Sanofi, Regeneron Expand Immunology Partnership in $1 Billion Deal

03:53 AM EDT, 10/01/2026 (MT Newswires) -- Sanofi (SNY) and Regeneron Pharmaceuticals (REGN) said Thursday that they have expanded their global immunology collaboration to develop four long-acting antibody treatments for conditions with type 2 inflammation. Under the expanded agreement, Sanofi will pay $1 billion upfront and up to $7 billion in milestone payments to Regeneron, while both companies split development costs and future profits equally, the companies said. Regeneron will oversee research and development activities, while Sanofi handles global commercialization of REGN20423 for atopic dermatitis, alongside three preclinical antibodies that will go into clinical trials in 2027. The companies also said that they have settled prior legal disputes between them related to their previous partnership.