Sanofi expands Regeneron alliance in deal worth up to $8B

Sanofi announced on October 1, 2026, an expansion of its long-term alliance with Regeneron Pharmaceuticals to develop and commercialize next-generation, long-acting immunology antibodies. Under the agreement, Sanofi will pay Regeneron $1 billion upfront, with potential development, regulatory and commercial milestone payments of up to an additional $7 billion.

The expanded collaboration adds four Regeneron-invented antibodies targeting interleukin-13 (IL-13), IL-4xIL-13 bispecific, interleukin-4 (IL-4) and interleukin-4 receptor alpha (IL-4Rα). IL-13 antibody REGN20423 is in a phase 1 clinical study for atopic dermatitis, while the other three candidates are scheduled to enter clinical trials in 2027. Regeneron also receives an option to join Sanofi's lunsekimig program following completion of its phase 3 studies for chronic obstructive pulmonary disease.

The companies will share development and commercialization costs equally and split any future profits 50:50 globally. Regeneron will lead research and development, while Sanofi leads commercialization. The existing profit-sharing terms for Dupixent remain unchanged, and the companies confirmed they have settled prior litigation linked to their collaboration.