Sanofi has agreed to acquire Blueprint Medicines, a Cambridge, Massachusetts-based bio/pharmaceutical company specializing in rare diseases, in a $9.5-billion deal ($9.1 billion upfront and up to $400 million in milestone payments).   

Blueprint’s lead commercial product is Ayvakit/Ayvakyt (avapritinib), a rare immunology disease medicine approved in the US and the European Union. The drug  had net revenues of $479 million in 2024 and nearly $150 million in the first quarter of 2025. In its first-quarter 2025 earnings results, Blueprint projected full-year 2025 global net product revenues of Ayvakit/Ayvakyt of $700 million to $720 million with potential global net product revenues of $2 billion by 2030. 

Ayvakit/Ayvakyt is approved for treating advanced and indolent systemic mastocytosis, a rare immunology disease, which is characterized by the accumulation and activation of aberrant mast cells in the bone marrow, skin, the gastrointestinal tract, and other organs. Mast cells play a role in immune responses and are typically found in tissues that encounter the external environment, such as the skin, lungs, and gastrointestinal tract, according to information from Sanofi. Upon activation, mast cells release pro-inflammatory molecules such as histamines and proteases. Systemic mastocytosis is a rare immunologic disorder that can lead to a range of symptoms across multiple organ systems.   

Blueprint’s key pipeline assets include elenestinib, a next-generation medicine for treating systemic mastocytosis, as well as BLU-808, an oral wild-type KIT inhibitor that has the potential to treat a broad range of diseases in immunology. 

Under the acquisition, Sanofi will pay $129.00 per share in cash at closing, representing an equity value of approximately $9.1 billion. Blueprint shareholders also will receive one non-tradeable contingent value right (CVR) which will entitle the holder to receive two potential milestone payments of $2 and $4 per CVR for the achievement, respectively, of future development and regulatory milestones for BLU-808. The total equity value of the transaction, including potential CVR payments, represents approximately $9.5 billion on a fully diluted basis. 

Subject to the satisfaction or waiver of customary closing conditions, Sanofi currently expects to complete the acquisition in the third quarter of 2025. 

Source: Sanofi and Blueprint Medicines