Sanofi to acquire Blueprint Medicines, expanding portfolio in rare immunological disease and adding early-stage pipeline in immunology Adds fast-growing and only approved medicine for advanced and indolenT systemic mastocyTosis to the Sanofi portfolio Paris and Cambridge, MA. June 2, 2025 . Sanofi and Blueprint Medicines Corporation (Blueprint), a US-based, publicly traded biopharmaceutical company specializing in systemic mastocyTosis (SM), a rare immunological disease, and other KIT-driven diseases, have entered into an agreement under which Sanofi will acquire Blueprint. The acquisition includes a rare immunology disease medicine, Ayvakit/Ayvakyt (avapritinib), approved in the US and the EU, and a promising advanced and early-stage immunology pipeline. Furthermore, Blueprint's established presence among allergists, dermatologists, and immunologists is expected to enhance Sanofi's growing immunology pipeline. Ayvakit/Ayvakyt is the only approved medicine for advanced and indolenT systemic mastocyTosis (ASM & ISM), a rare immunology disease, which is characterized by the accumulation and activation of aberrant mast cells in bone marrow, skin, the gastrointestinal tract, and other organs. The acquisition will also bring elenestinib, a next-generation medicine for SM, as well as BLU-808, a highly selective and potent oral wild-type KIT inhibitor that has the potential to treat a broad range of diseases in immunology. Under the terms of 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.

Paul Hudson CEO, Sanofi "The proposed acquisition of Blueprint Medicines represents a strategic step forward in our rare and immunology portfolios. It enhances our pipeline and accelerates our transformation into the world's leading immunology company. 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. It complements recent acquisitions of early-stage medicines that remain our main field of interest. Sanofi still retains a sizeable capacity for further acquisitions. We are excited to welcome Blueprint's talented people and we look forward to chasing the miracles of science together. This makes sense for science, for both companies, for healthcare professionals, and – most of all – for patients."

Kate Haviland CEO, Blueprint Medicines "Since our founding, Blueprint Medicines has worked at the intersection of scientific innovation and operational excellence. I'm incredibly proud of the medical innovations our people have created and delivered to patients. We have translated our unique scientific understanding of mast cell biology into a portfolio of important therapies including Ayvakit – the first and only medicine approved to treat the root cause of systemic mastocyTosis – and worked collaboratively with communities to improve standards of care and patient outcomes. With this agreement, we begin our next chapter with Sanofi, whose exceptional 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."

Additional information for US shareholders and where to find it The tender offer for the outstanding shares of Blueprint Medicines Corporation common stock ("Blueprint") referenced in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicitation of an offer to sell shares of Blueprint, nor is it a substitute for the tender offer materials that Sanofi and its acquisition subsidiary will file with the U.S. Securities and Exchange Commission (the "SEC") upon commencement of the tender offer. At the time the tender offer is commenced, Sanofi and its acquisition subsidiary will file tender offer materials on Schedule TO, and Blueprint will file a Solicitation/Recommendation Statement on Schedule 14D-9 with the SEC with respect to the tender offer. The tender offer materials (including an Offer to Purchase, a related Letter of Transmittal and certain other tender offer documents), as well as the Solicitation/Recommendation Statement, will contain important information. HOLDERS OF SHARES OF BLUEPPRINT ARE URGED TO READ THESE DOCUMENTS WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION THAT BLUEPPRINT STOCKHOLDERs SHOULD CONSIDER BEFORE MAKING ANY DECISION REGARDING TENDERING THEIR SHAREs. The Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, will be made available to all holders of shares of Blueprint at no expense to them. The tender offer materials and the Solicitation/Recommendation Statement will be made available for free at the SEC's web site at www.sec.gov . Additional copies may be obtained for free by contacting Sanofi’s Investor Relations Team at [email protected] or on Sanofi’s website at https://www.sanofi.com/en/investors . In addition to the Offer to Purchase, the related Letter of Transmittal and certain other tender offer documents, as well as the Solicitation/Recommendation Statement, Sanofi files annual and special reports and other information with the SEC and Blueprint files annual, quarterly and special reports and other information with the SEC. You may read and copy any reports or other information filed by Sanofi and Blueprint at the SEC public reference room at 100 F. Street, N.E., Washington D.C. 20549. Please call the Commission at 1-800-SEC-0330 for further information on the public reference room. Sanofi’s and Blueprint’s filings with the SEC are also available to the public from commercial document-retrieval services and at the website maintained by the SEC at www.sec.gov . Trademarks Blueprint Medicines, AYVAKIT, AYVAKYT and associated logos are trademarks of Blueprint Medicines Corporation. Attachment Press_Release © 2025 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.