French drugmaker Sanofi said Thursday it will acquire Vigil Neuroscience, a U.S.-based biotech company focused on neurodegenerative diseases, for up to $600 million, in a move to bolster its neurology pipeline with a potential Alzheimer’s treatment.

The transaction, advised by Goodwin Procter LLP, will give Sanofi full control of VG-3927, an experimental small-molecule drug that aims to prevent neural degeneration. The deal follows Sanofi’s earlier $40 million investment in June 2024, which gave it exclusive development and commercialization rights to the drug.

Under the terms of the acquisition, Sanofi will pay $8 per share upfront for all outstanding Vigil stock it doesn’t already own. An additional $2 per share will be paid upon the first commercial sale of VG-3927, bringing the total deal value to approximately $600 million.

“This acquisition aligns perfectly with our strategic focus on neurology,” said Houman Ashrafian, Sanofi’s head of research and development. “Vigil’s expertise enhances our capabilities and underscores our commitment to advancing innovative medicines.”

Sanofi, Europe’s largest pharmaceutical company, is listed on both the Euronext Paris and Nasdaq stock exchanges. Vigil, also listed on Nasdaq, is being advised financially by Centerview Partners LLC.

The acquisition is expected to close by September, subject to shareholder approval and customary closing conditions. Vigil CEO Ivana Magovčević-Liebisch, board chair Bruce Booth, and Atlas Ventures, who collectively hold 16% of Vigil’s shares, have agreed to support the deal.

VG-3927, still in the development stage, is designed to activate a protective brain response and has shown promise in slowing neurodegeneration—making it a potentially significant entry into the competitive Alzheimer’s market.

Sanofi’s major shareholders include L'Oréal SA and BlackRock Inc., the latter holding a 6.85% stake. Earlier this year, L’Oréal announced it would sell a €3 billion stake in Sanofi back to the company, retaining a 7.2% holding after Sanofi’s stock outperformed broader markets.