Multinational phase 2 study of avapritinib for advanced systemic mastocytosis

Systemic mastocytosis is a clonal, hematologic neoplasm driven by KITD816V mutation in more than 90% of cases, with limited treatment options. In a phase 1 study, avapritinib (ava), a potent inhibitor of D816V-altered KIT, induced durable responses of advanced systemic mastocytosis (AdvSM). The multinational phase 2 study PATHFINDER evaluated ava for AdvSM. The study found rapid responses of AdvSM to ava 200 mg QD. The responses deepened over the course of treatment. Ava resulted in improvement of symptoms, and was generally well tolerated.