Studie zur Beurteilung der Sicherheit und Wirksamkeit von Avapritinib (BLU-285) bei Patienten mit indolenter und systemischer Mastozytose

Drug: Avapritinib;Drug: Placebo

Gender: All
Maximum age: N/A
Minimum age: 18 Years

Key Inclusion Criteria:

- 1. Patient must have SM, confirmed by Central Pathology Review of BM biopsy, and
central review of B- and C-findings by WHO diagnostic criteria.

- 2. 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.

- 3. Patient must have failed to achieve adequate symptom control for 1 or more Baseline
symptoms.

- 4. For patients receiving corticosteroids, the dose must be = 20 mg/d prednisone or
equivalent, and the dose must be stable for = 14 days.

- 5. Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status
(PS) of 0 to 2.

Key Exclusion Criteria:

- 1. Patient has been diagnosed with any of the following WHO SM subclassifications:
cutaneous mastocytosis only, smoldering SM, SM with associated hematologic neoplasm,
aggressive SM, mast cell leukemia, or mast cell sarcoma.

- 2. Patient must not have received prior treatment with avapritinib.

- 3. Patient must not have had any cytoreductive therapy including but not limited to
masitinib and midostaurin, or investigational agent for < 14 days or 5 half-lives of
the drug (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 14-day ISM-SAF eligibility TSS assessment.

- 4. Patient must not have received radiotherapy or psoralen and ultraviolet A (PUVA)
therapy < 14 days before beginning the 14-day ISM-SAF eligibility TSS assessment.

- 5. Patient must not have received any hematopoietic growth factor the preceding 14
days before beginning the 14-day ISM-SAF eligibility TSS assessment.

- 6. Patient must not have a QT interval corrected using Fridericia's formula (QTcF) of
> 480 msec.