Sanofi has announced that it will be expanding its immunology capabilities by acquiring US-based Blueprint Medicines Corporation in a deal worth up to approximately $9.5bn.
The acquisition will grant Sanofi access to Ayvakit/Ayvakyt (avapritinib), the only approved medicine for advanced and indolent forms of the rare immunologic disorder systemic mastocytosis (SM).
Approximately one in 10,000 people in the UK are thought to be affected by SM, with indolent forms accounting for the majority of cases.
SM is caused by the abnormal buildup of mast cells, a key part of the body’s immune system. Patients can experience symptoms such as skin lesions, diarrhoea, bone pain, fatigue and anaphylaxis, and the disease can lead to organ damage, anaemia and bone fractures.
Blueprint’s avapritinib works by targeting KIT D816V, the primary underlying cause of the disease.
Alongside the drug, the deal will give Sanofi access to an advanced and early-stage immunology pipeline. This includes elenestinib, an oral KIT D816V inhibitor for SM, and BLU-808, an oral wild-type KIT inhibitor that has the potential to treat a broad range of inflammatory diseases.
Under the terms of the agreement, which is expected to close in the third quarter of 2025, Sanofi will acquire Blueprint for $129 per share in cash, representing an equity value of approximately $9.1bn.
Blueprint shareholders also will be given one non-tradeable contingent value right (CVR) entitling them to two potential milestone payments of $2 and $4 per CVR tied to the achievement of future development and regulatory milestones for BLU-808, respectively.
Sanofi’s chief executive officer, Paul Hudson, said the proposed acquisition “represents a strategic step forward in [the company’s] rare and immunology portfolios”.
“This acquisition is fully aligned with our strategic intent to strengthen our existing therapeutic areas, to bring relevant and differentiated medicines to patients and to secure attractive returns to our shareholders,” Hudson said.
Kate Haviland, chief executive officer of Blueprint, added: “With this agreement, we begin our next chapter with Sanofi, whose… leadership in rare disease and immunology and proven ability to solve medical challenges at scale stand to accelerate our joint mission to bring life-changing medicines to many more patients around the world.”