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Study identifier: NCT04910685 Synced from ClinicalTrials.gov · July 29, 2026
● Recruiting

(HARBOR) Study to Evaluate Efficacy and Safety of BLU-263 Versus Placebo in Patients With Indolent Systemic Mastocytosis

Condition: Indolent Systemic Mastocytosis · Smoldering Systemic Mastocytosis  ·  Sponsor: Blueprint Medicines Corporation

PhasePhase 2/Phase 3
Planned participants534
Who can joinAll sexes, 18 Years to no upper limit
Healthy volunteersNo

About this study

This is a randomized, double-blind, placebo-controlled, Phase 2/3 study comparing the efficacy and safety of elenestinib (BLU-263) + symptom directed therapy (SDT) with placebo + SDT in participants with indolent systemic mastocytosis (ISM) whose symptoms are not adequately controlled by SDT. Parts 1 and 2 will enroll participants with ISM. Participants enrolled in Part 2 will roll over onto Part 3 to receive treatment with elenestinib in an open-label fashion following completion of the earlier Part. Part K will enroll participants with ISM who have previously received an approved selective KIT inhibitor. The study also includes pharmacokinetic (PK) groups that will enroll participants with ISM.

This description comes directly from the study's public registry record.

Talk to the study team

Blueprint Medicines  ·  617-714-6707  ·  medinfo@blueprintmedicines.com

Always discuss trial participation with your own doctor first.

Locations (71)

University of Alabama at BirminghamBirmingham, Alabama, United StatesRecruiting
David Geffen School of Medicine at UCLALos Angeles, California, United StatesRecruiting
Stanford Cancer InstitutePalo Alto, California, United StatesRecruiting
UCHealth Blood Disorders and Cell Therapies Center - Anschutz Medical CampusAurora, Colorado, United StatesRecruiting
Winship Cancer Institute, Emory UniversityAtlanta, Georgia, United StatesRecruiting
Brigham and Women's HospitalBoston, Massachusetts, United StatesRecruiting
Michigan Medicine University of MichiganAnn Arbor, Michigan, United StatesRecruiting
Mayo ClinicRochester, Minnesota, United StatesRecruiting
Roswell Park Cancer InstituteBuffalo, New York, United StatesRecruiting
Columbia University Medical CenterNew York, New York, United StatesRecruiting
Duke Asthma, Allergy and Airway CenterDurham, North Carolina, United StatesRecruiting
University of Cincinnati Medical CenterCincinnati, Ohio, United StatesRecruiting

+ 59 more locations — full list on the registry record.

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Source record: clinicaltrials.gov/study/NCT04910685