An Observational Study in Participants With Indolent Systemic Mastocytosis (ISM)

NCT07264959 | Recruiting

• 1 other identifier: BLU-285-2406
• Study Type: observational
• Target: 150
• Locations: 1 country
• Sites: 1

Brief Summary

This is a Phase 4, non-interventional, observational study to collect detailed data on the clinical characteristics, clinical outcomes and medical management of ISM in real-world settings. The study will describe the demographic and clinical characteristics of ISM participants, including anaphylaxis and bone manifestations in ISM. Quality of life and disease control will be assessed through participant questionnaires. The study will also evaluate real world ISM treatment management, including use of avapritinib.

Conditions

Indolent Systemic Mastocytosis

Keywords

ISM; Avapritinib; BLU-285; Selective KIT mutation-targeted tyrosine kinase inhibitor; Tyrosine kinase inhibitor; Mastocytosis; Neoplastic mast cells

Outcome Measures

Primary Outcomes (5)

• Baseline Demographics

  Baseline (Month 1)

• Change From Baseline in Patient-Reported Outcomes Scores

  Baseline up to Month 61

• Change From Baseline in Serum KIT D816V Variant Allele Frequency (VAF)

  Baseline up to Month 61

• Change From Baseline in Serum Tryptase

  Baseline up to Month 61

• Change From Baseline in Indolent Systemic Mastocytosis (ISM) Symptom-Directed Therapies

  Baseline up to Month 61

Study Arms (1)

Participants With ISM

Patients who are currently being treated or plan to be treated for ISM

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Participants with ISM who are currently being treated or plan to be treated with symptom-directed therapies and/or avapritinib for ISM.

You may qualify if:

• Male or female adult participants (≥ 18 years of age) with a diagnosis of ISM according to the World Health Organization (WHO) diagnostic criteria
• Participant is currently being treated or plans to be treated with symptom-directed therapies and/or avapritinib for ISM.

You may not qualify if:

• Participants with advanced systemic mastocytosis (AdvSM) or another associated hematologic neoplasm
• Participants with smoldering systemic mastocytosis
• Ongoing participation in interventional studies in systemic mastocytosis (SM) at the time of enrollment
• Participants currently receiving treatment with a KIT inhibitor other than avapritinib at the time of enrollment.

Sponsors & Collaborators

• Blueprint Medicines Corporation: lead

Study Sites (1)

Brigham and Women's Allergy and Clinical Immunology, Mass General Brigham Healthcare Center (Chestnut Hill)

Chestnut Hill, Massachusetts, 02467, United States

RECRUITING

Biospecimen

Retention: SAMPLES WITHOUT DNA

With the participant's informed consent and as approved by local IRBs/IECs, de-identified biological samples may be stored at a biosample repository and may be shared with the data repository. These samples could be used to research the causes of ISM, its complications and other conditions for which individuals with ISM are at increased risk, and to improve treatment. The repository will also be provided with a code-link that will allow linking the biological specimens with the phenotypic data from each participant, maintaining the blinding of the identity of the participant.

MeSH Terms

Conditions

Mastocytosis, Systemic; Mastocytosis

Condition Hierarchy (Ancestors)

Neoplasms, Connective Tissue; Neoplasms, Connective and Soft Tissue; Neoplasms by Histologic Type; Neoplasms; Mast Cell Activation Disorders; Immune System Diseases

Central Study Contacts

Blueprint Medicines

CONTACT

1-888-258-7768; medinfo@blueprintmedicines.com

Blueprint Medicines, EU Contact

CONTACT

+31 85 064 4001; medinfoeurope@blueprintmedicines.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: November 24, 2025
• First Posted: December 4, 2025
• Study Start: April 15, 2026
• Primary Completion (Estimated): December 1, 2032
• Study Completion (Estimated): December 1, 2032
• Last Updated: April 22, 2026

Record last verified: 2026-04

Locations

US (1)