Cogent Biosciences Presents Full SUMMIT Results of Bezuclastinib in Patients with NonAdvanced Systemic Mastocytosis (NonAdvSM) at the 67th Annual Meeting of the American Society of Hematology (ASH)

Core Insights - Cogent Biosciences announced complete results from the SUMMIT clinical trial of bezuclastinib, showing significant improvements in patients with nonadvanced systemic mastocytosis (NonAdvSM) [1][2] - Bezuclastinib is expected to be a best-in-class treatment option, with a New Drug Application (NDA) submission to the FDA planned for December 2025 [2][6] SUMMIT Trial Data - The trial involved 118 patients receiving bezuclastinib and 60 receiving placebo, with a focus on those with moderate-to-severe symptoms despite best supportive care [3][4] - At 24 weeks, bezuclastinib showed a mean change in Total Symptom Score (TSS) of -24.3% compared to -15.4% for placebo, with a p-value of <0.001 [5] - 34.3% of patients on bezuclastinib achieved a ≥50% reduction in TSS, compared to 18.1% on placebo [5] Symptomatic and Objective Improvements - Bezuclastinib demonstrated significant improvements across 11 individual symptoms and objective measures of disease, including serum tryptase levels [6][7] - At 48 weeks, 87.4% of patients achieved a ≥50% reduction in serum tryptase levels, and 75.6% showed a ≥50% reduction in bone marrow mast cells [7] Safety Profile - The majority of treatment-emergent adverse events (TEAEs) were low grade, with 98.3% in the bezuclastinib arm versus 88.3% in the placebo arm [9] - Common TEAEs included hair color change (69.5% in bezuclastinib vs. 5.0% placebo) and nausea (22.0% in bezuclastinib vs. 13.3% placebo) [9] Future Plans - Cogent plans to present longer-term follow-up data from the SUMMIT trial at a scientific meeting in Q1 2026 [10] - An investor conference call is scheduled for December 8, 2025, to discuss the additional data from the SUMMIT trial [11]