Sanofi has officially completed its acquisition of Blueprint Medicines Corporation, significantly strengthening its position in rare immunological diseases and KIT-driven conditions such as systemic mastocytosis (SM). This strategic move adds to Sanofi’s portfolio a marketed therapy, a robust pipeline, and specialized expertise in SM—a rare disorder involving the abnormal accumulation of mast cells in organs like the bone marrow, skin, and gastrointestinal tract.
As part of the acquisition, Sanofi gains Ayvakit/Ayvakyt (avapritinib), the only approved treatment in both the U.S. and EU for advanced and indolent systemic mastocytosis (ASM & ISM). The drug provides a critical therapeutic option for patients with this complex condition.
In addition to Ayvakit/Ayvakyt, the deal brings in elenestinib, a promising next-generation oral therapy currently under evaluation in the Phase 2/3 HARBOR trial (NCT04910685). Elenestinib is a potent and highly selective KIT D816V inhibitor designed for patients with ISM and smoldering SM, with the advantage of limited central nervous system penetration.
Sanofi also acquires BLU-808, a highly potent, investigational oral inhibitor targeting wild-type KIT, which plays a central role in mast cell activation implicated in various inflammatory diseases.
Beyond the pipeline, the acquisition gives Sanofi a deeper presence among allergists, dermatologists, and immunologists, aligning with the company’s broader goal of accelerating growth across its immunology portfolio.
The tender offer for all outstanding Blueprint shares at $129.00 per share in cash expired at 5:00 PM EDT on July 17, 2025. All conditions for the offer were met, and Sanofi promptly accepted and began payment for the validly tendered shares. The acquisition was completed through a merger of a Sanofi subsidiary with Blueprint under Delaware law, making Blueprint an indirect, wholly owned Sanofi subsidiary.
As part of the merger, Blueprint shares not tendered were converted into the right to receive $129.00 in cash per share, along with a non-transferable contingent value right (CVR) of up to $6.00 per share, payable upon achievement of predefined milestones within a set timeframe.
Sanofi financed the acquisition using a mix of cash reserves and proceeds from commercial paper. While the transaction is not expected to materially affect the company’s 2025 financial guidance, it will be immediately accretive to gross margin and will positively impact business operating income and earnings per share (EPS) starting in 2026.