Compass Therapeutics Announces First Patient Dosed in the Phase 1b CTX-471 Combination Trial with KEYTRUDA® (pembrolizumab)

• First patient dosed in Phase 1b study of CTX-471 in combination with KEYTRUDA^® in cancers of the lung, head and neck, as well as melanoma
• In the first part of this Phase 1b study, CTX-471 was dosed as a monotherapy and demonstrated signs of activity in patients with various metastatic or locally advanced solid tumors who initially benefited from a checkpoint inhibitor
• The study is designed to evaluate the potential of CTX-471 in combination with KEYTRUDA^® to address treatment resistance and improve patient outcomes
• CTX-471 is a fully human IgG4 agonistic antibody that binds to a unique epitope of the CD137 receptor that has a co-stimulatory effect on T-Cells and NK Cells, two important components of the innate immune system

BOSTON, Dec. 01, 2022 (GLOBE NEWSWIRE) — Compass Therapeutics, Inc. (“Compass”; Nasdaq: CMPX), a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases, today announced that the first patient has been dosed in the Phase 1b study of CTX-471 in combination with KEYTRUDA^®, Merck’s anti-PD-1 therapy, in patients with advanced solid tumors.

CTX-471 is supplied by Compass, which is also the sponsor of this study, and KEYTRUDA^® will be supplied by Merck (known as MSD outside the United States and Canada) under a clinical collaboration and supply agreement between the companies. This study enrolls 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 checkpoint inhibitor. Patients enrolled in the study will be treated with CTX-471 in combination with KEYTRUDA^® with the goal of restoring response.

“We are very pleased to be making progress on our CTX-471 clinical program with dosing of the first patient in the combination arm with KEYTRUDA^®,” said Thomas Schuetz, M.D., Ph.D., Chief Executive Officer and Scientific Founder of Compass. “We are excited about the potential to build upon the responses observed with CTX-471 monotherapy across multiple tumor types and address significant unmet need in the field of cancer immunotherapy.”

CTX-471 is a next generation, CD137 agonist, fully human, IgG4, with optimized affinity for an agonistic antibody. It binds to a unique, membrane proximal epitope of the CD137 receptor, leading to enhanced activation of T-Cells and NK Cells. CTX-471 has completed a Phase 1 dose escalation and cohort expansion study, where it was shown to be well-tolerated. The Phase 1b monotherapy study is fully enrolled and ongoing. In this study, CTX-471 has been evaluated as a monotherapy treatment in patients with advanced solid tumors who received at least one checkpoint inhibitor post progression. As of September 30, 2022, 4 partial responses (PRs) have been observed in the Phase 1b study and 3 of the 4 were confirmed by RECIST 1.1.

ClinicalTrials.gov Identifier: NCT03881488

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

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. Compass’s 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. Compass was founded in 2014 and is headquartered in Boston, Massachusetts. For more information, visit the Compass Therapeutics, Inc. website at https://www.compasstherapeutics.com.

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 Compass’s product candidate, CTX-471, its development, regulatory plans with respect thereto and therapeutic potential thereof. Actual results could differ from those projected in any forward-looking statements due to numerous factors. Such factors include, among others, Compass’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, Compass’s ability to identify additional product candidates for development, Compass’s ability to develop, complete clinical trials for, obtain approvals for and commercialize any of its product candidates, competition in the industry in which Compass operates and market conditions. These forward-looking statements are made as of the date of this press release, and Compass 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 Compass files with the SEC available at www.sec.gov, including without limitation Compass’s latest Form 10-Q and subsequent filings with the SEC.

Investor Contact
Mario Corso, Investor Relations
ir@compasstherapeutics.com 

Media Contact
Anna Gifford, Communications Manager
media@compasstherapeutics.com 
617-500-8099