Cogent Biosciences Reports Positive Phase 3 PEAK Trial Data on Bezuclastinib and Sunitinib for GIST at ASCO Meeting

Cogent Biosciences, Inc., a biotechnology firm specializing in precision therapies for genetically defined diseases, has recently unveiled promising updates from its ongoing Phase 3 PEAK trial. This trial evaluates the combination of bezuclastinib, a potent KIT mutant inhibitor, and sunitinib in patients with Gastrointestinal Stromal Tumors (GIST). The latest data will be showcased at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago on June 1, 2024. Additionally, the company has announced a new Phase 2 clinical trial for later-line GIST patients, in collaboration with the Sarcoma Alliance for Research through Collaboration (SARC), The Life Raft Group, and Dana-Farber Cancer Institute.

Andrew Robbins, President and CEO of Cogent Biosciences, expressed excitement about the combination therapy's potential to set a new standard of care for advanced GIST patients. He praised the clinical activity and safety profile of the bezuclastinib and sunitinib combination. The PEAK trial has been enrolling participants faster than anticipated, with full enrollment now expected by the third quarter of 2024.

The updated lead-in data from the PEAK trial, as of April 1, 2024, includes 42 patients who have been on the study for a median of 15.3 months. The median progression-free survival (mPFS) for patients treated with the combination therapy was 10.2 months. However, in a subset of patients who had only one prior treatment with imatinib, the mPFS extended to 19.4 months. The objective response rate (ORR) was 27.5% for all patients, with a notable 33.3% ORR in the second-line treatment subset. Furthermore, the combination achieved a disease control rate of 80% across all patients and 100% in those who had only been treated with imatinib prior to the study.

Safety data from the trial indicated that the combination therapy was well-tolerated, with no additional severe adverse events beyond those typically associated with sunitinib monotherapy. Most treatment-emergent adverse events (TEAEs) were low-grade and reversible. No new serious adverse reactions or discontinuations due to TEAEs have been reported since November 2023.

The new Phase 2 trial, sponsored by SARC and conducted in collaboration with The Life Raft Group and Dana-Farber Cancer Institute, will evaluate the mPFS and safety of the bezuclastinib and sunitinib combination in 40 GIST patients who have previously progressed on sunitinib treatment. This trial aims to address the treatment gap for later-line GIST patients who have limited options available.

Cogent Biosciences is also progressing with other clinical trials. The company anticipates completing enrollment for the PEAK study, which includes approximately 388 second-line, post-imatinib GIST patients, by the third quarter of 2024, with top-line results expected by the end of 2025. Cogent also aims to complete enrollment in the APEX trial for advanced systemic mastocytosis (AdvSM) by the end of 2024 and report top-line results in mid-2025. Additionally, the SUMMIT Part 2 trial's enrollment is projected to finish in the second quarter of 2025, with results expected by the end of that year.

Cogent Biosciences will present at the Jefferies Global Healthcare Conference on June 5, 2024. A live webcast of the presentation will be available on the company's website, and a replay will be accessible for up to 30 days.

In summary, Cogent Biosciences continues to make significant strides in the development of bezuclastinib in combination with sunitinib for the treatment of GIST and other genetically defined diseases, with ongoing trials showing promising efficacy and safety profiles.