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TREOS Bio Launches Pivotal Phase II Trial for PolyPEPI1018 in Treatment-Resistant Colorectal Cancer

5 days ago3 min read

Key Insights

  • TREOS Bio has initiated OBERTO-202, a potentially registration-enabling Phase II trial evaluating PolyPEPI1018 combined with toripalimab and standard care in 140 patients with microsatellite stable metastatic colorectal cancer.

  • The study targets the 85% of colorectal cancer cases that show limited response to current immunotherapies, representing approximately 130,000 new US patients annually.

  • PolyPEPI1018 has demonstrated encouraging clinical activity across three Phase I/II trials involving 44 patients, with consistent correlations between immune activation and clinical benefit.

TREOS Bio has announced the launch of OBERTO-202, a potentially registration-enabling Phase II clinical trial that could address one of oncology's most challenging treatment gaps. The study will evaluate the company's lead immunotherapy PolyPEPI1018 in combination with toripalimab and standard of care in approximately 140 patients with microsatellite stable (MSS) metastatic colorectal cancer.
The clinical-stage biotechnology company executed collaboration agreements with Charité - Universitätsmedizin Berlin and Junshi Biosciences to conduct the randomized, controlled trial. TREOS Bio also completed $2.1 million in bridge financing from existing investors, bringing total financing raised to date to $47 million, not counting non-dilutive support from grants and clinical collaborations.

Addressing a Critical Unmet Medical Need

MSS colorectal cancer represents approximately 85% of all colorectal cancer cases, affecting an estimated 130,000 new patients annually in the US alone and over 1.6 million new patients globally. Current immunotherapies, including checkpoint inhibitors, have shown limited efficacy in this patient population, creating a significant treatment challenge for oncologists.
"The collaboration with Charité Berlin and Junshi Biosciences represents a significant milestone as we work toward demonstrating the potential of our precision immunotherapy approach in one of the largest oncology markets with significant unmet medical need," said Dr. Christopher Gallen, Chairman and CEO of TREOS Bio.

Trial Design and Methodology

The OBERTO-202 study will be conducted as an investigator-led trial at Charité - Universitätsmedizin Berlin, one of Europe's largest university hospitals, with Prof. Sebastian Stintzing as principal investigator. The trial involves collaboration with 14 other leading academic hospitals and will evaluate PolyPEPI1018 and toripalimab in combination with standard of care (Lonsurf + Avastin) versus standard of care alone in patients with relapsed/refractory MSS CRC.

Promising Preclinical Foundation

PolyPEPI1018 is TREOS Bio's lead off-the-shelf multi-peptide active cancer immunotherapy designed to convert immunologically "cold" tumors to "hot" tumors. The therapy has demonstrated encouraging clinical activity across three Phase I/II trials involving 44 patients in total in advanced MSS CRC conducted in partnership with the Mayo Clinic, with consistent correlations between immune activation and clinical benefit.
"This randomized, controlled clinical trial represents a logical next step in the development of PolyPEPI1018," said Dr. Hagop Youssoufian, Chair of Medical Strategy of TREOS Bio and Adjunct Professor of Medicine at Brown University. "Leveraging the built-in antigenic diversity of this unique active immunotherapy that can dampen multiple immunosuppressive mechanisms, in combination with toripalimab and chemotherapy, provides an exciting opportunity to overcome the well-known resistance to immunotherapies in MSS CRC."

Strategic Partnerships and Platform Technology

TREOS Bio is developing precision cancer immunotherapies based on its proprietary PASCal (Personal Antigen Selection Calculator) platform. The company's lead program, PolyPEPI1018, is an off-the-shelf multi-peptide immunotherapy targeting shared tumor antigens with demonstrated clinical activity in MSS colorectal cancer. TREOS Bio has established partnerships with leading institutions including Mayo Clinic, Charité - Universitätsmedizin Berlin, Roche and Junshi Biosciences.
"The bridge financing provides us with the runway to advance our lead program toward what we anticipate will be a registration-enabling Phase II study," Gallen noted, highlighting the company's strategic positioning for this pivotal trial phase.
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