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

Phase 2
Active, not recruiting
Conditions
SSM
Mastocytosis, Indolent
Mastocytosis, Systemic
Mastocytosis
ISM
BMM
Smoldering Systemic Mastocytosis
Bone Marrow Mastocytosis
Interventions
Registration Number
NCT05186753
Lead Sponsor
Cogent Biosciences, Inc.
Brief Summary

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.

Detailed Description

Not available

Recruitment & Eligibility

Status
ACTIVE_NOT_RECRUITING
Sex
All
Target Recruitment
207
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. Moderate-to-severe symptoms based on a minimum total symptom scoew (TSS) of the Mastocytosis Activity Score (MAS) and after establishing a stable regimen of at least 2 antimediator therapies over a 14-day eligibility period

  3. Eastern Cooperative Oncology Group (ECOG) Performance Status 0 to 2

  4. For patients receiving corticosteroids, the dose must be ≤10 mg/day of prednisone or equivalent

Key

Exclusion Criteria
  1. Persistent toxicity from previous therapy for NonAdvSM that has not resolved to ≤ Grade 1
  2. Diagnosed with any of the following WHO SM classifications: bone marrow mastocytosis, advanced systemic mastocytosis including SM with associated hematologic neoplasm, aggressive SM, mast cell leukemia; or mast cell sarcoma
  3. Diagnosed with mastocytosis of the skin without systemic involvement
  4. Received prior treatment with any targeted KIT inhibitor with the exception of approved agents for the treatment of SM
  5. Received prior cytoreductive therapy or investigational agent for <14 days or 5 half- lives of the drug and for cladribine, interferon alpha, pegylated interferon, or antibody therapy <28 days or 5 half-lives of the drug (whichever is longer), before starting screening assessments
  6. Received radiotherapy or psoralen and ultraviolet A therapy <14 days before starting screening assessments
  7. Received any hematopoietic growth factor support <14 days or 5 half lives of the drug before starting screening assessments
  8. History of clinically significant bleeding event within 30 days before the first dose of study drug or need for therapeutic anticoagulation on study
  9. Need for treatment of corticosteroids at >10 mg/day of prednisone or equivalent
  10. Received strong CYP3A4 inhibitors or inducers within 14 days or 5 drug half-lives before the first dose of study drug

Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
(Part 1b) Bezuclastinib Dose 1 + BSCBezuclastinib Tablets (Formulation B)-
(Part 1a) Bezuclastinib Dose 2 + BSCBezuclastinib Tablets (Formulation A)-
(Part 2) Placebo + BSCPlacebo Tablets-
(Part 3) Bezuclastinib + BSCBezuclastinib Tablets (Formulation A)-
(Part 1a) Bezuclastinib Dose 1 + BSCBezuclastinib Tablets (Formulation A)-
(Part 1a) Placebo + BSCPlacebo Tablets-
(Part 1b) Placebo + BSCPlacebo Tablets-
(Part 1b) Bezuclastinib Dose 2 + BSCBezuclastinib Tablets (Formulation B)-
(Part 2) Bezuclastinib Selected Dose + BSCBezuclastinib Tablets (Formulation B)-
(Part 3) Bezuclastinib + BSCBezuclastinib Tablets (Formulation B)-
Primary Outcome Measures
NameTimeMethod
Part 1: Determine recommended dose of bezuclastinib (CGT9486) in subjects with NonAdvSM3 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 placebo24 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 eventsUp to 5 years

CTCAE v5

Secondary Outcome Measures
NameTimeMethod
Part 3: Change and percent change in the levels of KIT D816V mutation allele burdenUp to 12 months
Parts 2 & 3: Determine change of the lead (most severe) symptom and lead (most severe) subdomain of the MS2D2 in subjects treated with bezuclastinib versus placeboUp to 5 years

Change and percent change from baseline in the symptom score of the subject's most severe symptom.

Change and percent change from baseline in the MS2D2 subdomain score of the subject's most severe subdomain.

Part 2: Proportion of subjects who had at least 50% reduction in serum tryptase24 weeks
Part 2: Proportion of subjects who had at least a 50% reduction in peripheral blood D816V allele fraction24 weeks
Part 2: Determine responder rates of subjects treated with bezuclastinib at the selected dose versus placebo24 weeks

Proportion of subjects with at least a 30% reduction of the total symptom score (TSS) on the MS2D2.

Proportion of subjects with at least a 50% reduction of the total symptom score (TSS) on the MS2D2.

Part 2: Proportion of subjects who had at least 50% reduction in mast cell burden24 weeks
Parts 1 & 2: Safety and tolerability of bezuclastinib as assessed by number of adverse eventsUp to 24 weeks

CTCAE v5

Parts 1, 2, & 3: Change and percent change in patient reported outcome (PRO) measuresUp to 5 years
Parts 1 & 3: Change and percent change in serum tryptaseUp to 12 months
Parts 1 & 3: Change and percent change in bone marrow mast cellsUp to 18 months
Part 1: Assess the pharmacokinetics (PK) of bezuclastinib in subjects with NonAdvSM3 months

Plasma concentrations of CGT9846

Part 2: Determine mean change from baseline in predetermined PRO sub-domain and individual item scores24 weeks
Part 3: To determine the efficacy of bezuclastinib at the selected doseUp to 2 years

Proportion of subjects with at least a 50% reduction in MS2D2 TSS from baseline at 1 year and 2 years from start of bezuclastinib

Change and percent change from baseline in the MS2D2 TSS, subdomain, and individual item scores

Part 3: Usage of concomitant medications as rescue therapy for NonAdvSM and changes from baseline in rescue therapy and best supportive care medications regimenUp to 5 years

Trial Locations

Locations (69)

University of Alabama at Birmingham

🇺🇸

Birmingham, Alabama, United States

Mayo Clinic Arizona

🇺🇸

Phoenix, Arizona, United States

One of a Kind Clinical Research Center

🇺🇸

Scottsdale, Arizona, United States

Modena Allergy and Asthma Clinical

🇺🇸

La Jolla, California, United States

University of California, Los Angeles (UCLA) - Medical Center

🇺🇸

Los Angeles, California, United States

Innovative Research of West Florida

🇺🇸

Clearwater, Florida, United States

Mayo Clinic - Jacksonville

🇺🇸

Jacksonville, Florida, United States

University of South Florida

🇺🇸

Tampa, Florida, United States

Emory University

🇺🇸

Atlanta, Georgia, United States

Rush University

🇺🇸

Chicago, Illinois, United States

Walter Reed National Military Medical Center

🇺🇸

Bethesda, Maryland, United States

Allervie Clinical Research

🇺🇸

Glenn Dale, Maryland, United States

Institute for Asthma and Allergy

🇺🇸

Wheaton, Maryland, United States

Chesapeake Research Center

🇺🇸

White Marsh, Maryland, United States

Brigham and Women's Hospital

🇺🇸

Boston, Massachusetts, United States

Dana Farber Cancer Institute

🇺🇸

Boston, Massachusetts, United States

University of Michigan

🇺🇸

Ann Arbor, Michigan, United States

Mayo Clinic- Rochester

🇺🇸

Rochester, Minnesota, United States

Washington University at St. Louis

🇺🇸

Saint Louis, Missouri, United States

Dartmouth Hitchcock Medical Center

🇺🇸

Lebanon, New Hampshire, United States

Icahn School of Medicine at Mount Sinai

🇺🇸

New York, New York, United States

Duke University

🇺🇸

Raleigh, North Carolina, United States

University of Cincinnati

🇺🇸

Cincinnati, Ohio, United States

The Ohio State University

🇺🇸

Columbus, Ohio, United States

Medical University of South Carolina

🇺🇸

Charleston, South Carolina, United States

Vanderbilt University Medical Center

🇺🇸

Nashville, Tennessee, United States

AIR Care

🇺🇸

Dallas, Texas, United States

The University of Texas MD Anderson Cancer Center

🇺🇸

Houston, Texas, United States

Metrodora Institute of Technology

🇺🇸

West Valley City, Utah, United States

Royal Prince Alfred Hospital

🇦🇺

Camperdown, New South Wales, Australia

Royal Adelaide Hospital

🇦🇺

Adelaide, South Australia, Australia

Kepler Universitaetsklinikum GmbH

🇦🇹

Linz, Austria

Medizinische Universitaet Wien

🇦🇹

Wien, Austria

Antwerp University Hospital (UZA)

🇧🇪

Edegem, Belgium

CHU Tivoli

🇧🇪

La Louvière, Belgium

Tom Baker Cancer Centre

🇨🇦

Calgary, Alberta, Canada

University of Alberta

🇨🇦

Edmonton, Alberta, Canada

St. Michael's Hospital

🇨🇦

Toronto, Ontario, Canada

McGill University

🇨🇦

Montréal, Quebec, Canada

Fakultni nemocnice Kralovske Vinohrady

🇨🇿

Praha 10, Czechia

AP-HM - Hopital de la Timone

🇫🇷

Marseille, France

AP-HP- Hopital Pitie-Salpetriere

🇫🇷

Paris, France

CHU de Toulouse - Hopital Larrey

🇫🇷

Toulouse, France

Universitaetsklinikum Aachen, AoeR

🇩🇪

Aachen, Germany

Charité Universitätsmedizin Berlin

🇩🇪

Berlin, Germany

Universitaetsklinikum Hamburg-Eppendorf

🇩🇪

Hamburg, Germany

Universitätsklinikum Schleswig-Holstein

🇩🇪

Kiel, Germany

University Medical Centre Mannheim

🇩🇪

Mannheim, Germany

Attikon University General Hospital Athens

🇬🇷

Athens, Greece

Cork University Hospital

🇮🇪

Cork, Ireland

St. James's Hospital

🇮🇪

Dublin, Ireland

IRCCS Azienda Ospedaliero-Universitaria di Bologna - Policlinico di Sant'Orsola

🇮🇹

Bologna, Italy

AOU Policlinico Rodolico San Marco

🇮🇹

Catania, Italy

Azienda Ospedaliero-Universitaria Careggi

🇮🇹

Firenze, Italy

Fondazione IRCCS Policlinico San Matteo

🇮🇹

Pavia, Italy

AUSL della Romagna-Ospedale S.Maria delle Croci

🇮🇹

Ravenna, Italy

Policlinico Universitario Agostino Gemelli

🇮🇹

Rome, Italy

Azienda Ospedaliera Universitaria Integrata Verona-Ospedale Borgo Trento

🇮🇹

Verona, Italy

University Medical Center Groningen

🇳🇱

Groningen, Netherlands

Erasmus Rotterdam

🇳🇱

Rotterdam, Netherlands

Oslo University Hospital

🇳🇴

Oslo, Norway

Uniwersyteckie Centrum Kliniczne, Klinika Hematologii i Transplantologii

🇵🇱

Gdańsk, Poland

Samodzielny Publiczny Szpital Kliniczny Nr 1 - Klinika Hematoonkologii i Transplantacji Szpiku

🇵🇱

Lublin, Poland

Hospital Universitario Vall d'Hebron

🇪🇸

Barcelona, Spain

Institut Catala d'Oncologia - L'Hospitalet

🇪🇸

Barcelona, Spain

Hospital Universitario Ramon y Cajal

🇪🇸

Madrid, Spain

Instituto de Estudios de Mastocitosis de Castilla La Mancha-Hospital Virgen del Valle

🇪🇸

Toledo, Spain

University Hospital Basel

🇨🇭

Basel, Switzerland

Guy's Hospital

🇬🇧

London, United Kingdom

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