CytomX Therapeutics Presents Preclinical Profile of EpCAM-directed Antibody Drug Conjugate CX-2051 at 2023 World ADC Conference

– CX-2051 is tailored for treatment of EpCAM-expressing cancers by matching target expression and tumor sensitivity with a topoisomerase-1 inhibitor payload – – Preclinical data demonstrate a favorable predicted therapeutic index and efficacy across multiple EpCAM-expressing tumors, including colorectal cancer (CRC) – – CX-2051 IND filing expected by year-end 2023 – SOUTH SAN FRANCISCO, Calif., Oct. 18, 2023 (GLOBE NEWSWIRE) — CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of conditionally activated, localized biologics, today announced that the Company presented data characterizing the preclinical profile of its EpCAM-targeting ADC, CX-2051, at the World ADC conference taking place October 16-19, 2023, in San Diego, CA. “CX-2051 is designed to address the unmet needs of patients with EpCAM-expressing tumors, including colorectal cancer, where EpCAM expression is uniformly high. EpCAM is a broadly expressed, validated anti-cancer target that to date has been limited in its development potential due to systemic, on-target off-tumor dose-limiting toxicities”, said Marcia P. Belvin, Ph.D., senior vice president and chief scientific officer at CytomX. Continued Dr. Belvin, “Based on our experience with the Probody® Platform and our clinical experience with Probody-ADCs, we have designed CX-2051 to mask target binding in normal tissues and include a next-generation topoisomerase-1 inhibitor payload. We are encouraged by the compelling preclinical profile of CX-2051 and anticipate filing an IND for the program by the end of the year. We aim to launch Phase 1 dose escalation for CX-2051 in solid tumors in 2024, with an initial focus in metastatic colorectal cancer as a priority indication.” Details for the presentation are as follows:Presentation Title: Leveraging Conditional Activation to Localize Antibody Drug Conjugates to the Tumor “Clinical Lessons” TrackSession Date and Time: October 18, 2023, 12:30 pm PST The full presentation is available at the following link: Leveraging Conditional Activation to Localize Antibody Drug Conjugates to the TumorMarcia P. Belvin, Ph.D., Senior Vice President, Chief Scientific Officer, CytomX Therapeutics About CytomX TherapeuticsCytomX is a clinical-stage, oncology-focused biopharmaceutical company focused on developing novel conditionally activated biologics localized to the tumor microenvironment. By pioneering a novel class of conditionally activated biologics, powered by its Probody® technology platform, CytomX’s goal is to transcend the limits of current cancer treatments. CytomX’s robust and differentiated pipeline comprises therapeutic candidates across multiple treatment modalities including antibody-drug conjugates (“ADCs”), T-cell engaging bispecific antibodies, and immune modulators such as cytokines and checkpoint inhibitors. CX-2029 is an investigational conditionally activated ADC directed toward CD71. CytomX’s clinical pipeline also includes cancer immunotherapeutic candidates against validated targets such as the CTLA-4-targeting Probody therapeutic BMS-986288, partnered with Bristol Myers Squibb, and CX-904, a conditionally activated T-cell-engaging bispecific antibody targeting the epidermal growth factor receptor (EGFR) on tumor cells and the CD3 receptor on T cells, partnered with Amgen. In addition, CytomX has a diverse preclinical portfolio of wholly-owned assets including CX-801, an interferon alpha-2b Probody cytokine that has broad potential applicability in traditionally immuno-oncology sensitive as well as insensitive (cold) tumors and CX-20511, a conditionally activated ADC directed toward EpCAM, with potential applicability across multiple EpCAM-expressing epithelial cancers. CytomX has also established strategic collaborations with multiple leaders in oncology, including Amgen, Astellas, Bristol Myers Squibb, Regeneron and Moderna. For more information about CytomX and how it is working to make conditionally activated treatments the new standard-of-care in the fight against cancer, visit www.cytomx.com and follow us on LinkedIn and Twitter. CytomX Therapeutics Forward-Looking StatementsThis press release includes forward-looking statements. Such forward-looking statements involve known and unknown risks, uncertainties and other important factors that are difficult to predict, may be beyond our control, and may cause the actual results, performance, or achievements to be materially different from any future results, performance or achievements expressed or implied in such statements, including those related to the future potential of partnerships or collaboration agreements. Accordingly, you should not rely on any of these forward-looking statements, including those relating to the potential benefits, safety and efficacy or progress of CytomX’s or any of its collaborative partners’ product candidates, including CX-2051, CX-2029, BMS-986288, CX-904, and CX-801, the potential benefits or applications of CytomX’s Probody platform technology, CytomX’s ability to develop and advance product candidates into and successfully complete clinical trials, including the ongoing and planned clinical trials of BMS-986288, and CX-904, the timing of the commencement of clinical trials or initial and ongoing data availability, and the timing of investigational new drug applications, including for CX-801 and CX-2051, and other development milestones. Risks and uncertainties that contribute to the uncertain nature of the forward-looking statements include: the unproven nature of CytomX’s novel Probody Platform technology; CytomX’s clinical trial product candidates are in the initial stages of clinical development and its other product candidates are currently in preclinical development, and the process by which preclinical and clinical development could potentially lead to an approved product is long and subject to significant risks and uncertainties, including the possibility that the results of preclinical research and early clinical trials may not be predictive of future results; the possibility that CytomX’s clinical trials will not be successful; the possibility that current preclinical research may not result in additional product candidates; CytomX’s dependence on the success of CX-2029, BMS-986288, CX-904, CX-801, and CX-2051; CytomX’s reliance on third parties for the manufacture of the Company’s product candidates; possible regulatory developments in the United States and foreign countries; and the risk that we may incur higher costs than expected for research and development or unexpected costs and expenses. Additional applicable risks and uncertainties include those relating to our preclinical research and development, clinical development, and other risks identified under the heading “Risk Factors” included in CytomX’s Quarterly Report on Form 10-Q filed with the SEC on August 8, 2023. The forward-looking statements contained in this press release are based on information currently available to CytomX and speak only as of the date on which they are made. CytomX does not undertake and specifically disclaims any obligation to update any forward-looking statements, whether as a result of any new information, future events, changed circumstances or otherwise. _______________1 Licensed from Immunogen Probody is a U.S. registered trademark of CytomX Therapeutics, Inc. Investor Contact:Chris OgdenSVP, Finance and [email protected]: (317) 767-4764 Investor and Media Contact:Stern Investor RelationsStephanie [email protected](212) 362-1200