CytomX Therapeutics Announces First Patient Dosed with CX-904 in Phase 1 Study in Patients with Advanced Solid Tumors

SOUTH SAN FRANCISCO, Calif., May 26, 2022 (GLOBE NEWSWIRE) -- CytomX Therapeutics, Inc. (Nasdaq: CTMX), a leader in the field of conditionally activated oncology therapeutics, today announced that the first patient has been dosed in a Phase 1 dose-escalation study of CX-904 (NCT05387265). CX-904 is a conditionally activated T-cell-engaging bispecific (TCB) designed to target the epidermal growth factor receptor (EGFR) on cancer cells and the CD3 receptor on T cells within the tumor microenvironment.

“The successful initiation of this first-in-human study represents another major milestone for CytomX, as it marks the third therapeutic modality to enter the clinic from our versatile Probody platform,” said Amy C. Peterson, M.D., president and chief operating officer at CytomX Therapeutics. “Our conditionally activated TCB platform is designed to localize both target binding and T-cell activation selectively to the tumor microenvironment, minimizing extra-tumoral activation of T cells and potentially widening the therapeutic window for solid tumor-directed TCBs. This study underscores our commitment to destroying cancer differently and bolsters our leadership in the field of conditional activation in oncology.”

Utilizing CytomX’s proprietary masking technology to reduce systemic target engagement, conditionally activated TCBs are constructed to direct the activity of CD3-positive, cytotoxic T cells to cancer cells expressing the target of interest, with the goal of improving the therapeutic window of these highly potent agents for the treatment of solid tumors. CytomX has shown in preclinical models that dual-masked, conditionally activated TCBs targeting EGFR and CD3 have the potential for an improved therapeutic window compared to conventional, unmasked TCBs.

“We look forward to exploring CX-904 in solid tumors,” said Meredith Pelster, M.D., MSCI, a study investigator at Sarah Cannon Research Institute at Tennessee Oncology. “Given that EGFR is widely expressed in a number of solid tumors, the opportunity for this therapeutic candidate to address an unmet need in multiple tumor types is noteworthy.”

About CytomX Therapeutics, Inc.
CytomX is a clinical-stage, oncology-focused biopharmaceutical company dedicated to destroying cancer differently. 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 by successfully leveraging therapeutic targets that were once thought to be inaccessible. CytomX’s robust and differentiated pipeline includes the wholly-owned praluzatamab ravtansine, an investigational conditionally activated antibody-drug conjugate (ADC) directed toward CD166, and CX-2029, an investigational conditionally activated ADC directed toward CD71 being developed in collaboration with AbbVie. These two programs are currently being evaluated in Phase 2 studies, targeting a variety of late-stage, difficult-to-treat cancer types, including breast cancer for praluzatamab ravtansine, and squamous non-small cell lung cancer, and head and neck squamous cell carcinoma for CX-2029. CytomX’s clinical pipeline also includes cancer immunotherapeutic candidates against validated targets such as the CTLA-4-targeting Probody therapeutics, BMS-986249 and BMS-986288, partnered with Bristol Myers Squibb, and our wholly-owned conditionally activated anti-PD-L1 antibody, pacmilimab, as well as CX-904, a conditionally activated T-cell-engaging bispecific antibody targeting the epidermal growth factor receptor on tumor cells and the CD3 receptor on T cells, which is partnered with Amgen. In addition, CytomX has a diverse preclinical portfolio and strategic collaborations with multiple leaders in oncology, including AbbVie, Amgen, Astellas, and Bristol Myers Squibb. 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.

Forward-Looking Statements
This 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. 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 CX-904 or CytomX’s or any of its collaborative partners’ other product candidates, including praluzatamab ravtansine, CX-2029, BMS-986249, BMS-986288, and pacmilimab, 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 praluzatamab ravtansine, CX-2029, BMS-986249, BMS-986288, pacmilimab, and CX-904, and the timing of the commencement of clinical trials, initial and ongoing data availability, investigational new drug applications 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, including CX-904, 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 risk that the COVID-19 worldwide pandemic may continue to negatively impact the business, research and clinical operations of CytomX or its partners, including the development of preclinical drug candidates due to delays in and disruption of research activities and the development of clinical drug candidates due to delays in or disruption of clinical trials, including impacts on the enrollment of patients in clinical trials or other clinical trial disruptions; the possibility that the results of 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 praluzatamab ravtansine, CX-2029, BMS-986249, BMS-986288, pacmilimab, and CX-904; CytomX’s reliance on third parties for the manufacture of the Company’s product candidates; and possible regulatory developments in the United States and foreign countries. 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 May 5, 2022. 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.

Probody is a U.S. registered trademark of CytomX Therapeutics, Inc.

Investor Contact:
Chau Cheng, PhD MBA
VP, Investor Relations & Corp. Communications
ccheng@cytomx.com
Direct: (650) 273-4999

Media Contact:
Bret Coons
Director, Corporate Communications
bcoons@cytomx.com
Direct: (650) 528 2929