Expansion Phase to Evaluate CTLA-4-Directed Probody^® Therapeutic in Combination with Opdivo^® in Metastatic Melanoma 

Bristol-Myers Squibb also AdvancesBMS-986288 into a Separate Phase 1/2a Clinical Trial

SOUTH SAN FRANCISCO, Calif., Feb. 24, 2020 (GLOBE NEWSWIRE) — CytomX Therapeutics, Inc. (Nasdaq: CTMX), a clinical-stage oncology-focused biopharmaceutical company pioneering a novel class of investigational antibody therapeutics based on its Probody^® therapeutic technology platform, today announced that its partner, Bristol-Myers Squibb, has initiated a randomized Phase 2 cohort expansion in its ongoing first-in-human Phase 1/2a trial of the anti-CTLA-4 Probody BMS-986249 alone and in combination with Opdivo^® (nivolumab). BMS-986249 is a peptide masked version of the anti-CTLA-4 antibody Yervoy^® (ipilimumab). The randomized cohort expansion is designed to further evaluate the safety and efficacy of BMS-986249 in combination with Opdivo^® in patients with metastatic melanoma, as part of the larger clinical trial (NCT03369223). The advancement of BMS-986249 into this part of the planned study triggers a milestone payment of $10 million from Bristol-Myers Squibb to CytomX.

In September 2019, Bristol-Myers Squibb also initiated the dose escalation phase of a Phase 1/2a clinical trial (NCT03994601) of a second anti-CTLA-4 Probody, BMS-986288, based on a modified version of ipilimumab, administered as monotherapy and in combination with nivolumab in patients with selected advanced solid tumors.

These Probody programs, designed to optimize the risk-benefit profile of CTLA-4-directed therapy, arose from the companies’ foundational 2014 worldwide oncology license and collaboration agreement.

“CTLA-4 is the prototypical checkpoint target and blocking this mechanism has proven highly effective in the treatment of melanoma and other cancer types. This exciting progress within our alliance with Bristol-Myers Squibb is aimed at the development of anti-CTLA-4 therapies to broaden the reach of this foundational pathway for cancer patients,” said Sean McCarthy D.Phil., president, chief executive officer and chairman of CytomX Therapeutics. “This ongoing work by the Bristol-Myers Squibb team complements CytomX’s own work and continued clinical progress with the combination of our anti-PD-L1 Probody, CX-072, with ipilimumab, which will further delineate the potential of our Probody therapeutic platform to deliver differentiated anti-cancer therapies.”

Additional details on the Phase 1/2a trial of BMS-986249 are available at ClinicalTrials.gov using the Identifier NCT03369223.

Additional details on the Phase 1/2a trial of BMS-986288 are available at ClinicalTrials.gov using the Identifier NCT03994601.

About CytomX Therapeutics

CytomX is a clinical-stage, oncology-focused biopharmaceutical company with a vision of transforming lives with safer, more effective therapies. We are developing a novel class of investigational antibody therapeutics, based on our Probody^® technology platform, for the treatment of cancer. As leaders in the field, our innovative technology is designed to turn previously undruggable targets into druggable targets and to enable more effective combination therapies. CytomX and its partners, comprised of leading biotechnology and pharmaceutical companies, have developed a robust pipeline of potential best-in-class immunotherapies against clinically validated targets and potential first-in-class therapeutics against novel, difficult to drug targets. Five novel drug-candidates utilizing our Probody technology are in clinical trials, with three in Phase 2 studies and two in Phase 1. These clinical programs include cancer immunotherapies against validated targets such as a PD-L1-targeting Probody therapeutic wholly owned by CytomX (CX-072) and a CTLA-4-targeting Probody therapeutic partnered with Bristol Myers Squibb (BMS-986249). The CytomX clinical stage pipeline also includes first-in-class Probody drug conjugates against previously undruggable targets, including a CD166-targeting Probody drug conjugate wholly owned by CytomX (CX-2009) and a CD71-targeting Probody drug conjugate partnered with AbbVie (CX-2029). CD166 and CD71 are among cancer targets considered to be inaccessible to conventional antibody drug conjugates due to their presence on many healthy tissues. In addition to its wholly owned programs, CytomX has strategic collaborations with AbbVie, Amgen and BMS. For additional information about CytomX Therapeutics, visit www.cytomx.com and follow us on LinkedIn and Twitter.

CytomX Therapeutics 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 of CytomX’s or any of its collaborative partners’ product candidates, administered separately or in combination, 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 clinical trials of CX-072 and CX-2009,  and the timing of any future clinical trials to be initiated by CytomX or its collaborative partners. 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 and its partners have five product candidates utilizing CytomX’s Probody platform 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; 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; CytomX’s dependence on the success of CX-072, CX-2009, CX-2029 and BMS-986249; 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 November 7, 2019. 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 registered trademark of CytomX Therapeutics.

Yervoy and Opdivo are registered trademarks of Bristol-Myers Squibb.

Contact:

Investors and Media: