Blueprint Medicines is a commercial-stage biopharmaceutical company focused on treating mast cell diseases and cancer. Its core product is AYVAKIT (avapritinib), an oral small molecule inhibitor that targets the KIT D816V mutation — the genetic driver of systemic mastocytosis (SM) in roughly 95% of cases. SM is a rare disease where abnormal mast cells accumulate in bone marrow and organs, causing symptoms ranging from anaphylaxis and GI distress to organ failure. AYVAKIT is the only FDA-approved disease-modifying therapy for indolent SM and is also approved for a rare GI cancer (PDGFRA Exon 18 mutant GIST). Blueprint sells AYVAKIT directly through specialty pharmacy channels in the U.S. and through its own commercial organization in Europe, where the drug is marketed as AYVAKYT and is approved and reimbursed in 15 countries. Revenue is driven almost entirely by AYVAKIT net product sales, and scales with new patient starts, therapy duration (SM is chronic, so patients stay on drug for years), and commercial insurance mix. Blueprint's pipeline centers on extending its mast cell franchise: elenestinib is a next-generation KIT D816V inhibitor in Phase 3 for indolent SM, and BLU-808 is an oral wild-type KIT inhibitor targeting broader mast cell-driven allergic diseases like chronic urticaria. Blueprint also has CDK2/CDK4 oncology programs, though these are a secondary priority. The company is pre-profitability but is reducing cash burn as AYVAKIT revenue grows.