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(PIONEER) Study to Evaluate Efficacy and Safety of Avapritinib (BLU-285), A Selective KIT Mutation-targeted Tyrosine Kinase Inhibitor, Versus Placebo in Patients With Indolent Systemic Mastocytosis

Phase 2
Active, not recruiting
Conditions
Indolent Systemic Mastocytosis
Interventions
Drug: Placebo
Registration Number
NCT03731260
Lead Sponsor
Blueprint Medicines Corporation
Brief Summary

This is a Phase 2, randomized, double-blind, placebo-controlled study comparing the efficacy and safety of avapritinib + best supportive care (BSC) with placebo + BSC in patients with indolent systemic mastocytosis (ISM) whose symptoms are not adequately controlled by BSC. The study will be conducted in 3 parts. All patients will receive treatment with avapritinib during Part 3 including those rolling over from the placebo group.

Detailed Description

Not available

Recruitment & Eligibility

Status
ACTIVE_NOT_RECRUITING
Sex
All
Target Recruitment
251
Inclusion Criteria
    1. Patient must have SM, confirmed by Central Pathology Review of BM biopsy, and central review of B- and C-findings by WHO diagnostic criteria.
    1. Patient must have moderate-to-severe symptoms based on minimum mean total symptom score (TSS) of the ISM Symptom Assessment Form (ISM-SAF) over the 14-day eligibility screening period.
    1. Patient must have failed to achieve adequate symptom control for 1 or more Baseline symptoms.
    1. For patients receiving corticosteroids, the dose must be ≤ 20 mg/d prednisone or equivalent, and the dose must be stable for ≥ 14 days.
    1. Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 to 2.

Key

Exclusion Criteria
    1. Patient has been diagnosed with any of the following WHO SM subclassifications: cutaneous mastocytosis only, smoldering SM, SM with associated hematologic neoplasm, aggressive SM, mast cell leukemia, or mast cell sarcoma.
    1. Patient must not have received prior treatment with avapritinib.
    1. Patient must not have had any cytoreductive therapy including but not limited to masitinib and midostaurin, or investigational agent for < 14 days or 5 half-lives of the drug (whichever is longer), and for cladribine, interferon alpha, pegylated interferon, or antibody therapy < 28 days or 5 half-lives of the drug (whichever is longer), before beginning the 14-day ISM-SAF eligibility TSS assessment.
    1. Patient must not have received radiotherapy or psoralen and ultraviolet A (PUVA) therapy < 14 days before beginning the 14-day ISM-SAF eligibility TSS assessment.
    1. Patient must not have received any hematopoietic growth factor the preceding 14 days before beginning the 14-day ISM-SAF eligibility TSS assessment.
    1. Patient must not have a QT interval corrected using Fridericia's formula (QTcF) of > 480 msec.

Study & Design

Study Type
INTERVENTIONAL
Study Design
PARALLEL
Arm && Interventions
GroupInterventionDescription
(Part 1) Placebo + BSCPlaceboPlacebo will be administered orally in continuous 28-day cycles
(Part 1) Avapritinib Dose 1 + BSCAvapritinibAvapritinib will be administered orally in continuous 28-day cycles
(Part 2) Avapritinib RP2D + BSCAvapritinibAvapritinib will be administered orally in continuous 28-day cycles
(Part 2) Placebo + BSCPlaceboPlacebo will be administered orally in continuous 28-day cycles
(Part 1) Avapritinib Dose 2 + BSCAvapritinibAvapritinib will be administered orally in continuous 28-day cycles
(Part 1) Avapritinib Dose 3 + BSCAvapritinibAvapritinib will be administered orally in continuous 28-day cycles
(Part 3) Avapritinib RP2D + BSCAvapritinibAvapritinib will be administered orally in continuous 28-day cycles
Primary Outcome Measures
NameTimeMethod
Part 1: Recommended Phase 2 dose (RP2D) in patients with ISM9 months
Part 2: Mean change in ISM Symptom Assessment Form (ISM-SAF) total symptom score (TSS) as compared to placebo6 months

0 - 110 points (higher value represents worse symptom outcomes)

Part 3: Number of Participants with Adverse EventsUp to 5 years
Secondary Outcome Measures
NameTimeMethod
Part 2: Proportion of patients with a ≥50% reduction in peripheral blood V-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog aspartate 816 valine (KIT D816V) allele fraction or undetectable for patients with detectable mutation at Baseline6 months
Part 2: Proportion of patients with a ≥50% reduction in serum tryptase6 months
Part 2: Proportion of patients with a ≥50% reduction in bone marrow mast cells or no aggregates for patients with aggregates at Baseline6 months
Parts 1, 2, and 3: Change in best supportive care (BSC) concomitant medication usageUp to 5 years
Parts 1, 2, and 3: Change in Patient's Global Impression of Symptom Severity (PGIS)Up to 5 years
Part 2: Proportion of patients with ≥30% reduction in ISM-SAF TSS6 months
Parts 1, 2, and 3: Change in bone marrow mast cellsUp to 5 years
Parts 1, 2, and 3: Change from Baseline in ISM-SAF ScoreUp to 5 years
Parts 1, 2, and 3: Change in Patients' Global Impression of Change (PGIC)Up to 5 years

1 - 7 (higher value represents worse symptom outcomes)

Parts 1, 2, and 3: Change in EuroQuol 5 Dimensions 5 Levels (EQ 5D-5L)Up to 5 years

0 - 100 (higher value represents better symptom outcomes)

Part 2: Proportion of patients with ≥50% reduction in ISM-SAF TSS6 months
Parts 1, 2, and 3: Change in KIT D816V allele burden in bloodUp to 5 years
Parts 1, 2, and 3: Change in Mastocytosis Quality of Life Questionnaire (MC-QoL)Up to 5 years
Parts 1, 2, and 3: Change in 12-item Short Form Health Survey (SF-12)Up to 5 years

0 - 100 points (higher value represents better symptom outcomes)

Parts 1, 2, and 3: Safety of avapritinib as assessed by number of adverse eventsUp to 5 years

CTCAE version 5.0

Parts 1, 2, and 3: Change in serum tryptaseUp to 5 years

Trial Locations

Locations (49)

University of Alabama at Birmingham

🇺🇸

Birmingham, Alabama, United States

Mayo Clinic Hospital

🇺🇸

Phoenix, Arizona, United States

Stanford Cancer Institute

🇺🇸

Stanford, California, United States

Mayo Clinic Florida

🇺🇸

Jacksonville, Florida, United States

H. Lee Moffitt Cancer Center

🇺🇸

Tampa, Florida, United States

Winship Cancer Institute, Emory University

🇺🇸

Atlanta, Georgia, United States

Rush University Medical Center

🇺🇸

Chicago, Illinois, United States

University of Kansas Hospital

🇺🇸

Kansas City, Kansas, United States

Brigham & Women's Hospital

🇺🇸

Boston, Massachusetts, United States

Dana Farber Cancer Institute

🇺🇸

Boston, Massachusetts, United States

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University of Alabama at Birmingham
🇺🇸Birmingham, Alabama, United States
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