Sanofi, Regeneron to Expand Alliance in Up to $8 Billion Deal — Update

By Adria Calatayud

France's Sanofi and Regeneron Pharmaceuticals said they would expand their longstanding alliance to jointly develop and market new immunology medicines, in a deal that could net the U.S. drugmaker up to $8 billion.

The two companies have collaborated for more than two decades in a partnership that spawned one of the top-selling medicines worldwide, Dupixent, approved for a range of conditions that include asthma and eczema.

With Dupixent due to begin losing patent protection in the early 2030s, both sides had signaled they were discussing an updated framework for their relationship. Regeneron sued Sanofi in 2024, but the companies said they settled prior litigation related to the collaboration as part of the deal.

Under the new agreement, Tarrytown, N.Y.-based Regeneron will receive $1 billion upfront from Sanofi and be eligible for additional payments of up to $7 billion subject to development, regulatory and commercial targets, the companies said.

Shares in Sanofi climbed as much as 3.7% Thursday before paring back their gains, while those in Regeneron opened 1.1% higher and slid later.

The expanded collaboration will see four next-generation immunology drug candidates invented by Regeneron added to the alliance, the companies said. One of them is currently being evaluated in early-stage studies for atopic dermatitis, also known as eczema, and the other three are expected to enter clinical trials next year.

Regeneron will also have the option to include Sanofi's lunsekimig, which is being tested for chronic obstructive pulmonary disease, the companies added.

The companies will equally share development and commercialization costs as well as potential future profits from the new drugs, they said. Their existing profit-sharing agreement for Dupixent won't be affected.

Sanofi has been under pressure from investors after some of its experimental drugs disappointed in clinical trials, and earlier this year appointed Belen Garijo as chief executive to lead a turnaround. The expanded relationship with Regeneron marks one of her first moves to fill the company's pipeline.

"This is a deliberate first step in the transformation of Sanofi," Garijo said on a call with analysts.

Regeneron will have final decision-making authority on drug-development matters, while Sanofi will have the right to make the final call on commercial decisions, Garijo said.

In July, Garijo said she had sought to rebuild trust with Regeneron to find a path forward for the alliance.

Regeneron CEO Leonard Schleifer said the renewed alliance would pair next-generation assets with proven development and commercial platforms to expand the kind of work that their collaboration on Dupixent has achieved.

Write to Adria Calatayud at adria.calatayud@wsj.com

(END) Dow Jones Newswires

October 01, 2026 10:55 ET (14:55 GMT)