French drugmaker adds Ayvakit and next-gen immunology pipeline in strategic move to dominate rare disease space
Sanofi has agreed to acquire US-based Blueprint Medicines for up to US$9.5bn, marking one of the largest European pharmaceutical deals of the year and a significant expansion of its rare disease and immunology portfolio.
Under the terms of the agreement, Sanofi will pay US$129 per share in cash—valuing Blueprint at approximately US$9.1bn upfront—with the potential for an additional US$400m in milestone payments tied to regulatory progress on BLU-808, a next-generation oral KIT inhibitor. The deal, which represents a 34% premium over Blueprint’s 30-day average, is expected to close in the third quarter of 2025 pending shareholder and regulatory approvals.
Blueprint specialises in treatments for systemic mastocytosis (SM), a rare immunological disease driven by abnormal mast cell proliferation. Its flagship drug, Ayvakit (avapritinib), is the only approved therapy for both advanced and indolent forms of SM in the US and EU. The product generated US$479m in 2024 revenue and posted more than US$150m in Q1 2025 alone—up over 60% year-on-year. Analysts at JP Morgan forecast it could reach US$2bn in annual sales by 2030.
Beyond Ayvakit, the deal gives Sanofi access to two promising candidates: elenestinib, a KIT D816V inhibitor currently in Phase 2/3 trials, and BLU-808, a selective, oral wild-type KIT inhibitor with potential applications across a broader range of inflammatory diseases.
Sanofi CEO Paul Hudson described the acquisition as “a strategic step forward in our rare and immunology portfolios,” adding that it enhances Sanofi’s pipeline and accelerates its ambition to become a global immunology leader. The company said the deal complements its recent acquisitions of early-stage assets—including Vigil Neuroscience (US$470m) and Inhibrx (US$2.2bn)—and stressed that it retains capacity for further deals. Sanofi also reiterated its plan to invest at least US$20bn in the US by 2030 to expand manufacturing and R&D.
The deal comes at a pivotal time for Sanofi. While its blockbuster eczema drug Dupixent continues to perform strongly, recent late-stage failures—including a COPD therapy developed with Regeneron and an E. coli vaccine—have raised pressure on its pipeline. The addition of Ayvakit and Blueprint’s early-stage programs could help bolster revenue from 2026 onwards.
