Sanofi, Regeneron Expand Drug Partnership in $8 Billion Deal

Sanofi SA is expanding its long-running partnership with Regeneron Pharmaceuticals in a deal potentially worth $8 billion, strengthening the French drugmaker’s pipeline of treatments for inflammatory diseases beyond blockbuster therapy Dupixent.

Under the agreement announced Thursday, Sanofi will pay Regeneron $1 billion upfront, with as much as $7 billion in additional payments tied to development, regulatory and commercial milestones.

The companies will jointly develop and commercialize four long-acting, antibody-based medicines targeting immune-related inflammatory conditions. Development and sales expenses will be shared, while profits will be divided equally worldwide.

Regeneron will take the lead on developing the four experimental medicines, while Sanofi will oversee their global commercialization.

The most advanced candidate, REGN20423, has already entered an early-stage clinical trial for atopic dermatitis, a common chronic inflammatory skin disease. The remaining three medicines are expected to enter human clinical trials in 2027, although two are still in early development.

The expanded Sanofi-Regeneron partnership also gives Regeneron an option to include Sanofi’s experimental drug lunsekimig after the treatment completes late-stage testing for chronic obstructive pulmonary disease, or COPD. Lunsekimig is being evaluated as another potential addition to Sanofi’s growing immunology portfolio.

Separately, Sanofi and Regeneron said they have resolved a previous legal dispute related to their partnership. The companies did not disclose details of the settlement.

Their existing agreement covering Dupixent will remain unchanged. Developed jointly by Sanofi and Regeneron, Dupixent has become a major treatment for several inflammatory diseases and a key source of revenue for Sanofi.

The latest agreement gives Sanofi access to four additional potential inflammatory disease treatments as it seeks to diversify its drug pipeline. For Regeneron, the arrangement preserves a major role in developing the medicines while providing access to Sanofi’s global commercial infrastructure if the candidates successfully reach the market.