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Press Release sanofi Sanofi and Regeneron expand global Alliance with multiple next - generation , long - acting long - acting immunology antibodies • • REGN20423 , a clinical - stage long - acting IL - 13 monoclonal antibody invented and developed by Regeneron , is added to the Alliance , along with a long - acting IL - 4XIL- 13 bispecific and two other long - acting pre - clinical antibodies from Regeneron Regeneron to receive $ 1 billion upfront , with potential for up to an additional $ 7 billion in future milestone payments ; companies to equally share development and commercialization costs , as well as any future profits Sanofi and Regeneron to host a conference call for investors and analysts today at 14:00 CET / 8 : 00am ET Paris and Tarrytown , NY , October 1 , 2026. Sanofi and Regeneron Pharmaceuticals , Inc. today announce an expansion of their longstanding antibody collaboration , adding multiple next - generation , long - acting antibodies to the Alliance that has jointly established DupixentⓇ ( dupilumab ) as the world - leading treatment for diseases driven by type 2 inflammation . The agreement builds on the companies ' more than 20 - year collaboration , through which more than 1.5 million people are currently receiving Dupixent across nine indications , making it one of the most widely used antibody medicines in the world . " This is a deliberate first step in igniting Sanofi's innovation engine . Our longstanding Alliance with Regeneron has transformed the treatment landscape for millions of patients living with diseases driven by type 2 inflammation and created one of the world's leading immunology businesses , " said Belén Garijo , Chief Executive Officer of Sanofi . " By deepening our collaboration , we will make rapid progress in creating the next generation of meaningful therapies for patients with immune - mediated diseases , while contributing to Sanofi's long - term future . ” Under the expanded license and collaboration agreement , the companies will co - develop and co - commercialize four new long - acting , Regeneron - invented antibodies targeting interleukin- 13 ( IL - 13 ) , IL - 4xIL - 13 bispecific , interleukin - 4 ( IL - 4 ) and interleukin - 4 receptor alpha ( IL- 4Ra ) . IL - 13 antibody REGN20423 is currently in a phase 1 clinical study for atopic dermatitis , and the other three antibodies are expected to enter clinical studies in 2027. Regeneron will also have the option to include in the collaboration Sanofi's lunsekimig , an investigational bispecific NanobodyⓇ VHH therapy targeting TSLP and IL - 13 , exercisable upon completion of its phase 3 studies for chronic obstructive pulmonary disease . " The Regeneron - Sanofi Alliance has been one of the most productive in biopharma history . This agreement builds on that foundation to bring the next generation of immunology medicines to patients even faster , " said Leonard S. Schleifer , MD , PhD , Board co - Chair , President and Chief Executive Officer of Regeneron . " By expanding our Alliance , we are positioning promising new long - acting antibodies for the kind of rapid , global impact that our shared work on Dupixent has already achieved . "