CTMX US Equity☆

10-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31, 2023

OR

For the transition period from to

Commission File Number 001-37587

CytomX Therapeutics, Inc.

(Exact Name of Registrant as Specified in Its Charter)

151 Oyster Point Boulevard, Suite 400South San Francisco, California 94080

(Address of principal executive offices) (Zip Code)

(650) 515-3185

(Registrant’s telephone number, including area code)

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

Title of each class Trading Symbol(s) Name of each exchange on which registered

Common Stock, $0.00001 par value CTMX The Nasdaq Global Select Market

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

None

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

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

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

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

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

Large accelerated filer ☐ Accelerated filer ☐

Non-accelerated filer ☒ Smaller reporting company ☒

Emerging growth company ☐

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

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

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

As of June 30, 2023, the last business day of the registrant’s most recently completed second fiscal quarter, the aggregate market value of the registrant’s common stock held by non-affiliates of the registrant was approximately $114.1 million, based on the closing price of the registrant’s common stock on the Nasdaq Global Select Market on June 30, 2023 of $1.72 per share. Shares of the registrant’s common stock held by each officer and director and each person known to the registrant to own 10% or more of the outstanding common stock of the registrant have been excluded in that such persons may be deemed affiliates. This determination of affiliate status is not a determination for other purposes.

As of February 29, 2024, 67,721,658 shares of the registrant’s common stock, $0.00001 par value per share, were outstanding. This number does not include 14,423,077 shares of common stock issuable upon the exercise of pre-funded warrants outstanding as of February 29, 2024 (which are immediately exercisable at an exercise price of $0.00001 per share of common stock, subject to beneficial ownership limitations) sold in the registrant’s private placement in July 2023. See Note 12— Common Stock to the registrant’s audited financial statements.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive proxy statement to be filed for its 2024 Annual Meeting of Stockholders are incorporated by reference into Part III hereof. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the end of the fiscal year covered by this Annual Report on Form 10-K.

CYTOMX THERAPEUTICS, INC.

ANNUAL REPORT ON FORM 10-K

TABLE OF CONTENTS

Page

PART I

ITEM 1. Business 4

ITEM 1A. Risk Factors 30

ITEM 1B. Unresolved Staff Comments 73

ITEM 1C. Cybersecurity 73

ITEM 2. Properties 74

ITEM 3. Legal Proceedings 74

ITEM 4. Mine Safety Disclosures 74

PART II

ITEM 6. [Reserved] 75

ITEM 7A. Quantitative and Qualitative Disclosures About Market Risk 85

ITEM 8. Financial Statements and Supplementary Data 86

ITEM 9A. Controls and Procedures 117

ITEM 9B. Other Information 118

ITEM 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections 118

PART III

ITEM 10. Directors, Executive Officers and Corporate Governance 119

ITEM 11. Executive Compensation 119

ITEM 14. Principal Accountant Fees and Services 119

PART IV

ITEM 15. Exhibits and Financial Statement Schedules 120

Forward-Looking Statements

This Annual Report on Form 10-K contains certain forward-looking statements that involve risks and uncertainties. These forward-looking statements reflect our current views with respect to, among other things, future events and our financial performance. These statements are often, but not always, made through the use of words or phrases such as “may,” “might,” “should,” “could,” “predict,” “potential,” “believe,” “expect,” “continue,” “will,” “anticipate,” “seek,” “estimate,” “intend,” “plan,” “projection,” “would,” “annualized” and “outlook,” or the negative version of those words or other comparable words or phrases of a future or forward-looking nature. These forward-looking statements are not historical facts, and are based on current expectations, estimates and projections about our industry, management’s beliefs and certain assumptions made by management, many of which, by their nature, are inherently uncertain and beyond our control. Accordingly, we caution you that any such forward-looking statements are not guarantees of future performance and are subject to risks, assumptions, estimates and uncertainties that are difficult to predict. Although we believe that the expectations reflected in these forward-looking statements are reasonable as of the date made, actual results may prove to be materially different from the results expressed or implied by the forward-looking statements.

A number of important factors could cause our actual results to differ materially from those indicated in these forward-looking statements, including those factors identified in “Risk Factors” or “Management’s Discussion and Analysis of Financial Condition and Results of Operations” or the following:

•

our expectations regarding the potential benefits, activity, effectiveness and safety of our product candidates and therapeutics developed utilizing our PROBODY® conditionally activated platform technology;

•

the initiation, timing, progress and results of our ongoing clinical trials, research and development programs, preclinical studies, and Investigational New Drug Application (“IND”), Clinical Trial Application, New Drug Application (“NDA”), Biologics License Application (“BLA”); and other regulatory submissions;

•

the timing of the completion of our ongoing clinical trials and the timing and availability of clinical data from such clinical trials;

•

our ability to identify and develop additional product candidates;

•

our dependence on collaborators for developing, obtaining regulatory approval for and commercializing product candidates in the collaboration;

•

our or a collaborator’s ability to obtain and maintain regulatory approval of any of our product candidates;

•

our receipt and timing of any milestone payments or royalties under any research collaboration and license agreements or arrangements;

•

our expectations and beliefs regarding the evolution of the market for cancer therapies and development of the immuno-oncology industry;

•

the rate and degree of market acceptance of any approved product candidates;

•

the commercialization of any approved product candidates;

•

our ability to establish and maintain collaborations and retain commercial rights for our product candidates in such collaborations;

•

the implementation of our business model and strategic plans for our business, technologies and product candidates;

•

our estimates of our expenses, ongoing losses, future revenue and capital requirements;

•

our ability to obtain additional funds for our operations;

•

our or any collaborator’s ability to obtain and maintain intellectual property protection for our technologies and product candidates and our ability to operate our business without infringing the intellectual property rights of others;

•

our reliance on third parties to conduct our preclinical studies or any future clinical trials;

•

our reliance on third-party supply and manufacturing partners to supply the materials and components for, and manufacture, our research and development, preclinical and clinical trial product supplies;

•

our ability to attract and retain qualified key management and technical personnel;

1

•

our ability to secure and maintain licenses of intellectual property to protect our technologies and product candidates;

•

our financial performance;

•

developments relating to our competitors, our industry, international conflict or uncertainties; and

•

the extent to which any future pandemic and related governmental regulations and restrictions may impact our business, including our research, clinical trials, which include ongoing site initiation and patient enrollment, manufacturing and financial condition;

Any forward-looking statements in this Annual Report on Form 10-K reflect our current views with respect to future events or to our future financial performance and involve known and unknown risks, uncertainties and other factors that may cause our actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by these forward-looking statements. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed under Part I, Item 1A. Risk Factors and discussed elsewhere in this Annual Report on Form 10-K. Given these uncertainties, you should not place undue reliance on these forward-looking statements. Except as required by law, we assume no obligation to update or revise these forward-looking statements for any reason, even if new information becomes available in the future.

This Annual Report on Form 10-K also contains estimates, projections and other information concerning our industry, our business and the markets for certain drugs and therapeutic biologics, including data regarding the estimated size of those markets, their projected growth rates and the incidence of certain medical conditions. Information that is based on estimates, forecasts, projections or similar methodologies is inherently subject to uncertainties and actual events or circumstances may differ materially from events and circumstances reflected in this information. Unless otherwise expressly stated, we obtained these industry, business, market and other data from reports, research surveys, studies and similar data prepared by third parties, industry, medical and general publications, government data and similar sources. In some cases, we do not expressly refer to the sources from which these data are derived.

Except where the context otherwise requires, in this Annual Report on Form 10-K, “we,” “us,” “our” and the “Company” refer to CytomX Therapeutics, Inc.

Trademarks

This Annual Report on Form 10-K includes trademarks, service marks and trade names owned by us or other companies. All trademarks, service marks and trade names included in this Annual Report on Form 10-K are the property of their respective owners.

Risk Factors Summary

We are providing the following summary of risk factors contained in this Annual Report on Form 10-K to enhance the readability and accessibility of our risk factor disclosures in accordance with SEC rules. Please carefully review the full risk factors pertaining to this summary and to additional general risk factors contained in this Annual Report on Form 10-K in their entirety for additional information regarding the material factors that make an investment in our securities speculative or risky. These risks and uncertainties include, but are not limited to, the following:

•

We are a clinical-stage biopharmaceutical company with a limited operating history and have not generated any revenue from product sales.

•

We expect that we will need to raise substantial additional funds to advance development of our product candidates and we cannot guarantee that this additional funding will be available on acceptable terms or at all.

•

Clinical development involves a lengthy and expensive process with an uncertain outcome, and results of earlier studies and trials may not be predictive of future trial results.

•

Our product candidates are in early stages of development and may fail or suffer delays that materially and adversely affect their commercial viability.

•

Interim, “top-line,” and preliminary data from our clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

•

Our product candidates may cause undesirable side effects at any time during or after the clinical trial process that could delay or prevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any, including withdrawal from the market.

2

•

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

•

We are currently conducting and will continue to conduct clinical trials and will contract with third-party manufacturers in foreign countries, including China, which could expose us to risks that could have a material adverse effect on the success of our business.

•

Because we have no long-term contracts with and rely on third-party manufacturing and supply partners, most of which are sole source suppliers, our supply of research and development, preclinical and clinical development materials may become limited or interrupted or may not be of satisfactory quantity or quality.

•

We, or third-party manufacturers, may be unable to successfully scale-up manufacturing of our product candidates in sufficient quality and quantity, which would delay or prevent us from developing our product candidates and commercializing approved products, if any.

•

We rely on third parties to conduct all of our clinical trials and certain of our preclinical studies and intend to continue to do so, and if such third parties do not perform as contractually required, fail to satisfy regulatory or legal requirements or miss expected deadlines, our development programs could be delayed with material and adverse effects on our business, financial condition, results of operations and prospects.

•

Our approach to the discovery and development of our therapeutic treatments is based on novel technologies that are unproven and may not result in marketable products.

•

The market may not be receptive to our product candidates based on a novel therapeutic modality, and we may not generate any future revenue from the sale or licensing of product candidates.

•

We have entered, and may in the future seek to enter, into collaborations with third parties for the development and commercialization of our product candidates using our PROBODY platform. If we fail to enter into such collaborations, or such collaborations are not successful, we may not be able to capitalize on the market potential of our PROBODY platform and resulting product candidates.

•

If our collaborators cease development efforts under our collaboration agreements, or if any of those agreements are terminated, these collaborations may fail to lead to commercial products and we may never receive milestone payments or future royalties under these agreements.

•

If we do not achieve our projected development and commercialization goals in the timeframes we announce and expect, the commercialization of any of our product candidates may be delayed, or never attained, and our business will be harmed.

•

We may not successfully engage in strategic transactions, including any additional collaborations we seek, which could adversely affect our ability to develop and commercialize product candidates, impact our cash position, increase our expense and present significant distractions to our management.

•

If we are unable to successfully develop companion diagnostic tests for certain of our product candidates, or experience significant delays in doing so, we may not realize the full commercial potential of our product candidates.

•

We face competition from entities that have developed or may develop product candidates for cancer, including companies developing novel treatments and technology platforms. If these companies develop technologies or product candidates more rapidly than we do or their technologies are more effective, our ability to develop and successfully commercialize product candidates may be adversely affected.

•

If we are not able to comply with the requirements of Section 404 of the Sarbanes-Oxley Act of 2002 in a timely manner or with adequate compliance, we may be subject to a loss of stockholder confidence and sanctions or investigations by regulatory authorities or litigation.

•

Our stock price may be volatile and purchasers of our common stock could incur substantial losses.

•

Any future pandemic could adversely impact our business, including our research, clinical trials, including clinical trial site initiation and patient enrollment, and financial condition.

3

PART I

Item 1. Business

Overview

We are a clinical-stage, oncology-focused biopharmaceutical company focused on developing novel, conditionally activated biologics designed to be localized to the tumor microenvironment. We aim to build a commercial enterprise to maximize our impact on the treatment of cancer. By pioneering a novel class of localized biologic drug candidates, powered by our PROBODY® therapeutic technology platform, we lead the field of conditionally activated oncology therapeutics and have established biologics localization as a strategic area of research and development. Our vision is to transform lives with safer, more effective therapies with the goal of addressing major unmet needs in oncology.

Our proprietary, versatile, multi-modality PROBODY technology platform is designed to enable conditional activation of biologic therapeutic candidates within the tumor microenvironment while minimizing drug activity in healthy tissues and circulation. Our platform is built on a strong foundation of tumor biology expertise including deep knowledge of tumor-associated enzymes known as proteases. Proteases are tightly controlled in normal tissues but often dysregulated and active in tumor microenvironments where they play important roles in cancer cell migration, invasion and metastasis. Leveraging our deep scientific knowledge, we conceived of and constructed our PROBODY therapeutic platform which allows us to genetically engineer biologic therapeutic candidates to contain protease-cleavable masks. Our masking strategy is designed to reduce binding of biologic drugs to their targets until the mask is removed by proteases in the tumor microenvironment, providing more selective targeting of the tumor.

We are employing our leading, conditional activation platform technology to address some of the biggest challenges in oncology biologics research and development. These include the validation of potential new targets for antibody-drug conjugates (“ADCs”), opening therapeutic window for novel T-cell engagers (“TCEs”) targeting solid tumors, and increasing the therapeutic index for immune modulators such as cytokines. We are also exploring the potential of our PROBODY platform in preclinical research in areas outside of oncology, including in our collaboration with Moderna.

We have utilized our PROBODY therapeutic platform to build a promising, broad pipeline of potential first-in-class and best-in-class clinical-stage molecules. These are CX-904, a conditionally activated, PROBODY® TCE, targeting the epidermal growth factor receptor (“EGFR”) on tumor cells and the CD3 receptor on T cells; CX-2051, an investigational, conditionally activated ADC targeting epithelial cell adhesion molecule (“EpCAM”); and CX-801, an investigational, masked version of interferon alpha-2b (“IFNα2b”). Our current clinical-stage molecules address targets or mechanisms that have been previously validated as having anti-cancer activity but have been limited in their utilization due to systemic toxicities. We have incorporated our significant platform expertise and ongoing clinical learnings to optimize predicted therapeutic index and the clinical potential of these promising agents through tumor localized conditional activation.

We also have a broad pre-clinical pipeline that spans multiple therapeutic modalities. CytomX’s total pipeline spans more than 15 programs across its partnered and internal pipeline.

Our Corporate Strategy

We are utilizing our proprietary, versatile, multi-modality PROBODY platform to create a robust pipeline of biologic therapeutics to improve the lives of people with cancer and to build a long-term, multi-product, commercial biopharmaceutical company. We aim to achieve this goal by:

•

Leveraging the multi-modality breadth of our platform to advance novel, high potential therapeutic formats into the clinic such as T-cell engagers. The field of TCEs for solid tumors has gained momentum as a strategic area of research and development but continues to remain challenged for many targets due to limited therapeutic window. We believe our PROBODY platform is well-suited to address this challenge by localizing the potent anti-tumor activity of TCEs and potentially limiting systemic toxicities. We have a broad and growing effort in the field of TCEs including active programs with our partners, Astellas, Regeneron, Bristol Myers Squibb and Amgen. Our lead program in our pipeline of TCEs is CX-904, which is partnered with Amgen in a global co-development alliance. We are conducting early development as part of the Amgen alliance and retains a portion of U.S. commercial rights. CX-904 is designed to have broad potential in EGFR positive tumors by preferentially localizing T-cells to solid tumors. In May 2022, the first patient was dosed in a Phase 1 study in patients with advanced solid tumors. We reported in January 2023 that the initial single patient cohort phase of the study was complete and that the “3+3” patient cohort phase had been initiated. Backfilling of certain dose escalation cohorts has also been initiated and dose ranging continues. Initial Phase 1a data are expected in

4

the second half of 2024. A decision to potentially expand into Phase 1b is also anticipated in 2024, which will be taken in conjunction with our partner, Amgen.

•

Advancing potentially first-in-class therapies against validated, high potential anti-cancer targets that have not yet been broadly developed as systemic therapies because of target expression in healthy tissue. CX-2051, targeting EpCAM, is a novel ADC program in this category. CX-2051 is designed to optimize the therapeutic index for EpCAM-expressing epithelial cancers, including colorectal cancer. CX-2051’s payload is a camptothecin derivative, a topoisomerase-1 inhibitor, which has a well characterized profile base on the strong clinical activity observed with other topoisomerase-1 inhibiting ADCs and is also optimized for bystander effect. The investigational new drug application (“IND”) for CX-2051 was allowed to proceed by the FDA in January of 2024 and the molecule is expected to enter Phase 1 clinical testing in the first half of 2024.

•

Unlocking high potential immunotherapeutics that have been previously limited in their systemic use due to toxicities. To this end, we have advanced CX-801, a masked interferon alpha-2b program, towards the clinic. Interferon alpha-2b is a validated previously approved immunotherapeutic that has demonstrated clinical activity in multiple cancer types, including in combination with checkpoint inhibitors. Despite the potential and previous validation, previous IFNα2b-based systemic therapies have been limited in their utilization due to systemic toxicities. CX-801 is an investigational, dually masked, conditionally activated version of IFNα2b that is designed to be preferentially active in the tumor microenvironment. The IND for CX-801 was allowed to proceed by the FDA in January of 2024 and the molecule is expected to enter Phase 1 clinical testing in the first half of 2024.

•

Partnering with leading global biopharmaceutical companies to access capital, additional resources and expertise, as well as increase the number of PROBODY therapeutic candidates being advanced into clinical studies. We currently have several strategic alliances with major multinational drug companies, including Amgen, Inc. (“Amgen”), Bristol Myers Squibb, Astellas Pharma Inc. (“Astellas”), Regeneron Pharmaceuticals Inc. (“Regeneron”), and ModernaTX, Inc., a wholly owned subsidiary of Moderna, Inc (“Moderna”).

•

Fostering a unique, patient-focused culture centered around our Company vision of transforming lives with safer, more effective therapies and executing with focus towards our mission to urgently advance our pipeline of PROBODY therapeutics.

Our Pipeline of Conditionally Activated, Localized Product Candidates

We are leveraging our multi-modality PROBODY platform across to build a robust pipeline of potential therapies that are designed to address high unmet needs. CytomX’s pipeline spans pre-clinical and clinical programs and includes a range of therapeutic formats including T-cell engagers, immunotherapies, antibody drug conjugates, and, most recently, mRNA. The table below depicts the current status of our clinical-stage, conditionally activated product candidates, including both collaboration and wholly owned programs and potential milestones in 2024. Our current lead clinical programs focus on validated targets, for which substantial potential remains if they can be improved by widening the therapeutic index. By employing tailored masking strategies and choosing an optimal effector function (e.g. ADC, TCE), each program has been designed to optimize therapeutic window in order to address large unmet needs in oncology.

5

CytomX Pipeline of Clinical Stage PROBODY Therapeutics and 2024 Potential Milestones

as of March 2024

*Licensed from ImmunoGen (acquired by AbbVie in 2024)

CX-904, A Conditionally Activated PROBODY TCE Targeting EGFR and CD3

We have extended our PROBODY platform to the new and promising modality of TCEs. Conventional TCEs are a highly potent therapeutic modality designed to direct the activity of cytotoxic T cells to tumors. TCEs such as the BiTE® molecule, Blincyto®, a CD19-directed TCE commercialized by Amgen, have shown clinical activity in hematologic malignancies, but development of TCEs for solid tumor indications has been challenging. Due to their high potency, TCEs can target normal tissues with low antigen expression, which may result in significant toxicity. We believe these toxicity challenges could be addressed using our PROBODY platform by localizing the activity of TCEs to the tumor microenvironment thereby increasing the therapeutic index for TCEs in solid tumors.

Our most advanced program in this modality is CX-904, a conditionally activated epidermal growth factor receptor-CD3 (“EGFRxCD3”) TCE, which we partnered with Amgen. The strategy for CX-904 is to utilize EGFR expression as an "address" to localize T-cells to solid tumors. EGFR is a broadly expressed, highly validated antibody target with multiple approved therapies on the market. CX-904 is a bispecific antibody targeting EGFR and CD3 and is masked on both binding domains to potentially mediate both EGFR and CD3 related toxicities. CX-904 has been optimized in preclinical studies and we believe may result in a novel approach to address the large number of EGFR positive solid tumors.

In preclinical studies, our PROBODY EGFRxCD3 TCE therapeutics demonstrated anti-tumor activity and better tolerability when compared to EGFRxCD3 TCEs without PROBODY masking. In May 2022, the first patient was dosed in a Phase 1 study in patients with advanced solid tumors. We reported in January 2023 that the initial single patient cohort phase of the study was complete and that the “3+3” patient cohort phase had been initiated. Backfilling of certain dose escalation cohorts has also been initiated and dose ranging continues. Initial Phase 1a data are expected in the second half of 2024. A decision to potentially expand into Phase 1b is also anticipated in 2024, which will be taken in conjunction with our partner, Amgen, with whom we entered into a global collaboration in 2017.

CX-2051, A Conditionally Activated PROBODY ADC Targeting EpCAM

The field of ADCs has made tremendous progress in recent years in hematologic and increasingly, in solid tumors. ADCs are making a difference for patients across a wide range of tumors and continue to move earlier in the treatment paradigm across certain malignancies. The success of the field has driven increased interest in this modality including the need to identify novel ADC targets as well as optimized linker payloads.

EpCAM is a strategic pan-tumor target with high potential across many tumor types. EpCAM has been clinically validated with locally administered, approved cancer therapies. However, efforts to generate systemic anti-EpCAM therapeutics have, to date, not been successful due to toxicities in epithelial tissues. CX-2051, a conditionally activated ADC, is designed to optimize the therapeutic index for EpCAM-expressing epithelial cancers, including colorectal cancer. CX-2051’s payload is a camptothecin derivative, a topoisomerase-1 inhibitor, which has a well characterized profile base on the strong clinical activity observed with other topoisomerase-1 inhibiting ADCs and is also optimized for bystander effect .

6

Preclinically, CX-2051 has demonstrated a wide predicted therapeutic index, as well as strong activity and tolerability in multiple preclinical models, including in colorectal cancer. In preclinical safety studies in cynomolgus monkeys, CX-2051 was tolerated at doses at least six times higher than an unmasked EpCAM ADC. Based on the wide predicted therapeutic index, we believe CX-2051 has the potential to address a broad range of EpCAM expressing solid tumors and make a significant difference for patients. The preclinical results for CX-2051 were presented at the World ADC Conference in 2023.

The IND for CX-2051 was allowed to proceed by the FDA in January 2024 and we expect Phase 1 clinical initiation in EpCAM expressing solid tumors, including CRC, in the first half of 2024. The Phase 1 dose escalation design will follow a Bayesian Optimal Interval ("BOIN") design and intended to evaluate clinical proof of concept and potentially move into dose expansion studies in 2025.

CX-801, A Conditionally Activated PROBODY Cytokine, Interferon alpha-2b (IFNα2b)

With the emergence and impact of checkpoint inhibitors, many patients have benefited from immunotherapy treatment yet significant unmet need remains in patients who either do not respond to immunotherapies or who need additional treatments upon recurrence of their disease. We believe IFNα2b provides a potentially superior approach to activating anti-tumor immune responses than other cytokines. Based on the novel properties of IFNα2b, it has a dual mechanism of action, in that it is designed to directly kill cancer cells while also increasing antigen presenting cells.

Interferon alpha-2b is also a validated previously approved immunotherapeutic that has demonstrated clinical activity in multiple cancer types, including in combination with checkpoint inhibitors. Additionally, Adstiladrin® , a gene therapy encoding interferon alpha-2b locally for BCG-unresponsive non-muscle invasive bladder cancer ("NMIBC"), was approved in 2022 and achieved a 51 percent complete response rate in a clinical study.

Despite the potential and previous validation, previous IFNα2b-based systemic therapies have been limited in their utilization due to systemic toxicities. CX-801 is an investigational, dually masked, conditionally activated version of IFNα2b that is designed to be preferentially active in the tumor microenvironment. Preclinically, we optimized the predicted therapeutic index by tightly masking the molecule using both a peptide mask to block binding to the receptor in the periphery and an Fc steric mask, both of which are unmasked by protease activity in the tumor tissue. In preclinical studies, CX-801 was tolerated at doses more than 100-fold higher than unmasked IFNα2b. PROBODY IFNα2b also showed synergistic effects with checkpoint inhibitors in preclinical models and the ability to inflame the tumor microenvironment. The preclinical profile of CX-801 was presented at SITC 2023.

The IND for CX-801 was allowed to proceed by the FDA in January 2024 and initiation of Phase 1 dose escalation in solid tumors including melanoma, renal, and head and neck squamous cell carcinoma is expected in the first half of 2024. In Phase 1 dose escalation, we will use a BOIN design to evaluate safety and signs of clinical activity for CX-801 and progress into combinations, where we believe CX-801 has the potential to be cornerstone of therapy, if approved, including in combination with checkpoint inhibitors.

CX-2029: A Conditionally Activated ADC Targeting CD71, The Transferrin Receptor

CX-2029 was originally developed in a global co-development collaboration with AbbVie. This program is intended to open a therapeutic index for successful targeting of CD71, also known as the transferrin receptor 1 (“TfR1”). CD71 is a cell surface protein essential for iron uptake in dividing cells and is highly expressed in a number of solid and hematologic cancers. However, given its central role in iron metabolism, CD71 is present on most healthy cells and is thought to be an undruggable target with conventional ADCs. CX-2029 is conjugated with the tubulin inhibitor, monomethyl auristatin E (“MMAE”), as the payload.

Having demonstrated favorable tolerability results and encouraging anti-tumor activity in Phase 1 studies, CX-2029 entered into a four-cohort Phase 2 expansion study initially designed to enroll twenty-five efficacy evaluable patients per cohort in the following malignancies: squamous non-small cell lung cancer (“sqNSCLC”), head and neck squamous cell carcinoma (“HNSCC”), esophageal and gastro-esophageal junction (“E/GEJ”) cancers, and diffuse large B-cell lymphoma (“DLBCL”). The DLBCL cohort was later deprioritized due to strategic and competitive reasons and did not enroll any patients. In January 2023, a data update for the Phase 2 expansion was disclosed which included data across all fully enrolled cohorts. The study results reflected an August 5, 2022 full data cut-off and an October 4, 2022 data snapshot for efficacy. The data demonstrated encouraging clinical activity in unselected, heavily pre-treated patients with tumors of squamous histology, including a 21% objective response rate (ORR) in squamous esophageal cancer and a 10% ORR in squamous non-small cell lung cancer (sqNSCLC). The adverse event (AE) profile was consistent with Phase 1 observations with anemia (82.6%) being the most common treatment related adverse event (TRAE), including 76.1% Grade 3 TRAEs. Anemia was managed with transfusions, dose delays, and dose reductions. The treatment discontinuation rate due to AEs was 3.3% as a result of anemia. In March 2023, AbbVie notified CytomX that it decided not to advance CX-2029 into additional clinical studies and terminated the 2016 CD71 License and Collaboration Agreement.

7

CytomX re-acquired full rights to CX-2029 and the CD71 target but does not currently have plans to make further significant investments in the solid tumor CX-2029 program in the near-term. However, given the high potential of the CD71 target and previous clinical validation and learnings from the CX-2029 development program, including the observation of confirmed anti-tumor responses in squamous esophageal cancer, the Company continues to explore next-generation CD71 strategies.

Next Generation CTLA-4 Therapies (BMS-986288)

BMS-986288 is a PROBODY version of non-fucosylated ipilimumab. The non-fucosylated Fc region of BMS-986288 enhances antigen-presenting cell-mediated T-cell priming and regulatory T-cell (Treg) modulation and is therefore intended to confer increased potency compared to fucosylated ipilimumab. Bristol Myers Squibb was evaluating the safety and efficacy of BMS-986288 alone and in combination with nivolumab in a Phase 1/2 study in patients with certain advanced solid tumors. In February 2023, BMS advanced BMS-986288 to Phase 2 and prioritized the molecule as its lead next-generation CTLA-4 program over its non-fucosylated CTLA-4 antibody ("BMS-986218") and the PROBODY version of ipilumamab ("BMS-986249"). The Phase 2 study for BMS-986288 included proof-of-concept studies in NSCLC and MSS CRC.

Following a corporate portfolio prioritization process, Bristol Myers Squibb notified CytomX on March 6th, 2024, that it does not intend to continue the development of BMS-986288 beyond the current Phase 2 study and terminated its work on the CTLA-4 target under the collaboration.

Bristol Myers Squibb’s first generation PROBODY CTLA-4, BMS-986249, was a masked version of ipilumamab, which was advanced into a Phase 2 clinical trial. The Phase 1 clinical data for BMS-986249 were presented by Bristol Myers Squibb at the European Society for Medical Oncology congress in 2022. The data demonstrated that the PROBODY platform, including that BMS-986249 could be dosed alone and in combination with nivolumab at doses that were higher than the FDA approved doses of ipilumamab alone or in combination with nivolumab. Additionally, the tumor pharmokinetic data indicated that BMS-986249 was unmasked in a dose-dependent manner across multiple tumor types. Bristol Myers Squibb also indicated that BMS-986249 was generally well tolerated with no unexpected or new safety signals in the Phase 1 results and both BMS-986249 monotherapy and BMS-986249 in combination with nivolumab showed promising preliminary activity.

CytomX Platform and Pipeline Breadth Including Partnered Pipeline

We continue to innovate and improve our platform technology and extend the reach of our science through partnering and internal development of our wholly-owned pipeline. Our sustained efforts in research have resulted in an industry-leading level of breadth and depth with conditional activation and a wide range of therapeutic conditionally activated modalities including ADCs cytokines and mRNAs. Over more than ten years, we have gained substantial experience and learnings from the preclinical and clinical work conducted on our earlier programs. We have taken these lessons and applied them to advancing our current pipeline programs. Our total partnered and wholly owned pipeline includes more than 15 active programs, including multiple programs across each collaboration. Our current generation of pipeline molecules integrate learnings in how to best utilize our technology and optimize the design of product candidates to enhance probability of success.

8

CytomX Pipeline of Clinical and Pre-Clinical Molecules Including All Partnered Programs as of March 2024

The successful development of our product candidates involves a lengthy and expensive process with an uncertain outcome, and preliminary or interim results of our studies may not be predictive of the final results from those trials and the results of earlier studies and trials may not be predictive of future trial results. This is due to the numerous risks and uncertainties associated with the development of product candidates. If our PROBODY therapeutic technology and product candidates generally prove to be ineffective, unsafe or commercially unviable, it would have a material and adverse effect on our business, financial condition, results of operations and prospects. See “Risk Factors” for a discussion of the risks and uncertainties associated with our product candidates and our research and development projects.

Our PROBODY Platform

Localization of therapeutic activity of potent biologics within disease tissue is of increasing interest in the biopharmaceutical industry due to the desire to maximize the activity of biologics while reducing their toxicities. We call our approach to therapeutic localization of biologics our PROBODY therapeutic platform. A PROBODY therapeutic candidate consists of three components: an active anti-cancer biologic, a mask for the biologic, and a protease-cleavable linker which connects the mask to the biologic. The mask is a peptide designed to disguise the active binding site of the biologic to prevent it from binding to the target present on healthy tissue. PROBODY therapeutic candidates are produced as a single protein through biologic production technologies. The Company has had sustained research efforts and continuous innovation around the PROBODY Platform and has invested significant resources to develop the technology. As of January 2024, our fully- and co-owned patent portfolio contains at least 250 granted patents and at least 400 pending patent applications. The following graphic depicts the three components of a PROBODY therapeutic candidate:

9

Depiction of the structure of a PROBODY therapeutic candidate and a protease interacting with the PROBODY candidate to cleave the linker and activate the molecule

When a PROBODY therapeutic candidate enters a tumor, it encounters proteases, which are enzymes that cleave proteins and have increased activity in the tumor microenvironment. The proteases in the tumor cleave the linker, releasing the mask and allowing the biologic to bind to the target on the tumor. The following graphic depicts the way a PROBODY therapeutic candidate is designed to be activated by proteases:

Depiction of how a PROBODY therapeutic is designed to enter the tumor microenvironment (left), be activated by protease cleavage to remove the mask (middle), thereby enabling the released biologic to bind to the tumor target (right)

Proteases play an essential role in many aspects of normal physiology, such as digestion of food in the gastrointestinal tract, wound healing and metabolic function. However, uncontrolled protease activity can lead to destruction of essential proteins and tissues. Therefore, proteases are normally very tightly regulated by multiple mechanisms, with only small amounts of extracellular protease activity being detectable in healthy tissues. In contrast, it has been well documented that proteases are not only present, but also activated, in virtually all types of tumors, playing a key role in tumor growth, invasion and metastasis. PROBODY therapeutics are designed to be activated in this protease-rich tumor microenvironment, but not in healthy tissue where proteases are under tight control. Consequently, we believe that toxicities that arise from the binding of a biologic therapeutic to a target in healthy tissues can be reduced, while biological activity against the tumor where it is desired can be preserved. We and our partners have demonstrated the potential of our PROBODY platform across multiple modalities, including ADCs, cancer immunotherapy, TCEs, and cytokines.

We believe that our multi-modality PROBODY therapeutic platform provides the following key advantages:

•

A novel biologic therapeutic class enabled by our proprietary platform. By pioneering a novel class of conditionally activated, localized biologic candidates, we are a leader in the field and have established conditional activation as a strategic area of biologics research and development. Our technology platform is supported by more than a decade of

10

research and a strong intellectual property portfolio. More than 500 patients with diverse tumor types have been treated with our PROBODY therapeutic candidates in multiple clinical studies, providing clinical proof of concept and a deep knowledge base for translational advancement and optimization of our drug candidates and platform.

•

A broad multi-modality technology for improvement of therapeutic index. By engineering our therapeutics to selectively activate in the tumor microenvironment, our PROBODY product candidates have the potential to improve safety and tolerability. We are applying our technology to some of the biggest challenges in oncology biologics research and development today. Namely, the validation of potential new targets for ADCs, opening solid tumor opportunities for TCEs, and increasing the therapeutic index for immunotherapies such as cytokines and CPIs.

•

Ability to combine more effectively with other therapies. We believe the therapeutic index and tumor specificity of our drug candidates have the potential to reduce the dose-limiting toxicities observed in combination therapies and thus enable new combinations with other cancer therapies that are difficult or impossible to use.

•

Molecular tunability and applicability across many targets. Our proprietary masking technologies, leveraging affinity-based and steric approaches and broad protease substrate libraries, allow for unique customization of large drug candidate pools from which high potential clinical candidates are selected. Our technology has the potential to address many different molecular targets expressed by a wide range of tumor types, including targets that are difficult to address due to their widespread expression on healthy cells. EpCAM is an example of such a target, for which we have developed CX-2051, a conditionally activated PROBODY ADC.

•

Deep knowledge of the tumor protease microenvironment. Our extensive protease biology expertise, driven by state-of-the-art experimental and computational methods, allows us to employ multiple approaches to generate novel targeted, multi-selective, and potentially indication-tailored protease-cleavable substrates.

Our Collaborations

We believe that the PROBODY platform has broad applicability across many cancer types, biological targets and antibody modalities. We have leveraged strategic partnering to (a) extend the reach of our technology, and (b) bring in significant non-dilutive capital into the Company. Since 2013, we have entered into several collaborations, including with Amgen, Astellas, Bristol Myers Squibb, ImmunoGen, Moderna, and Regeneron to enable development of certain PROBODY therapeutics. In constructing each of these collaborations, our primary objectives are to collaborate with leading biopharmaceutical players to realize the potential of PROBODY therapeutics, gain meaningful near-term funding or access technology to enable the advancement of our wholly owned PROBODY therapeutics pipeline, and broaden the number of PROBODY therapeutics that ultimately reach the clinic.

AbbVie Ireland Unlimited Company

In April 2016, we entered into two agreements with AbbVie, a CD71 Co-Development and Licensing Agreement (the “CD71 Agreement”) and the Discovery Agreement (the Discovery Agreement, together with the CD71 Agreement are collectively referred to as the “AbbVie Agreements”). Under the terms of the CD71 Agreement, we and AbbVie were co-developing CX-2029, an ADC against CD71, with CytomX being responsible for pre-clinical and early clinical development. AbbVie was responsible for later development and commercialization, with global late-stage development costs shared between the two companies from Phase 3 onwards.

Under the CD71 Agreement, we received an upfront payment of $20.0 million in April 2016, and a milestone payment of $40.0 million in May 2020 for completion of the dose-escalation phase of the ongoing Phase 1/2 study. In March 2023, AbbVie notified us that it would not advance CX-2029 into additional clinical studies and terminated the CD71 Agreement. CytomX re-acquired full rights to CX-2029 and in the fourth quarter of 2023, the Company decided not to make any further significant investments in the CX-2029 solid tumor program in the near-term.

Under the Discovery Agreement, we received an upfront payment of $10.0 million in April 2016 and AbbVie received exclusive worldwide rights to develop and commercialize conditionally activated ADCs against up to two targets, one of which was selected in March 2017 and the second of which was selected in July 2019. We received an additional upfront payment of $10.0 million in July 2019 upon the selection by AbbVie of the second target and the satisfaction of certain performance conditions under the CD71 Agreement.

As of December 31, 2022, research on the two discovery targets concluded and in March 2023, AbbVie terminated the Discovery Agreement.

11

Amgen, Inc.

In September 2017, we entered into a Collaboration and License Agreement (the “Amgen Agreement”) with Amgen. Pursuant to the Amgen Agreement, we received an upfront payment of $40.0 million in October 2017. Concurrent with the entry into the Amgen Agreement, Amgen purchased 1,156,069 shares of our common stock for $20.0 million.

Under the terms of the Amgen Agreement, we and Amgen are co-developing a conditionally activated T-cell engaging bispecific therapeutic targeting EGFR (“EGFR Products”). We are responsible for early-stage development of EGFR Products and all related costs (up to certain pre-set limits based on clinical study size). Amgen will be responsible for late-stage development, commercialization, and all related costs of EGFR Products. Following early-stage development, we will have the right to elect to participate financially in the global co-development of EGFR Products with Amgen, during which we would bear certain of the worldwide development costs for EGFR Products and Amgen would bear the rest of such costs (the “EGFR Co-Development Option”). If we exercise our EGFR Co-Development Option, we will share in somewhat less than 50% of the profit and losses from sales of such EGFR Products in the U.S., subject to certain caps, offsets, and deferrals. If we choose not to exercise our EGFR Co-Development Option, we will not bear any costs of later stage development. We are eligible to receive up to $460.0 million in development, regulatory, and commercial milestone payments for EGFR Products, and royalties in the low-double digit to mid-teen percentage of worldwide commercial sales, provided that if we exercise our EGFR Co-Development option, we shall only receive royalties in the low-double digit to mid-teen percentage of commercial sales outside of the United States.

In October 2021, we and Amgen executed an amendment to the Amgen Agreement primarily to (1) extend the target selection date for Amgen to select its additional targets for research and development, and (2) reduce the total number of milestone events and increase the total amount of milestone payments for EGFR Products.

Amgen also has the right to select a total of up to three targets, including the two additional targets discussed below. We and Amgen will collaborate in the research and development of conditionally activated T-cell engaging bispecifics therapies directed against such targets. Amgen has selected one such target (the “Amgen Other Product”). If Amgen exercises its option within a specified period of time, it can select two such additional targets (the “Amgen Option Products” and, together with the Amgen Other Product, the “Amgen Products”). Except with respect to preclinical activities to be conducted by us, Amgen will be responsible, at its expense, for the development, manufacture, and commercialization of all Amgen Products. If Amgen exercises all of its options and advances all three of the Amgen Products, we are eligible to receive up to $950.0 million in upfront, development, regulatory, and commercial milestones and tiered high single-digit to low-teen percentage royalties.

We had the option to select from programs specified in the Amgen Agreement, an existing pre-clinical stage T-cell Engager product from the Amgen pre-clinical pipeline. In March 2018, CytomX selected the program and this program is currently in preclinical development. We will be responsible, at our expense, for converting this program to a conditionally activated T-cell Engager product, and thereafter, be responsible for development, manufacturing, and commercialization of the product (“CytomX Product”). Amgen is eligible to receive up to $203.0 million in development, regulatory, and commercial milestone payments for the CytomX Product, and tiered mid-single digit to low double-digit percentage royalties.

Astellas Pharma Inc

In March 2020, we entered into a Collaboration and License Agreement (the “Astellas Agreement”) with Astellas, pursuant to which we and Astellas will collaborate on the research, development and commercialization of T-cell engaging bispecific antibody products (“Products”) directed to CD3 and selected tumor antigen targets using our PROBODY® platform and other proprietary technology. Under the Astellas Agreement, we granted Astellas an exclusive, worldwide, royalty-bearing license to develop and commercialize Products in all fields. Astellas may select up to four targets to develop, and had an option to expand to six targets. We will lead preclinical research and discovery activities up to clinical candidate selection for Products directed against up to four targets. Astellas will lead preclinical and clinical development of and regulatory approval for all Products. Astellas will be responsible for commercializing each Product, provided that we will have the option to elect to co-commercialize certain Products with Astellas in the United States, subject to the terms of a separate commercialization agreement to be entered into between us and Astellas.

Under the terms of the Astellas Agreement, we received an upfront payment of $80 million, and Astellas will be responsible for funding the cost of preclinical research and discovery activities of both parties for all Products and for funding the cost of development and commercialization of all Products worldwide. Under the agreement, we are eligible to receive future preclinical, clinical and commercial milestones of approximately $1.6 billion. Astellas will pay us tiered royalties on global net sales of Products from high single-digit to mid-teens percentages, subject to certain reductions. Astellas’ royalty obligations continue with respect to each country and each Product until the later of (i) the date on which such Product is no longer covered by certain intellectual property

12

rights, (ii) the 10th anniversary of the first commercial sale of such product in such country, and (iii) the loss of regulatory exclusivity for such Product in such country.

In addition, for a specified number of targets, at a pre-specified time prior to the initiation of the first pivotal study of a Product directed against such target, we will have an option to elect to co-fund certain subsequently initiated clinical trials for such Product. If we opt in, we would be responsible for a pre-determined portion of the costs of such trials, subject to specified caps, deferrals and offsets. We would then have the option to elect to co-commercialize such Products in the United States. For any such Products, in lieu of royalties in the United States, we will receive less than 40% of the profits for such Products in the United States and tiered low double-digit to mid-teens percentage royalties on net sales of such Products outside of the United States, subject to certain reductions.

In January 2023, Astellas nominated the first clinical candidate under the collaboration which resulted in a $5.0 million milestone payment to CytomX.

Bristol Myers Squibb Company

In May 2014, we and Bristol Myers Squibb entered into a Collaboration and License Agreement (the “BMS Agreement”) to discover and develop compounds for use in human therapeutics aimed at multiple immuno-oncology targets using our PROBODY therapeutic technology.

Under the terms of the BMS Agreement, we granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize PROBODY therapeutics for up to four oncology targets, two of which were selected upon the execution of the BMS Agreement. Pursuant to the BMS Agreement, we received an upfront payment of $50.0 million and were entitled to receive contingent payments in development, regulatory and commercial milestone payments, which can be reduced by any such payments received or by any termination of targets being pursued. We are entitled to royalty payments in the mid-single-digit to low double-digits percentage from potential future sales. We also received research and development service fees. Bristol Myers Squibb has terminated certain targets from the BMS Agreement, as described below.

In January 2016, Bristol Myers Squibb selected the third target pursuant to the BMS Agreement and paid us $10.0 million. In December 2016, Bristol Myers Squibb selected the fourth and its final target pursuant to the BMS Agreement and paid us $15.0 million. In December 2016, Bristol Myers Squibb selected BMS-986249, a CTLA-4 PROBODY therapeutic, as a clinical candidate pursuant to the BMS Agreement, which triggered a $2.0 million pre-clinical milestone payment to us. In November 2017, Bristol Myers Squibb received acceptance of the IND for BMS-986249 from the FDA, which triggered a $10.0 million milestone payment to us. Bristol Myers Squibb recently advanced BMS-986249 into a randomized Phase 2 cohort expansion in patients with metastatic melanoma in combination with the PD-1 inhibitor nivolumab as part of the larger clinical trial, triggering, in February 2020, a $10.0 million milestone payment from Bristol Myers Squibb to us. This study has been modified to include three additional single-arm cohorts: advanced hepatocellular carcinoma, metastatic castration-resistant prostate cancer, and unresectable locally advanced or metastatic TNBC.

In March 2017, we and Bristol Myers Squibb entered into Amendment Number 1 to Extend the BMS Agreement (“Amendment 1”). Amendment 1 granted Bristol Myers Squibb exclusive worldwide rights to develop and commercialize PROBODY therapeutics for up to six additional oncology targets and two non-oncology targets. Under the terms of Amendment 1, we continued to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against targets selected by Bristol Myers Squibb. Pursuant to Amendment 1, we received an upfront payment of $200.0 million and were eligible to receive contingent payments for development, regulatory and sales milestones. We were also entitled to tiered mid-single to low double-digit percentage of royalties from potential future sales.

In September 2019, Bristol Myers Squibb initiated the dose escalation phase of a Phase 1/2a clinical trial of a second anti-CTLA-4-directed therapeutic, BMS-986288, based on a modified version of ipilimumab, administered as monotherapy and in combination with nivolumab in patients with selected advanced solid tumors. In February 2023, BMS updated its pipeline to prioritize the a-fucosylated PROBODY anti-CTLA-4 molecule, BMS-986288 as its lead next-generation CTLA-4 program and removed BMS-986249 from its pipeline.

In February 2021, we and Bristol Myers Squibb entered into Amendment Number 2 to amend the BMS Agreement (“Amendment 2”), as amended by Amendment 1. Pursuant to Amendment 2, the available targets under Amendment 1 were reduced to five oncology targets. Under the terms of Amendment 2, the period for target selection was extended and in 2022, all remaining targets were selected. We will continue to collaborate with Bristol Myers Squibb to discover and conduct preclinical development of PROBODY therapeutics against targets selected by Bristol Myers Squibb over the estimated research period, which is projected to end in April

13

2025. Pursuant to Amendment 2, we are eligible to receive contingent payments for development, regulatory and sales milestones. We are also entitled to tiered mid-single- to low double-digit percentage of royalties from potential future sales.

In October 2022, the Company and Bristol Myers Squibb amended the BMS Agreement and entered into Amendment Number 3 (“Amendment 3”), as previously amended by Amendment 1 and Amendment 2, to clarify the rights and restrictions of certain new proprietary antibodies that the parties exchanged. There were no substantive changes to each party's performance obligations. As of December 31, 2023, the Company was eligible for up to approximately $2.1 billion in contingent payments for development, regulatory and sales milestones based on the ongoing collaboration projects, including the CTLA-4 program, with Bristol Myers Squibb.

On March 6, 2024, following a Bristol Myers Squibb corporate portfolio prioritization process, Bristol Myers Squibb notified CytomX that it does not intend to continue the development of BMS-986288 beyond the current Phase 2 study and terminated its work on the CTLA-4 target under the collaboration. As of March 6, 2024, CytomX is eligible to receive approximately $1.8 billion in contingent payments for development, regulatory and sales milestones for the ongoing collaboration programs.

ImmunoGen, Inc. (acquired by AbbVie in 2024)

In January 2014, CytomX and ImmunoGen entered into the Research Collaboration Agreement (the “ImmunoGen Research Agreement”). The ImmunoGen Research Agreement provides us with the right to use ImmunoGen’s ADC technology in combination with our PROBODY therapeutic technology to create a conditionally activated ADC directed at one specified target under a research license, and to subsequently obtain an exclusive, worldwide development and commercialization license to use ImmunoGen’s ADC technology to develop and commercialize such conditionally activated ADCs. Under the agreement, we provided ImmunoGen with the rights to our PROBODY therapeutic technology to create conditionally activated ADCs directed at two targets under the research license and to subsequently obtain exclusive, worldwide development and commercialization licenses to develop and commercialize such conditionally activated ADCs. In February 2016, we exercised our option to obtain a development and commercialization license for praluzatamab ravtansine (CX-2009) (the “CX-2009 License”). In December 2017, ImmunoGen exercised an option to obtain a development and commercialization license pursuant to the ImmunoGen Research Agreement (the “ImmunoGen 2017 License”) for a target, EpCAM. At the end of 2019, as a result of a strategic restructuring by ImmunoGen and its decision to out-license certain programs, we obtained a worldwide, exclusive, sublicensable license to the EpCAM conditionally activated ADC program from ImmunoGen (the “ImmunoGen 2019 License”) and the ImmunoGen 2017 license ended.

Under the ImmunoGen 2019 License, we gained worldwide development and commercialization rights to the EpCAM conditionally activated ADC program and, in return, we made an upfront payment of $7.5 million, and we will pay up to $35.0 million in certain clinical development milestones and up to $320.0 million in regulatory approval and commercial milestones payments, if achieved. Immunogen is also entitled to royalties on product sales ranging from the mid-to-high single digits percentages.

Moderna, Inc.

In December 2022, the “Company entered into a Collaboration and License Agreement (the “Moderna Agreement”) with Moderna, pursuant to which the Company and Moderna will collaborate on the creation of mRNA-based conditionally-activated investigational therapies utilizing the Company's PROBODY® therapeutic platform and Moderna’s mRNA and lipid nanoparticle technologies. The collaboration will leverage core scientific advances at Moderna and the Company to open up the strategy of encoding potent, masked biologics through mRNA technologies, for the potential treatment of oncology and non-oncology conditions. The Company and Moderna will collaborate on a specified number of preclinical research and discovery programs (“Moderna Collaboration Programs”) within a specified period under the Collaboration and License Agreement.

Under the Moderna Agreement, the Company granted Moderna an exclusive, worldwide, royalty-bearing license under certain Company intellectual property to develop, manufacture, commercialize and otherwise exploit certain products (“Moderna Licensed Products”) for all human and non-human diagnostic, prophylactic and therapeutic uses, subject to certain exceptions with respect to Licensed Products within certain Collaboration Programs.

Under the terms of the Moderna Agreement, Moderna made an upfront payment to the Company of $35 million, including $5 million of pre-paid research funding. CytomX will continue to receive research funding and the Company will be eligible to receive future development, regulatory and commercial milestone payments of up to $1.2 billion for all Moderna Licensed Products in total under the Moderna Agreement. Moderna will pay the Company tiered royalties on global net sales of Moderna Licensed Products from high single digit to low-teen percentages, subject to certain reductions. Moderna's royalty obligations continue with respect to each country and each Product until the later of (i) the date on which such Licensed Product is no longer covered by certain patent rights, (ii) the 10th anniversary of the first commercial sale of such product in such country, and (iii) the loss of regulatory exclusivity for such Moderna Licensed Product in such country.

14

The Moderna Agreement also provides Moderna with a one-time option to participate in a future equity financing by the Company subject to certain terms, conditions and regulatory requirements.

Regeneron Pharmaceuticals, Inc.

The Company and Regeneron entered into a Collaboration and License Agreement (the “Regeneron Agreement”) in November 2022, to collaborate on the creation of conditionally activated investigational bispecific cancer therapies utilizing the Company’s PROBODY® therapeutic platform and Regeneron’s Veloci-Bi® bispecific antibody development platform. The Company and Regeneron will collaborate on preclinical research and discovery activities for initially agreed upon collaboration programs (“Regeneron Collaboration Programs”) with an option to include additional Collaboration Programs (“Additional Collaboration Program Option”).

Under the Regeneron Agreement, the Company granted Regeneron an exclusive, worldwide, royalty-bearing license under certain Company intellectual property to develop, manufacture, commercialize and otherwise exploit licensed products (“Regeneron Licensed Products”) for all human and non-human diagnostic, prophylactic and therapeutic uses in oncology.

Regeneron is responsible for funding the cost of preclinical research and discovery activities of both parties for all Regeneron Licensed Products and for funding the cost of development, manufacture and commercialization of all Regeneron Licensed Products worldwide. Pursuant to the Regeneron Agreement, Regeneron made an upfront payment of $30.0 million to the Company. Upon the achievement of certain development and regulatory milestones and commercial milestones, the Company is eligible to receive milestone payments of up to approximately $0.8 billion for the initial Regeneron Collaboration Programs. In addition, the Company will receive research and development funding for the work related to the collaboration. If Regeneron exercises its Additional Collaboration Program Options, the Company would be eligible to receive additional upfront payments, development and regulatory milestones payments, and commercial milestone payments of up to approximately $1.2 billion in aggregate for the additional Regeneron Collaboration Programs, which amount is exclusive of the $0.8 billion for the initial Regeneron Collaboration Programs. The Company is also entitled to tiered royalties from high-single digit to low-teen percentage royalties from potential future sales, subject to certain reductions. Regeneron's royalty obligations continue with respect to each country and each Regeneron Licensed Product until the later of (i) the date on which such Regeneron Licensed Product is no longer covered by certain patent rights, (ii) the 10th anniversary of the first commercial sale of such product in such country, and (iii) the loss of regulatory exclusivity for such Regeneron Licensed Product in such country.

Manufacturing

Our PROBODY therapeutic candidates are designed to be produced as fully recombinant biologic prodrugs. Our PROBODY therapeutic candidates are also designed to maintain the manufacturability benefits of biologics such as antibodies and leverage manufacturing process technologies used for biologics production in the industry. We conduct cell line development and process development both in-house and in collaboration with contract development and manufacturing organizations (“CMO”). CMOs are responsible for manufacturing of drug substance and clinical drug product materials.

To date, we have generally been able to successfully manufacture our investigational product candidates including for CX-904, for our ongoing early-stage clinical trials with contract manufacturers. Our partner, Bristol Myers Squibb, has also been successful in independently manufacturing drug product for BMS-986249 and BMS-986288. However, the supply chain for the manufacturing of each of our product candidates is complicated and can involve many parties, including for CX-904, CX-2051 and CX-801. We do not own manufacturing facilities for producing such supplies and rely on third-party contract manufacturers to manufacture our clinical trial and preclinical study product supplies. Our clinical trial manufacturing contractors and suppliers are our sole source for their respective manufacturing and supplies. Failure of any of these contractors could affect our ability to have clinical trial material available when needed and could result in substantial delay of our clinical trials. For example, beginning in October 2023, one of our contract manufacturers for CX-2051 experienced production failures. Although we are taking steps to manage our long-term supply of CX-2051, there can be no assurance that we will not have future production failures, which could affect our ability to conduct our trials for CX-2051 or any other clinical trial drug candidates, including CX-801 and CX-904, on our planned timeline or at all. We do not have any long-term contracts and we do not currently have an alternative to any of our third-party contract manufacturers. Consequently, there can be no assurance that our preclinical and clinical development product supplies will not be limited, interrupted, or of satisfactory quality or continue to be available at acceptable prices. In particular, any replacement of any of our third-party contract manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements. In addition, we may encounter issues with transferring technology to a new third-party manufacturer, and we may encounter regulatory delays if we need to move the manufacturing of our products from one third-party manufacturer to another.

15

In order to conduct later-stage clinical trials of our product candidates, and eventually, if approved, commercial products, we will need to manufacture them in larger quantities. We, or any manufacturing partners, may be unable to successfully increase the manufacturing scale and capacity for any of our product candidates in a timely or cost-effective manner, or at all. Additionally, in some cases, we may have to start late-stage trials with our earlier clinical trial drug product and later switch to the late-stage or commercial drug product in trial. In such cases, the FDA will require us to complete bridging studies to compare the earlier stage material with the late-stage or commercial material to assure comparability between the earlier trial material and the late-stage or commercial material. Changing the formulation and scale up process is a complicated and difficult task and there can be no assurances that the changes we make to the drug product and manufacturing process will be successful or completed in a timely manner or that the FDA will not require additional development steps or studies.

In-Licenses

License from UCSB

In August 2010, we entered into an agreement with UCSB, that grants us an exclusive license, with the right to sublicense, under the patent rights owned by UCSB covering mask and screening technologies relating to the identification and discovery of pro-protein biologics, including masks and substrates, for the identification of pro-proteins, for use in the fields of therapeutics, in vivo diagnostics, and prophylactics (the “UCSB Agreement”). The UCSB Agreement also grants us an exclusive license, with the right to sublicense, under UCSB’s interest in certain patent rights we co-own with UCSB covering PROBODY antibodies and other pro-proteins in the fields of therapeutics, in vivo diagnostics and prophylactics.

We are obligated to pay to UCSB royalties on net sales of licensed products in the low single digit percentages, subject to annual minimum amounts as well as certain reductions. We are required to make milestone payments to UCSB on the accomplishment of certain milestones totaling up to $1.1 million for each of the first two indications for each licensed product consisting of a molecule or compound covered by the licensed patent rights. We were also obligated to make a payment to UCSB upon the first occurrence of an IPO or change of control. If the Company sublicenses its rights under the UCSB Agreement, it must pay UCSB a percentage of our total sublicense revenues ranging from the mid-single to mid-teen percentages, which total amount would be first reduced by the aggregate amount of certain research and development related expenses incurred by the Company and other permitted deductions.

License from ImmunoGen

Under the ImmunoGen 2019 License, we gained rights to the EpCAM conditionally activated ADC program and, in return, we made an upfront payment of $7.5 million, and we will pay up to $35.0 million in certain clinical development milestones, and up to $320.0 million in regulatory approval and commercialization milestone payments, if achieved. Immunogen is also entitled to royalties on any product sales ranging from the mid-to-high single digits percentages.

Competition

CytomX is pioneering a new potential class of potent, anti-cancer biologic therapeutics – the PROBODY conditionally activated therapeutic platform. The biotechnology and biopharmaceutical industries, including the ADC and immuno-oncology subsectors, are characterized by rapid evolution of technologies, fierce competition and strong defense of intellectual property. Any product candidates that we successfully develop and commercialize will have to compete with existing therapies and new therapies that may become available in the future. While we believe that our proprietary PROBODY platform and scientific expertise in the field of biologics and immuno-oncology provide us with competitive advantages, a wide variety of institutions, including large biopharmaceutical companies, specialty biotechnology companies, academic research departments and public and private research institutions, are actively developing potentially competitive products and technologies. We face substantial competition from biotechnology and biopharmaceutical companies developing biopharmaceutical products, particularly with respect to ADC, TCE and immuno-oncology therapeutics, where competition is intense and rapidly evolving. These competitors generally fall within the following categories:

Masking and conditional activation: Several companies, including AbbVie, Adagene, Amgen, BioAtla, Halozyme Therapeutics, Harpoon Therapeutics, Roche, Sanofi, Takeda Pharmaceutical, Werewolf Therapeutics, Janux Therapeutics and Xilio Therapeutics are exploring, researching or developing antibody masking and/or conditional activation strategies, which could compete with our PROBODY platform.

Antibody-drug conjugates: Several large pharmaceutical companies, such as AbbVie, Daiichi Sankyo, Gilead Sciences, Pfizer, Roche, Merck and Takeda Pharmaceutical are researching, developing, and in some cases, commercializing ADCs. In addition, numerous smaller companies have ongoing efforts in the space.

16

Cancer immunotherapies: Cancer immunotherapy is one of the most competitive and fastest growing segments of the pharmaceutical industry. Almost every large pharmaceutical company is developing or commercializing cancer immunotherapies, including Amgen, AstraZeneca, Bristol Myers Squibb, Celgene, GlaxoSmithKline, Merck, Novartis, Pfizer, Roche, and Sanofi. In addition, many large and mid-sized biotech companies such as BeiGene, Incyte, Nektar Therapeutics, and Alkermes have ongoing efforts in cancer immunotherapy. Numerous smaller companies are also working in this space.

T-cell engaging therapies: Several large pharmaceutics companies, such as Amgen, Novartis, and Roche, have on-going efforts in the field of T-cell engagers. In addition, several mid-sized biotech companies such as MacroGenics and Xencor, as well as numerous smaller companies, including Janux Therapeutics, have ongoing efforts in TCEs.

Cytokines: Several companies have ongoing efforts or molecules in development in the field of cytokines including Bristol Myers Squibb, ImmunityBio, Jazz Pharmaceuticals, Merck, Nektar Therapeutics, Novartis, Sanofi, Werewolf Therapeutics, Xencor, and Xilio Therapeutics.

Many of our competitors, either alone or with strategic partners, have substantially greater financial, technical and human resources than we do. Accordingly, our competitors may be more successful than us in obtaining approval for treatments and achieving widespread market acceptance, rendering our treatments obsolete or non-competitive. Accelerated merger and acquisition activity in the biotechnology and biopharmaceutical industries may result in even more resources being concentrated among a smaller number of our competitors. These companies also compete with us in recruiting and retaining qualified scientific and management personnel, establishing clinical study sites and patient registration for clinical studies and acquiring technologies complementary to, or necessary for, our programs. Smaller or early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. Our commercial opportunity could be substantially limited in the event that our competitors develop and commercialize products that are more effective, safer, less toxic, more convenient or less expensive than our comparable products. In geographies that are critical to our commercial success, competitors may also obtain regulatory approvals before us, resulting in our competitors building a strong market position in advance of our products’ entry. We believe the factors determining the success of our programs will be the efficacy, safety and convenience of our product candidates.

Intellectual Property

We strive to protect and enhance the proprietary technology, inventions, and improvements that are commercially important to our business, including seeking, maintaining, and defending patent rights, whether developed internally or licensed from third parties. Our policy is to seek to protect our proprietary position by, among other methods, pursuing and obtaining patent protection in the United States and in jurisdictions outside of the United States related to our proprietary technology, inventions, improvements, platforms and product candidates that are important to the development and implementation of our business. Our patent portfolio is intended to cover, but is not limited to, our technology platforms, our product candidates and components thereof, their methods of use and processes for their manufacture, our proprietary reagents and assays, and any other inventions that are commercially important to our business. We also rely on trade secret protection of our confidential information and know-how relating to our proprietary technology, platforms and product candidates, continuing innovation, and in-licensing opportunities to develop, strengthen, and maintain our proprietary position in our PROBODY platform and product candidates. We expect to rely on data exclusivity, market exclusivity, patent term adjustment and patent term extensions when available. Our commercial success may depend in part on our ability to obtain and maintain patent and other proprietary protection for our technology, inventions, and improvements; to preserve the confidentiality of our trade secrets; to maintain our licenses to use intellectual property owned or controlled by third parties; to defend and enforce our proprietary rights, including our patents; to defend against and challenge the assertion by third parties of their purported intellectual property rights; and to operate without the unauthorized infringement of valid and enforceable patents and other proprietary rights of third parties.

We believe that we have a strong global intellectual property position and substantial know-how and trade secrets relating to our PROBODY therapeutic technology, platform and product candidates. As of January 2024, our patent portfolio contains at least 250 granted patents (some of which are co-owned with a third party) and at least 400 pending patent applications (some of which are co-owned with a third party). We have exclusively licensed UCSB’s interest in the co-owned patent family covering PROBODY technology in the fields of therapeutics, in vivo diagnostics and prophylactics.

These patents and patent applications include claims directed to our PROBODY platform technology, including PROBODY drug conjugates, bispecific and other multi-specific PROBODY therapeutics (including T-cell engaging bispecific PROBODY therapeutics), protease cleavable linkers, and cancer immunotherapy PROBODY therapeutics.

In addition, we have exclusively licensed a patent portfolio of patent families from UCSB patents and patent applications that cover compositions and methods related to screening for and identification of masks and protease-cleavable linkers that we have incorporated into our PROBODY therapeutics and may incorporate into future PROBODY therapeutics.

17

As for the PROBODY platform, product candidates and processes we develop and commercialize, in the normal course of business, we intend to pursue, where appropriate, patent protection or trade secret protection relating to compositions, methods of manufacture, assay methods, methods of use, treatment of indications, dosing and formulations. We may also pursue patent protection with respect to product development processes and technology.

We continually assess and refine our intellectual property strategy as we develop new platform technologies and product candidates. To that end, we are prepared to file additional patent applications if our intellectual property strategy requires such filings, or where we seek to adapt to competition or seize business opportunities. Further, we are prepared to file patent applications, as we consider appropriate under the circumstances, relating to the new technologies that we develop. In addition to filing and prosecuting patent applications in the United States, we often file counterpart patent applications in the European Union and in additional countries where we believe such foreign filing is likely to be beneficial.

Our currently issued patents will likely expire on dates ranging from 2028 to 2037, unless we receive patent term extension or adjustment as might be available under applicable law. If patents are issued on our pending patent applications, the resulting patents are projected to expire on dates ranging from 2028 to 2041, unless we receive patent term extension or adjustment. However, the actual protection afforded by a patent varies on a product-by-product basis, from country-to-country, and depends upon many factors, including the type of patent, the scope of its coverage, the availability of regulatory-related extensions, the availability of legal remedies in a particular country, and the validity and enforceability of the patent.

All of our patents and patent applications are subject to risks and uncertainties under U.S. and foreign law. We also rely on trademark registration to protect our trademarks. For a more comprehensive discussion of risks related to our proprietary technology, inventions, improvements, platforms and product candidates, please see the section entitled “Risk Factors—Risks Related to Intellectual Property.”

We also rely on trade secret protection for our confidential and proprietary information. It is our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon the commencement of employment or consulting relationships with us. In the case of employees, the agreements provide that all inventions conceived by the individual, and which are related to our current or planned business or research and development or made during normal working hours, on our premises or using our equipment or proprietary information, are our exclusive property. In many cases our confidentiality and other agreements with consultants, outside scientific collaborators, sponsored researchers and other advisors require them to assign or grant us licenses to inventions they invent as a result of the work or services they render under such agreements or grant us an option to negotiate a license to use such inventions.

Government Regulation and Product Approval

Governmental authorities in the U.S., at the federal, state and local level, and other countries extensively regulate, among other things, the research, development, testing, manufacture, labeling, packaging, promotion, storage, advertising, distribution, marketing and export and import of products such as those we are developing. Our product candidates are subject to regulation in the U.S. as biologics, which must be approved by the FDA through the BLA process before they may be legally marketed in the U.S. and will be subject to similar requirements in other countries prior to marketing in those countries. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations require the expenditure of substantial time and financial resources.

U.S. Government Regulation

In the U.S., the FDA regulates biologics under the Federal Food, Drug, and Cosmetic Act (“FDCA”) and the Public Health Service Act (“PHSA”), and their respective implementing regulations.

BLA Approval Process

The process required by the FDA before a biologic may be marketed in the U.S. generally involves the following:

•

completion of nonclinical laboratory tests, animal studies and formulation studies conducted according to good laboratory practices (“GLPs”), and other applicable regulations;

•

submission to the FDA of an IND, which must become effective before human clinical trials may begin;

•

approval by an institutional review board (“IRB”) or ethics committee at each clinical site before the trial is commenced;

18

•

performance of adequate and well-controlled human clinical trials according to good clinical practices (“GCPs”), to establish the safety, purity and potency of the product candidate for its intended use;

•

preparation and submission to the FDA of a BLA after completion of all pivotal trials;

•

satisfactory completion of an FDA pre-approval inspection of the manufacturing facility or facilities at which the product candidate is produced to assess compliance with current good manufacturing practices (“cGMPs”) to assure that the facilities, methods and controls are adequate to preserve the product candidate’s continued safety, purity and potency, and of potential inspections of selected clinical investigation sites to assess compliance with GCPs; and

•

FDA review and approval of the BLA to permit commercial marketing of the product for its particular labeled uses in the United States.

Preclinical and Clinical Studies

Once a biologic product candidate is identified for development, it enters the preclinical, or nonclinical, testing stage. Nonclinical tests include laboratory evaluations of product chemistry, toxicity and formulation, as well as animal studies. An IND sponsor must submit the results of the nonclinical tests, together with manufacturing information and analytical data, to the FDA as part of the IND. Some nonclinical testing may continue even after the IND is submitted. In addition to including the results of the nonclinical studies, the IND will also include a protocol detailing, among other things, the objectives of the clinical trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated if the first phase lends itself to an efficacy evaluation. The IND automatically becomes effective 30 days after receipt by the FDA, unless the FDA, within the 30-day time period, places the IND on clinical hold. In such a case, the IND sponsor and the FDA must resolve any outstanding concerns before clinical trials can begin. A clinical hold may occur at any time while an IND is active and may affect one or more specific studies or all studies conducted under the IND.

All clinical trials must be conducted under the supervision of one or more qualified investigators in accordance with GCPs. Clinical trials must be conducted under protocols detailing the objectives of the trial, dosing procedures, research subject selection and exclusion criteria and the safety and effectiveness criteria to be evaluated. Each protocol, and any subsequent material amendment to the protocol, must be submitted to the FDA as part of the IND. While the IND is active, progress reports summarizing the results of the clinical trials and nonclinical studies performed since the last progress report, among other information, must be submitted at least annually to the FDA, and written IND safety reports must be submitted to the FDA and investigators for serious and unexpected suspected adverse events, findings from other studies suggesting a significant risk to humans exposed to the same or similar drugs, findings from animal or in vitro testing suggesting a significant risk to humans, and any clinically important increased incidence of a serious suspected adverse reaction compared to that listed in the protocol or investigator brochure.

Furthermore, an independent IRB for each site proposing to conduct each clinical trial must review and approve the plan for any clinical trial and its informed consent form before the clinical trial begins at that site and must monitor the study until completion. Some studies also include oversight by an independent group of qualified experts organized by the clinical study sponsor, generally known as a data safety monitoring board, which provides authorization for whether or not a study may move forward at designated check points based on access to certain data from the study and may halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy. Depending on its charter, this group may determine whether a trial may move forward at designated check points based on access to certain data from the trial. The FDA or the sponsor may suspend a clinical trial at any time on various grounds, including a finding that the research subjects or patients are being exposed to an unacceptable health risk. Similarly, an IRB can suspend or terminate approval of a clinical trial at its institution if the clinical trial is not being conducted in accordance with the IRB’s requirements or if the drug has been associated with unexpected serious harm to patients. There are also requirements governing the reporting of ongoing clinical trials and completed clinical trial results to public registries.

Human clinical trials are typically conducted in three sequential phases that may overlap or be combined.

•

Phase 1—The product candidate is initially introduced into healthy human subjects and tested for safety, dosage tolerance, absorption, metabolism, distribution and elimination. In the case of some therapeutic candidates for severe or life-threatening diseases, such as cancer, especially when the product candidate may be inherently too toxic to ethically administer to healthy volunteers, the initial human testing is often conducted in patients.

19

•

Phase 2—The product candidate is administered to a limited patient population with the specified disease or condition to identify possible adverse effects and safety risks, to preliminarily evaluate the efficacy of the product for specific targeted diseases and to determine dosage tolerance and optimal dosage.

•

Phase 3—The product candidate is administered to an expanded patient population to further evaluate dosage, clinical efficacy and safety, generally at geographically dispersed clinical study sites. These studies are intended to establish the overall risk-benefit ratio of the product and provide an adequate basis for product approval.

Post-approval trials, sometimes referred to as “Phase 4” clinical trials, may be conducted after initial marketing approval. These trials are used to gain additional experience from the treatment of patients in the intended therapeutic indication. In certain instances, FDA may mandate the performance of such “Phase 4” clinical trials as a condition of approval for a BLA

During the development of a new biologic product candidate, sponsors are given opportunities to meet with the FDA at certain points; specifically, prior to the submission of an IND, at the end of Phase 2 and before a BLA is submitted. Meetings at other times may be requested. These meetings can provide an opportunity for the sponsor to share information about the data gathered to date and for the FDA to provide advice on the next phase of development. Sponsors typically use the meeting at the end of Phase 2 to discuss their Phase 2 clinical results and present their plans for the pivotal Phase 3 clinical trial that they believe will support the approval of the new therapeutic.

Concurrent with clinical trials, sponsors usually complete additional animal safety studies, develop additional information about the chemistry and physical characteristics of the product candidate and finalize a process for manufacturing commercial quantities of the product candidate in accordance with cGMP requirements. The manufacturing process must be capable of consistently producing quality batches of the product candidate and the manufacturer must develop methods for testing the safety, purity and potency of the product candidate. Additionally, appropriate packaging must be selected and tested, and stability studies must be conducted to demonstrate that the biologic product candidate does not undergo unacceptable deterioration over its shelf life.

Submission of a BLA to the FDA

The results of product development, including results from nonclinical studies and clinical trials, along with descriptions of the manufacturing process, analytical tests and other control mechanisms, proposed labeling and other relevant information are submitted to the FDA as part of a BLA requesting approval to market the product for one or more indications.

Under the Prescription Drug User Fee Act (“PDUFA”) as amended, each BLA must be accompanied by a significant user fee. The FDA adjusts the PDUFA user fees on an annual basis. PDUFA also imposes an annual program fee for marketed products. Fee waivers or reductions are available in certain circumstances, such as where a waiver is necessary to protect the public health, where the application seeks an indication covered by an Orphan Drug Designation, where the fee would present a significant barrier to innovation, or where the applicant is a small business submitting its first human therapeutic application for review.

Within 60 days following submission of the application, the FDA reviews a BLA to determine if it is substantially complete before the agency accepts it for filing. The FDA may refuse to file any BLA that it deems incomplete or not properly reviewable at the time of submission and may request additional information. In this event, the BLA must be resubmitted with the additional information. The resubmitted application also is subject to review before the FDA accepts it for filing. Once the submission is accepted for filing, the FDA begins an in-depth substantive review of the BLA. The FDA reviews a BLA to determine, among other things, whether the proposed product is safe, pure and potent for its intended use, and whether the facility in which it is being manufactured, processed, packaged, or held meets standards designed to assure the product’s continued safety, purity and potency in accordance with cGMP.

The FDA may refer applications for novel products or products that present difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether the application should be approved and under what conditions. The FDA is not bound by the recommendations of an advisory committee, but it considers such recommendations carefully when making decisions.

Before approving a BLA, the FDA will inspect the facilities at which the product is manufactured. The FDA will not approve the product unless it determines that the manufacturing processes and facilities are in compliance with cGMP requirements and adequate to assure consistent production of the product within required specifications. Additionally, before approving a BLA, the FDA will typically inspect one or more clinical sites to assure that the clinical trials were conducted in compliance with GCP requirements.

After the FDA evaluates the BLA and the manufacturing facilities, it issues either an approval letter or a complete response letter. An approval letter authorizes commercial marketing of the product with specific prescribing information for specific indications. A complete response letter generally describes all of the specific deficiencies in the BLA identified by the FDA. The deficiencies

20

identified may be minor, for example, requiring labeling changes, or major, for example, requiring additional clinical trials. Additionally, the complete response letter may include recommended actions that the applicant might take to place a resubmitted application in a condition for approval. If a complete response letter is issued, the applicant may either resubmit the BLA, addressing all of the deficiencies identified in the letter, or withdraw the application.

Even if a product receives regulatory approval, the approval may be significantly limited to specific indications and dosages or the indications for use may otherwise be limited, which could restrict the commercial value of the product. Further, the FDA may require that certain contraindications, warnings or precautions be included in the product labeling.

As a condition of BLA approval, the FDA may require a Risk Evaluation and Mitigation Strategy (“REMS”) to ensure that the benefits of the drug outweigh its risks. If the FDA determines a REMS is necessary prior to or during review of the application, the sponsor must submit a REMS as part of its application, and the FDA will not approve a BLA without a REMS, if required. A REMS program may be required to include various elements, such as a medication guide or patient package insert, a communication plan to educate healthcare providers of the product’s risks, or other elements to assure safe use, such as limitations on who may prescribe or dispense the drug, dispensing only under certain circumstances, special monitoring and the use of patient registries. In addition, all REMS programs must include a timetable to periodically assess the strategy following implementation.

Further, product approval may require substantial post-approval testing and surveillance to monitor the product’s safety and efficacy, and the FDA has the authority to prevent or limit further marketing of a product based on the results of these post-marketing programs. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems are identified following initial marketing. Moreover, changes to the conditions established in an approved application, including changes in indications, labeling or manufacturing processes or facilities may require submission and FDA approval of a new supplement before the changes can be implemented. A supplement for a new indication typically requires clinical data, and the FDA uses similar procedures in reviewing supplements as it does in reviewing original applications.

Companion Diagnostics

Some of our product candidates may require use of an in vitro diagnostic to identify appropriate patient populations. These diagnostics, often referred to as companion diagnostics, are regulated as medical devices. In the United States, the FDCA and its implementing regulations, and other federal and state statutes and regulations govern, among other things, medical device design and development, pre-clinical and clinical testing, premarket clearance or approval, registration and listing, manufacturing, labeling, storage, advertising and promotion, sales and distribution, export and import, and post-market surveillance. Unless an exemption applies, companion diagnostic tests require marketing clearance or approval from the FDA prior to commercial distribution. The two primary types of FDA marketing authorization applicable to a medical device are premarket notification, also called 510(k) clearance, and premarket approval (“PMA”).

If use of companion diagnostic is essential to safe and effective use of a biologic product, then the FDA generally will require approval or clearance of the diagnostic contemporaneously with the approval of the biologic product. According to FDA guidance, for novel product candidates such as drugs and therapeutic biologics, a companion diagnostic device and its corresponding product candidate should be approved or cleared contemporaneously by FDA for the use indicated in the product labeling. The guidance also explains that a companion diagnostic device used to make treatment decisions in clinical trials of a product candidate generally will be considered an investigational device unless it is employed for an intended use for which the device is already approved or cleared. If used to make critical treatment decisions, such as patient selection, the diagnostic device generally will be considered a significant risk device under the FDA’s Investigational Device Exemption (“IDE”) regulations. Thus, the sponsor of the diagnostic device will be required to comply with the IDE regulations. Even where a diagnostic is not considered a significant risk device, the sponsor must still follow abbreviated IDE regulations in connection with its use. According to FDA guidance, if a diagnostic device and a drug or biologic product candidate are to be studied together to support their respective approvals, both products can be studied in the same investigational study, if the study meets both the requirements of the IDE regulations and the IND regulations. Depending on the details of the study plan and subjects, a sponsor may seek to submit an IND alone, or both an IND and an IDE.

The FDA generally requires companion diagnostics intended to select the patients who will respond to cancer treatment to obtain approval of a PMA for that diagnostic contemporaneously with approval of the therapeutic product. The PMA process, including the gathering of clinical and pre-clinical data and the submission to and review by the FDA, can take several years or longer. It involves a rigorous premarket review during which the applicant must prepare and provide the FDA with reasonable assurance of the device’s safety and effectiveness and information about the device and its components regarding, among other things, device design, manufacturing and labeling. PMA applications are also subject to an application fee. In addition, PMAs for certain devices must generally include the results from extensive pre-clinical and adequate and well-controlled clinical trials to establish the safety and effectiveness of the device for each indication for which FDA approval is sought. In particular, for a diagnostic, the applicant must demonstrate that the diagnostic produces reproducible results when the same sample is tested multiple times by multiple users at

21

multiple laboratories. In addition, as part of the PMA review, the FDA will typically inspect the manufacturer’s facilities for compliance with the Quality System Regulation (“QSR”) which currently represents FDA’s GMP requirements for medical devices, and imposes elaborate testing, control, documentation and other quality assurance requirements.

PMA approval is not guaranteed, and the FDA may ultimately respond to a PMA submission with a not approvable determination based on deficiencies in the application and require additional clinical trial or other data that may be expensive and time-consuming to generate and that can substantially delay approval. If the FDA’s evaluation of the PMA application is favorable, the FDA typically issues an approvable letter requiring the applicant’s agreement to specific conditions, such as changes in labeling, or specific additional information, such as submission of final labeling, in order to secure final approval of the PMA. If the FDA’s evaluation of the PMA or manufacturing facilities is not favorable, the FDA will deny approval of the PMA or issue a not approvable letter. A not approvable letter will outline the deficiencies in the application and, where practical, will identify what is necessary to make the PMA approvable. The FDA may also determine that additional clinical trials are necessary, in which case the PMA approval may be delayed for several months or years while the trials are conducted and then the data submitted in an amendment to the PMA. If the FDA concludes that the applicable criteria have been met, the FDA will issue a PMA for the approved indications, which can be more limited than those originally sought by the applicant. The PMA can include post-approval conditions that the FDA believes necessary to ensure the safety and effectiveness of the device, including, among other things, restrictions on labeling, promotion, sale and distribution. Once granted, PMA approval may be withdrawn by the FDA if compliance with post approval requirements, conditions of approval or other regulatory standards are not maintained or problems are identified following initial marketing.

After a device is placed on the market, it remains subject to significant regulatory requirements. Medical devices may be marketed only for the uses and indications for which they are cleared or approved. Device manufacturers must also establish registration and device listings with the FDA. A medical device manufacturer’s manufacturing processes and those of its suppliers are required to comply with the applicable portions of the QSR, which cover the methods and documentation of the design, testing, production, processes, controls, quality assurance, labeling, packaging and shipping of medical devices. Domestic facility records and manufacturing processes are subject to periodic unscheduled inspections by the FDA. The FDA also may inspect foreign facilities that export products to the United States.

Expedited Development and Review Programs

The FDA offers a number of expedited development and review programs for qualifying product candidates.

A product candidate may be eligible for Fast Track designation if it is intended to treat a serious or life-threatening disease or condition and demonstrates the potential to address unmet medical needs for the disease or condition. Fast Track designation applies to the combination of the product candidate and the specific indication for which it is being studied. The sponsor of a Fast Track product candidate has opportunities for frequent interactions with the review team during product development and, once a BLA is submitted, the application may be eligible for Priority Review. A BLA for a Fast Track product candidate may also be eligible for Rolling Review, where the FDA may consider for review sections of the BLA on a rolling basis before the complete application is submitted, if the sponsor provides a schedule for the submission of the sections of the BLA, the FDA agrees to accept sections of the BLA and determines that the schedule is acceptable, and the sponsor pays any required user fees upon submission of the first section of the BLA.

A product candidate intended to treat a serious or life-threatening disease or condition may also be eligible for Breakthrough Therapy designation to expedite its development and review. A product candidate can receive Breakthrough Therapy designation if preliminary clinical evidence indicates that the product candidate may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. The designation includes all of the Fast Track program features, as well as more intensive FDA interaction and guidance beginning as early as Phase 1 and an organizational commitment to expedite the development and review of the product candidate, including involvement of senior managers.

After a BLA is submitted for a product candidate, including a product candidate with a Fast Track designation and/or Breakthrough Therapy designation, the BLA may be eligible for other types of FDA programs intended to expedite the FDA review and approval process, such as Priority Review. A BLA is eligible for Priority Review if the product candidate has the potential to provide a significant improvement in the treatment, diagnosis or prevention of a serious disease or condition compared available products. Priority review designation means the FDA’s goal is to take action on the marketing application within six months of the 60-day filing date, compared to ten months under standard review.

22

Additionally, depending on the design of the applicable clinical trials, product candidates studied for their safety and effectiveness in treating serious or life-threatening diseases or conditions may receive Accelerated Approval upon a determination that the product candidate has an effect on a surrogate endpoint that is reasonably likely to predict clinical benefit, or on a clinical endpoint that can be measured earlier than irreversible morbidity or mortality, that is reasonably likely to predict an effect on irreversible morbidity or mortality or other clinical benefit, taking into account the severity, rarity, or prevalence of the condition and the availability or lack of alternative treatments. As a condition of Accelerated Approval, the FDA will generally require the sponsor to perform adequate and well-controlled confirmatory clinical studies to verify and describe the anticipated effect on irreversible morbidity or mortality or other clinical benefit, and may require that such confirmatory trials be underway prior to granting accelerated approval. Products receiving Accelerated Approval may be subject to expedited withdrawal procedures if the sponsor fails to conduct the required confirmatory studies in a timely manner or if such studies fail to verify the predicted clinical benefit. In addition, the FDA currently requires as a condition for Accelerated Approval pre-approval of promotional materials, which could adversely impact the timing of the commercial launch of the product.

Patent Term Restoration and Marketing Exclusivity

Depending upon the timing, duration and specifics of FDA approval of the use of our therapeutic candidates, some of our U.S. patents may be eligible for limited patent term extension under the Drug Price Competition and Patent Term Restoration Act of 1984, referred to as the Hatch-Waxman Act. The Hatch-Waxman Act permits a patent restoration term of up to five years as compensation for patent term lost during product development and the FDA regulatory review process. However, patent term restoration cannot extend the remaining term of a patent beyond a total of 14 years from the product candidate’s approval date. The patent term restoration period is generally one half of the time between the effective date of an IND and the submission date of a BLA, plus the time between the submission date of a BLA and the approval of that application, except that the review period is reduced by any time during which the applicant failed to exercise due diligence. Only one patent applicable to an approved product candidate is eligible for the extension and the application for extension must be made prior to expiration of the patent. The USPTO, in consultation with the FDA, reviews and approves the application for any patent term extension or restoration. In the future, we intend to apply for restorations of patent term for some of our currently owned or licensed patents to add patent life beyond their current expiration date, depending on the expected length of clinical trials and other factors involved in the submission of the relevant BLA.

Biosimilars and Exclusivity

The Affordable Care Act, signed into law in 2010, includes the Biologics Price Competition and Innovation Act (“BPCIA”), which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. The FDA has issued several guidance documents outlining an approach to review and approval of biosimilars. Biosimilarity, which requires that there be no clinically meaningful differences between the biological product and the reference product in terms of safety, purity, and potency, can be shown through analytical studies, animal studies, and a clinical study or studies. Interchangeability requires that a product is biosimilar to the reference product and the product must demonstrate that it can be expected to produce the same clinical results as the reference product in any given patient and, for products that are administered multiple times to an individual, the biologic and the reference biologic may be alternated or switched after one has been previously administered without increasing safety risks or risks of diminished efficacy relative to exclusive use of the reference biologic.

Under the BPCIA, an application for a biosimilar product may not be submitted to the FDA until four years following the date that the reference product was first licensed by the FDA. In addition, the approval of a biosimilar product may not be made effective by the FDA until 12 years from the date on which the reference product was first licensed. During this 12-year period of exclusivity, another company may still market a competing version of the reference product if the FDA approves a full BLA for the competing product containing that applicant’s own preclinical data and data from adequate and well-controlled clinical trials to demonstrate the safety, purity and potency of its product. The BPCIA also created certain exclusivity periods for biosimilars approved as interchangeable products. At this juncture, it is unclear whether products deemed “interchangeable” by the FDA will, in fact, be readily substituted by pharmacies, which are governed by state pharmacy law.

A biological product can also obtain pediatric market exclusivity in the United States. Pediatric exclusivity, if granted, adds six months to existing exclusivity periods and patent terms. This six-month exclusivity, which runs from the end of other exclusivity protection or patent term, may be granted based on the voluntary completion of a pediatric study in accordance with an FDA-issued “Written Request” for such a study. The FDA’s issuance of a written request does not obligate the sponsor to conduct the requested study.

Orphan Drug Designation

Under the Orphan Drug Act, the FDA may grant Orphan Drug Designation to therapeutic candidates intended to treat a rare disease or condition, which is generally a disease or condition that affects either (1) fewer than 200,000 individuals in the U.S., or (2) more than

23

200,000 individuals in the U.S. and for which there is no reasonable expectation that the cost of developing and making available in the U.S. a product candidate for this type of disease or condition will be recovered from sales in the U.S. for that product candidate. Orphan drug designation entitles the applicant to incentives, which may include grant funding towards clinical study costs, tax advantages, and waivers of FDA user fees. Orphan Drug Designation must be requested before submitting a BLA. After the FDA grants Orphan Drug Designation, the identity of the therapeutic agent and its potential orphan use are disclosed publicly by the FDA. Orphan Drug Designation does not convey any advantage in or shorten the duration of the regulatory review and approval process.

If a product candidate that has Orphan Drug Designation subsequently receives the first FDA approval for the disease or condition for which it has such designation, the product candidate is entitled to orphan product exclusivity, which means that the FDA may not approve any other applications to market the same product candidate for the same disease or condition for seven years, except under limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or if the FDA finds that the holder of the orphan drug exclusivity has not shown that it can assure the availability of sufficient quantities of the orphan drug to meet the needs of patients with the disease or condition for which the drug was designated. Orphan drug exclusivity does not prevent the FDA from approving a different drug for the same disease or condition, or the same drug for a different disease or condition. Among the other benefits of orphan drug designation are tax credits for certain research and a waiver of the NDA application user fee.

A designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. In addition, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or, as noted above, if a second applicant demonstrates that its product is clinically superior to the approved product with orphan exclusivity or the manufacturer of the approved product is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition

Pediatric Studies

The Pediatric Research Equity Act (“PREA”) requires a sponsor to conduct pediatric studies for most therapeutic candidates and biologics, for a new active ingredient, new indication, new dosage form, new dosing regimen or new route of administration. Under PREA, original BLAs and supplements thereto must contain a pediatric assessment unless the sponsor has received a deferral or waiver. The required assessment must assess the safety and effectiveness of the product candidate for the claimed indications in all relevant pediatric subpopulations and support dosing and administration for each pediatric subpopulation for which the product candidate is determined to be safe, pure and potent. The sponsor or FDA may request a deferral of pediatric studies for some or all of the pediatric subpopulations. A deferral may be granted for several reasons, including a finding that the product candidate or biologic is ready for approval for use in adults before pediatric studies are complete or that additional safety or effectiveness data needs to be collected before the pediatric studies begin. The law requires the FDA to send a PREA Non-Compliance letter to sponsors who have failed to submit their pediatric assessments required under PREA, have failed to seek or obtain a deferral or deferral extension or have failed to request approval for a required pediatric formulation. It further requires the FDA to post the PREA Non- Compliance letter and sponsor’s responses.

Post-Approval Requirements

Once a BLA approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements is not maintained or if problems occur after the biologic product reaches the market. Later discovery of previously unknown problems with a product candidate may result in restrictions on the product candidate or even complete withdrawal of the product candidate from the market. After approval, some types of changes to the approved product, such as adding new indications, manufacturing changes and additional labeling claims, are subject to further FDA review and approval. In addition, the FDA may under some circumstances require testing and surveillance programs to monitor the effect of approved product that have been commercialized, and the FDA under some circumstances has the power to prevent or limit further marketing of a product candidate based on the results of these post-marketing programs.

Biologic manufacturers and other entities involved in the manufacture and distribution of approved therapeutic products are required to register their establishments with the FDA and certain state agencies and are subject to periodic unannounced inspections by the FDA and some state agencies for compliance with cGMPs and other laws. The FDA periodically inspects manufacturing facilities to assess compliance with cGMP, which imposes extensive procedural, substantive and record-keeping requirements. In addition, changes to the manufacturing process are strictly regulated, and, depending on the significance of the change, may require FDA approval before being implemented. FDA regulations would also require investigation and correction of any deviations from cGMP and impose reporting and documentation requirements upon us and any third-party manufacturers that we may decide to use if our product candidates are approved. Accordingly, manufacturers must continue to expend time, money and effort in the area of production and quality control to maintain compliance with cGMP and other aspects of regulatory compliance.

24

Once an approval is granted, the FDA may withdraw the approval if compliance with regulatory requirements and standards is not maintained or if problems occur after the product reaches the market. Later discovery of previously unknown problems with a product, including adverse events of unanticipated severity or frequency, or with manufacturing processes, or failure to comply with regulatory requirements, may result in mandatory revisions to the approved labeling to add new safety information; imposition of post-market studies or clinical trials to assess new safety risks; or imposition of distribution or other restrictions under a REMS program. Other potential consequences include, among other things:

•

restrictions on the marketing or manufacturing of the product, complete withdrawal of the product from the market or product recalls;

•

safety alerts, Dear Healthcare Provider letters, press releases or other communications containing warning or other safety information about the product;

•

fines, warning letters or holds on post-approval clinical trials;

•

refusal of the FDA to approve pending BLAs or supplements to approved BLAs, or suspension or revocation of product approvals;

•

product seizure or detention, or refusal to permit the import or export of products; or

•

injunctions or the imposition of civil or criminal penalties.

The FDA closely regulates the marketing, labeling, advertising and promotion of drug products. A company can make only those claims relating to safety and efficacy that are approved by the FDA and in accordance with the provisions of the approved label. The FDA and other agencies actively enforce the laws and regulations prohibiting the promotion of off-label uses. Failure to comply with these requirements can result in, among other things, adverse publicity, warning letters, corrective advertising and potential civil and criminal penalties. Physicians may prescribe, in their independent professional medical judgment, legally available products for uses that are not described in the product’s labeling and that differ from those tested by us and approved by the FDA. Physicians may believe that such off-label uses are the best treatment for many patients in varied circumstances. The FDA does not regulate the behavior of physicians in their choice of treatments. The FDA does, however, restrict manufacturer’s communications on the subject of off-label use of their products. However, companies may share truthful and not misleading information that is otherwise consistent with a product’s FDA-approved labelling.

Regulation Outside of the U.S.

In addition to regulations in the U.S., we will be subject to regulations of other jurisdictions governing any clinical trials and commercial sales and distribution of our therapeutic candidates. Whether or not we obtain FDA approval for a product, we must obtain approval by the comparable regulatory authorities of countries outside of the U.S. before we can commence clinical trials in such countries and approval of the regulators of such countries or economic areas, such as the European Union, before we may market products in those countries or areas. The approval process and requirements governing the conduct of clinical trials, product licensing, pricing and reimbursement vary greatly from place to place, and the time may be longer or shorter than that required for FDA approval.

Under European Union regulatory systems, a company can consider applying for marketing authorization in several European Union member states by submitting its marketing authorization application(s) under a centralized, decentralized or mutual recognition procedure. The centralized procedure provides for the grant of a single marketing authorization that is valid for all European Union member states. The centralized procedure is compulsory for medicines derived from biotechnology, orphan medicinal products, or those medicines with an active substance not authorized in the European Union on or before May 20, 2004 intended to treat acquired immune deficiency syndrome (“AIDS”), cancer, neurodegenerative disorders or diabetes and optional for those medicines containing a new active substance not authorized in the European Union on or before May 20, 2004, medicines which are highly innovative, or medicines to which the granting of a marketing authorization under the centralized procedure would be in the interest of patients at the European Union-level. The decentralized procedure provides for recognition by European Union national authorities of a first assessment performed by one of the member states. Under this procedure, an identical application for marketing authorization is submitted simultaneously to the national authorities of several European Union member states, one of them being chosen as the “Reference Member State”, and the remaining being the “Concerned Member States”. The Reference Member State must prepare and send drafts of an assessment report, summary of product characteristics and the labelling and package leaflet within 120 days after receipt of a valid marketing authorization application to the Concerned Member States, which must decide within 90 days whether to recognize approval. If any Concerned Member State does not recognize the marketing authorization on the grounds of potential serious risk to public health, the disputed points are eventually referred to the European Commission, whose decision is binding on all member states. The mutual recognition procedure is similar to the decentralized procedure except that a medicine must have already received a marketing authorization in at least one of the member states, and that member state acts as the Reference Member State.

25

As in the U.S., we may apply for designation of a product candidate as an orphan drug for the treatment of a specific indication in the European Union before the application for marketing authorization is made.

Orphan drugs in the European Union enjoy economic and marketing benefits, including up to ten years of market exclusivity for the approved indication unless another applicant can show that its product is safer, more effective or otherwise clinically superior to the orphan-designated product, the marketing authorization holder is unable to supply sufficient quantity of the medicinal product or the marketing authorization holder has given its consent.

Coverage and Reimbursement

Sales of our products will depend, in part, on the extent to which our products will be covered by third-party payors, such as government health programs, commercial insurance and managed healthcare organizations. These third-party payors are increasingly reducing reimbursements for medical products and services. Additionally, the containment of healthcare costs has become a priority of federal and state governments and the prices of therapeutics have been a focus in this effort. The U.S. government, state legislatures and foreign governments have shown significant interest in implementing cost-containment programs, including price controls, restrictions on reimbursement and requirements for substitution of generic products. Adoption of price controls and cost-containment measures, and adoption of more restrictive policies in jurisdictions with existing controls and measures, could further limit our net revenue and results. If these third- party payors do not consider our products to be cost-effective compared to other therapies, they may not cover our products after approval as a benefit under their plans or, if they do, the level of payment may not be sufficient to allow us to sell our products on a profitable basis.

Healthcare Reform

The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act (together, the “ACA”) has had a significant impact on the health care industry. The ACA expanded coverage for the uninsured while at the same time containing overall healthcare costs. With regard to biopharmaceutical products, the ACA, among other things, addressed a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for drugs that are inhaled, infused, instilled, implanted or injected, increased the minimum Medicaid rebates owed by manufacturers under the Medicaid Drug Rebate Program and extended the rebate program to individuals enrolled in Medicaid managed care organizations, established annual fees and taxes on manufacturers of certain branded prescription drugs, and a Medicare Part D coverage gap discount program, in which manufacturers had to offer 50% point-of-sale discounts, which, through subsequent legislative amendments, was increased to 70%, off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer’s outpatient drugs to be covered under Medicare Part D.

Since its enactment, there have been judicial, executive and Congressional challenges to certain aspects of the ACA. On June 17, 2021, the U.S. Supreme Court dismissed the most recent judicial challenge to the ACA brought by several states without specifically ruling on the constitutionality of the ACA. Prior to the Supreme Court’s decision, President Biden issued an executive order initiating a special enrollment period from February 15, 2021 through August 15, 2021 for purposes of obtaining health insurance coverage through the ACA marketplace. The executive order also instructed certain governmental agencies to review and reconsider their existing policies and rules that limit access to healthcare.

In addition, other legislative changes have been proposed and adopted in the United States since the ACA was enacted that impact payment methodologies and reimbursement amounts. On August 2, 2011, the Budget Control Act of 2011 among other things, created measures for spending reductions by Congress, which led to aggregate reductions to Medicare payments to providers, starting in April 2013, and due to subsequent legislative amendments, will stay in effect through 2032, with the exception of a temporary suspension from May 1, 2020 through March 31, 2022, unless additional Congressional action is taken. On January 2, 2013, the American Taxpayer Relief Act of 2012 (the “ATRA”) was signed into law which, among other things, also reduced Medicare payments to several types of providers, including hospitals, imaging centers and cancer treatment centers, and increased the statute of limitations period for the government to recover overpayments to providers from three to five years. In addition, in March 2021, the American Rescue Plan Act of 2021 was signed into law, which eliminates the statutory Medicaid drug rebate cap, currently set at 100% of a drug’s average manufacturer price, beginning January 1, 2024.

Recently, there has been heightened governmental scrutiny over the manner in which manufacturers set prices for their marketed products, which has resulted in several Congressional inquiries and proposed bills designed to, among other things, bring more transparency to product pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drug products. Most recently, on August 16, 2022, the Inflation Reduction Act of 2022, or IRA, was signed into law. Among other things, the IRA requires manufacturers of certain drugs to engage in price negotiations with Medicare (beginning in 2026), imposes rebates under Medicare Part B and Medicare Part D to penalize price increases that outpace inflation (first due in 2023), and replaces the Part D coverage gap discount program with a new discounting program (beginning in

26

2025). The IRA permits the Secretary of the Department of Health and Human Services (HHS) to implement many of these provisions through guidance, as opposed to regulation, for the initial years. For that and other reasons, it is currently unclear how the IRA will be effectuated. 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. We cannot predict the extent of the impact of any changes to any of these laws on us.

Finally, in some foreign countries, the proposed pricing for a product candidate must be approved before it may be lawfully marketed. The requirements governing therapeutic pricing vary widely from country to country. For example, the European Union provides options for its member states to restrict the range of medicinal products for which their national health insurance systems provide reimbursement and to control the prices of medicinal products for human use. A member state may approve a specific price for the medicinal product, or it may instead adopt a system of direct or indirect controls on the profitability of the company placing the medicinal product on the market. There can be no assurance that any country that has price controls or reimbursement limitations for pharmaceutical products will allow favorable reimbursement and pricing arrangements for any of our product candidates. Historically, therapeutic candidates launched in the European Union do not follow price structures of the U.S. and generally tend to be significantly lower.

Other Healthcare Laws

We may also be subject to healthcare regulation and enforcement by the federal government and the states and foreign governments where we may market our product candidates, if approved. These laws include, without limitation, state and federal anti-kickback, fraud and abuse, false claims, physician and other health care provider payment and drug pricing transparency laws and regulations.

The federal Anti-Kickback Statute prohibits, among other things, any person from knowingly and willfully offering, soliciting, receiving or providing remuneration, directly or indirectly, to induce either the referral of an individual, for an item or service or the purchasing or ordering of a good or service, for which payment may be made under federal healthcare programs such as the Medicare and Medicaid programs. The Anti-Kickback Statute is subject to evolving interpretations. In the past, the government has enforced the Anti-Kickback Statute to reach large settlements with healthcare companies based on sham consulting and other financial arrangements with physicians. A person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation. The majority of states also have anti-kickback laws, which establish similar prohibitions and, in some cases, may apply to items or services reimbursed by any third-party payor, including commercial insurers.

Additionally, the civil False Claims Act prohibits knowingly presenting or causing the presentation of a false, fictitious or fraudulent claim for payment to the U.S. government, knowingly making, using, or causing to be made or used a false record or statement material to a false or fraudulent claim to the U.S. government, or from knowingly making a false statement to avoid, decrease or conceal an obligation to pay money to the U.S. government. In addition, the government may assert that a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the federal False Claims Act. Actions under the False Claims Act may be brought by the Attorney General or as a qui tam action by a private individual in the name of the government. The federal government is using the False Claims Act, and the accompanying threat of significant liability, in its investigation and prosecution of pharmaceutical and biotechnology companies throughout the U.S., for example, in connection with the promotion of products for unapproved uses and other sales and marketing practices. The government has obtained multi-million and multi-billion-dollar settlements under the False Claims Act in addition to individual criminal convictions under applicable criminal statutes. Given the significant size of actual and potential settlements, it is expected that the government will continue to devote substantial resources to investigating healthcare providers’ and manufacturers’ compliance with applicable fraud and abuse laws.

The U.S. federal Health Insurance Portability and Accountability Act of 1996 (“HIPAA”), created new federal criminal statutes that prohibit among other actions, knowingly and willfully 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, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services. Similar to the federal Anti-Kickback Statute, a person or entity does not need to have actual knowledge of the statute or specific intent to violate it in order to have committed a violation.

27

There has also been a recent trend of increased federal and state regulation of payments made to physicians and other healthcare providers. The ACA, among other things, imposes new reporting requirements on drug manufacturers for payments made by them to physicians (as defined by statute), certain non-physician practitioners including physician assistants and nurse practitioners and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members. Certain states also mandate implementation of compliance programs and compliance with the pharmaceutical industry’s voluntary compliance guidelines and the relevant compliance guidance promulgated by the federal government, impose restrictions on drug manufacturer marketing practices and/or require the tracking and reporting of pricing and marketing information as well as gifts, compensation and other remuneration or items of value provided to physicians and other healthcare professionals and entities.

Penalties for violating any of such laws or any other governmental regulations that apply include, without limitation, administrative, civil and criminal penalties, damages, fines, disgorgement, the curtailment or restructuring of operations, exclusion from participation in federal and state healthcare programs, integrity oversight and reporting obligations to resolve allegations of non-compliance and imprisonment.

Data Privacy and Security Laws

Numerous state, federal and foreign laws, regulations and standards govern the collection, use, access to, confidentiality and security of health-related and other personal information, and could apply now or in the future to our operations or the operations of our partners. In the United States, numerous federal and state laws and regulations, including data breach notification laws, health information privacy and security laws and consumer protection laws and regulations govern the collection, use, disclosure, and protection of health-related and other personal information. In addition, certain foreign laws govern the privacy and security of personal data, including health-related data. Privacy and security laws, regulations, and other obligations are constantly evolving, may conflict with each other to complicate compliance efforts, and can result in investigations, proceedings, or actions that lead to significant civil and/or criminal penalties and restrictions on data processing.

Environment

Our third-party manufacturers are subject to inspections by the FDA for compliance with cGMP and other U.S. regulatory requirements, including U.S. federal, state and local regulations regarding environmental protection and hazardous and controlled substance controls, among others. Environmental laws and regulations are complex, change frequently and have tended to become more stringent over time. We have incurred, and may continue to incur, significant expenditures to ensure we are in compliance with these laws and regulations. We would be subject to significant penalties for failure to comply with these laws and regulations.

Our Company Origins and Team

Our PROBODY platform technology has its origins in work performed at the University of California, Santa Barbara (“UCSB”), by our scientific founder Professor Patrick Daugherty. Since our inception, we have continued developing and adding to this technology and aspire to design a pipeline of PROBODY therapeutics that will better the lives of cancer patients. We have assembled an experienced and talented group of individuals dedicated to the advancement of cancer care. Our chief executive officer and chairman, Dr. Sean McCarthy, leads a team that draws on robust experience in all phases of product discovery, clinical development and commercialization. Our management team members have significant experience in oncology with previous experience at Amylin Pharmaceuticals, Catalyst Biosciences, Coherus BioSciences, Elan Phramaceuticals, Eli Lilly and Company, Exelixis, Genentech, Millennium, Novartis, Onyx Pharmaceuticals, Portola Pharmaceuticals, SGX, Xencor and other companies.

Human Capital

As of December 31, 2023, we had 120 full-time employees and 2 part-time employees. Of these employees, 88 were primarily engaged in research and development activities. None of our employees are represented by a labor union or covered by collective bargaining agreements and we consider our employee relations to be good. Our human capital resources objectives include, as applicable, identifying, recruiting, retaining, incentivizing and integrating our existing and additional employees. The principal purposes of our equity incentive plans are to attract, retain and motivate selected employees, consultants and directors through the granting of stock-based compensation awards and cash-based performance bonus awards.

28

Corporate Information

Our operations commenced in February 2008 when our predecessor entity was formed. We were incorporated in Delaware in September 2010. We maintain our executive offices at 151 Oyster Point Blvd., Suite 400, South San Francisco, California 94080, and our main telephone number is (650) 515-3185.

We view our operations and measure our business as one reportable segment operating in the United States. See Note 2 to our audited financial statement included elsewhere in this Annual Report on Form 10-K for additional information. Additional information required by this item is incorporated herein by reference to PART II. Item 6 of this Annual Report on Form 10-K.

Our research and development expenses were $77.7 million and $111.6 million for the years ended December 31, 2023 and 2022, respectively. Please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations-Research and Development Expenses” for additional detail regarding our research and development activities.

We maintain a website at www.cytomx.com, which contains information about us. The information in, or that can be accessed through, our website is not part of this Annual Report on Form 10-K. Our annual reports on Form 10-K, quarterly reports on Form 10-Q and current reports on Form 8-K and amendments to those reports are available, free of charge, on or through our website as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. The SEC maintains an Internet site that contains reports, proxy and information statements and other information regarding our filings at www.sec.gov.

29

Item 1A. Risk Factors

You should consider carefully the risks and uncertainties described below, together with all of the other information in this Annual Report on Form 10-K, including our financial statements and the related notes and “Management’s Discussion and Analysis of Financial Condition and Results of Operations.” If any of the following risks are realized, our business, financial condition, results of operations and prospects could be materially and adversely affected. The risks described below are not the only risks facing the Company. Risks and uncertainties not currently known to us or that we currently deem to be immaterial also may materially adversely affect our business, financial condition, results of operations and/or prospects.

Risks Related to Our Business

We are a clinical-stage biopharmaceutical company with a limited operating history and have not generated any revenue from product sales. We have a history of losses, expect to continue to incur significant losses for the foreseeable future and may never achieve or maintain profitability, which could result in a decline in the market value of our common stock.