(Apex) CGT9486 in Patients With Advanced Systemic Mastocytosis

Key Inclusion Criteria:

Diagnosed with 1 of the following advanced mastocytosis diagnoses by Eligibility Committee

Aggressive Systemic Mastocytosis (ASM)
Systemic Mastocytosis with an Associated Hematologic Neoplasm (SM-AHN)
Mast Cell Leukemia (MCL)
Measurable disease according to modified IWG-MRT-ECNM criteria. (A subset of patients inevaluble per mIWG-MRT-ECNM will be included in the study).
ECOG (0 to 3)
Have clinically acceptable local laboratory screening results (clinical chemistry, hematology) within certain limits.

Key Exclusion Criteria:

Persistent toxicity from previous therapy for Advanced Systemic Mastocytosis that has not resolved to ≤ Grade 1
Associated hematologic neoplasm requiring immediate antineoplastic therapy
Clinically significant cardiac disease
Known positivity for the FIP1L1 PDGFRA fusion (Patients with eosinophilia without detectable KIT D816V mutation must also lack the PDGFRA fusion mutation prior to enrollment)
Seropositive for human immunodeficiency virus (HIV) 1 or 2, or positive for hepatitis B surface antigen or hepatitis C virus (HCV) antibody
History of clinically significant bleeding event within 30 days before the first dose of study drug or need for therapeutic anticoagulation on study
Diagnosed with or treated for malignancy other than the disease under study within the prior 3 years before enrollment
Received any cytoreductive therapy or any investigational agent less than 14 days, and for cladribine, interferon alpha, pegylated interferon, and any antibody therapy less than 28 days, before screening bone marrow biopsy
Received hematopoietic growth factor support within 14 days before the first dose of study drug
Received strong CYP3A4 inhibitors or inducers before the first dose of study drug
Need for treatment with steroids