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

> **NCT04910685** · PHASE2,PHASE3 · RECRUITING · sponsor: **Blueprint Medicines Corporation** · enrollment: 534 (estimated)

## Conditions studied

- Indolent Systemic Mastocytosis
- Smoldering Systemic Mastocytosis

## Interventions

- **DRUG:** Elenestinib
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT04910685
- **Lead sponsor:** Blueprint Medicines Corporation
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE2,PHASE3
- **Study type:** INTERVENTIONAL
- **Status:** RECRUITING
- **Start date:** 2021-11-30
- **Primary completion:** 2032-09-30
- **Final completion:** 2032-09-30
- **Target enrollment:** 534 (ESTIMATED)
- **Last updated:** 2026-04-20


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT04910685

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT04910685, "(HARBOR) Study to Evaluate Efficacy and Safety of BLU-263 Versus Placebo in Patients With Indolent Systemic Mastocytosis". Retrieved via AI Analytics 2026-06-22 from https://api.ai-analytics.org/clinical/NCT04910685. Licensed CC0.

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*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*