Efficacy and Safety of Midostaurin in Patients With Aggressive Systemic Mastocytosis or Mast Cell Leukemia

Key inclusion criteria: * Patients ≥ 18 years of age who provided written informed consent, Eastern Cooperative Oncology Group (ECOG) performance status of 0-3 and a life expectancy of \>12 weeks, electrocardiogram with a QTcF of ≤ 450 ms, with a diagnosis of SM and sub-variants based on WHO criteria. * Patients with ASM or MCL were to have one or more measurable clinical findings (termed "C-findings") and defined as those attributable to the mast cell disease component and not to AHNMD or any other cause. * Patients with MCL were to have BM aspirate smears with ≥ 20% immature MCs. Patients with AHNMD were eligible if it was not life-threatening or in an acute stage. Key exclusion criteria: * Patients with cardiovascular disease including congestive heart failure class III or IV according to the New York Heart Association classification, left ventricular ejection fraction (LVEF) of \<50%, myocardial infarction within the previous 6 months, or poorly controlled hypertension. * Patients with a heart block of any degree at screening (for Canada only). * Patients with an AHNMD who required immediate cytoreductive therapy or targeted therapy (other than midostaurin). * Patients who had demonstrated relapse after 3 or more prior regimens of SM treatment regardless of treatment regimen for supportive care (e.g., symptom-limiting therapies). * Patients who had received any investigational agent, targeted therapy, chemotherapy, interferon-α, or 2 chlorodeoxyadenosine within 30 days…