Reductions in Polypharmacy for Patients with Indolent Systemic Mastocytosis on Avapritinib

Indolent systemic mastocytosis (ISM) is a clonal mast cell disease driven by D816V-mutant KIT in ∼95% of cases and characterized by chronic debilitating symptoms across multiple organ systems. Most patients with ISM rely on symptom-directed polypharmacy (best supportive care [BSC]) for the management of symptoms, but many patients' symptoms remain inadequately controlled, leading to a poor quality of life and adverse effects from prolonged BSC use. PIONEER (NCT03731260), a double-blind, randomized, placebo-controlled study, assessed safety and efficacy of avapritinib, a potent inhibitor of KIT D816V, versus placebo, both with BSC.