Compass Therapeutics Announces Publication of CTX-8371 Preclinical Data in OncoImmunology, its Bispecific Antibody Checkpoint Inhibitor, now Advancing to First-in-Human Clinical Trial

• CTX-8371, a bispecific checkpoint inhibitor that simultaneously targets PD-1 and PD-L1, exhibits a novel mechanism-of-action leading to proteolytic cleavage and subsequent loss of cell surface PD-1
• CTX-8371 provides enhanced anti-tumor activity relative to approved anti-PD-1 and PD-L1 therapies in a series of in vitro and in vivo experimental settings and models
• The combination of CTX-8371 and the Compass agonistic anti-CD137 antibody, CTX-471, further increased anti-tumor efficacy in a mouse tumor model
• These data were published in the peer-reviewed journal, OncoImmunology on February 16^th, 2024.

BOSTON, Feb. 28, 2024 (GLOBE NEWSWIRE) -- Compass Therapeutics, Inc. (Nasdaq: CMPX), a clinical-stage, oncology-focused biopharmaceutical company developing proprietary antibody-based therapeutics to treat multiple human diseases, announced the publication of a peer-reviewed article titled, “A bispecific anti-PD-1 and PD-L1 antibody induces PD-1 cleavage and provides enhanced anti-tumor activity” in the journal OncoImmunology. CTX-8371 is a fully-human, tetravalent bispecific antibody, discovered and developed by Compass Therapeutics as a next generation checkpoint blocker. The data highlighted the unique mechanism-of-action of CTX-8371, inducing dual blockade of PD-1 and PDL-1 and cleavage of cell surface PD-1. In addition, CTX-8371 demonstrates enhanced anti-tumor activity relative to approved anti-PD-1 blockers and anti-PD-L1 blockers in a series of in vitro and in vivo experimental settings.

“We are very pleased that our bispecific antibody, CTX-8371, outperformed known checkpoint blockers in a series of in vitro and in vivo experiments and, in particular, demonstrated enhanced in vivo anti-tumor efficacy in a mouse tumor model. Moreover, the data also suggested that the combination of checkpoint blockade with CTX-8371 and CTX-471, the CD137 agonistic antibody was potentially synergistic, suggesting a unique opportunity for proprietary combination regimens using our Compass antibodies,” says Thomas Schuetz, MD, PhD, Co-founder, President of R&D, and Vice Chairman of the board at Compass. “These compelling data are a testament to the functionality of our novel checkpoint inhibitor and we are excited to continue evaluating its potential in clinical studies. Our IND was cleared by the FDA at the end of 2023, and we expect to dose a first patient before the end of this quarter.”

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 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 candidates, including CTX-8371, and its development and clinical trial milestones such as the expected trial design, timing of enrollment, patient dosing and data readouts, regulatory plans with respect to Compass’s product candidates and the 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 U.S. Securities and Exchange Commission (SEC) available at www.sec.gov, including without limitation Compass’s latest Annual Report on Form 10-K, Quarterly Report on Form 10-Q and subsequent filings with the SEC.

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