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Bezuclastinib

Phase 2

SSM | Small molecule | Hematology |Cogent Biosciences, Inc.|Last Updated: Jul 31, 2026

Target and mechanism

Target class-Tinib (Kinase)
ModalitySmall molecule

Also known as Bezuclastinib Tablets (Formulation A)

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment237

FDA Designations

BREAKTHROUGH_THERAPYPRIORITY_REVIEW

Clinical trial landscape

Bezuclastinib · 2 trials · 12 indications

Phase 2 2
NCT05186753(Summit) A Study to Evaluate the Efficacy and Safety of CGT9486 Versus Placebo in Patients With Indolent or Smoldering Systemic MastocytosisSSM
ACTIVE NOT_RECRUITING237 Analytics
NCT04996875(Apex) Bezuclastinib in Patients With Advanced Systemic MastocytosisAdvanced Systemic Mastocytosis (AdvSM)
RECRUITING140 Analytics
PHASE2ACTIVE NOT_RECRUITING
(Summit) A Study to Evaluate the Efficacy and Safety of CGT9486 Versus Placebo in Patients With Indolent or Smoldering Systemic Mastocytosis
SSM
NCT05186753237
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PHASE2RECRUITING
(Apex) Bezuclastinib in Patients With Advanced Systemic Mastocytosis
Advanced Systemic Mastocytosis (AdvSM)
NCT04996875140
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Study Endpoints

Primary Endpoints

Part 1: Determine recommended dose of bezuclastinib (CGT9486) in subjects with NonAdvSM
3 months

Selection of the recommended dose to be used in subsequent parts of the study.

Part 2: Efficacy of bezuclastinib at the selected dose versus placebo
24 Weeks

Mean absolute change on the Mastocytosis Symptom Severity Daily Diary (MS2D2)

Part 3: Safety and tolerability of bezuclastinib as assessed by number of adverse events
Up to 5 years

CTCAE v5

Part I: Identify clinically active and tolerable exposures of bezuclastinib in patients with AdvSM
18 months
Part II: - Determine efficacy of bezuclastinib as measured by mIWG Objective Response Rate (ORR) - Confirm the exposure-response relationship of bezuclastinib
18 months

Secondary Endpoints

Part 2: Proportion of subjects who had at least 50% reduction in serum tryptase
24 weeks
Part 2: Proportion of subjects who had at least a 50% reduction in peripheral blood D816V allele fraction
24 weeks
Part 2: Determine responder rates of subjects treated with bezuclastinib at the selected dose versus placebo
24 weeks
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
(Part 1a) Bezuclastinib Dose 1 + BSCEXPERIMENTAL -
(Part 1a) Bezuclastinib Dose 2 + BSCEXPERIMENTAL -
(Part 1a) Placebo + BSCPLACEBO_COMPARATOR -
(Part 1b) Bezuclastinib Dose 1 + BSCEXPERIMENTAL -
(Part 1b) Bezuclastinib Dose 2 + BSCEXPERIMENTAL -
(Part 1b) Placebo + BSCPLACEBO_COMPARATOR -
(Part 2) Bezuclastinib Selected Dose + BSCEXPERIMENTAL -
(Part 2) Placebo + BSCPLACEBO_COMPARATOR -
(Part 3) Bezuclastinib + BSCEXPERIMENTAL -
(Prior Therapy Sub-study) BezuclastinibEXPERIMENTAL -
bezuclastinibEXPERIMENTAL -

Interventions

NameTypeDescription
Bezuclastinib Tablets (Formulation A)DRUGBezuclastinib will be administered orally, once daily continuously for 28-day cycles
Bezuclastinib Tablets (Formulation B)DRUGBezuclastinib will be administered orally, once daily continuously for 28-day cycles
Placebo TabletsDRUGPlacebo will be administered orally, once daily continuously for 28-day cycles
bezuclastinibDRUGBezuclastinib is administered as tablets to be taken orally, continuously in 28-day cycles.
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites57

Key Inclusion Criteria: 1. Diagnosed with 1 of the following diagnoses according to the 2016 World Health Organization (WHO) classification for systemic mastocytosis (SM): * Indolent systemic mastocytosis (ISM), * Bone marrow mastocytosis (BMM) * Smoldering systemic mastocytosis (SSM) 2. ...

Countries:United StatesAustraliaBelgiumCanadaCzechiaFranceGermanyIrelandItalyNetherlandsNorwayPolandSpainSwitzerlandUnited KingdomAustria
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Recent Changes (Last 90 Days)

LOWJul 31, 2026NCT04996875lastUpdatePostDate: changed
LOWJul 31, 2026NCT04996875lastUpdatePostDate: changed

Frequently asked questions about Bezuclastinib

What is Bezuclastinib used for?

Bezuclastinib is an investigational small molecule being studied for advanced systemic mastocytosis (AdvSM) and smoldering systemic mastocytosis (SSM). It is a kinase inhibitor in development by Cogent Biosciences for these hematologic conditions.

What does Bezuclastinib target?

Bezuclastinib is a kinase inhibitor, belonging to the -tinib class of drugs that target kinases. It is being studied in systemic mastocytosis, a disease driven by abnormal mast cell growth and activation.

Who makes Bezuclastinib?

Bezuclastinib is being developed by Cogent Biosciences, Inc., a biopharmaceutical company traded on the stock exchange under the ticker symbol COGT.

What phase is Bezuclastinib in?

Bezuclastinib is in Phase 2 clinical development. It has received breakthrough therapy designation and priority review from the FDA for its investigational use in advanced systemic mastocytosis.

What clinical trials is Bezuclastinib in?

Bezuclastinib is being studied in two Phase 2 trials: NCT04996875 (Apex) in advanced systemic mastocytosis and NCT05186753 (Summit) in indolent or smoldering systemic mastocytosis. Both are randomized, double-blind, placebo-controlled studies.

Is Bezuclastinib the same as Bezuclastinib Tablets (Formulation A)?

Yes, Bezuclastinib Tablets (Formulation A) is an alternative name for Bezuclastinib. It is also referred to as Bezuclastinib in combination with sunitinib in some contexts.