Live News • Jul 16
Cogent Biosciences Submits FDA Application for Bezuclastinib in Advanced Systemic Mastocytosis Cogent Biosciences filed a New Drug Application with the U.S. FDA on June 30 for bezuclastinib, a treatment for Advanced Systemic Mastocytosis, supported by clinical data from the APEX trial.
This NDA is a key regulatory step that could open a commercial path for bezuclastinib if the FDA ultimately grants approval, which would introduce a potential new therapy option in a rare, serious disease area.
Cogent Biosciences shares trade at US$39.30, with the stock up 13.1% year to date, indicating that the market has already reacted to a series of developments around the company.
The main read-through is that Cogent is moving from being purely a clinical-stage story to one with a defined regulatory review on the horizon, which concentrates risk around FDA outcomes and any feedback on the APEX data package. Live News • Jun 30
Cogent Biosciences Files Third FDA Application for Bezuclastinib in Advanced Systemic Mastocytosis Cogent Biosciences has submitted a New Drug Application to the FDA for bezuclastinib to treat Advanced Systemic Mastocytosis, supported by pivotal APEX trial data showing a 65% objective response rate and an 81% overall response rate, with what the company reports as a well-tolerated safety profile.
This is the third bezuclastinib-related filing with the FDA within six months. It signals an active regulatory pipeline that could create a new commercial opportunity for Cogent Biosciences if reviews progress as the company expects, including a potential approval timeline it currently guides to late 2026.
Cogent Biosciences shares trade at $38.70, with the stock up 11.4% year to date, reflecting a market that has already been reacting to the company’s recent stream of updates.
The key issue to track is regulatory execution. Multiple concurrent FDA reviews can expand Cogent Biosciences’ addressable market if outcomes are favorable, but any delay, data questions, or unexpected safety concerns could materially change the company’s prospects. Announcement • Jun 30
Cogent Biosciences Submits New Drug Application for Bezuclastinib in Advanced Systemic Mastocytosis Cogent Biosciences, Inc. has submitted its New Drug Application (NDA) to the U.S. Food and Drug Administration (FDA) for bezuclastinib in Advanced Systemic Mastocytosis (AdvSM). The submission is based on positive clinical data from the APEX pivotal trial. The NDA submission is supported by data from the pivotal APEX trial, which were most recently presented at the 2026 European Hematology Association (EHA) Congress. As of the March 31, 2026 data cutoff, 81 AdvSM patients were treated with 150 mg of bezuclastinib, including 57 patients with SM-AHN, 11 patients with ASM and 13 patients with MCL. The primary endpoint of response per mIWG-MRT-ECNM was assessed on 68 evaluable patients and showed 65% ORR (CR+CRh+PR+CI), including 57% of patients who achieved CR, CRh or PR as best response. Key secondary endpoint of response per pure pathological response (PPR) criteria was assessed on 81 patients which showed an 81% ORR (CR+CRh+PR). Bezuclastinib demonstrated reversal of bone marrow pathobiology including rapid and deep reductions in aberrant CD25 and CD30 expression, normalization of mast cell morphology, normalization of bone marrow cellularity, and improvement in myelofibrosis. Bezuclastinib demonstrated durable clinical activity and prolonged PFS with a 12-month PFS rate of 79% and a 12-month OS rate of 87%. Median duration of PFS and OS were immature at the time of the data cutoff. Bezuclastinib achieved clear and clinically significant reductions in objective disease markers for these AdvSM patients: Proportion with =50% reduction in serum tryptase (n=80) 89%, Proportion with =50% reduction in bone marrow mast cells or clearance of aggregates (n=80) 89%, Proportion with =50% reduction in KIT D816V variant allele frequency (n=43) 91%. In the APEX study, bezuclastinib also demonstrated robust improvement in disease pathology, with effects observed as early as eight weeks, including high PPR rates, improvement (including normalization) in bone marrow mast cell distribution, improvement in broader bone marrow characteristics and a majority of patients achieving normalization of serum tryptase. In addition, approximately one-third of patients treated with bezuclastinib achieved undetectable levels of KIT D816V VAF, suggesting modification of the underlying AdvSM disease with bezuclastinib treatment. As of the data cutoff, bezuclastinib was well-tolerated, with infrequent need for dose reduction or discontinuation for treatment-related adverse events (TRAEs). The most frequent TRAEs reported on bezuclastinib treatment were hair color change (31%), neutropenia (31%), altered taste (28%), thrombocytopenia (25%), and ALT/AST elevations (21%). The majority of transaminase elevations were of low grade, asymptomatic and reversible. Of the two patients who experienced Grade 3 transaminase elevation, one discontinued treatment and one remains on therapy following dose reduction. Working with the FDA, Cogent has established active Expanded Access Programs (EAPs) for U.S. patients SM or GIST who meet disease-specific criteria and could benefit from treatment with bezuclastinib or the combination of bezuclastinib and sunitinib. 
