Treos Bio Announces First Patient Dosed in Phase 2 Trial of PolyPEPI1018 in Combination with Roche’s PD-L1-Inhibitor for the Treatment of Metastatic Colorectal Cancer

LONDON, June 27, 2022 (GLOBE NEWSWIRE) — Treos Bio Limited (“Treos”), a clinical stage biotechnology company using data science and proprietary biomarkers to develop precision peptide immunotherapies, today announced that the first patient has been dosed in the OBERTO 301 Phase 2 trial of PolyPEPI1018, the Company’s lead product candidate, in combination with atezolizumab, Roche’s PD-L1 inhibitor, for the treatment of patients with late-stage microsatellite stable metastatic colorectal cancer (MSS mCRC).

“The initiation of OBERTO 301, our third trial to date in metastatic colorectal cancer, is an important milestone as we explore potential synergistic effects of our lead asset, PolyPEPI1018, an off-the-shelf immunotherapy, with an immune checkpoint inhibitor in a third line setting,” said Dr. Christopher C. Gallen, M.D. Ph.D., Chief Executive Officer for Treos. “We are humbled by the work in front of us in partnership with Roche as we explore the anti-tumor activity of our immunotherapy candidate in combination with atezolizumab to see if our exciting results in 1st line maintenance therapy can be extended to advanced stage disease by the use of this combination of therapies.”

OBERTO 301 is a multicenter, open label, Phase 2 trial evaluating the combination treatment of PolyPEPI1018 and atezolizumab in patients with metastatic colorectal cancer (MSS mCRC) who have progressed on two or three prior treatment regimens. The primary endpoint of the study is incidence and severity of treatment related adverse events and secondary endpoints include objective response rate, duration of response, progression-free survival and overall survival. More information about the trial is available at NCT05243862.

Under the terms of the non-exclusive collaboration, Treos is responsible for conducting the study, with Roche providing all required doses of atezolizumab. Treos maintains full ownership of PolyPEPI1018.

About Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and cause of death in the United States and the third leading cause of cancer-related deaths worldwide. There are approximately 1.4 million people living with colorectal cancer in the United States. Current treatments for CRC include surgery and chemotherapy in early stages of disease and chemotherapy, biologics and targeted therapies in later stages.

About PolyPEPI1018

PolyPEPI1018, Treos’ lead product candidate, is an immunotherapy in clinical development for the treatment of metastatic colorectal cancer, with plans to incorporate a candidate companion diagnostic in future clinical trials. The therapy is in development as add-on to first-line maintenance therapy and to third-line treatment. PolyPEPI1018 has been developed using Treos’ proprietary PASCal computational tool to identify Personal EPItopes (PEPIs) that are likely to induce multiple tumor-specific T cell responses in a patient.

About Treos Bio Limited

Treos Bio develops precision peptide cancer immunotherapies using proprietary computational data science integrating HLA genetics, tumor profile and clinical outcome of thousands of real subjects. Treos’ lead candidate is PolyPEPI1018, an off-the-shelf immunotherapy for the treatment of metastatic colorectal cancer currently in a Phase 1b clinical trial which also investigates proprietary and novel biomarkers. Treos has completed preclinical development of additional off-the-shelf immunotherapies in ovarian, breast, bladder, gastric, lung cancers, and melanoma. The Company is also developing off-the-shelf immunotherapies personalized to an individual patient’s HLA genotype for several types of solid tumors. Treos has raised $42 million to date. More information can be found at

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