Cogent announces statistical significance across all endpoints from SUMMIT trial

Cogent Biosciences (COGT) announced top-line results from the registration-directed Part 2 of the SUMMIT clinical trial of bezuclastinib in patients with non-advanced systemic mastocytosis demonstrating clinically meaningful and highly statistically significant improvements across the primary and all key secondary endpoints, including patient-reported symptoms and objective measures of mast cell burden. Based on these data, Cogent is on track to submit its first new drug application to the U.S. Food and Drug Administration for bezuclastinib in NonAdvSM by the end of 2025. In addition, Cogent plans to present detailed results from the SUMMIT trial at an upcoming medical meeting later this year. The SUMMIT trial, which was designed to assess the clinical benefit of bezuclastinib versus placebo, achieved its primary endpoint with a highly statistically significant difference in the mean change in total symptom score at 24 weeks. TSS was assessed by the Mastocytosis Symptom Severity Daily Diary. The bezuclastinib arm had a mean reduction of 24.3 points in TSS at 24 weeks, versus the placebo arm which had a mean reduction of 15.4 points in TSS, resulting in a placebo-adjusted TSS improvement of 8.91 points. In addition, the SUMMIT trial demonstrated highly statistically significant benefit across all key secondary endpoints, including reduction of serum tryptase on which 87.4% of bezuclastinib-treated patients had greater than or equal to50% reduction, compared to no patients in the control arm. All primary and secondary endpoints demonstrated statistically significant comparisons in favor of bezuclastinib over placebo. The majority of treatment emergent adverse events were of low grade. The most frequent TEAEs reported on bezuclastinib treatment were hair color change, altered taste, nausea and ALT/AST elevations. Serious AEs occurred in 4.2% of patients treated with bezuclastinib, compared to 5.0% of patients treated with placebo. Discontinuations due to treatment-related AEs occurred in 5.9% of patients treated with bezuclastinib, all due to ALT/AST elevations and all patients fully resolved. There were no hepatic AEs reported in any patient other than transient and manageable lab abnormalities. Complete analysis of the full SUMMIT Part 2 data are ongoing, and Cogent plans to present detailed results at an upcoming major medical conference later this year. Cogent remains on track to provide top-line results from both PEAK, a Phase 3 trial of bezuclastinib in combination with sunitinib in patients with gastrointestinal stromal tumors, and APEX, a registration-directed trial of bezuclastinib in advanced systemic mastocytosis patients, during the second half of 2025.