WALTHAM, Mass. and BOULDER, Colo., May 28, 2026
Cogent Biosciences has announced a major regulatory milestone with the U.S. Food and Drug Administration (FDA) accepting its New Drug Application (NDA) and granting Priority Review for bezuclastinib in combination with sunitinib for the treatment of patients with gastrointestinal stromal tumors (GIST) previously treated with imatinib. The FDA has assigned a Prescription Drug User Fee Act (PDUFA) target action date of November 30, 2026, bringing the investigational therapy one step closer to potential approval. The regulatory decision builds on the therapy’s previously awarded Breakthrough Therapy Designation and participation in the FDA’s Real-Time Oncology Review program following compelling results from the pivotal Phase 3 PEAK trial. The development marks a significant advancement for patients with advanced GIST, a rare and difficult-to-treat cancer driven by mutations in the KIT signaling pathway.
Phase 3 PEAK Trial Demonstrates Unprecedented Clinical Benefit
The FDA submission is supported by results from the global PEAK Phase 3 clinical trial, which evaluated bezuclastinib plus sunitinib against standard-of-care sunitinib monotherapy in patients with imatinib-resistant or imatinib-intolerant GIST. The study achieved its primary endpoint with highly significant improvements in progression-free survival (PFS). Patients receiving the combination therapy experienced a median PFS of 16.5 months, compared with 9.2 months for patients receiving sunitinib alone.
The results translated into a remarkable 50% reduction in the risk of disease progression or death (HR=0.50; p<0.0001), representing one of the most meaningful advances reported in the GIST treatment landscape. Investigators also observed a substantial improvement in objective response rate (ORR), with 46% of patients in the combination arm achieving tumor response compared with 26% in the monotherapy group. According to Cogent, this is the first treatment regimen ever to demonstrate a statistically significant advantage over an active comparator in GIST, establishing a potentially new benchmark for second-line treatment.
Favorable Safety Profile Supports Regulatory Progress
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In addition to its efficacy advantages, the combination of bezuclastinib and sunitinib demonstrated a manageable safety profile. Researchers reported that the therapy was generally well tolerated, with no unexpected safety signals identified beyond those associated with established sunitinib treatment. Common Grade 3 or higher adverse events included hypertension, neutropenia, elevated liver enzymes, anemia, and diarrhea.
Importantly, hepatic adverse events were largely transient, reversible, and asymptomatic, with all Grade 3 liver enzyme elevations resolving during treatment. Only 7.4% of patients receiving the combination therapy discontinued treatment because of treatment-related adverse events, supporting the overall benefit-risk profile. These findings have contributed to regulatory confidence in the program and strengthened expectations for a potential approval decision later this year.
Regulatory Momentum Positions Bezuclastinib for Potential Launch
The FDA’s Priority Review designation shortens the review timeline and reflects the agency’s recognition of the therapy’s potential to address a significant unmet medical need. Cogent Biosciences noted that the FDA currently has no plans to convene an advisory committee meeting and has not identified major review concerns at this stage of the application process.
Full Phase 3 PEAK trial results are scheduled for presentation during an oral session at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, where the data are expected to receive significant attention from the oncology community. As preparations continue for potential commercial launches in both GIST and systemic mastocytosis, bezuclastinib is emerging as a key asset within Cogent’s precision oncology portfolio. If approved, the therapy could offer patients a highly effective new treatment option capable of extending disease control and improving outcomes in one of the most challenging forms of KIT-driven cancer.
Source: Cogent Biosciences press release
