Exhibit 99.1 Blueprint Medicines Reports Strong First Quarter 2024 Results and Raises AYVAKIT®/AYVAKYT® (avapritinib) Full Year Revenue Guidance -- Achieved $92.5 million in AYVAKIT net product revenues in the first quarter 2024 -- -- Raising guidance to$390 million to $410 million in full year AYVAKIT net product revenues -- -- Strengthening presence in allergy and inflammation with the IND for wild-type KIT inhibitor BLU-808 on track for filing in Q2 -- CAMBRIDGE, Mass., May 2, 2024 – Blueprint Medicines ...