(Summit) A Study to Evaluate the Efficacy and Safety of CGT9486 Versus Placebo in Patients With Indolent or Smoldering Systemic Mastocytosis

This is a multi-part, randomized, double-blind, placebo-controlled Phase 2 clinical study comparing the safety and efficacy of bezuclastinib (CGT9486) plus best supportive care (BSC) with placebo plus BSC in patients with nonadvanced systemic mastocytosis (NonAdvSM), including indolent systemic mastocytosis and smoldering systemic mastocytosis, whose symptoms are not adequately controlled by BSC. This study will be conducted in three parts. Patients in Parts 1a, 1b and 2 will receive bezuclastinib or placebo, and may roll over onto Part 3 to receive treatment with bezuclastinib. Additionally, a substudy of subjects will investigate the efficacy, safety, and tolerability of bezuclastinib in patients who are experiencing inadequate symptom control with avapritinib.

NCT Number	NCT05186753
Lead Sponsor	Cogent Biosciences, Inc.
Conditions	SSM, Mastocytosis, Indolent, Mastocytosis, Systemic, Mastocytosis, ISM, BMM, Smoldering Systemic Mastocytosis, Bone Marrow Mastocytosis
Enrollment	237 participants
Start Date	2022-06-27
Primary Completion	2025-05-22 (estimated)
Study Completion	2030-04 (estimated)
Updated on ClinicalTrials.gov	2026-05-22