Sanofi Expands Regeneron Partnership with Four New Antibodies for Up to $8 Billion

05:51 AM EDT, 10/01/2026 (MT Newswires) -- Sanofi (SAN.PA) is expanding its over 20-year partnership with Regeneron Pharmaceuticals (RGO.F) by adding four new antibodies in a deal worth up to $8 billion. The drugmakers will jointly develop and commercialize Regeneron-invented antibodies targeting interleukin-13, IL-4xIL-13 bispecific, interleukin-4 and interleukin-4 receptor alpha, according to a Thursday release. Of the four therapies, the IL-13 antibody REGN20423 is in a phase 1 study for atopic dermatitis, while the other three are expected to enter clinical studies in 2027. Meanwhile, the expanded license and collaboration deal gives Regeneron an option to include Sanofi's lunsekimig upon completion of late-stage studies evaluating the bispecific Nanobody VHH as a potential treatment for chronic obstructive pulmonary disease. The Paris-listed pharmaceutical giant will pay $1 billion upfront, with Regeneron also eligible for up to an additional $7 billion in development, regulatory and commercial milestone payments. Development and commercialization expenses will be shared by both companies, while future profits from potential products will be split equally on a global basis. The companies added that they have settled their prior collaboration-related litigation. "Today's agreement extends a productive (but at some points contentious) partnership, positioning both companies for continued leadership in the development of the next generation of therapeutics for type 2 inflammation-driven disease, in our view," analysts at BMO Capital Markets said. "Most interesting to us is the announced settlement regarding prior collaboration-related litigation. We believe today's deal marks an important step in repairing their relationship and removes a key overhang for both stories." Regeneron's shares were up almost 2% in Frankfurt, while Sanofi's Paris stock was nearly 1% in the green during morning trading.