Regeneron and Sanofi expand their antibody alliance with four long-acting immunology programs targeting IL-13, IL-4, IL-4xIL-13 and IL-4Rα.
Written By: Umesh Hanumante, PharmD
Reviewed By: Pharmacally Editorial Team
Regeneron and Sanofi have expanded their more than 20-year antibody collaboration to add four next-generation, long-acting immunology antibodies targeting the IL-13, IL-4/IL-13, IL-4 and IL-4 receptor alpha (IL-4Rα) pathways. The agreement brings clinical-stage REGN20423, a long-acting IL-13 monoclonal antibody, into the alliance alongside three preclinical programs, with the companies sharing global development and commercialization. Regeneron and Sanofi Expand Glo…
Four Long-Acting Antibodies Added to Alliance
Under the expanded agreement, Regeneron will lead research and development, while Sanofi will lead global commercial activities. The companies will share development and commercialization costs and split potential future profits equally worldwide.
REGN20423 is already being evaluated in a Phase 1 trial in atopic dermatitis. The other three antibodies are expected to enter clinical studies in 2027. The programs include antibodies directed against IL-13, IL-4xIL-13, IL-4 and IL-4Rα, extending the collaboration across several central pathways involved in type 2 inflammation. Regeneron and Sanofi Expand Glo…
The agreement also gives Regeneron and Sanofi an option to include lunsekimig, Sanofi’s investigational bispecific Nanobody targeting thymic stromal lymphopoietin (TSLP) and IL-13. The option can be exercised after completion of Phase 3 trials in chronic obstructive pulmonary disease (COPD). Regeneron and Sanofi Expand Glo…
Building on the Dupixent Platform
The expanded alliance builds on the companies’ development of Dupixent (dupilumab), which blocks signaling through the IL-4 and IL-13 pathways. The companies report that more than 1.5 million people currently receive Dupixent across nine indications worldwide. The antibody has regulatory approvals in more than 60 countries for several type 2 inflammatory and allergic diseases, including atopic dermatitis, asthma, chronic rhinosinusitis with nasal polyps, eosinophilic esophagitis and COPD. Regeneron and Sanofi Expand Glo… Regeneron and Sanofi Expand Glo…
The new programs move beyond the established IL-4/IL-13 blockade represented by dupilumab by pursuing long-acting antibodies against individual cytokine pathways and a bispecific approach. However, the clinical value of these newer approaches will depend on forthcoming human efficacy, safety and dosing data.
$1 Billion Upfront Payment
Sanofi will pay Regeneron $1 billion upfront, with up to an additional $7 billion available in development, regulatory and commercial milestone payments. The companies will share development and commercialization costs and divide potential future profits 50:50 globally. The existing profit-sharing arrangement for Dupixent remains unchanged. Regeneron and Sanofi Expand Glo…
The companies also confirmed that they have settled their previous collaboration-related litigation. Regeneron and Sanofi Expand Glo…
Clinical Development Begins with REGN20423
REGN20423 represents the most advanced of the four newly added Regeneron antibodies, with Phase 1 clinical development underway in atopic dermatitis. The remaining three programs are expected to move into clinical testing in 2027. At this stage, the source provides no clinical efficacy or safety results for REGN20423, so the therapeutic potential of the new long-acting antibodies remains to be established in clinical studies. Regeneron and Sanofi Expand Glo…
The expansion gives the partners a broader immunology pipeline while preserving the commercial and development structure that supported Dupixent. The next major milestones will be initiation of clinical studies for the three preclinical antibodies in 2027, together with further clinical development of REGN20423 and potential progression of lunsekimig following its Phase 3 COPD program.
Reference
Regeneron and Sanofi Expand Global Alliance with Multiple Next-Generation, Long-Acting Immunology Antibodies, Regeneron, 01 October 2026
About the Writer
Umesh Hanumante (M.Pharm) (LinkedIn) is a pharmacy professional and healthcare writer with a background in Regulatory Affairs, pharmaceutical innovation, and clinical research. He has around two years of industry experience as an Executive PMT at Troikaa Pharmaceuticals Ltd and qualified GPAT 2024. His areas of interest include regulatory compliance, dossier preparation, clinical trials, emerging therapies, and advancements in the global pharmaceutical and healthcare sector.