LONDON, UK I February 7, 2022 I 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 201 Phase 1b trial of PolyPEPI1018, the Company’s lead product candidate, as an add-on to standard-of-care third-line chemotherapy (TAS-102) for the treatment of patients with late-stage microsatellite stable (MSS) metastatic colorectal cancer (mCRC).

“We are pleased to initiate OBERTO 201, a Phase 1b trial designed to evaluate the efficacy of PolyPEPI1018 in late-stage MSS mCRC, a patient population with a poor prognosis and few available therapies,” said Dr. Christopher C. Gallen, M.D. Ph.D., Chief Executive Officer for Treos. “PolyPEPI1018 previously demonstrated robust immune responses and initial efficacy in maintenance-stage therapy for mCRC in our completed Phase 1/2 trial. As a result of this encouraging data, we are excited to leverage the Mayo Clinic’s clinical expertise to more deeply study PolyPEPI1018’s potential to address the variability of patients’ responses to cancer immunotherapies.”

OBERTO 201 is a single arm, open-label, investigator-initiated Phase 1b trial evaluating 15 patients with metastatic colorectal cancer who are beginning a third-line treatment of the oral chemotherapy TAS-102. The primary endpoint of the study is safety and secondary endpoints are progression-free survival as well as other measures of anti-tumor activity and immunologic response.

The trial is funded by a grant awarded to Mayo Clinic in Minnesota (awardee) and to Treos (sub-awardee) by the U.S. Department of Defense Congressionally Directed Medical Research Program.

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 an 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

SOURCE: Treos Bio