On August 17, 2022, before trading hours, Blueprint Medicines announced top-line results from the registrational Part 2 of its PIONEER clinical trial of AYVAKIT® (avapritinib) in patients with non-advanced systemic mastocytosis (SM). The results showed a deterioration in the absolute improvement in the symptom score from 15.6 points in this most recent trial versus 19.7 in Phase 1.
On this news, Blueprint Medicines’ share price fell $7.38 per share, or 10%, to close at $61.17 per share on August 17, 2022, on unusually heavy trading volume.
