Regeneron Pharmaceuticals and Sanofi are expanding their long-running alliance to develop and commercialize four next-generation immunology medicines invented by Regeneron. Sanofi will pay $1 billion upfront and up to $7 billion in development, regulatory and commercial milestones, while the companies will split development and commercialization costs and future profits equally. Their existing Dupixent profit-sharing agreement remains unchanged. One candidate is in early-stage testing for atopic dermatitis, or eczema, while the other three are expected to enter clinical trials in 2027. The deal settles prior collaboration-related litigation and gives Regeneron final authority over drug-development decisions, while Sanofi has the final say on commercial decisions. Jefferies raised its price target for Regeneron to $930, citing the expanded partnership and its four long-acting antibodies targeting inflammatory pathways.