Compass Therapeutics Announces Clinical Collaboration with Merck to Evaluate CTX-471 in Combination with KEYTRUDA® (pembrolizumab)

BOSTON, Oct. 11, 2022 (GLOBE NEWSWIRE) -- Compass Therapeutics, Inc. (Nasdaq: CMPX), a clinical-stage biopharmaceutical company developing proprietary antibody-based therapeutics to treat cancer, today announced a clinical trial collaboration and supply agreement with Merck (known as MSD outside the United States and Canada). The collaboration enables the evaluation of the safety and efficacy of Compass’ CTX-471, a fully human monoclonal antibody that binds and activates a novel epitope of the co-stimulatory receptor CD137 (expressed on T cells and NK cells) in combination with Merck’s anti-PD-1 therapy KEYTRUDA® (pembrolizumab) in a Phase 1b trial. Under the agreement, Compass is the study sponsor, and Merck will provide the clinical supply of KEYTRUDA; the companies will form a Joint Development Committee to review the clinical trial results.

“We are excited to collaborate with Merck, a leader in immuno-oncology, and leverage their expertise in the pursuit of therapies to treat patients who have progressed on previous anti-PD-1 therapy. Given our Phase 1b trial of CTX-471 showed monotherapy responses in patients in the post PD-1/PD-L1 setting, we believe a combination study is a logical progression,” said Vered Bisker-Leib, Ph.D., President and Chief Operating Officer of Compass Therapeutics.

The combination arm of the Phase 1b trial will enroll patients with metastatic or locally advanced non-small cell lung cancer, melanoma, small cell lung cancer, mesothelioma, and head and neck cancer that have progressed after treatment with a PD-1 or PD-L1 inhibitor. Immediately following progression, patients will be treated with KEYTRUDA in combination with CTX-471. The first part of the study includes escalating doses of CTX-471 with a fixed dose of KEYTRUDA, followed by dose expansion in the second part of the study. Patient evaluation will assess safety, pharmacokinetics, pharmacodynamics and clinical activity of CTX-471 in combination with KEYTRUDA.

KEYTRUDA® is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About CTX-471
CTX-471 is a fully human monoclonal antibody that binds and activates a novel epitope of the co-stimulatory receptor CD137, also known as 4-1BB, a member of the tumor necrosis factor receptor superfamily. The antibody is currently being evaluated in a Phase 1b clinical trial in patients with solid tumors that have progressed after at least three months on an approved PD-1 or PD-L1 inhibitor. Initial results reported from a monotherapy cohort of the study included partial responses in melanoma, small cell lung cancer, and mesothelioma, and CTX-471 has been generally well tolerated. In preclinical studies, CTX-471 has demonstrated potent monotherapy activity against multiple syngeneic tumor models, including the generation of long-term functional immunological memory.

About Compass Therapeutics
Compass Therapeutics, Inc. is a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases. Compass’s scientific focus is on the relationship between angiogenesis, the immune system, and tumor growth. The company pipeline of novel product candidates is designed to target multiple critical biological pathways required for an effective anti-tumor response. These include modulation of the microvasculature via angiogenesis-targeted agents, induction of a potent immune response via activators on effector cells in the tumor microenvironment, and alleviation of immunosuppressive mechanisms used by tumors to evade immune surveillance. Compass plans to advance its product candidates through clinical development as both standalone therapies and in combination with proprietary pipeline antibodies based on supportive clinical and nonclinical data. The company was founded in 2014 and is headquartered in Boston, Massachusetts. For more information, visit the Compass Therapeutics website at

Forward Looking Statements
This press release contains forward-looking statements. Statements in this press release that are not purely historical are forward-looking statements. Such forward-looking statements include, among other things, references to the Company’s clinical collaboration with Merck, business and development plans, and statements regarding the Company’s product candidates, their development, regulatory plans with respect thereto and therapeutic potential thereof, planned interactions with regulatory authorities, and planned clinical development. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, the Company’s ability to raise the additional funding it will need to continue to pursue its business and product development plans, the inherent uncertainties associated with developing product candidates and operating as a development stage company, the Company’s ability to identify additional product candidates for development, the Company’s ability to develop, complete clinical trials for, obtain approvals for and commercialize any of our product candidates, competition in the industry in which the Company operates and market conditions. These forward-looking statements are made as of the date of this press release, and the Company assumes no obligation to update the forward-looking statements, or to update the reasons why actual results could differ from those projected in the forward-looking statements, except as required by law. Investors should consult all of the information set forth herein and should also refer to the risk factor disclosure set forth in the reports and other documents we file with the SEC available at, including without limitation our latest Form 10-Q and our subsequent filings with the SEC.

Investor Contact
Mario Corso, Executive Director and Head of Investor Relations

Media Contact
Anna Gifford, Communications Manager