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OncoMatch/Clinical Trials/NCT04910685

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

Is NCT04910685 recruiting? Yes, currently enrolling (May 2026). This Phase 2/3 trial studies Elenestinib for indolent systemic mastocytosis.

Phase 2/3RecruitingBlueprint Medicines CorporationNCT04910685Data as of May 2026

Treatment: ElenestinibThis 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.

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Extracted eligibility criteria

Performance status

ECOG 0–2(Ambulatory, capable of self-care)

Prior therapy

Must have received: symptom-directed therapy (H1 blockers, H2 blockers, proton-pump inhibitors, leukotriene inhibitors, cromolyn sodium, corticosteroids, omalizumab) — for ISM symptom management

failed to achieve adequate symptom control for 1 or more Baseline symptoms, as determined by the Investigator, with at least 2 of the following symptom-directed therapies administered: H1 blockers, H2 blockers, proton-pump inhibitors, leukotriene inhibitors, cromolyn sodium, corticosteroids, or omalizumab

Lab requirements

Cardiac function

QTcF > 470 ms (females) or > 450 ms (males) excluded; clinically significant, uncontrolled, cardiovascular disease excluded

clinically significant, uncontrolled, cardiovascular disease; QT interval corrected using Fridericia's formula (QTcF) > 470 milliseconds (msec) (for females) or > 450 msec (for males)

Structured fields extracted by AI. May contain errors — verify against the official protocol.

US trial sites

  • University of Alabama at Birmingham · Birmingham, Alabama
  • David Geffen School of Medicine at UCLA · Los Angeles, California
  • Stanford Cancer Institute · Palo Alto, California
  • UCHealth Blood Disorders and Cell Therapies Center - Anschutz Medical Campus · Aurora, Colorado
  • Winship Cancer Institute, Emory University · Atlanta, Georgia

Showing up to 5 US sites. See all sites on ClinicalTrials.gov →

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