resources. In addition, even if we believe any third-party intellectual property claims are without merit, there is no assurance that a court would find in our favor on questions of validity, enforceability, priority or non-infringement. A court of competent jurisdiction could hold that such third-party patents are valid, enforceable and infringed, which could materially and adversely affect our ability to commercialize any of our products, product candidates or technologies covered by the asserted third-party patents. In order to successfully challenge the validity of any such third-party U.S. patents in federal court, we would need to overcome a presumption of validity. As this burden is a high one requiring us to present clear and convincing evidence as to the invalidity of any such U.S. patent claim, there is no assurance that a court of competent jurisdiction would invalidate the claims of any such U.S. patent. An unfavorable outcome could require us or our current and future licensors to cease using the related technology or developing or commercializing our products and product candidates, or to attempt to license rights to it from the prevailing party. If we are not successful in defending a third-party claim of infringement, we may be enjoined from continuing to sell our products or our business could be harmed if the prevailing party does not offer us or our current and future licensors a license on commercially reasonable terms or at all. Even if we or our current and future licensors obtain a license, it may be non-exclusive, thereby giving our competitors access to the same technologies licensed to us or our current and future licensors, and it could require us to make substantial licensing and royalty payments. In addition, we could be found liable for monetary damages, including treble damages and attorneys’ fees, if we are found to have willfully infringed a patent. A finding of infringement, misappropriation or other violation of third-party intellectual property could prevent us from commercializing our products and product candidates or force us to cease some of our business operations, which could harm our business. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar material adverse effect on our business, results of operations, financial condition and prospects. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation or administrative proceedings, there is a risk that some of our confidential information could be compromised by disclosure.

We may be subject to claims by third parties asserting that we or our employees, consultants or advisors have misappropriated their intellectual property, or claiming ownership of what we regard as our own intellectual property.

Many of our employees, consultants, and advisors, including our senior management, were previously employed at other biopharmaceutical companies, including our competitors or potential competitors. Some of these employees executed proprietary rights, non-disclosure and/or non-competition agreements in connection with such previous employment. Although we try to ensure that our employees, consultants and advisors do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these individuals have used or disclosed confidential information or intellectual property, including trade secrets or other proprietary information, of any such individual’s current or former employer. Litigation may be necessary to defend against these claims. If we fail in defending against any such claims, in addition to paying monetary damages, we may lose valuable intellectual property rights or personnel. Such intellectual property rights could be awarded to a third party, and we could be required to obtain a license from such third party to commercialize our technology or products. Such a license may not be available on commercially reasonable terms, or at all.

In addition, while it is our policy to require our employees and contractors who may be involved in the conception or development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who, in fact, conceives or develops intellectual property that we regard as our own. The assignment of intellectual property rights may not be self-executing, or the assignment agreements may be breached, and we may be forced to bring claims against third parties, or defend claims that they may bring against us, to determine the ownership of what we regard as our intellectual property. Such claims could have a material adverse effect on our business, results of operations, financial condition and prospects.


Changes in patent law could diminish the value of patents in general, thereby impairing our ability to protect our products and product candidates.

Obtaining and enforcing patents in the biopharmaceutical industry involves both technological and legal complexity and is therefore costly, time-consuming and inherently uncertain. Changes in either the patent laws or the interpretation of the patent laws in the United States or other jurisdictions could increase the uncertainties and costs surrounding the prosecution of patent applications and the enforcement or defense of issued patents. Depending on future actions by the U.S. Congress, the U.S. courts, the USPTO and the relevant law-making bodies in other countries, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

If we do not obtain patent term extension for any product candidates we may develop, our business may be materially harmed.

Patents have a limited lifespan. Due to the amount of time required for the development, testing and regulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. As a result, our owned and licensed patent portfolio may not provide us with sufficient rights to exclude others from commercializing products similar or identical to ours. In the United States, if all maintenance fees are timely paid, the natural expiration of a patent is generally 20 years from its earliest U.S. non-provisional filing date. Various extensions may be available, but the life of a patent, and the protection it affords, is limited. Even if patents covering our product candidates are obtained, once the patent life has expired for a product, we may be open to competition from competitive
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medications, including biosimilar or generic medications. At the time of the expiration of any relevant patents, the underlying technology covered by such patents can be used by any third party, including competitors. Although the patent term extensions under the Drug Price Competition and Patent Term Restoration Action of 1984 (the “Hatch-Waxman Amendments”) in the United States may be available to extend the patent term, we cannot provide any assurances that any such patent term extension will be obtained and, if so, for how long.

We may not be able to protect our intellectual property rights throughout the world.

Filing, prosecuting, enforcing and defending patents on products and product candidates in all countries throughout the world would be prohibitively expensive, and our owned or licensed intellectual property rights may not exist in some countries outside the United States or may be less extensive in some countries than in the United States. In addition, the laws of some foreign countries do not protect intellectual property rights to the same extent as federal and state laws in the United States. For example, in some jurisdictions, including Europe, it is more difficult to obtain patents protecting a medical method of use, and any such patents we are able to obtain in such jurisdictions may issue with narrower scope than their U.S. counterparts. Many countries have compulsory licensing laws under which a patent owner may be compelled to grant licenses to third parties, and many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of such patent. Consequently, we and our current and future licensors may not be able to prevent third parties from practicing our owned or licensed inventions in all countries outside the United States, or from selling or importing products made using our owned or licensed inventions in and into the United States or other jurisdictions.

If we are unable to protect our confidential information and trade secrets, our business and competitive position would be harmed.

In addition to seeking patents for some of our technology, products and product candidates, we also rely on trade secrets, including unpatented know-how, technology and other proprietary information to maintain our competitive position. Trade secrets can be difficult to protect. We seek to protect these trade secrets, in part, by entering into non-disclosure, confidentiality and invention assignment agreements with parties who have access to them, such as our employees, corporate collaborators, outside scientific collaborators, CROs, contract manufacturers, consultants, advisors and other third parties. We also enter into confidentiality agreements with our employees and consultants. However, there can be no assurance that we have entered into such agreements with each party that may have or have had access to our trade secrets or proprietary technology and processes. Despite these efforts, any of these parties may breach the agreements and disclose our proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Misappropriation or unauthorized disclosure of our trade secrets could significantly affect our competitive position and may have a material adverse effect on our business.

Enforcing a claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. Some courts both within and outside the United States may be less willing or unwilling to protect trade secrets. Furthermore, trade secret protection does not prevent competitors from independently developing substantially equivalent information and techniques, and we cannot guarantee that our competitors will not independently develop substantially equivalent information and techniques. If a competitor lawfully obtained or independently developed any of our trade secrets, we would have no right to prevent such competitor from using that technology or information to compete with us. Failure on our part to adequately protect our trade secrets or confidential information could have a material adverse effect on our business, results of operations, financial condition and prospects.

If our trademarks and trade names are not adequately protected, then we may not be able to build name recognition in our markets and our business may be adversely affected.

Our registered or unregistered trademarks or trade names may be challenged, circumvented, declared generic or determined to be infringing on other marks. There can be no assurance that competitors will not infringe our trademarks, that we will have adequate resources to enforce our trademarks or that any of our current or future trademark applications will be approved. During trademark registration proceedings, we may receive rejections and, although we are given an opportunity to respond, we may be unable to overcome such rejections. In addition, in proceedings before the USPTO and in proceedings before comparable agencies in many foreign jurisdictions, trademarks are examined for registrability against prior pending and registered third-party trademarks, and third parties are given an opportunity to oppose registration of pending trademark applications and/or to seek cancellation of registered trademarks. Applications to register our trademarks may be finally rejected, and opposition or cancellation proceedings may be filed against our trademarks, which may necessitate a change in branding strategy if such rejections and proceedings cannot be overcome or resolved. For example, in some jurisdictions the applicable trademark office has rejected our corporate name for registration, or a third party has objected to a published application for a product trademark, which, in some cases, has caused us to abandon or limit our applications, and rely more on the registration for our corporate logo.

Risks Related to Our Business and Industry

We may be unable to attract and retain senior management and key scientific personnel.

Our ability to compete in the highly competitive biotechnology industry depends upon our ability to attract, motivate and retain highly qualified managerial, scientific and medical personnel. The loss of the services of our other senior management members, other key employees and scientific and medical advisors could impede the achievement of our research, development and commercialization objectives. Members of our senior management are employed pursuant to employment agreements with no term and that require advance notice for termination, but these persons may terminate their employment with us at any time. In addition, laws and regulations on executive compensation, including
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legislation in our home country, Switzerland, may restrict our ability to attract, motivate and retain the required level of qualified personnel. In Switzerland, legislation affecting public companies has been passed that, among other things, (i) imposes an annual binding shareholders’ “say-on-pay” vote with respect to the compensation of the members of (a) the executive committee and (b) the board of directors, (ii) prohibits severance, advances, transaction premiums and similar payments to executive officers and directors, and (iii) requires companies to specify various compensation-related matters in their articles of association, thus requiring them to be approved by a shareholders’ vote. We do not maintain “key person” insurance for any of our executives or other employees. Further, we compensate our employees, in part, using share-based compensation, the effectiveness of which is influenced by the price of our common shares. If the price of our common shares continues to decrease or is subject to continued volatility, which may occur for various factors, including those beyond our control, we may be unable to attract or retain qualified personnel. Competition for skilled personnel is intense, particularly in the biotechnology industry. We face competition for personnel from other companies, universities, public and private research institutions and other organizations. This competition may limit our ability to hire and retain highly qualified personnel on acceptable terms, or at all. This possibility is further compounded by the novel nature of our product candidates, as fewer people are trained in or are experienced with product candidates of this type.

Our employees, agents, contractors or collaborators may engage in misconduct or other improper activities.

We cannot ensure that our compliance controls, policies and procedures will in every instance protect us from acts committed by our employees, agents, contractors or collaborators that would violate the laws or regulations of the jurisdictions in which we operate, including, without limitation, healthcare, employment, foreign corrupt practices, environmental, competition, and patient privacy and other privacy laws and regulations. In particular, because our business is heavily regulated and therefore involves significant interaction with public officials and because the healthcare providers and drug purchasers in certain countries are employed by their government, we face heightened risk with respect to compliance with the Foreign Corrupt Practices Act (the “FCPA”). There is no certainty that all of our employees, agents, contractors, or collaborators, or those of our affiliates, will comply with all applicable laws and regulations, particularly given the high level of complexity of these laws. We have provisions in our Code of Business Conduct and Ethics, an anti-corruption policy and certain controls and procedures in place that are designed to mitigate the risk of non-compliance with anti-corruption and anti-bribery laws. However, it is not always possible to identify and deter employee misconduct, and the precautions we take to detect and prevent this activity may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from government investigations or other actions stemming from a failure to comply with these laws or regulations. Violations of these laws and regulations could result in, among other things, significant administrative, civil and criminal fines and sanctions against us, our officers, or our employees, the closing of our facilities, exclusion from participation in federal healthcare programs including Medicare and Medicaid, implementation of compliance programs, integrity oversight and reporting obligations, and prohibitions on the conduct of our business.

Product liability lawsuits and product recalls could cause us to incur substantial liabilities and to limit development and commercialization of our products.

We face an inherent risk of product liability and product recalls as a result of the clinical testing of our product candidates in human clinical trials and as a result of the commercialization of approved products. Side effects or adverse events known or reported to be associated with, or manufacturing defects in, the products sold by us could exacerbate a patient’s condition or could result in serious injury or impairments or even death. This risk is heightened by our use of highly potent PBD-based ADCs. If we cannot successfully defend ourselves against product liability claims, we may incur substantial liabilities or be required to limit the research and development and commercialization of our products and product candidates. Even a successful defense would require significant financial and management resources. We currently carry product liability insurance in an amount that we believe is appropriate for our business. Although we maintain such insurance, any claim that may be brought against us could result in a court judgment or settlement in an amount that is not covered, in whole or in part, by our insurance or that is in excess of the limits of our insurance coverage. Our insurance policies also have various exclusions, and we may be subject to a product liability claim for which we have no coverage. If we are unable to obtain or maintain sufficient insurance coverage at an acceptable cost or to otherwise protect against potential product liability claims, it could prevent or inhibit the development of our products and product candidates and the commercial production and sale of our products.

To the extent that a product fails to conform to its specifications or comply with the applicable laws or regulations, we or our partners may be required to or may decide to voluntarily recall the product or regulatory authorities may request or require that we recall a product even if there is no immediate potential harm to a patient. Recalls are costly and take time and effort to administer and damage our reputation and attractiveness as a collaborator. Even if a recall only initially relates to a single product, product batch, or a portion of a batch, recalls may later be expanded to additional products or batches or we or our partners may incur additional costs and need to dedicate additional efforts to investigate and rule out the potential for additional impacted products or batches. Moreover, if any of our partners recall a product due to an issue with a product or component that we supplied, they may claim that we are responsible for such issue and may seek to recover the costs related to such recall or be entitled to certain contractual remedies from us. Recalls may further result in decreased demand for our or our partners’ products, could cause our partners or distributors to return products to us for which we may be required to provide refunds or replacement products, or could result in product shortages. Recalls may also require regulatory reporting and prompt regulators to conduct additional inspections of our or our partners’ or contractors’ facilities, which could result in findings of noncompliance and regulatory enforcement actions. A recall could also result in product liability claims by individuals and third-party payers and the suspension, variation, or withdrawal of regulatory approval.


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Our internal computer systems, or those of our partners, third-party CROs or other contractors or consultants, may fail or suffer security incidents, which could result in a material disruption of our research and development and commercialization programs and significant monetary losses.

Despite the implementation of security measures, our internal computer systems and those of our current or future partners, third-party CROs and other contractors and consultants have been subject to attacks by, and may be vulnerable to damage from, various methods, including cybersecurity attacks, breaches, intentional or accidental mistakes or errors, or other technological failures which can include, among other things, computer viruses, malicious codes, employee theft or misuse, unauthorized copying of our website or its content, unauthorized access attempts including third parties gaining access to systems using stolen or inferred credentials, denial-of-service attacks, phishing attempts, service disruptions, natural disasters, fire, terrorism, war and telecommunication and electrical failures. As the cyber-threat landscape evolves, these attacks are growing in frequency, sophistication and intensity, and are becoming increasingly difficult to detect. If a failure, accident or security breach were to occur and cause interruptions in our, our partners’ or our CROs’ operations, it could result in a misappropriation of confidential information, including our intellectual property or financial information, a material disruption of our programs and significant monetary losses. In particular, because of our approach to running multiple clinical trials in parallel, any breach of our computer systems may result in a loss of data or compromised data integrity across many of our programs in many stages of development. Any such breach, loss or compromise of clinical trial participant personal data may also subject us to civil fines and penalties, including under the GDPR and relevant member state law in the European Union, the UK GDPR or the CCPA, HIPAA and other relevant state and federal privacy laws in the United States. Moreover, because we maintain sensitive company data on our computer networks, including our intellectual property and proprietary business information, any such security breach may compromise information stored on our networks and may result in significant data losses or theft of our intellectual property or proprietary business information. We currently carry cybersecurity liability insurance in an amount that we believe is appropriate for our business. However, our current cybersecurity liability insurance, and any such insurance that we may obtain in the future, may not cover the damages we would sustain based on any breach of our computer security protocols or other cybersecurity attack. To the extent that any disruption or security breach results in a loss of or damage to our data or applications or other data or applications relating to our technology, products or product candidates, or inappropriate disclosure of confidential or proprietary information, our reputation could be harmed and we could incur significant liabilities and the development and commercialization of our products and product candidates could be disrupted.

Our business is subject to economic, political, regulatory and other risks associated with conducting business internationally.

We are a global organization and thus subject to the risks associated with international operations, including inflationary pressures, economic weakness or political instability in particular non-U.S. economies and markets; global trends involving pharmaceutical pricing; differing regulatory requirements for drug approvals in non-U.S. countries; differing reimbursement, pricing and insurance regimes; potentially reduced protection for, and complexities and difficulties in obtaining, maintaining, protecting and enforcing, intellectual property rights; difficulties in compliance with non-U.S. laws and regulations; changes in non-U.S. regulations and customs, tariffs and trade barriers; changes in non-U.S. currency exchange rates and currency controls; changes in a specific country’s or region’s political or economic environment; trade protection measures, economic sanctions and embargoes, import or export licensing requirements or other restrictive actions by U.S. or non-U.S. governments; negative consequences from changes in tax laws; difficulties associated with staffing and managing international operations, including differing labor relations; production shortages resulting from any events affecting raw material supply or manufacturing capabilities abroad; business interruptions resulting from geopolitical actions and conflict, war and terrorism, including the recent conflict between Russia and the Ukraine and resulting sanctions, retaliatory measures, changes in the availability and price of various materials and effects on global financial markets; business interruptions resulting from natural disasters; and the impact of public health epidemics on employees and the global economy. In addition, as a result of the United Kingdom’s exit from the European Union, we may face increasingly divergent regulations in Europe, with which may be expensive and time-consuming for us to comply.

Our business could be adversely affected by the effects of health epidemics, pandemics and natural disasters.

Our business could be adversely affected by health epidemics, pandemics and natural disasters. During the height of the COVID-19 pandemic, we modified our business practices to restrict employee travel and physical participation in meetings, events and conferences and experienced certain adverse impacts on our clinical trials and results of our commercialization efforts. In addition to these observed impacts of the COVID-19 pandemic, pandemics, epidemics or outbreaks of infectious diseases generally, including new variants of COVID-19, could also disrupt our research and development outcomes and schedules, clinical trials, commercialization efforts, supply and manufacturing of our products and regulatory submissions and interactions and could subject us to additional expenses and obligations. To the extent any pandemic, epidemic or outbreak of an infectious disease adversely affects our business and financial results, it may also have the effect of heightening many of the other risks described in this “Risk Factors” section.

In addition, any unplanned event, such as a flood, fire, explosion, earthquake, extreme weather condition, medical epidemic, power shortage, telecommunication failure or other natural or man-made accidents or incidents that result in us being unable to fully use our facilities, or the manufacturing facilities of our third-party contract manufacturers, may have a material and adverse effect on our ability to operate our business and have significant negative consequences on our financial and operating conditions. Certain of these events may become more frequent and severe as a result of the effects of climate change. Loss of access to these facilities may result in increased costs, reduced revenues, delays in the development of our products and product candidates or the interruption of our business operations for a substantial period of time. We maintain business continuity insurance coverage at levels that we believe are appropriate for our business. However, in the event of an accident or incident at these facilities, there can be no assurance that the amounts of insurance will be sufficient to satisfy any damages and losses. If our facilities, or the manufacturing facilities of our third-party contract manufacturers, are unable to operate because of
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an accident or incident or for any other reason, even for a short period of time, any or all of our research and development programs and commercialization efforts may be harmed.

If we fail to maintain an effective system of internal controls over financial reporting, we may not be able to accurately or timely report our financial condition or results of operations or prevent fraud.

Effective internal controls over financial reporting are necessary for us to provide reliable financial reports and, together with adequate disclosure controls and procedures, are designed to prevent fraud. Any failure to implement required new or improved controls, or difficulties encountered in their implementation could cause us to fail to meet our reporting obligations. In addition, any testing conducted by us in connection with Section 404 of the Sarbanes-Oxley Act of 2002, or any subsequent testing conducted by our independent registered public accounting firm, may reveal deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses or that may require prospective or retroactive changes to our financial statements, or identify other areas for further attention or improvement. The failure to maintain controls compliant with Sarbanes-Oxley Act could also cause investors to lose confidence in our reported financial information, which could have a negative effect on the trading price of our shares.

Our corporate compliance program cannot guarantee that we are in compliance with all potentially applicable laws and regulations and we have incurred and will continue to incur costs relating to compliance with applicable laws and regulations.

As a biotechnology and pharmaceutical company, we are subject to a large body of legal and regulatory requirements, guidance, and recommendations from a variety of regulatory authorities, such as the FDA, the EMA, and HHS OIG. In addition, as a publicly traded company we are subject to significant regulations, including the Sarbanes-Oxley Act of 2002. While we have developed and instituted a corporate compliance program based on what we believe are the current best practices and continue to update the program in response to newly implemented regulatory requirements and guidance, we cannot ensure that we are or will be in compliance with all potentially applicable regulations. Failure to comply with all potentially applicable laws and regulations could lead to the imposition of fines, cause the value of our common stock to decline, and impede our ability to raise capital or list our securities on certain securities exchanges.

Risks Related to Our Common Shares

The market price of our common shares has been volatile.

The market price of shares of our common shares could be subject to wide fluctuations in response to many risk factors listed in this “Risk Factors” section, and others beyond our control such as actions by our shareholders, collaborators or competitors and general market and economic conditions. In particular, pharmaceutical, biotechnology and other life sciences company stocks have historically experienced significant volatility. As we operate in a single industry, we are especially vulnerable to these factors to the extent that they affect our industry. In the past, securities class action litigation has often been initiated against companies following periods of volatility in their stock price. This risk is especially relevant for biotechnology companies, which have experienced significant stock price volatility in recent years. Securities litigation could result in substantial costs and divert our management’s attention and resources, and could also require us to make substantial payments to satisfy judgments or to settle litigation.

Future sales, or the possibility of future sales, of a substantial number of our common shares could adversely affect the price of our common shares.

Certain of our shareholders have entered into agreements with us, which contain certain lockup obligations that expire on February 2, 2024. A.T. Holdings II Sàrl (“A.T. Holdings II”) agreed that, without our prior written consent, it will not, and will not publicly disclose an intention to offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any of our common shares or any other securities convertible into or exercisable or exchangeable for our common shares, or enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of our common shares. The foregoing restrictions do not apply to any transfers or dispositions to affiliates (provided that such recipient enters into a customary lock-up agreement with us), any transfers or dispositions to partners, members, stockholders or other equity holders or those of a subsidiary (provided that such recipient is not the lockup party or an affiliate of the lockup party and such recipient enters into a customary lock-up agreement with us), sales in the public offering that occurred on February 2, 2023, pledges to Oaktree Fund Administration, LLC (“Oaktree”) pursuant to debt agreements and any transfers to Oaktree upon foreclosure, and transfers in connection with a change-of-control transaction. Oaktree Fund Administration LLC, OCM Strategic Credit Investments S.à r.l., OCM Strategic Credit Investments 2 S.à.r.l., OCM Strategic Credit Investments 3 S.à r.l., Oaktree Gilead Investment Fund AIF (Delaware), L.P., Oaktree Huntington-GCF Investment Fund (Direct Lending AIF), L.P., Oaktree Specialty Lending Corporation, and Pathway Strategic Credit Fund III, L.P. (collectively, the “Counterparties”) agreed that, without our prior written consent, it will not, and will not publicly disclose an intention to offer, pledge, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, lend, or otherwise transfer or dispose of, directly or indirectly, any of the shares held by A.T. Holdings II pledged to the Counterparties, or enter into any swap or other arrangement that transfers to another, in whole or in part, any of the economic consequences of ownership of such shares. The foregoing restrictions do not apply to any transfers or dispositions to affiliates (provided that such recipient enters into a customary lock-up agreement with us), any transfer or dispositions to partners, members, stockholders or other equity holders (provided that such recipient enters into a customary lock-up agreement with us), and transfers in connection with a change-of-control transaction. We, in our sole discretion, may release the common shares subject to the foregoing
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restrictions in whole or in part at any time. After the end of the restricted period or if we waive the foregoing restrictions, if substantial amounts of common shares are sold in the public market or if the market perceives that such sales may occur, the market price of our common shares and our ability to raise capital through an issue of equity securities in the future could be adversely affected.

Exercise of outstanding warrants will dilute existing shareholders’ ownership interest.

As of the date of this Annual Report, we have outstanding warrants to purchase an aggregate of 2,631,578 common shares at an exercise price of USD 24.70 per share (which are exercisable, on a cash or cashless basis, at the option of the holder at any time on or prior to May 19, 2025), warrants to purchase an aggregate of 1,781,262 common shares at an exercise price of USD 28.07 (which are exercisable, on a cash or cashless basis, at the option of the holder at any time on or prior to May 19, 2025) and warrants to purchase an aggregate of 527,295 common shares at an exercise price of USD 8.30 per share (which are exercisable, on a cash or a cashless basis, at the option of the holder at any time on or prior to August 15, 2032). The warrants also contain customary anti-dilution adjustments and will entitle holders to receive any dividends or other distributions paid on the underlying common shares prior to their expiration on an as-exercised basis. If our outstanding warrants are exercised into common shares, our existing shareholders’ ownership interest will be diluted.
We have never paid dividends and do not expect to pay any dividends in the foreseeable future.

We have not paid any cash dividends since our incorporation. Even if future operations lead to significant levels of distributable profits, we currently intend to reinvest any earnings in our business and do not anticipate declaring or paying any cash dividends until we have an established revenue stream to support continuing dividends. In addition, any proposal for the payment of future dividends will be at the discretion of our board of directors after taking into account various factors including our business prospects, liquidity requirements, financial performance and new product development. Furthermore, payment of future dividends is subject to certain limitations pursuant to our current and future debt instruments, Swiss law and our articles of association. In addition, the Loan Agreement limits our ability to pay dividends. See “—Risks Related to Our Financial Position and Capital Requirements.” Accordingly, investors cannot rely on dividend income from our common shares, and any returns on an investment in our common shares will likely depend entirely upon any future appreciation in the price of our common shares.

If securities or industry analysts do not continue to publish research, or publish inaccurate or unfavorable research, about our business, the price of our common shares and our trading volume could decline.

The trading market for our common shares depends, in part, on the research and reports that securities or industry analysts publish about us or our business. If one or more of the analysts who cover us downgrade our common shares or publish inaccurate or unfavorable research about our business, the price of our common shares would likely decline. In addition, if our operating results fail to meet the forecast of analysts, the price of our common shares would likely decline. If one or more of these analysts cease coverage of our company or fail to publish reports on us regularly, demand for our common shares could decrease, which might cause the price of our common shares and trading volume to decline.

The rights of our shareholders may be different from the rights of shareholders in companies governed by the laws of U.S. jurisdictions.

We are a Swiss corporation. Our corporate affairs are governed by our articles of association and by the laws governing companies incorporated in Switzerland. The rights of our shareholders and the responsibilities of members of our board of directors may be different from the rights and obligations of shareholders and directors of companies governed by the laws of U.S. jurisdictions. In particular, in the performance of its duties, our board of directors is required by Swiss law to consider the interests of our company, our shareholders, our employees and other stakeholders, in all cases with due observation of the principles of reasonableness and fairness. It is possible that some of these parties will have interests that are different from, or in addition to, shareholders’ interests. Swiss law limits the ability of our shareholders to challenge resolutions made or other actions taken by our board of directors in court. Our shareholders generally are not permitted to file a suit to reverse a decision or an action taken by our board of directors, but are instead only permitted to seek damages for breaches of fiduciary duty. As a matter of Swiss law, shareholder claims against a member of our board of directors for breach of fiduciary duty would have to be brought to the competent courts in Epalinges, Canton of Vaud, Switzerland, or where the relevant member of our board of directors is domiciled. In addition, under Swiss law, any claims by our shareholders against us must be brought exclusively to the competent courts in Epalinges, Canton of Vaud, Switzerland. For a further summary of applicable Swiss company law, see “Item 10. Additional Information—B. Memorandum and Articles of Association”. Accordingly, our shareholders do not have the same rights as those of a Delaware-incorporated company.


Our shareholders enjoy certain rights that may limit our flexibility to raise capital, issue dividends and otherwise manage ongoing capital needs.

Swiss law reserves for approval by shareholders certain corporate actions over which a board of directors would have authority in some other jurisdictions. For example, the payment of dividends and cancellation of treasury shares must be approved by shareholders. Swiss law also requires that our shareholders themselves resolve to, or authorize our board of directors to, increase our share capital. While our shareholders may authorize share capital that can be issued by our board of directors without additional shareholder approval, Swiss law limits this authorization to 50% of the issued share capital at the time of the authorization. The authorization, furthermore, has a limited duration of up to two years and must be renewed by the shareholders from time to time thereafter in order to be available for raising capital. Additionally, subject to specified exceptions, including exceptions explicitly described in our articles of association, Swiss law grants pre-emptive
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subscription rights to existing shareholders to subscribe for new issuances of shares. Swiss law also does not provide as much flexibility in the various rights and regulations that can attach to different categories of shares as do the laws of some other jurisdictions. These Swiss law requirements relating to our capital management may limit our flexibility, and situations may arise where greater flexibility would have provided benefits to our shareholders. See “Item 10. Additional Information—B. Memorandum and Articles of Association.”

Our shares are not listed in Switzerland, our home jurisdiction. As a result, our shareholders do not benefit from certain provisions of Swiss law that are designed to protect shareholders in a public takeover offer or a change-of-control transaction.

Because our common shares are listed exclusively on the New York Stock Exchange (“NYSE”) and not in Switzerland, our shareholders do not benefit from the protection afforded by certain provisions of Swiss law that are designed to protect shareholders in the event of a public takeover offer or a change-of-control transaction. For example, Article 120 of the Swiss Financial Market Infrastructure Act and its implementing provisions require investors to disclose their interest in our company if they reach, exceed or fall below certain ownership thresholds. Similarly, the Swiss takeover regime imposes a duty on any person or group of persons who acquires more than one-third of a company’s voting rights to make a mandatory offer for all of the company’s outstanding listed equity securities. In addition, the Swiss takeover regime imposes certain restrictions and obligations on bidders in a voluntary public takeover offer that are designed to protect shareholders. However, these protections are applicable only to issuers that list their equity securities in Switzerland and, because our common shares are listed exclusively on the NYSE, are not be applicable to us. Furthermore, since Swiss law restricts our ability to implement rights plans or U.S.-style “poison pills,” our ability to resist an unsolicited takeover attempt or to protect minority shareholders in the event of a change of control transaction may be limited. Therefore, our shareholders may not be protected in the same degree in a public takeover offer or a change-of-control transaction as are shareholders in a Swiss company listed in Switzerland.

U.S. shareholders may not be able to obtain judgments or enforce civil liabilities against us or certain of our executive officers and directors.

We are organized under the laws of Switzerland and our registered office and domicile is located in Epalinges, Canton of Vaud, Switzerland. Moreover, a number of our directors and executive officers are not residents of the United States, and all or a substantial portion of the assets of such persons are located outside the United States. As a result, it may not be possible for investors to effect service of process within the United States upon us or upon such persons or to enforce against them judgments obtained in U.S. courts, including judgments in actions predicated upon the civil liability provisions of the federal securities laws of the United States. We have been advised by our Swiss counsel that there is doubt as to the enforceability in Switzerland of original actions, or in actions for enforcement of judgments of U.S. courts, of civil liabilities to the extent solely predicated upon the federal and state securities laws of the United States. Original actions against persons in Switzerland based solely upon the U.S. federal or state securities laws are governed, among other things, by the principles set forth in the Swiss Federal Act on Private International Law (the “PILA”). This statute provides that the application of provisions of non-Swiss law by the courts in Switzerland shall be precluded if the result is incompatible with Swiss public policy. Also, certain mandatory provisions of Swiss law may be applicable regardless of any other law that would otherwise apply.

Switzerland and the United States do not have a treaty providing for reciprocal recognition and enforcement of judgments in civil and commercial matters. The recognition and enforcement of a judgment of the courts of the United States in Switzerland is governed by the principles set forth in the PILA. This statute provides in principle that a judgment rendered by a non-Swiss court may be enforced in Switzerland only if:

the non-Swiss court had jurisdiction pursuant to the PILA;

the judgment of such non-Swiss court has become final and non-appealable;

the judgment does not contravene Swiss public policy;

the court procedures and the service of documents leading to the judgment were in accordance with the due process of law; and

no proceeding involving the same parties and the same subject matter was first brought in Switzerland, or adjudicated in Switzerland, or was earlier adjudicated in a third state, and this decision is recognizable in Switzerland.

Anti-takeover provisions in our articles of association could make an acquisition of us, which may be beneficial to our shareholders, more difficult.

Our articles of association contain provisions that may have the effect of discouraging, delaying or preventing a change in control of us that shareholders may consider favorable, including transactions in which our shareholders may receive a premium for their shares. Our articles of association include provisions that:

in certain cases, allow our board of directors to place up to 30,753,351 common shares, as well as any treasury shares that the Company may hold from time to time, and rights to acquire an additional 17,909,703 common shares with affiliates or third parties, without existing shareholders having statutory pre-emptive rights in relation to this share placement;

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allow our board of directors not to record any acquirer of common shares, or several acquirers acting in concert, in our share register as a shareholder with voting rights with respect to more than 15% of our share capital as set forth in the commercial register;

limit the size of our board of directors to 12 members; and

require two-thirds of the votes represented at a shareholder meeting for amending or repealing the above-mentioned voting and recording restrictions, for amending the provision setting a maximum board size or providing for indemnification of our directors and members of our executive committee and for removing the chairman or any member of the board of directors before the end of his or her term of office.

These and other provisions, alone or together, could delay or prevent takeovers and changes in control. See “Item 10. Additional Information—B. Memorandum and Articles of Association.” These provisions could also limit the price that investors might be willing to pay in the future for our common shares, thereby depressing the market price of our common shares.

We are a foreign private issuer, and, as a result, we are not subject to certain rules and obligations that are applicable to a U.S. domestic public company and are not subject to certain NYSE corporate governance listing standards that are applicable to a NYSE-listed U.S. domestic public company.

We report under the Exchange Act as a non-U.S. company with foreign private issuer status. Because we qualify as a foreign private issuer under the Exchange Act and although we furnish quarterly financial information to the SEC, we are exempt from certain provisions of the Exchange Act that are applicable to U.S. domestic public companies, including (i) the sections of the Exchange Act regulating the solicitation of proxies, consents or authorizations in respect of a security registered under the Exchange Act; (ii) the sections of the Exchange Act requiring insiders to file public reports of their stock ownership and trading activities, and liability for insiders who profit from trades made in a short period of time; and (iii) the rules under the Exchange Act requiring the filing with the SEC of quarterly reports on Form 10-Q containing unaudited financial and other specified information, or current reports on Form 8-K upon the occurrence of specified significant events. Foreign private issuers are also exempt from the Regulation Fair Disclosure, aimed at preventing issuers from making selective disclosures of material information.

Furthermore, because we are a foreign private issuer, we have elected to comply with our home country governance requirements and certain exemptions thereunder, rather than complying with certain of the NYSE corporate governance listing standards that are applicable to U.S. companies listed on the NYSE. For example, we are exempt from NYSE listing standards that require a listed U.S. company to have (i) a majority of the board of directors consist of independent directors, (ii) regularly scheduled executive sessions with only independent directors, (iii) a compensation committee and a nomination and corporate governance committee consist entirely of independent directors and (iv) an internal audit function. Our audit committee is required to comply with the provisions of Section 301 of the Sarbanes-Oxley Act and Rule 10A-3 of the Exchange Act, both of which are also applicable to NYSE-listed U.S. companies. Furthermore, NYSE listing standards generally require NYSE-listed U.S. companies to, among other things, seek shareholder approval for the implementation of certain equity compensation plans and issuances of securities, which we are not required to follow as a foreign private issuer. Accordingly, our shareholders may not have the same protections afforded to shareholders of companies that are not foreign private issuers. For an overview of our corporate governance principles, see “Item 10. Additional Information—B. Memorandum and Articles of Association” and “Item 16G. Corporate Governance.”

We expect that we will lose our foreign private issuer status, which would then require us to comply with the Exchange Act’s domestic reporting regime and cause us to incur significant legal, accounting and other expenses.

We qualify as a foreign private issuer and therefore we are not required to comply with all of the periodic disclosure and current reporting requirements of the Exchange Act applicable to U.S. domestic issuers. We expect that we will no longer be a foreign private issuer as of June 30, 2023, which would require us to comply with all requirements of the Exchange Act applicable to U.S. domestic issuers, as of January 1, 2024. If we lose this status, we would be required to comply with the Exchange Act reporting and other requirements applicable to U.S. domestic issuers, which are more detailed and extensive than the requirements for foreign private issuers. We will also be required to make changes in our corporate governance practices in accordance with various SEC and stock exchange rules. We expect to incur significant legal, accounting and other expenses to comply with the reporting requirements applicable to a U.S. domestic issuer and additional expenses to obtain director and officer liability insurance.
ITEM 4.    INFORMATION ON THE COMPANY
A.History and Development of the Company
ADC Therapeutics SA is a Swiss stock corporation (société anonyme) organized under the laws of Switzerland. We were incorporated as a Swiss limited liability company (société à responsabilité limitée) on June 6, 2011, with our registered office and domicile in Epalinges, Canton of Vaud, Switzerland. We converted to a Swiss stock corporation under the laws of Switzerland on October 13, 2015. In May 2020, we completed our initial public offering on the NYSE under the ticker symbol “ADCT”.
Our registered office is located at Biopôle, Route de la Corniche 3B, 1066 Epalinges, Switzerland and our phone number is +41 21 653 02 00. We are headquartered in Lausanne, Switzerland, and maintain research and development laboratories in London, clinical development operations in New Jersey and in Lausanne, commercial operations in New Jersey and CMC operations in the San Francisco Bay Area. Our
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website is www.adctherapeutics.com. Information contained on or accessible through our website is not part of, and is not incorporated by reference into, this Annual Report.
Our principal expenditures in the past three fiscal years have been our research and development expenses, and commercial expenses during the past two fiscal years, as more fully described elsewhere in this Annual Report.
We are subject to the informational requirements of the Exchange Act. Accordingly, we are required to file reports and other information with the SEC, including annual reports on Form 20-F and reports on Form 6-K. The SEC maintains an Internet site at www.sec.gov that contains reports, proxy and information statements and other information we have filed electronically with the SEC. We maintain a corporate website at www.adctherapeutics.com. The reference to our website is an inactive textual reference only, and information contained therein or connected thereto is not incorporated into this Annual Report.
B.Business Overview

We are a fully-integrated commercial-stage biotechnology company helping to improve the lives of those affected by cancer with our next-generation, targeted antibody drug conjugates (“ADCs”). Our flagship product, ZYNLONTA® (loncastuximab tesirine or Lonca) received accelerated approval from the FDA on April 23, 2021, and launched commercially in the U.S. shortly thereafter, for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including diffuse large B-cell lymphoma (“DLBCL”) not otherwise specified, DLBCL arising from low-grade lymphoma, and also high-grade B-cell lymphoma. Our objective is to establish ZYNLONTA as the third line+ DLBCL standard of care while exploring ZYNLONTA in earlier lines of therapy and in combinations to expand our market opportunity. We have a strong validated technology platform including our highly potent pyrrolobenzodiazepine (PBD) technology and are advancing this proprietary PBD-based ADC technology to transform the treatment paradigm for patients with hematologic malignancies and solid tumors. Additionally, we have a growing toolbox of different components allowing us to work on next-generation ADC products. By leveraging our R&D strengths, our disciplined approach to target selection and our preclinical and clinical development strategy, we have created a diverse portfolio and research pipeline. Our clinical-stage PBD-based pipeline consists of two company-sponsored candidates, ADCT-901 (KAAG1) and ADCT-601 (mipasetamab uzoptirine) (AXL), as well as one clinical-stage candidate, ADCT-602 (CD22), which is being developed in collaboration with a partner. Our preclinical-stage PBD-based pipeline consists of one company-sponsored candidate, ADCT-212 (PSMA), as well as one preclinical-stage candidate, ADCT-701(DLK-1), which is being developed in collaboration with our partner NCI. We are also committed to broadening our ADC platform by expanding new antibody constructs and payloads and advancing our differentiated next-generation assets.
Strengths

We are a pioneer and leader in the ADC field with best-in-class specialized capabilities unique to ADCs. We have a strong validated technology platform in highly potent PBD-based ADCs, a growing toolbox to develop next-generation assets and a proven executional track record. In the discovery stage, we utilize intelligent choices of targeting moiety, linker and drug permutation. The intersection of our technical capabilities, integrated organization and depth of experience allows us to move efficiently through preclinical development into the clinic in pursuit of therapeutic window. Further, our CMC capabilities include high quality, consistent and scalable drug manufacturing for complex, highly potent molecules through third party CMOs. Our proven track record includes three clinical assets with proof of concept and two additional assets in the clinic. We have validated and integrated capabilities enabling the FDA and EMA approval and launch of ZYNLONTA, as well as success with a PBD-based ADC payload despite failures from others.

Strategy

Our longer-term strategy to maximize the value of the Company is based on three core pillars: optimizing the ZYNLONTA opportunity, advancing the PBD-based pipeline and broadening our ADC platform and leadership, as further described below.
Maximize the ZYNLONTA opportunity.
Establish ZYNLONTA as the DLBCL standard of care in the third and later lines of therapy. Our experienced commercial organization is unlocking this market opportunity by engaging with both academic and community-based physicians regarding ZYNLONTA’s differentiated product profile. ZYNLONTA is also well-positioned in the evolving DLBCL market as ~60% of CAR-T patients will relapse and in a recent survey of relevant prescribing physicians, 27% have not referred a single patient for CAR-T and another 20% have referred only 1 patient over the last 3 years.

Establish ZYNLONTA as the combination agent of choice. We are exploring the potential to move ZYNLONTA into earlier lines of therapy in combination with rituximab and other novel combinations. We are conducting LOTIS-5, a confirmatory Phase 3 clinical trial of ZYNLONTA in combination with rituximab that, if successful, we believe will serve as the basis for a supplemental BLA (“sBLA”) for ZYNLONTA for the treatment of relapsed or refractory DLBCL in second or later line transplant-ineligible patients. In addition, we are conducting LOTIS-9 which is a Phase 2 clinical trial of ZYNLONTA in combination with rituximab in previously untreated unfit or frail patients with DLBCL who typically do not receive full doses
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of R-CHOP and LOTIS-7 which is a Phase 1b clinical trial of ZYNLONTA in combination with other anti-cancer agents such as polatuzumab, as well as a bispecific antibodies such as glofitamab and mosunetuzumab, in patients with relapsed or refractory B-cell non-Hodgkin lymphoma. We are also collaborating with IGM Biosciences on exploring the combination of ZYNLONTA and imvotamab (another bispecific antibody). In aggregate, we believe these development efforts, if successful, will enable ZYNLONTA to ultimately move into earlier lines of treatment with significant patient populations, potential for extended treatment and in turn greater ability to address unmet medical need.

Continue to advance the development of ZYNLONTA outside of the United States through strategic partnerships. We are committed to providing global access to ZYNLONTA to patients who may benefit from treatment. We have entered into strategic agreements to maximize the commercial potential of ZYNLONTA, including an exclusive license agreement with Sobi for all regions other than the U.S., greater China, Singapore and Japan, an exclusive license agreement with Mitsubishi Tanabe Corporation (“MTPC”) in Japan, and a joint venture with Overland Pharmaceuticals in greater China and Singapore. On December 20, 2022 the European Commission (“EC”) granted conditional marketing authorization for the use of ZYNLONTA for the treatment of relapsed or refractory DLBCL in third or later lines of therapy.

Advance our other clinical-stage and preclinical PBD-based programs, to address multiple indications in areas of high unmet medical need. We have two clinical-stage company-sponsored candidates, ADCT-901 (KAAG1) and ADCT-601 (mipasetamab uzoptirine) (AXL), as well as one clinical-stage candidate, ADCT-602 (CD22), which is being developed in collaboration with a partner. We have one preclinical-stage company-sponsored candidate, ADCT-212 (PSMA), as well as one preclinical-stage candidate, ADCT-701 (DLK-1), which is being developed in collaboration with our partner NCI. We are also pursuing partnering opportunities with our clinical-stage product candidate, Cami, which produced positive results in our Phase 2 study.

Broaden our ADC platform and leadership. Our technology platform extends beyond PBD-based assets. Using new antibody constructs and payloads, we are leveraging our expertise in the ADC field to continue building our toolbox to study and advance differentiated next-generation assets.

Overview of Antibody Drug Conjugates
Antibody drug conjugates are an established therapeutic approach in oncology. ADCs selectively deliver potent chemotherapeutic cytotoxins directly to tumor cells, with the goal of maximizing activity in tumor cells while minimizing toxicity to healthy cells. An ADC consists of three components: (i) a monoclonal antibody that selectively targets a distinct antigen preferentially expressed on tumor cells or other cells in the tumor microenvironment; (ii) a cytotoxic molecule, often referred to as the toxin or the warhead, that kills the target cell; and (iii) a chemical linker that joins together the antibody and the warhead. The warhead and the linker are together referred to as the payload. The figure below shows the three components of an ADC.
adc-20221231_g1.jpg

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Schematic representation of an ADC, showing its three components.
Because the antibody is designed to selectively target a distinct antigen preferentially expressed on tumor cells or other cells in the tumor microenvironment, an ADC will bind preferentially to those cells that express the specific antigen. Upon binding to the antigen, most ADC molecules are internalized by the cell where the cytotoxic warhead is released through either cleavage of the linker or degradation of the entire antibody by cellular processes. Once a sufficient number of cytotoxic molecules have been released intracellularly, apoptosis occurs when the cell next attempts to replicate.
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Components of Antibody Drug Conjugates
Monoclonal Antibodies
The first component of an ADC is the monoclonal antibody, which is a highly specific targeting agent that selectively binds to a distinct antigen preferentially expressed on tumor cells or other cells in the tumor microenvironment. Since ADCs are designed to selectively target an antigen that is expressed in the tumor microenvironment, ADCs have less effect on cells that do not express the target antigen. Due to this specificity, the cytotoxins used in ADCs can be much more potent than those used in traditional chemotherapies, allowing normally systemically intolerable doses of cytotoxins to be directed at tumors.
In an ADC, two significant factors are considered in the selection of the antigen to which the antibody is targeted: (i) the preferential expression on tumor cells or other cells in the tumor microenvironment; and (ii) the level of antigen expression on these cells. As a result, it is generally recognized that high and consistent (i.e., homogeneous) antigen expression throughout the tumor microenvironment correlates with higher efficacy of the ADC. By contrast, the ability to achieve a therapeutic concentration of cytotoxins in the target cell diminishes as the level of antigen expression decreases.
Warheads

The second component of an ADC is the warhead which is conjugated to the antibody. Usually these warheads are cell-killing toxins. Cytotoxins commonly used in ADCs include tubulin inhibitors, such as maytansines and auristatins, and DNA-damaging toxins, such as calicheamicin. Recently, other DNA damaging or alkylating warheads such as camptothecins and pyrollobenzadiazepines have been utilized in approved ADCs. Once an ADC is internalized by the target cell, the warhead is released and ultimately causes cell death via a warhead-specific mechanism. Some warheads have the additional ability to diffuse into and kill neighboring cells in the tumor microenvironment. This bystander effect can be useful in enhancing the efficacy of ADCs in tumors with heterogeneous antigen expression by providing a mechanism to kill neighboring tumor cells that do not express the target antigen.

More recently, other drugs such as immunostimulants have been explored in an ADC format. Examples are TLR and STING agonists, which can activate the innate immune system driving an anti-tumor response. Systemic use of such immune agonists has been widely studied in the clinic but with limited success because the systemic exposure results in undesired toxicities in patients. Such systemic toxicities can be mitigated by conjugating the immune agonist to a tumor specific antibody, creating a so called Immunostimulatory Antibody Drug Conjugate (ISAC).
Chemical Linkers
The third component of an ADC is the chemical linker used to attach the warhead to the antibody. The chemical linker directly affects the efficacy, safety and tolerability of an ADC. Before an ADC is internalized by the target cell, it is critical that the chemical linker provides a stable connection between the warhead and the antibody in systemic circulation, as premature release of the warhead can cause significant off-target toxicity. After an ADC is internalized by the target cell, it is critical that the warhead is released from the antibody to promote rapid and efficient cell killing.
Linkers used in ADCs fall into two categories: cleavable and non-cleavable. Cleavable linkers release the warhead intracellularly after proteolytic cleavage of the linker by intracellular enzymes such as cathepsin or after weakening of the linker by the intracellular environment. In contrast, non-cleavable linkers are resistant to this type of cleavage and instead rely on the degradation of the entire antibody. As a result, the released payload in ADCs that use non-cleavable linkers remains attached to a fragment of the antibody, which limits the warhead’s permeability to adjacent cells, reducing the bystander effect and potentially the ADC’s efficacy in tumors with heterogeneous target antigen expression.
Key Strengths and Attributes of Antibody Drug Conjugates
Antibody drug conjugates are an important part of the cancer treatment paradigm for the following reasons:
Selective Targeting. Traditional chemotherapies are unable to distinguish between healthy cells and tumor cells. As a result, these therapies typically have a narrow therapeutic window (i.e., the dose range that can treat disease effectively without causing unacceptable toxic side effects). In contrast, ADCs, through their use of antigen-specific antibodies, target tumor cells or other cells in the tumor microenvironment with greater selectivity than do traditional chemotherapies. This selective targeting allows ADCs to use potent cytotoxins or immune agonists at dose levels that otherwise would not be tolerable. As a result, ADCs can represent a highly effective treatment approach while maintaining manageable side effects.
Wide Addressable Patient Population. ADCs represent a treatment approach that expands the treatment options available to cancer patients. Many therapies are not appropriate for certain patient populations. For example, chemotherapy may not be appropriate when the patient is too sick to tolerate or does not respond to available chemotherapeutics, stem cell transplant may not be appropriate when the patient is frail, and some novel targeted therapies such as CAR-T (i.e., a type of treatment in which a patient’s T cells are modified
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in the laboratory so they will attack cancer cells) may not be appropriate when there is significant comorbidity. As a result of these limitations, there remains a significant unmet medical need for patients for whom other treatment options are inappropriate or ineffective.
Potential in Relapsed or Refractory Patients. Traditional therapies typically have limited effectiveness for patients who exhibit relapsed (i.e., the cancer returns after an initial positive response to treatment) or refractory (i.e., the cancer is resistant to treatment) disease. In contrast, some ADCs have proven efficacious in such patient populations while maintaining a manageable tolerability profile. Therefore, ADCs represent an important part of the cancer treatment paradigm, expanding the treatment options available to patients suffering from relapsed or refractory disease.
The Antibody Drug Conjugates Landscape
While ADCs are an important part of cancer treatment, there are certain challenges in developing ADCs that achieve the optimal therapeutic index (i.e., the balance between efficacy and tolerability). These challenges include (i) developing warheads that are sufficiently potent to target cancers with low or heterogeneous antigen expression without causing unacceptable toxic side effects, (ii) designing linkers that are stable in systemic circulation but that release the warhead once the ADC has been internalized by the cell, and (iii) creating ADCs that achieve durable responses. We believe that our expertise in ADC research and development and access to a toolbox of different ADC technologies enables us to develop ADCs that overcome these challenges.
Our Next-Generation PBD-Based Antibody Drug Conjugates
We develop ADCs that use next-generation PBD warhead technology. Using this technology, we have developed a diverse and balanced portfolio of highly targeted ADCs with potential for improved therapeutic indices that may allow us to broaden the scope of addressable cancer patients for whom treatment with ADCs is feasible and appropriate.
PBDs are a class of antibiotic or anti-tumor molecules. First-generation PBDs, developed in the early 2000s, were originally used as stand-alone chemotherapeutics. They were subsequently explored for use as ADC warheads. However, these first-generation PBD warheads’ hydrophobicity generally resulted in manufacturability issues and they exhibited significant toxicities that resulted in very narrow therapeutic indices. In contrast, our ADCs use next-generation PBD technology, which is designed to produce warheads that are less hydrophobic, causing them to be easier to conjugate and, based on preclinical data, have less off-target toxicity than first-generation PBD warheads. Through further in-house development of conjugation technology and highly stable linker design, we aim to develop PBD-based ADCs that achieve significant clinical activity and durable responses in difficult-to-treat patients.
Our ADCs use PBD dimer warheads, which are two PBD monomer molecules bonded together. Once inside a target cell, these PBD dimers bind irreversibly to DNA without distorting the double helix, potentially evading DNA repair mechanisms that can otherwise reduce ADCs’ effectiveness. PBD dimers do this by covalently binding two guanines from opposite DNA strands in the minor groove, forming highly cytotoxic interstrand cross-links that block DNA strand separation, thus disrupting essential DNA metabolic processes such as replication, and ultimately resulting in cell death. The figure below shows the mechanism of action of our PBD-based ADCs.
adc-20221231_g2.jpg
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The mechanism of action of our PBD-based ADCs.

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We believe that our ADCs, using next-generation PBD technology, have the potential to become an important part of the cancer treatment paradigm due to their following potential benefits:
Cytotoxic Potency. The PBD dimer warheads used in our ADCs have been shown preclinically to be approximately 100 times more potent than warheads used in currently marketed ADCs, such as auristatin, maytansine and calicheamicin. The figure below shows the relative in vitro cytotoxic potency of various ADC warheads and common chemotherapeutics in comparison to a PBD dimer. Despite their potency, however, the PBD dimer warheads used in our ADCs have demonstrated a manageable tolerability profile in our preclinical studies and clinical trials to date.
adc-20221231_g3.jpg
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The relative in vitro cytotoxic potency of various ADC warheads (in red) and common chemotherapeutics (in black) in comparison to a PBD dimer. “IC50” means the drug concentration causing 50% inhibition of the desired activity, and “M” means molar. Source: Spirogen, a subsidiary of AstraZeneca plc.

Activity in Tumors with Low-Expressing Targets. Tumor cells typically require a threshold number of warhead molecules to be internalized for efficient cell killing. The high potency of our PBD-based warheads means that, compared to other warheads, fewer molecules of warhead should be needed to be internalized into the cancer cell to kill it. In cancer cells with low levels of antigen expression, ADCs with less potent warheads cannot bind in sufficient quantities to be effective. We believe that the potency of our PBD-based warheads may allow us to develop ADCs that target antigens with low expression levels in the tumor microenvironment, potentially increasing the range of cancers amenable to treatment with ADCs.
Durable Responses. Cross-links in DNA occur when an agent reacts with two nucleotides of DNA, forming a covalent linkage between them. The cross-links can occur in the same strand (i.e., intrastrand) or between opposite strands of DNA (i.e., interstrand). Our PBD-based ADCs create interstrand cross-links in the target cells’ DNA. These interstrand cross-links persist in target cells and can lie dormant, potentially for weeks. We believe that this allows our ADCs to target slowly proliferating cancer cells, including cancer stem cells. The persistence of the interstrand cross-links is explained by the fact that these cross-links do not distort the DNA helix. Cells have natural DNA repair mechanisms that detect structural changes to DNA, including those caused by cytotoxic warheads, and repair the DNA back to its original state. Warheads that create intrastrand cross-links, and even some warheads that create interstrand cross-links such as calicheamicin, distort the DNA helix, triggering the cells’ DNA repair mechanisms, thereby reducing their efficacy and leading to drug resistance. As PBD cross-links are non-distortive, they are designed to be able to evade the cells’ DNA repair mechanisms. In addition, tumor cells also induce the expression of certain transporter proteins (i.e., proteins that are able to transport warheads across the membrane outside the tumor cell) or the activation of detoxifying mechanisms that lead to inactive toxins. These potential resistance mechanisms limit traditional ADCs’ efficacy, resulting in limited clinical responses and relapses. Based on data to date, very few resistance mechanisms have been reported for PBDs. We believe that all of these factors may contribute to the frequency and durability of responses in heavily pre-treated and primary refractory patients that we have observed in our clinical trials.
Bystander Effect. The bystander effect occurs when a released warhead is able to diffuse into and kill neighboring cells in the tumor microenvironment, irrespective of those cells’ antigen expression. Upon binding to the target antigen and internalization of our ADCs
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into the tumor cell, the warhead is designed to induce apoptosis. This is followed by the release of free PBD dimers into the tumor microenvironment. Since our PBD-based warheads are cell-permeable, they may be able to diffuse into adjacent cells and kill them in an antigen-independent manner. We believe that this may allow us to develop ADCs that target antigens with heterogeneous expression levels in the tumor microenvironment, potentially increasing the range of cancers amenable to treatment with ADCs. Once the PBD is released into circulation outside the tumor microenvironment, it is rapidly excreted with a short half-life, thus limiting overall systemic toxicity. We believe that this results in our ADCs’ bystander effect being controlled and generally limited to tumor cells.
Immunogenic Cell Death. PBD warheads have been observed to induce immunogenic cell death, whereby a cancer cell’s death expresses certain stress signals that induce the body’s anti-tumor immune response through the activation of T cells and antigen-presenting cells. This opens up the potential for combining our ADCs with other therapies, particularly with immuno-oncology therapies such as checkpoint inhibitors, that are specifically designed to activate the patient’s own immune system to combat cancer.
Our New Technologies and Platforms

In addition to the PBD dimer platform, we have developed a proprietary exatecan drug-linker platform. Exatecans belong to the family of camptothecins, which are naturally occurring pentacyclic quinoline alkaloids that bind to DNA topoisomerase I, inhibiting DNA relegation and finally causing apoptosis. Campothecins such as exatecan therefore possesses high cytotoxic activity against a variety of tumors. Clinical development of exatecan as a stand-alone chemotherapy has been done, but was terminated due to the lack of a therapeutic window. Recently, the use of deruxtecan, based on a close analogue of exatecan was successfully used to develop the Her2 specific ADC trastuzumab deruxtecan which is now approved in the US and Europe for the treatment of Her2 expressing tumors.

The cytotoxic potency of exatecan is significantly lower compared to PBD dimer warheads, and hence we will develop exatecan based ADCs for those tumor targets that are not amenable for a PBD based ADC approach. For instance, targets that are not uniquely expressed on tumors but also show expression on healthy tissue (such as Her2) could be addressed with an exatecan based ADC. Like PBD warheads, exatecan itself has bystander activity and is also believed to cause immunogenic cell death.

Finally, we have access to a proprietary DNA alkylating cytotoxic under our development and option to license agreement with IntoCell (South Korea).

























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ADCT Toolbox


adc-20221231_g4.jpg
























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Our Portfolio and Pipeline

The following table provides an overview of our current product portfolio and research pipeline:adc-20221231_g5.jpg
adc-20221231_g6.jpg
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Anticipated milestones set forth in this chart are subject to further future adjustment. NTE: Non-Transplant Eligible
*Zynlonta was approved under the FDA accelerated approval program and continued approval for this indication is contingent upon verification and description of clinical benefit in a confirmatory trial and is underway in our Phase 3 confirmatory clinical trial, LOTIS 5.

The Lymphoma Disease Setting - ZYNLONTA

Lymphoma is a group of several closely related blood cancers that develop in the lymphatic system, an interconnected network of vessels and nodes that circulate a fluid called lymph. The lymph is rich in lymphocytes, a type of white blood cells that help the body fight off infections and other diseases. Lymphoma occurs when lymphocytes become cancerous and are typically classified into two groups: non-Hodgkin lymphoma (“NHL”) and Hodgkin lymphoma (“HL”).

Non-Hodgkin Lymphoma

Non-Hodgkin lymphoma is a heterogeneous group of cancers of the lymphatic system that is characterized by the overproduction and accumulation of lymphocytes, either B lymphocytes (“B cells”) or T lymphocytes (“T cells”). These cancerous lymphocytes travel to and accumulate in other organs, including the lymph nodes, bone marrow and spleen, and disrupt these organs’ normal functioning. According to Decision Resources Group (“DRG”), in 2022, there were an estimated 154,500 total new cases of NHL in the United States, France, Germany, Italy, Spain and the United Kingdom (“EU5”). The various types of NHL are distinguished by the characteristics of the cancer cells associated with each disease type. The designations “indolent” (i.e., slow growing) and “aggressive” (i.e., fast growing) are often applied to types of NHL based on the diseases’ progression and prognosis. The figure below shows the distribution of NHL in the United States and EU5.

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adc-20221231_g7.jpg
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The distribution of NHL in the United States and EU5. Figures represent the estimated total number of new cases of the respective diseases in 2022.
Diffuse Large B-Cell Lymphoma
Diffuse large B-cell lymphoma is an aggressive type of NHL that develops from the B cells in the lymphatic system. It is the most common type of NHL, with an estimated 50,400 total new cases of DLBCL in the United States and EU5 in 2022 according to DRG. Approximately 25,200 new cases were in the United States and approximately 25,200 new cases were in EU5.
Treatments for DLBCL can be divided into first-line, second-line and third-line and later therapies. The figure below shows the current DLBCL treatment landscape.

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adc-20221231_g8.jpg
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Westin J, Sehn LH. CAR T cells as a second-line therapy for large B-cell lymphoma: a paradigm shift? Blood. 2022 May 5;139(18):2737-2746, 2744. doi: 10.1182/blood.2022015789. PMID: 35240677. This Electronic Copy of Copyrighted Material Was Made and Delivered to the Government Under License from RightsDirect – No Further Reproduction is Permitted.
First-line therapy generally involves chemotherapy with a rituximab backbone, such as R-CHOP (i.e., a chemotherapy regimen consisting of cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate and prednisone, plus rituximab). Although first-line therapy is effective in some patients, according to DRG, approximately 40% of patients require second-line therapy. The prognosis is generally poor for patients who do not respond to first-line therapy. For example, a study of two large randomized trials and two academic databases found that for patients who exhibit primary refractory disease, only 20% displayed a response and only 3% displayed a complete response to subsequent chemotherapy.
Second-line therapy depends on whether the patient is eligible for stem cell transplant (i.e., transplant involving a healthy donor’s stem cells). Eligibility is determined by a patient’s physical fitness and response to high-dose salvage chemotherapy. Second-line therapy involves cellular therapies such as CAR-T, polatuzumab in combination with bendamustine and a rituximab product, tafasitamab in combination with lenalidomide and chemotherapy. According to DRG, of the patients who require treatment in the second-line setting, approximately 50% will require third-line therapy.
Current third-line therapies include ZYNLONTA, CAR-T, allogeneic stem cell transplant, polatuzumab in combination with bendamustine and a rituximab product, selinexor, tafasitamab in combination with lenalidomide and chemotherapy using small molecules. Given the side effects and the fitness required to undergo CAR-T and allogeneic stem cell transplant, patients who are ineligible to receive CAR-T and autologous stem cell transplant as a second-line therapy may also be ineligible to receive CAR-T or allogeneic stem cell transplant as a third-line therapy. Other treatment options may be limited in efficacy or associated with severe side effects. The limited treatment options and poor outcomes observed in patients with relapsed or refractory DLBCL highlights the urgent need for alternative treatment strategies. ZYNLONTA has the potential to address this unmet medical need.

Hodgkin Lymphoma– Camidanlumab Tesirine
Hodgkin lymphoma is a rare but highly curable type of neoplasm of the lymph nodes. These lymphoid malignancies travel to other organs, such as the liver, lungs and bone marrow, and disrupt these organs’ normal functioning. According to DRG, in 2020, there were an estimated 17,900 total new cases of HL in the United States and EU5. Approximately 9,300 new cases were in the United States and approximately 8,600
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new cases were in EU5. Patients diagnosed with HL generally have good prognoses, with a five-year overall survival rate of approximately 87%.
Treatments for HL can be divided into first-line, second-line and third-line and later therapies. The figure below shows the current HL treatment landscape.
adc-20221231_g9.jpg
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Current HL treatment landscape. Patient population data presented are for the United States and EU5. Not all relapsing patients will receive treatment. The blue box represents the initial potential addressable patient population for Cami, if approved as a third-line therapy.
Current third-line therapies include an alternative chemotherapy regimen not previously used or immunotherapy with brentuximab vedotin. Although brentuximab vedotin and checkpoint inhibitors have achieved relatively high ORRs compared to traditional chemotherapy regimens, these therapies are moving into earlier lines of treatment. Other third-line chemotherapy regimens involving bendamustine, everolimus or lenalidomide have only shown limited efficacy. Other therapies include allogeneic stem cell transplantation. However, given that stem cell transplant requires patients to be physically fit, the proportion of eligible patients is small. The limited treatment options and generally poor outcomes observed in patients with relapsed or refractory HL highlights the urgent need for alternative treatment strategies.

The Leukemia Disease Setting – ADCT-602

Leukemia is a group of several closely related blood cancers that develop in the bone marrow. Once the marrow cell undergoes a leukemic change, the leukemia cells may grow and survive better than healthy cells. Over time, the leukemia cells crowd out or suppress the development of healthy cells. Leukemia is classified into four groups: acute lymphoblastic leukemia, chronic lymphocytic leukemia, acute myeloid leukemia and chronic myeloid leukemia.

Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (“ALL”) is an aggressive form of blood cancer, characterized by the overproduction and accumulation of cancerous, immature white blood cells, known as leukemic blasts. These leukemic blasts are overproduced in the bone marrow affecting the synthesis of normal blood cells, causing a decrease in red blood cells, platelets and normal white blood cells. According to DRG, in 2016, there were an estimated 9,000 total new cases of ALL in the United States and Europe. ALL develops rapidly throughout the bone marrow and peripheral blood within a few days or a few weeks of the first symptoms. If left untreated, ALL is rapidly fatal.

Common therapies for ALL include multidrug chemotherapy regimens using available generic chemotherapeutics. Although first-line therapy is effective in some patients, according to DRG, approximately 30%-40% of patients require second-line therapy. For these patients, treatment options include targeted therapies such as tisagenlecleucel, a CD19-directed genetically modified autologous T cell immunotherapy, blinatumomab, a bispecific T cell engager targeting CD19, and inotuzumab ozogamicin, a CD22-directed ADC. However, there remains a
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significant unmet medical need for patients who exhibit relapsed or refractory ALL due to the heterogeneity of and the existence of different subgroups within ALL. We continue to investigate ADCT-602 (CD22) in this area of high unmet medical need.

The Solid Tumor Disease Setting – ADCT-601, ADCT-901, ADCT-701, ADCT-212

There are many different types of solid tumors and they account for the majority of cancers. The most commonly diagnosed solid tumor cancers include lung cancer, prostate cancer, breast cancer and colorectal cancer. The prognosis and treatment of solid tumor cancers vary based on the type of cancer. The remainder of the PBD-based portfolio has the potential to address unmet medical need across a number of these tumor types (dose escalation and dose expansion studies will be required to shape further clinical development and registration choices).

Despite recent significant advances in the treatment of some solid tumor cancers, there remains a high medical need for novel therapies. One of the significant recent advances in the treatment of solid tumor cancers is the introduction of PD1 and PD-L1 checkpoint inhibitors, such as pembrolizumab, that leverages the body’s immune system to attack tumor cells. However, only 45% of cancer patients are eligible for treatment with checkpoint inhibitors and only 12% of cancer patients respond to treatment with checkpoint inhibitors. We are developing product candidates directed at different targets from those targeted by checkpoint inhibitors. We believe that our product candidates may enhance the efficacy of checkpoint inhibitors when they are used in combination and may provide a treatment option for patients who are not eligible for or do not respond to treatment with checkpoint inhibitors. We believe that there is a significant opportunity for our product candidates to address the high unmet medical need of these patient populations.
ZYNLONTA (loncastuximab tesirine): PBD-Based ADC Targeting CD19
Overview

Our flagship product, ZYNLONTA, is an ADC targeting CD19-expressing cancers, and was approved by the FDA and EMA for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including DLBCL not otherwise specified, DLBCL arising from low-grade lymphoma, and also high-grade B-cell lymphoma.

We continue to commercialize ZYNLONTA in the United States through our own infrastructure and selectively pursued strategic collaborations, business combinations, acquisitions, licensing opportunities or similar strategies in other geographies. We are committed to providing global access to ZYNLONTA to patients who may benefit from treatment. We entered an exclusive license agreement with Swedish Orphan Biovitrum AB (“Sobi”) for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications in Europe and all other jurisdictions outside of the U.S., Japan, greater China and Singapore. On December 20, 2022 the EC granted conditional marketing authorization for the use of ZYNLONTA for the treatment of relapsed or refractory DLBCL. The approval follows a positive opinion issued in September 2022 by the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (“EMA”). Sobi expects to commence launching ZYNLONTA upon completion of the marketing authorization transfer. In January 2022, we entered an exclusive license agreement with MTPC for the development and commercialization of ZYNLONTA for all hematologic and solid tumor indications in Japan. In December 2020, we entered into a joint venture with Overland Pharmaceuticals to develop and commercialize ZYNLONTA, among other product candidates, in greater China and Singapore. See “Item 10. Additional Information—C. Material Contracts.”






















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Key ZYNLONTA Studies

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ASCT: Autologous Stem Cell Transplant; IST: Investigator-Sponsored Trials; NHL: Non-Hodgkin Lymphoma; * Data cutoff for 20 patients: February 28, 2022


Further, as part of our strategy, we intend to continue to evaluate ZYNLONTA in combination with other therapies for the treatment of other types of relapsed or B-cell non-Hodgkin lymphomas. We intend to move into earlier lines of treatment to ensure more patients can benefit from ZYNLONTA for a longer course of treatment.























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Critical ZYNLONTA Attributes
adc-20221231_g11.jpg
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1. Based on pivotal LOTIS-2 trial. Full prescribing information available at www.ZYNLONTA.com, including warnings and precautions. ORR: Overall Response Rate; CR: Complete Response; mDOR: Median Duration of Response; CRS: Cytokine Release Syndrome
2. Includes patients who did not respond to first-line therapy, patients refractory to all prior lines of therapy, patients with double/triple hit genetics ORR: Overall Response Rate; CR: Complete Response; mDOR: Median Duration of Response; CRS: Cytokine Release Syndrome

Commercialization

Upon receipt of FDA approval, we began to commercialize ZYNLONTA in the United States through our own U.S. organization infrastructure. Our U.S. commercial team has been able to commercialize ZYNLONTA due to the following:
Our commercial organization is led by a seasoned Chief Commercial Officer and senior commercial leadership team, including Head of Marketing and Head of Market Access each with deep experience in the oncology market;
Our Medical Affairs function is led by an experienced Medical Affairs Leadership Team, and includes a team of highly experienced, senior medical science liaisons;
A highly talented and efficient U.S. customer-facing organization of more than 60 cross-functional employees, which we believe has the potential to cover more than 90% of the DLBCL opportunity;
Continued investment in resources to educate on the differentiated profile of ZYNLONTA;
Increasing scientific interactions with academic and community thought leaders;
engaging payors and key access stakeholders to introduce ADC Therapeutics, align on the unmet medical needs in relapsed or refractory DLBCL and address questions regarding the differentiated product profile of ZYNLONTA and its unique value proposition for patients.
In addition, we have entered into strategic collaborations to maximize ZYNLONTA’s commercial potential outside of the United States, including an exclusive license agreement with Sobi for regions other than the U.S., greater China, Singapore and Japan, an exclusive license agreement with MTPC for Japan, and a joint venture with Overland Pharmaceuticals for greater China and Singapore. See “Item 10. Additional Information—C. Material Contracts.”
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Structure and Mechanism of Action
ZYNLONTA is composed of a humanized monoclonal antibody (RB4v1.2) directed against human CD19 and conjugated through a cathepsin-cleavable linker to SG3199, a PBD dimer cytotoxin. Once bound to a CD19-expressing cell, it is designed to be internalized by the cell, following which the warhead is released. The warhead is designed to bind irreversibly to DNA to create highly potent interstrand cross-links that block DNA strand separation, thus disrupting essential DNA metabolic processes such as replication and ultimately resulting in cell death. The figure below shows the structure of ZYNLONTA.
adc-20221231_g12.jpg
_______________

Visual representation of ZYNLONTA.
The human CD19 antigen is involved in the recognition, binding and adhesion processes of cells, mediating direct interactions between surfaces of different cell types and pathogen recognition. CD19 is expressed only on B cells (i.e., a type of white blood cell that plays a significant role in protecting the body from infection by producing antibodies) throughout all stages of B cell development and differentiation. Its expression is maintained in high levels in hematologic B cell malignancies, including NHL and certain types of leukemia. For example, CD19 is expressed in activated B cells and memory B cells in DLBCL, in naïve B cells in MCL, and in memory B cells in FL.
Regulatory Approval
Our flagship product, ZYNLONTA, received accelerated approval from the FDA on April 23, 2021, for the treatment of adult patients with relapsed or refractory large B-cell lymphoma after two or more lines of systemic therapy, including DLBCL not otherwise specified, DLBCL arising from low-grade lymphoma, and also high-grade B-cell lymphoma. Continued approval for this indication is contingent upon verification and description of clinical benefit in a confirmatory trial and is underway in our Phase 3 confirmatory clinical trial, LOTIS 5. On December 20, 2022, the EC granted conditional marketing authorization for the use of ZYNLONTA for the treatment of relapsed or refractory DLBCL. The EC decision is valid in all European Union Member States, Iceland, Norway, and Liechtenstein. The EC granted conditional marketing authorization for ZYNLONTA for this indication and continued approval is contingent upon verification in a confirmatory trial.
Confirmatory Clinical Trial
In September 2020, we commenced a confirmatory trial (LOTIS-5) concurrently with the BLA submission. The confirmatory clinical trial is a Phase 3, randomized, open-label, two-part, two-arm, multi-center clinical trial of ZYNLONTA combined with rituximab compared to immunochemotherapy in patients with relapsed or refractory DLBCL.
The primary objective of the clinical trial is to evaluate the efficacy of ZYNLONTA combined with rituximab compared to standard immunochemotherapy, as measured by progression-free survival (“PFS”). The secondary objectives of the clinical trial are to evaluate overall survival (OS) as well as: (i) characterize the safety profile of ZYNLONTA combined with rituximab, (ii) characterize the pharmacokinetic profile of ZYNLONTA combined with rituximab, (iii) evaluate the immunogenicity of ZYNLONTA combined with rituximab and (iv) evaluate the impact of ZYNLONTA combined with rituximab treatment on treatment-related and disease-related symptoms, patient-reported functions and overall health status.
The clinical trial is enrolling patients with pathologically confirmed relapsed or refractory DLBCL who are not considered by the investigator to be a candidate for SCT and who had failed at least one multi-agent systemic treatment regimen. The clinical trial is expected to enroll approximately 350 patients.
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The clinical trial is being conducted in two parts: In the safety run-in, the first 20 patients were non-randomly assigned to receive ZYNLONTA in combination with rituximab to compare the combination’s toxicity against historical safety data from monotherapy clinical trials of ZYNLONTA. The randomized part of the clinical trial was initiated after the last patient in the safety run-in completed the first treatment cycle and it was observed that there were no significant increases in toxicity of the combination as compared to historical safety data of ZYNLONTA used as a monotherapy. In addition, the initial response data suggests that the combination of ZYNLONTA and rituximab is additive. Patients are randomly assigned 1:1 to receive either ZYNLONTA in combination with rituximab or rituximab in combination with gemcitabine and oxaliplatin. The randomized part of the clinical trial is expected to enroll approximately 330 patients.
We believe that this clinical trial, if successful, will support an sBLA for ZYNLONTA to be used as a second-line therapy for the treatment of relapsed or refractory DLBCL in transplant-ineligible patients.
Phase 1 Clinical Trial in Relapsed or Refractory Non-Hodgkin Lymphoma
We have conducted a Phase 1, open-label, dose escalation and dose expansion clinical trial of the safety and tolerability of ZYNLONTA, used as monotherapy, in 183 patients with relapsed or refractory B-NHL, which includes de novo and transformed DLBCL, FL, chronic lymphocytic leukemia, MCL, marginal zone B-cell lymphoma, Burkitt’s lymphoma and lymphoplasmacytic lymphoma. The clinical trial’s design and our main findings are summarized below.
Clinical Trial Design
The primary objectives of the dose escalation stage of the clinical trial were to (i) evaluate the safety and tolerability, and determine, as appropriate, the maximum tolerated dose (“MTD”) of ZYNLONTA in patients with relapsed or refractory B-NHL and (ii) determine the recommended dose(s) of ZYNLONTA for the dose expansion stage of the clinical trial. The primary objective of the dose expansion stage was to evaluate the safety and tolerability of ZYNLONTA at the dose level(s) recommended from the results of the dose escalation stage. The secondary objectives of the clinical trial were to (i) evaluate the clinical activity of ZYNLONTA, as measured by ORR, DoR, overall survival (“OS”) and PFS, (ii) characterize the pharmacokinetic profile of ZYNLONTA and the free warhead SG3199 and (iii) evaluate anti-drug antibodies (“ADAs”) in patients’ blood before, during and after treatment with ZYNLONTA.
The clinical trial enrolled patients with pathologically confirmed relapsed or refractory B-NHL who had failed or were intolerant to established therapy or for whom no other treatment options were available. Of the 183 patients who participated in the clinical trial, 139 patients were diagnosed with relapsed or refractory DLBCL, 15 patients were diagnosed with relapsed or refractory MCL, 14 patients were diagnosed with FL and the remaining 15 patients were diagnosed with other forms of relapsed or refractory B-NHL.
In the dose escalation stage, patients received intravenous infusions of ZYNLONTA, at escalating doses, on the first day of each 21-day treatment cycle. The initial dose was 15 µg/kg and the highest allowed dose was planned at 300 µg/kg. Dose escalation was conducted using a 3+3 design with oversight by a Dose Escalation Steering Committee (“DESC”). In the dose expansion stage, patients received 120 µg/kg and 150 µg/kg doses on the first day of each 21-day treatment cycle. The dose levels were determined by the DESC based on the anti-tumor activity and tolerability observed during the dose escalation stage. In this clinical trial, response to treatment was determined as complete response (“CR”), partial response (“PR”), stable disease (“SD”) or progressive disease (“PD”), based on the 2014 Lugano Classification Criteria.

Clinical Trial Results
Diffuse Large B-Cell Lymphoma
For patients with relapsed or refractory DLBCL (n=139), the median prior lines of therapy received was three. The median number of treatment cycles received was two and the maximum number of treatment cycles received was 13. The median duration of treatment was 64 days.
The main observed safety and tolerability findings in patients with relapsed or refractory DLBCL were as follows:
The MTD was not reached in the dose escalation stage.
Grade ≥3 TEAEs were reported in 108 patients, or 77.7% of patients. The most common Grade ≥3 TEAEs that were reported in more than 10% of patients included neutrophil count decreased (reported in 38.1% of patients, including 37.1% of patients at the 150 µg/kg dose used in our pivotal Phase 2 clinical trial), platelet count decreased (reported in 26.6% of patients, including 25.7% of patients at the 150 µg/kg dose used in our pivotal Phase 2 clinical trial), gamma-glutamyltransferase increased (reported in 19.4% of patients, including 17.1% of patients at the 150 µg/kg dose used in our pivotal Phase 2 clinical trial) and anemia (reported in 13.7% of patients, including 15.7% of patients at the 150 µg/kg dose used in our pivotal Phase 2 clinical trial).
TEAEs in 26 patients, or 18.7% of patients, led to treatment discontinuation.
The main observed efficacy findings from the Phase 1 clinical trial in patients with relapsed or refractory DLBCL were as follows:
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Across all dose levels, 32 patients, or 23.4% of patients, achieved a complete response and another 26 patients, or 19.0% of patients, achieved a partial response, resulting in a 42.3% ORR. At the 150 µg/kg dose level used in our pivotal Phase 2 clinical trial, 15 patients, or 21.4% of patients, achieved a complete response and another 14 patients, or 20.0% of patients, achieved a partial response, resulting in a 41.4% ORR.
ZYNLONTA’s favorable clinical activity was observed across a broad patient population in this clinical trial, including transplant eligible and ineligible patients, patients who have not responded to first-line therapy or any prior therapy and patients with bulky disease, double-hit and triple-hit disease and transformed disease.
Across all dose levels, the median DoR was not reached for patients who achieved a complete response (indicating that more than half of the patients continued to show a complete response as of their most recent assessment) and 2.86 months for patients who achieved a partial response, for an overall DoR of 4.47 months. At dose levels ≥120 µg/kg, the median DoR was not reached for patients who achieved a complete response (indicating that more than half of the patients continued to show a complete response as of their most recent assessment) and was 2.69 months for patients who achieved a partial response, for an overall DoR of 4.17 months.
Mantle Cell Lymphoma
For patients with relapsed or refractory MCL (n=15), the median prior lines of therapy received was four. The median number of treatment cycles received was two and the maximum number of treatment cycles received was 11. The median duration of treatment was 65 days.
The main observed safety and tolerability findings in patients with relapsed or refractory MCL were similar in nature, frequency and severity to those in patients with relapsed or refractory DLBCL. The main observed efficacy findings from the Phase 1 clinical trial in patients with relapsed or refractory MCL were as follows:
Across all dose levels, five patients, or 33.3% of patients, achieved a complete response and another two patients, or 13.3% of patients, achieved a partial response, resulting in a 46.7% ORR.
The median DoR was not reached (indicating that more than half of the patients continued to show a complete response as of their most recent assessment).
Follicular Lymphoma
For patients with relapsed or refractory FL (n=14), the median prior lines of therapy received was four. The median number of treatment cycles received was three and the maximum number of treatment cycles received was 12. The median duration of treatment was 79 days.
The main observed safety and tolerability findings in patients with relapsed or refractory FL were similar in nature, frequency and severity to those in patients with relapsed or refractory DLBCL. The main efficacy findings from the Phase 1 clinical trial in patients with relapsed or refractory FL were as follows:
Across all dose levels, nine patients, or 64.3% of patients, achieved a complete response and another two patients, or 14.3% of patients, achieved a partial response, resulting in a 78.6% ORR.
The median DoR was not reached (indicating that more than half of the patients continued to show a complete response as of their most recent assessment).
Pivotal Phase 2 Clinical Trial in Relapsed or Refractory Diffuse Large B-Cell Lymphoma
We have conducted a 145-patient Phase 2, multi-center, open-label, single-arm clinical trial to evaluate the safety and efficacy of ZYNLONTA in patients with relapsed or refractory DLBCL, as defined according to the 2016 World Health Organization classification to include DLBCL not otherwise specified, primary mediastinal large B-cell lymphoma and high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements. The results of the clinical trial showed significant anti-tumor activity and manageable tolerability profile across a broad population of patients with relapsed or refractory DLBCL. The clinical trial’s design and our main findings are summarized below.
Clinical Trial Design
The primary objective of the Phase 2 clinical trial was to evaluate the efficacy of ZYNLONTA in patients with relapsed or refractory DLBCL, measured by ORR based on the 2014 Lugano Classification Criteria. The secondary objectives were to (i) further evaluate the efficacy of ZYNLONTA measured by DoR, CRR, PFS, relapse-free survival (“RFS”) and OS, (ii) characterize the safety profile of ZYNLONTA, (iii) characterize the pharmacokinetic profile of ZYNLONTA, (iv) evaluate the immunogenicity of ZYNLONTA and (v) evaluate the impact of ZYNLONTA treatment on health-related quality of life (“HRQoL”).
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The clinical trial enrolled patients with pathologically confirmed relapsed or refractory DLBCL who have previously received two or more multi-agent systemic treatment regimens. The table below presents information about the patients’ characteristics.
Patient Characteristicsn=145 
Age, median (minimum, maximum)66(23, 94)
Histology, n (%)DLBCL Not otherwise specified128(88.3)
 HGBCL*10(6.9)
 PMBCL**7(4.8)
Cancer characteristic, n (%)Double-hit or triple-hit disease***15(10.3)
 Double/triple expressor20(13.8)
 Transformed disease****29(20.0)
Disease stage*****, n (%)I-II33(22.8)
 III-IV112(77.2)
Number of previous systemic therapies received, median (minimum, maximum)3(2, 7)
Response to first-line prior systemic therapy, n (%)Relapsed99(68.3)
 Refractory29(20.0)
Response to most recent prior systemic therapy, n (%)Relapsed44(30.3)
 Refractory88(60.7)
Refractory to all prior systemic therapies, n (%)Yes24(16.6)
 No115(79.3)
Prior stem cell transplant, n (%)Autologous stem cell transplant21(14.5)
 Allogeneic stem cell transplant2(1.4)
 Both autologous and allogeneic stem cell transplant1(0.7)
 No121(83.4)
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Information about the patients’ characteristics. *High-grade diffuse large B-cell lymphoma. **Primary mediastinal large B-cell lymphoma. ***Double-hit or triple-hit DLBCL are rare subtypes of DLBCL characterized by two or three recurrent chromosome translocations and are generally associated with poor prognosis. ****Transformed disease is recorded for patients who had another type of lymphoma that transformed to DLBCL. *****Disease stage is determined by the location of the tumor: Stage I means that the cancer is located in a single region, usually one lymph node and the surrounding area. Stage II means that the cancer is located in two separate regions, an affected lymph node or lymphatic organ and a second affected area, and that both affected areas are confined to one side of the diaphragm; Stage III means that the cancer has spread to both sides of the diaphragm, including one organ or area near the lymph nodes or the spleen; Stage IV means diffuse or disseminated involvement of one or more extralymphatic organs, including any involvement of the liver, bone marrow, or nodular involvement of the lungs.
The clinical trial used a two-stage design, with an interim analysis for futility based on data collected from the first 52 patients. The results of the interim analysis for futility in May 2019 showed that the clinical trial met the criteria to continue to full enrollment. Patients received a 150 µg/kg dose on the first day of each 21-day treatment cycle for two treatment cycles, followed by a reduction to a 75 µg/kg dose on the first day of each 21-day treatment cycle for up to one year. The decision for initial dosing at the 150 µg/kg dose level was predicated on higher observed and predicted ORR as compared to lower dose levels. The decision to reduce the dose level after two treatment cycles was based on the rapid onset of initial response observed in the majority of patients in the Phase 1 clinical trial and the desire to optimize the risk-benefit profile for patients. Therefore, the dosing regimen was selected to optimize the frequency of objective response, while permitting continued exposure with manageable toxicity to optimize the durability of response. In this clinical trial, response to treatment was determined as CR, PR, SD or PD, based on the 2014 Lugano Classification Criteria. We also collected liquid biopsies from all patients before and after treatment with ZYNLONTA and we are applying multi-omics approaches (i.e., biological analysis approaches in which data sets of different “omic” groups, such as genome, proteome, and epigenome, are combined) to identify genetic signatures that may predict response to ZYNLONTA.
Clinical Trial Results
The mean number of treatment cycles received was 4.6 and the maximum number of treatment cycles received was 26.
As of March 1, 2021, the main observed safety and tolerability findings were as follows:
Grade ≥3 TEAEs were reported in 107 patients, or 73.8% of patients. The most common Grade ≥3 TEAEs that were reported in more than 10% of patients included neutropenia (reported in 26.2% of patients), thrombocytopenia (reported in 17.9% of patients), gamma-glutamyltransferase increased (reported in 17.2% of patients) and anemia (reported in 10.3% of patients).

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Treatment-related adverse events in 27 patients, or 18.6% of patients, led to treatment discontinuation. The most common of such adverse events that led to treatment discontinuation in more than 2% of patients included gamma-glutamyltransferase increased (led to treatment discontinuation in 11.7% of patients), peripheral edema (led to treatment discontinuation in 2.8% of patients) and localized edema (led to treatment discontinuation in 2.1% of patients).

No increase in adverse events was observed in patients aged ≥65 years compared to younger patients.
The main observed efficacy findings were as follows:

Thirty-six patients, or 24.8% of patients, achieved a complete response and another 34 patients, or 23.4% of patients, achieved a partial response, resulting in a 48.3% ORR. The table below shows the response rate data. The median time to first response was 41.0 days.
 Histology
Best Overall Response, n (%)
DLBCL-NOS
(n=128)
HGBCL
(n=10)
PMBCL
(n=7)
All Patients
(n=145)
Complete response (CR)31 (24.2)5 (50.0)0 (0.0)36 (24.8)
Partial response (PR)33 (25.8)0  (0.0)1 (14.3)34 (23.4)
Stable disease20 (15.6)1 (10.0)1 (14.3)22 (15.2)
Progressive disease24 (18.8)3 (30.0)3 (42.9)30 (20.7)
Not evaluable20 (15.6)1 (10.0)2 (28.6)23 (15.9)
Overall response rate (CR + PR)64 (50.0)5 (50.0)1 (14.3)70 (48.3)
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Response rate data. “Not evaluable” includes patients without any scan to independent reviewer (even clinical PD) or patients whose scan is determined as “not evaluable” by independent reviewer.
ZYNLONTA’s favorable clinical activity was observed across a broad patient population in this clinical trial, including transplant eligible and ineligible patients, patients who have not responded to first-line therapy or any prior therapy, patients with bulky disease, double-hit and triple-hit disease and transformed disease and patients who had received prior CD19 therapies or SCT. The tables below show the effect by tumor characteristics, age, response to prior therapy (i.e., stem cell transplant or CAR-T) on response rate data.
Tumor Characteristics
Overall Response Rate,
responders/total (%)
Double-hit or triple-hit disease 5/15 (33.3)
Transformed disease13/29 (44.8)
Double/triple expressor10/20 (50.0)
Germinal center B-cell DLBCL26/48 (54.2)
Activated B-cell DLBCL11/23 (47.8)
Age
Overall Response Rate,
responders/total (%)
Less than 6532/65 (49.2)
More than or equal to 6538/80 (47.5)

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Response to Prior Therapy
Overall Response Rate,
responders/total (%)
Response to first-line systemic therapyRefractory11/29 (37.9)
 Relapsed53/99 (53.5)
Response to prior last-line systemic therapyRefractory31/88 (35.2)
 Relapsed30/44 (68.2)
Response to any prior line systemic therapyRefractory9/24 (37.5)
 Relapsed60/115 (52.2)
Prior Therapy
Overall Response Rate,
responders/total (%)
Stem cell transplant14/24 (58.3)
CAR-T6/13 (46.2)
Prior Number of Systemic Therapies
Overall Response Rate,
responders/total (%)
Two prior lines30/63 (47.6)
Three prior lines17/35 (48.6)
More than three prior lines23/47 (48.9)
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Overall response rate data by various baseline patient characteristics.

The median DoR was 13.37 months for patients who achieved a response and was not reached for patients who achieved a complete response. The median DoR observed in subgroups at high risk of poor prognosis was comparable to that observed in the overall study population. The figure below shows the DoR.

adc-20221231_g13.jpg

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Duration of response. *mDoR for patients with a PR was 5.68 months.

Sixteen patients received CD-19 directed CAR-T after receiving treatment with ZYNLONTA, with an investigator-assessed ORR of 43.8% (6 CR and 1 PR). Eleven patients received SCT as consolidation after responding to treatment with ZYNLONTA.
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The median progression free survival was 4.93 months.

The median overall survival was 9.53 months.

Ongoing ZYNLONTA Studies

LOTIS-5: A Phase 3, randomized, open label, study of loncastuximab tesirine combined with rituximab versus immunochemotherapy in patients with diffuse large B-cell lymphoma (DLBCL) who are relapsed or refractory (r/r) after at least one prior therapy. A 2-part design is used to conduct the study. Part 1 was a non-randomized safety run-in with loncastuximab tesirine + rituximab (Lonca-R) to characterize the safety of the combination therapy. Part 2 is a randomized study evaluating the efficacy and safety of Lonca-R versus standard immunochemotherapy. The primary endpoint is PFS, defined as the time between randomization and the first documentation of recurrence or progression by independent central review, or death from any cause. The study will also assess OS, ORR, CR rate, and DOR.

In Part 1, 20 patients enrolled to receive Lonca-R in the safety run-in. Loncastuximab tesirine was administered as an IV infusion on Day 1 of each cycle of three weeks. Patients received 150 μg/kg for two cycles, then 75 μg/kg for up to six additional cycles. Rituximab 375 mg/m2 was administered as an IV infusion on Day 1 of each cycle for a total of eight cycles. After the 20th patient in the safety run-in completed the first cycle of treatment, the toxicity of Lonca-R was compared with historical safety data from loncastuximab tesirine monotherapy studies. No significant increase in toxicity was observed, and Part 2 was initiated in February 2022. Patients are randomized (1:1 ratio) to receive either Lonca-R or rituximab/gemcitabine/oxaliplatin (R-GemOx). The IDMC met in January 2023 and recommended continuation of the study without modifications. Among the first 20 patients, ORR of 75% and CR of 40% were observed in SOHO 2022.

LOTIS-7: A Phase 1b, multi-center, open-label, multi-arm study to evaluate the safety and anti-cancer activity of loncastuximab tesirine in combination with other anti-cancer agents in patients with R/R B-NHL. The study is designed to evaluate various combinations in two parts: Dose Escalation (Part 1) and Dose Expansion (Part 2). Part 1 of the study is ongoing with a cohort of patients receiving loncastuximab tesirine + Polivy. Two additional cohorts in combination with CD20xCD3 bispecific antibodies (mosunetuzumab and glofitamab) are planned in Q3 of 2023.

LOTIS-9: A Phase 2 open-label study of loncastuximab tesirine in combination with rituximab (Lonca-R) in previously untreated unfit/frail patients with DLBCL, as determined by the simplified geriatric assessment tool (sGA). The study is defined to assess the efficacy and tolerability of Lonca-R in patients > 80 years who are unfit (Cohort A); or frail (Cohort B). Cohort B is also open to patients 65-79 with cardiac contraindication(s) to anthracycline therapy. At Cycle 1, patients will be administered rituximab 375 mg/m2 as an IV infusion on Day 1, followed by loncastuximab tesirine as an IV infusion on Day 2. Thereafter, both treatments are administered on Day 1 of each 3-week cycle. For the first 2 cycles, patients will receive 150 µg/kg; 75 µg/kg will be administered for subsequent cycles. All patients are intended to receive 4 cycles of Lonca-R, with an additional 2 cycles offered to those who do not achieve complete response at first disease assessment during prior to cycle 4. Enrollment is ongoing.

LOTIS-10: This is a Phase 1b open-label, multi-center study to evaluate the safety, PK, and anti-cancer activity of loncastuximab tesirine in patients with R/R DLBCL or HGBCL including a dose escalation in patients with moderate or severe hepatic impairment. Patients will be assigned to one of three arms: normal hepatic function (arm A), moderate hepatic impairment (arm B), or severe hepatic impairment (arm C) as defined by the Organ Dysfunction Working Group (ODWG) hepatic impairment classification. Patients assigned to Arm A will receive loncastuximab tesirine intravenously (IV) at 150 μg/kg for two cycles, then 75 μg/kg for subsequent cycles. Patients assigned to Arms B and C will receive loncastuximab tesirine IV in a standard 3+3 design, starting at 60% of the dose level used in LOTIS-2. Enrollment is expected to start in second half of 2023.

Pediatric Trial: ‘Glo-BNHL’ is a global study of novel agents in pediatric and adolescent relapsed and refractory B-cell non-Hodgkin Lymphoma (R/R BNHL), sponsored by the University of Birmingham, UK. This international multi-center, adaptive, platform trial will enroll children, adolescents, and young adults with R/R BNHL to receive treatment in one of three parallel cohorts; Arm I, bispecific antibody (BsAb); Arm II, antibody-drug conjugate (ADC) with standard chemotherapy; and Arm III, chimeric antigen receptor (CAR) T-cells. Novel agents are selected for inclusion in the platform according to an overarching prioritization list and a robust systematic scientific assessment of each proposed asset, performed by the international Trial Steering Committee (TSC). Loncastuximab tesirine was selected for study in arm II in combination with modified R-ICE (rituximab, ifosfamide, carboplatin and etoposide) chemotherapy to estimate the clinical efficacy of the combination in patients with R/R B-NHL in first (only one prior line of therapy) or subsequent relapse (more than one prior line of therapy). The study is anticipated to start in the second half of 2023.
Our PBD-based Franchise and Expanded Platform

Our PBD-based franchise comprises four clinical-stage product candidates and two preclinical product candidates for the treatment of lymphoma and leukemia, as well as various solid tumor cancers, including colorectal cancer, head and neck cancer, non-small cell lung cancer, gastric and esophageal cancers, pancreatic cancer, bladder cancer, renal cell carcinoma, melanoma, triple negative breast cancer, ovarian cancer and prostate cancer.


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Camidanlumab Tesirine: PBD-Based ADC Targeting CD25

Structure and Mechanism of Action

Cami is composed of a human monoclonal antibody (HuMax®-TAC) directed against human CD25 and conjugated through a cathepsin-cleavable linker to SG3199, a PBD dimer cytotoxin. Once bound to a CD25-expressing cell, it is designed to be internalized by the cell, following which the warhead is released. The warhead is designed to bind irreversibly to DNA to create highly potent interstrand cross-links that block DNA strand separation, thus disrupting essential DNA metabolic processes such as replication and ultimately resulting in cell death. The figure below shows a visual representation of Cami and its mechanism of action.
adc-20221231_g14.jpg
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Visual representation of Cami.

CD25, or T cell activation antigen, is the alpha chain of IL-2R. In normal human tissue, expression of CD25 is mainly limited to activated T cells and activated B cells. CD25 is involved in autoimmunity, organ transplantation, and graft rejection, and Tregs are involved in the prevention of autoimmune processes. The preponderance of CD25-expressing cells in hematological malignancies and the relationship between increased CD25 expression and poor prognosis raises the possibility of using an anti-CD25 antibody to deliver a potent cytotoxin to these cells in patients.
Phase 2 Clinical Trial in Relapsed or Refractory Hodgkin Lymphoma

We have completed a 117-patient Phase 2, multi-center, open-label, single-arm clinical trial to evaluate the safety and efficacy of Cami in patients with relapsed or refractory HL. The clinical trial’s design and our main findings are summarized below.
Clinical Trial Design
The primary objective of the Phase 2 clinical trial is to evaluate the efficacy of Cami in patients with relapsed or refractory HL, measured by ORR based on the 2014 Lugano Classification Criteria. The secondary objectives are to (i) characterize additional efficacy endpoints of Cami, including DoR, complete response rate, PFS and OS, (ii) characterize the safety profile of Cami, (iii) characterize the pharmacokinetic profile of Cami, (iv) evaluate the immunogenicity of Cami, and (v) evaluate the impact of Cami treatment on HRQoL.
The clinical trial enrolled patients with pathologically confirmed relapsed or refractory HL who have failed three prior lines of therapy (or at least two prior lines in SCT-ineligible patients), including brentuximab vedotin and a checkpoint inhibitor approved for HL, such as nivolumab or pembrolizumab. The table below presents information about the 117 patients’ characteristics as of March 16, 2022.
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Patient Characteristics
Age, median (minimum, maximum)37 (19, 87)
Histology, n (%)Nodular sclerosis cHL91 (77.8)
 Other/unknown/not evaluable*26 (22.2)
ECOG performance status**, n (%)064 (54.7)
147 (40.2)
 26 (5.1)
Number of previous systemic therapies received, median (minimum, maximum)6 (3,19)
Response to first-line systemic therapy, n (%)Relapsed79 (67.5)
 Refractory29 (24.8)
Response to last-line systemic therapy, n (%)Refractory66 (56.4)
Prior stem cell transplant, n (%)Autologous stem cell transplant59 (50.4)
 Allogeneic stem cell transplant3 (2.6)
Both autologous and allogeneic stem cell transplant12 (10.3)
Prior treatment with brentuximab vedotin and PD-1 blockade116 (99.1)
_______________
Information about the patients’ characteristics. One patient had a protocol deviation of no prior treatment with brentuximab vedotin. * Includes mixed cellularity and lymphocyte-rich cHL, and subtype not specified/unknown. **ECOG performance status describes a patient’s level of functioning in terms of their ability to care for themself, daily activity and physical ability: Grade 0 means fully active, able to carry on all pre-disease performance without restriction; Grade 1 means restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature; Grade 2 means ambulatory and capable of all self-care but unable to carry out any work activities.
In the clinical trial, patients received a 45 µg/kg dose of Cami on the first day of each 21-day treatment cycle for two treatment cycles and receive a 30 µg/kg dose on the first day of each 21-day treatment cycle for subsequent treatment cycles. The decision for the initial dose level is based on the following observations from our Phase 1 clinical trial: (i) the favorable ORR and complete response rate together with Cami’s tolerability profile, (ii) the high fraction of patients with HL who could tolerate at least two cycles of Cami before an AE leading to a dose delay or modification occurred and (iii) the ability to manage some of the severe TEAEs at this dose level. The decision to reduce the subsequent dose level to 30 µg/kg is based on the potential to mitigate the frequency and severity of AEs foreseen in patients treated with the 45 µg/kg dose level beyond two treatment cycles while being an active dose. Therefore, the dosing regimen was selected to optimize potential response to treatment, while maintaining a manageable tolerability profile. In this clinical trial, response to treatment was determined as CR, PR, SD or PD, based on the 2014 Lugano Classification Criteria.
Interim Data

In January 2021, we completed enrollment with 117 patients in this clinical trial. As of March 16, 2022, the median number of treatment cycles received was 5 and the maximum number of treatment cycles received was 15.

The main observed safety and tolerability findings were as follows:
Grade ≥3 TEAEs were reported in 79 patients, or 67.5% of patients. The most common Grade ≥3 TEAEs that were reported in more than 5% of patients included thrombocytopenia (9.4%), anemia (7.7%), hypophosphatemia (7.7%), neutropenia (7.7%), maculopapular rash (6.8%) and lymphopenia (6.0%).

Eight cases of Guillain–Barré syndrome/polyradiculopathy were reported, including two case of Grade 4 Guillain–Barré syndrome (inflammatory demyelinating polyneuropathy), 3 cases of Grade 3 Guillain-Barré syndrome/polyradiculopathy, one case of Grade 2 radiculopathy (radiculitis) and one case of Grade 2 Guillain–Barré syndrome. Another case was considered as a Grade 4 Guillain–Barré syndrome, with the following presentation: polyneuropathy, meningitis, facial paralysis and syndrome of inappropriate secretion of antidiuretic hormone. Four of eight patients recovered, three were ongoing at Grade 1 and one died of sepsis.
In March 2020, two patients in this clinical trial were diagnosed with Guillain–Barré syndrome. Pursuant to the clinical trial protocol, which included specific stopping rules for Guillain–Barré syndrome, we suspended enrollment of new patients in this clinical trial but continued to treat enrolled patients who could derive clinical benefit from continued treatment with Cami.

Before we resumed enrollment pursuant to the recommendations of an independent DSMB, on April 17, 2020, the FDA issued a
partial clinical hold on this clinical trial. The FDA agreed that, pending its review, we could continue to treat enrolled patients,
including patients with stable disease, who could derive clinical benefit from continued treatment with Cami. In May 2020, an
additional patient was diagnosed with Guillain–Barré syndrome. At the FDA’s request, we submitted certain information,
including an updated investigator’s brochure, an updated clinical trial protocol, the DSMB meeting minutes, an updated informed
consent form, dose and exposure analysis for safety and response and an updated safety monitoring plan. In July 2020, the FDA
lifted the partial clinical hold.
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TEAEs in 32 patients, or 27.4% of patients, led to treatment discontinuation.

The main observed efficacy findings were as follows:

39 patients, or 33.3% of patients, achieved a complete response and another 43 patients, or 36.8% of patients, achieved a partial response, resulting in a 70.1% ORR. The table below shows the response rate data.

Best Overall Response, n (%)
(n=117)
Complete response (CR)
39 (33.3)
Partial response (PR)
43 (36.8)
Stable disease
21 (17.9)
Progressive disease
8 (6.8)
Not evaluable
6 (5.1)
Overall response rate (CR + PR)
82 (70.1)
_______________

Response rate data.

14 patients (12%) discontinued Cami treatment with the intent to proceed to hematopoietic stem cell transplantation.

We held a pre-BLA meeting in September 2022 and a Type C meeting with the FDA in late October. During the Type C meeting, the FDA provided strong guidance that, for it to consider an accelerated approval path, a randomized confirmatory Phase 3 study must be well underway and ideally fully enrolled at the time of any BLA submission for Cami. After carefully weighing this program against the rest of our portfolio in terms of resource allocation, we have decided not to proceed on our own and to seek a partner to continue developing this program within this high unmet need patient segment.

ADCT-602: PBD-Based ADC Targeting CD22
Structure and Mechanism of Action
ADCT-602 (CD22) is composed of a humanized monoclonal antibody (hLL2-C220) directed against human CD22 and conjugated through a cathepsin-cleavable linker to SG3199, a PBD dimer cytotoxin. Once bound to a CD22-expressing cell, it is designed to be internalized by the cell, following which the warhead is released. The warhead is designed to bind irreversibly to DNA to create highly potent interstrand cross-links that block DNA strand separation, thus disrupting essential DNA metabolic processes such as replication and ultimately resulting in cell death. The figure below shows the structure of ADCT-602 (CD22).

adc-20221231_g15.jpg
_______________
Visual representation of ADCT-602.
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The human CD22 antigen plays a pivotal role in the recognition, binding and adhesion processes of cells. CD22 is only expressed on B cells throughout all stages of B cell development and differentiation. Its expression is maintained in high levels in hematological B cell malignancies, including in NHL and certain types of leukemia, including B-cell ALL. There was an estimated 7,000 new cases of ALL in the U.S. in 2022. We believe that CD22 is an attractive target for ADCs developed to treat hematological malignancies for the following reasons:
The CD22 antigen is rapidly internalized by the cell.
An increasing number of reports describe the outgrowth of CD19-negative tumor cells in patients who initially respond to CD19-targeted therapy. We believe that given CD22’s broad and favorable expression profile, it may be a viable alternative B cell marker to CD19 for the targeted delivery of highly potent cytotoxic drugs.
Preclinical Studies
Preclinical Efficacy Studies
We evaluated the in vivo efficacy of ADCT-602 (CD22) in the Ramos xenograft model, in which mice received a single dose of (i) ADCT-602 (CD22) at 0.3 mg/kg, (ii) ADCT-602 (CD22) at 1 mg/kg, (iii) a non-targeted ADC at 1 mg/kg, or (iv) a vehicle control. We observed that ADCT-602 (CD22) exhibited dose-dependent anti-tumor activity, while the non-targeted ADC and the vehicle control did not demonstrate any significant anti-tumor activity. The table below summarizes the response data, and the figures below show the mean tumor volume in the Ramos xenograft model and the Kaplan-Meier plot from the Ramos xenograft model.
 n (%)
Response
ADCT-602
0.3 mg/kg
(n=10)
ADCT-602
1 mg/kg
(n=10)
Non-Targeted ADC
1 mg/kg
(n=10)
Vehicle Control
(n=10)
Complete response0 (0.0)10 (100.0)0 (0.0)0 (0.0)
Partial response0 (0.0) 0   (0.0)0 (0.0)0 (0.0)
Tumor-free survivor0 (0.0) 9  (90.0)0 (0.0)0 (0.0)
_______________
Response data obtained in the Ramos xenograft model. Partial response is recorded when the tumor volume was 50% or less of its Day 1 volume for three consecutive measurements during the course of the study, and equal to or greater than 13.5 mm3 for one or more of these three measurements. Complete response is recorded when the tumor volume was <13.5 mm3 for three consecutive measurements during the course of the study. Tumor-free survivor is recorded when a complete response is recorded at the termination of a study.

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adc-20221231_g16.jpg_______________

The anti-tumor activity of ADCT-602 in the Ramos xenograft model. Data represent the mean tumor volume ± SEM for each group of mice.

adc-20221231_g17.jpg
_______________

The Kaplan-Meier plot of the activity of ADCT-602 in the Ramos xenograft model. Data represent Kaplan-Meier survival curves for each group of mice.



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Preclinical Safety Studies
We evaluated the toxicity of ADCT-602 (CD22) primarily in non-human primates and with a single-dose MTD study in rats. In non-human primates, ADCT-602 (CD22) was observed to be well tolerated at the 0.6 mg/kg dose. Toxicity was characterized by dose-dependent reversible myelosuppression, bodyweight loss, lymphocyte depletion with loss of germinal centers and CD20-positive cells and nephropathy. In rats, the MTD for ADCT-602 (CD22) was 2 mg/kg.
Phase 1/2 Clinical Trial in Relapsed or Refractory Acute Lymphoblastic Leukemia
Pursuant to our collaboration agreement with MD Anderson Cancer Center, MD Anderson Cancer Center is conducting a Phase 1/2, open-label, dose escalation and dose expansion clinical trial of the safety and anti-tumor activity of ADCT-602 (CD22), used as monotherapy, in patients with relapsed or refractory ALL. The clinical trial’s design and the interim findings are summarized below.
Clinical Trial Design
The primary objectives of the dose escalation stage are to (i) evaluate the safety and tolerability, and determine, as appropriate, the MTD of ADCT-602 (CD22) in patients with relapsed or refractory ALL and (ii) determine the recommended dose(s) of ADCT-602 (CD22) for the dose expansion stage. The primary objective of the dose expansion stage is to evaluate the efficacy of ADCT-602 (CD22) at the dose level(s) recommended from the results of the dose escalation stage. The secondary objectives of the clinical trial are to (i) evaluate the clinical activity of ADCT-602 (CD22), as measured by ORR, DoR, OS and PFS, (ii) characterize the pharmacokinetic profile of ADCT-602 (CD22) and the free warhead SG3199, (iii) evaluate the immunogenicity of ADCT-602 (CD22) and (iv) characterize the effect of ADCT-602 (CD22) exposure on the QT interval.
The clinical trial will enroll patients with pathologically confirmed relapsed or refractory B-ALL and patients with pathologically confirmed relapsed or refractory Ph+ ALL who have failed either first- or second-generation tyrosine kinase inhibitor. The clinical trial is expected to enroll approximately 65 patients.
In the dose escalation stage, patients receive intravenous infusions of ADCT-602 (CD22), at escalating doses, on the first day of each 21-day treatment cycle. The initial dose of ADCT-602 (CD22) is 30 µg/kg and the highest allowed dose will be 150 µg/kg. Dose escalation is conducted using a 3+3 design with oversight by a DESC. In the dose expansion stage, patients receive ADCT-602 (CD22) at the recommended dose determined by the DESC based on the anti-tumor activity and tolerability observed during the dose escalation stage. Dose expansion is conducted according to Simon’s Minimax two-stage design. In the first stage, 22 patients (including six patients treated at the MTD in the dose escalation stage) will be dosed. If there are four or fewer responses in these patients, the clinical trial will stop. Otherwise, 19 additional patients will be dosed for a total of 41 patients. In this clinical trial, response to treatment is determined as CR, PR, SD or PD, based on the 2014 Lugano Classification Criteria.
Interim Data

As of July 2022, 21 patients have been treated with ADCT-602 (CD22). Eleven patients were enrolled on the Q3 weekly schedule and then as the PK data indicated rapid clearance of the antibody, the trial was amended to allow for weekly dosing. As of the data cutoff, ten patients were treated on a weekly schedule. One patient at the 30 µg/kg weekly dose had grade 4 thrombocytopenia possibly related to ADCT-602 (CD22). Two heavily pretreated patients achieved MRD-negative remission, one at the 30 µg/kg weekly dose and one at the 3µg/kg dose every three weeks. Dose escalation continues at the 50µg/kg weekly dose and a subsequent higher dose level weekly may be planned before expansion phase.

In this ongoing Phase 1 study in pts with heavily pretreated R/R B-ALL with a median of 5 prior lines of therapy and high baseline bone marrow tumor burden, single-agent ADCT-602 (CD22) was well tolerated with one DLT noted.

Four pts achieved MRD-negative remission, including 2 of 6 pts at the 50µg/kg weekly dose level; One additional pt at 50µg/kg weekly dose level had marrow blast clearance without count recovery.

ADCT-901: PBD-Based ADC Targeting KAAG1

Structure and Mechanism of Action

KAAG1 is a novel tumor-associated antigen expressed in a high percentage of ovarian tumors and triple negative breast cancers, with limited expression in healthy tissues. There were an estimated ~ 20,000 new cases of ovarian cancer and ~ 29,000 new cases of triple negative breast cancer in the U.S. in 2022. ADCT-901 (KAAG1) is an antibody-drug conjugate (ADC) composed of a humanized monoclonal antibody (3A4) directed against human kidney associated antigen 1 (KAAG1) and conjugated through a cathepsin-cleavable linker to SG3199, a pyrrolobenzodiazepine (PBD)-dimer cytotoxin. The PBD dimer cytotoxin (SG3199) attached to the linker is designated as tesirine. The figure below shows the structure of ADCT-901 (KAAG1).
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adc-20221231_g18.jpg
_______________

Visual representation of ADCT-901
Once bound to KAAG1, ADCT-901 (KAAG1) is internalized and the cathepsin-cleavable linker is cleaved, releasing free PBD dimers (SG3199) inside the target cell. The PBD dimers are highly efficient anticancer drugs that covalently bind in the minor groove of DNA and form highly cytotoxic DNA interstrand cross-links. The cross-links formed by the PBD dimers are relatively non-distorting the DNA structure, making them hidden to DNA’s repair mechanisms.

Preclinical Studies

Preclinical Efficacy Studies

We evaluated the in vivo efficacy of ADCT-901 (KAAG1) in the CTG-0252, CTG-0711, CTG-1086, and CTG-1423 ovarian cancer patient-derived xenograft models, in which mice received a single dose of (i) ADCT-901 (KAAG1) at 1 mg/kg, (ii) a non-targeted ADC at 1 mg/kg, or (iii) a vehicle control. We observed that ADCT-901 (KAAG1) exhibited potent and specific anti-tumor activity, while the non-targeted ADC and the vehicle control did not exhibit any significant anti-tumor activity. The table below summarizes the response data and the figure below shows the mean tumor volumes in the CTG-0252, CTG-0711, CTG-1086, and CTG-1423 patient-derived xenograft models.

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Model #Test MaterialPRCRTFS
CTG-0252 (Day 58)
Vehicle
000
Isotype-control ADC000
ADCT-901
311
CTG-0711 (Day 63)
Vehicle
000
Isotype-control ADC000
ADCT-901
300
CTG-1086 (Day 61)
Vehicle
000