NCT03580655 2026-04-24(PATHFINDER) Study to Evaluate Efficacy and Safety of Avapritinib (BLU-285), A Selective KIT Mutation-targeted Tyrosine Kinase Inhibitor, in Patients With Advanced Systemic MastocytosisBlueprint Medicines CorporationPhase 2 Completed107 enrolled 30 charts 1 FDA