Sanofi, an R&D-driven, AI-powered biopharmaceutical company, has announced the successful completion of 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 acquisition brings Sanofi a commercialised treatment, a promising pipeline, and deep scientific expertise in SM and related diseases. It also enhances Sanofi’s footprint across allergy, dermatology, and immunology specialities, bolstering its expanding immunology pipeline.

As part of the acquisition, Sanofi adds Ayvakit/Ayvakyt (avapritinib)—the only approved treatment for both advanced and indolent systemic mastocytosis in the US and EU—to its portfolio. This rare disease is characterised by the overaccumulation and activation of mast cells across the body, including bone marrow, skin, and the gastrointestinal tract.

In addition, Sanofi gains elenestinib, a next-generation investigational therapy targeting KIT D816V mutations, now in Phase 2/3 clinical trials (HARBOR study, NCT04910685), as well as BLU-808, an oral wild-type KIT inhibitor in development for inflammatory diseases linked to mast cell activation.

The tender offer for Blueprint’s outstanding shares expired on 17 July 2025. With all conditions met, Sanofi has now completed a merger under Delaware law, making Blueprint a wholly owned subsidiary. Remaining Blueprint shares have been converted into the right to receive $129.00 per share in cash, plus up to $6.00 per share in milestone-based contingent payments.

This acquisition was financed through a mix of existing cash reserves and commercial paper issuances. It is not expected to significantly affect Sanofi’s 2025 financial guidance and is projected to be immediately accretive to gross margin, and earnings-per-share (EPS) accretive after 2026.

As of 18 July 2025, Blueprint common stock will no longer be traded on the NASDAQ Global Select Market.

Ayvakit is approved in 16 countries for one or more indications, including China (marketed by CStone Pharmaceuticals). In the US, it holds FDA approval for use in advanced and indolent systemic mastocytosis, as well as unresectable or metastatic GIST with PDGFRA exon 18 mutations. In the EU, it is approved as Ayvakyt for similar indications, including use after prior systemic therapies.

This acquisition further cements Sanofi’s commitment to patient-centric innovation in rare diseases, immunology, and targeted therapies.