Cogent Biosciences reports 65% response rate in mastocytosis trial

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Cogent Biosciences Announces Detailed Data from APEX Pivotal Trial of Bezuclastinib in Patients with Advanced Systemic Mastocytosis at the 2026 European Hematology Association (EHA) Congress

June 12, 2026 8:00 AM EDT

-- Bezuclastinib demonstrated rapid and deep clinical benefit in AdvSM patients resulting in an updated objective response rate (CR+CRh+PR+CI) of 65% per mIWG criteria and 81% ORR per PPR criteria

-- Bezuclastinib demonstrated a powerful effect on mast cell burden with 91% of patients achieving 50% reduction in variant allele frequency and 89% of patients achieving 50% reduction in bone marrow mast cells or clearance of aggregates

-- Bezuclastinib continues to demonstrate a favorable safety and tolerability profile

-- APEX NDA to be submitted in June 2026... More