Sanofi is paying Regeneron $1 billion upfront to collaborate on four early-stage immunology programs, teeing the longstanding partners up to try to replicate Dupixent’s success.
Dupixent, an antibody that targets IL-4 and IL-13, generated 5.2 billion euros ($5.9 billion) for Sanofi in the second quarter and is the cornerstone of the French pharma's business. With the U.S. patent on the compound expiring in 2031—and Sanofi’s efforts to develop new growth drivers stuttering—the Paris-based drugmaker has looked for next-generation assets under new CEO Belén Garijo, M.D., Ph.D.
The search led Sanofi back to Regeneron’s door. Sanofi is paying the blockbuster upfront fee and pledging up to $7 billion in milestones to split the costs and profits for four assets in development at Regeneron. In a statement, Garijo called the deal “a deliberate first step in igniting Sanofi’s innovation engine.”
REGN20423, a long-acting IL-13 monoclonal antibody, is the most advanced of the four assets covered by the deal. Regeneron began a first-in-human trial in May to test the drug candidate in healthy volunteers and eczema patients.
The three preclinical assets target IL-4 and IL-4 receptor alpha, including an IL-4xIL-13 bispecific. Regeneron aims to start clinical trials of the drug candidates next year. The U.S. biopharma has an option to add lunsekimig, a Sanofi asset targeting TSLP and IL-13, to the collaboration after seeing phase 3 data in chronic obstructive pulmonary disease.
Regeneron will lead R&D for its four assets and Sanofi will lead global commercialization. The agreement marks a new phase in an alliance that has been hugely successful but, in recent years, somewhat fraught. Regeneron sued Sanofi in 2024, alleging its partner violated the terms of the Dupixent collaboration by refusing to share certain commercialization details.
Sanofi and Regeneron revealed in July that they were in talks about a new partnership. On an earnings call at the time, Garijo said her main objective for the Regeneron relationship was “to rebuild trust.” The efforts have led to the deal and the settlement of the litigation.
The Sanofi deal coincided with Regeneron updates at the European Association for the Study of Diabetes (EASD) conference. Adding Regeneron’s trevogrumab to semaglutide preserved over 70% of muscle mass loss compared to Novo’s GLP-1 drug at Week 52 of a clinical trial, Reuters reported.
Regeneron’s muscle data are part of an attempt to position trevogrumab in a congested market. At an EASD event hosted by Regeneron, presenters “argued that waist-to-height ratio may be more informative than BMI and emphasized the importance of adiposity, body composition and the quality of weight loss rather than weight reduction alone,” BMO Capital Markets analysts said in a note to investors.