A Study of BLU-263 in patients with Indolent Systemic Mastocytosis

Phase 1

• Conditions: Indolent Systemic Mastocytosis (ISM) and monoclonal Mast Cell Activation Syndrome (mMCAS); MedDRA version: 27.0Level: PTClassification code 10056452Term: Indolent systemic mastocytosisSystem Organ Class: 10029104 - Neoplasms benign, malignant and unspecified (incl cysts and polyps); Therapeutic area: Diseases [C] - Blood and lymphatic diseases [C15]

• Registration Number: EUCTR2020-005173-28-AT
• Lead Sponsor: Blueprint Medicines Corporation

Brief Summary

Not available

Detailed Description

Not available

Study Timeline

• Study Start: 2021-07-23
• Last Update Posted: 15 July 2024

Recruitment & Eligibility

• Status: Authorised-recruitment may be ongoing or finished
• Sex: All
• Target Recruitment: 463

Inclusion Criteria

All Patients
1. Patient must be = 16 years of age at the time of signing the informed consent/assent. (In France, Sweden, Germany, and Spain, only patients
who are = 18 years of age are allowed).
2. Patient must have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 to 2.
With ISM in Part 1 and Part 2
3. 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.
With ISM in Part 1, Part 2 and PK groups
4. Patient has confirmed diagnosis of ISM, confirmed by Central Pathology Review of BM biopsy and central review of B- and C-findings
by WHO diagnostic criteria. Archival biopsy may be used if completed within the past 12 months.
5. Patient must have failed to achieve adequate symptom control for 1 or more Baseline symptoms, as determined by the Investigator, with at
least 2 of the following symptomatic therapies administered: H1 blockers, H2 blockers, proton-pump inhibitors, leukotriene inhibitors, cromolyn sodium, corticosteroids, or omalizumab.
6. Patients must have BSC for ISM symptom management stabilized for at least 14 days prior to starting screening procedures.
7. For patients receiving corticosteroids, the dose must be = 20 mg/d prednisone or equivalent, and the dose must be stable for = 14 days.
With mMCAS in Part M
8. Patients must have mMCAS, confirmed by Central Pathology Review of BM biopsy. An archival biopsy may be used if completed within the past
12 months.
9. Patients must have tryptase < 20 ng/mL.
10. Patients must have KIT D816V in PB or BM and/or CD25+ Mast cells in BM.
11. Patients must have symptoms consistent with mast cell activation (despite BSC) in at least two organ systems characterized by cutaneous
flushing, tachycardia, syncope, hypotension, diarrhea, nausea, vomiting and GI cramping and sBT levels above 8 ng/mL OR Severe (Ring and
Messmer grading = II), recurrent anaphylaxis, including but not limited to hymenoptera venom, drug or food, regardless of sBT levels.
With ISM in PK Groups
12. Accrual may be limited to patients who have specific disease manifestations (ie, GI involvement) or are taking acid-reducing agents to better explore the impact of these features on PK.
With SSM in Part S:
13.Patient has confirmed diagnosis of SSM, confirmed by Central Pathology Review of BM biopsy and central review of B- and C-findings by WHO 2022 diagnostic criteria . No archival BM biopsies will be accepted without approval from the Sponsor.
Are the trial subjects under 18? yes
Number of subjects for this age range: 3
F.1.2 Adults (18-64 years) yes
F.1.2.1 Number of subjects for this age range 435
F.1.3 Elderly (>=65 years) yes
F.1.3.1 Number of subjects for this age range 25

Exclusion Criteria

Key Exclusion Criteria:
1. Patient has been diagnosed with any of the following WHO SM subclassifications: cutaneous mastocytosis only, SM-AHN, ASM, MCL, Mast cell sarcoma.
2. Patient has been diagnosed with another myeloproliferative disorder.
3. Patient has organ damage C-findings attributable to SM.
4. Patient has a QT interval corrected using Fridericia's formula (QTcF) > 470 msec (for females) or > 450 msec (for males).
5. Patient has clinically significant, uncontrolled, cardiovascular disease.
6. Patient has previously received treatment with any selective KIT inhibitors (avapritinib, bezuclastinib, and ripretinib).
7. Patient has a history of a primary malignancy that has been diagnosed or required therapy within 3 years. The following prior malignancies are not exclusionary: completely resected basal cell and squamous cell skin cancer, curatively treated localized prostate cancer, and completely resected carcinoma in situ of any site.
8. Time since any cytoreductive therapy including mastinib and midostaurin should be at least 5 half-lives or 14 days (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 screening period.
9. Patient has received radiotherapy or PUVA therapy < 14 days before beginning the screening period.
10. Patient has known active SARS-CoV-2infection (Germany Only).
11. Patients not eligible for an MRI due to contraindications (eg, patients with implanted defibrillators or other metallic devices not approved for MRI [Germany only]).

Study & Design

• Study Type: Interventional clinical trial of medicinal product
• Study Design: Not specified