Sanofi SNY and Regeneron Pharmaceuticals REGN announced that they have expanded their existing longstanding antibody collaboration to include four next-generation, long-acting antibodies targeting type II inflammation.
More on the Latest SNY/REGN Agreement
Per the expanded agreement, the companies will co-develop and co-commercialize four Regeneron-invented antibodies targeting interleukin-13 (IL-13), IL-4xIL-13 bispecific, interleukin-4 (IL-4) and interleukin-4 receptor alpha (IL-4Rα).
One of the programs, REGN20423, is a long-acting IL-13 monoclonal antibody currently being evaluated in a phase I study for atopic dermatitis. The other three antibodies are expected to enter clinical studies in 2027.
Regeneron will also have an option to include Sanofi's investigational candidate, lunsekimig, a bispecific nanobody therapy targeting TSLP and IL-13, in the latest collaboration after completion of its phase III studies in chronic obstructive pulmonary disease.
REGN is entitled to receive an upfront payment of $1 billion from SNY. It is also eligible to receive up to $7 billion in additional development, regulatory and commercial milestone payments.
Both companies will equally share development and commercialization costs and future profits from the potential products globally. Regeneron will lead research and development activities, while Sanofi will oversee global commercial efforts.
Sanofi and Regeneron also agreed to settle their prior collaboration-related litigation.
The expanded collaboration builds on the companies' more than 20-year alliance, which has established Dupixent as a widely used treatment for diseases driven by type II inflammation. Per the press release, more than 1.5 million people are currently receiving Dupixent across nine indications.
The existing profit-sharing agreement for Dupixent will remain unchanged.
Dupixent Demand Drives SNY’s Top-Line Growth
Dupixent currently holds the number one new-to-brand prescription market share across all its approved indications in the United States. It is approved in several countries in one or more indications, covering nine distinct diseases, driven partly by type II inflammation.
The drug is presently approved for severe chronic rhinosinusitis with nasal polyposis, severe asthma, moderate-to-severe atopic dermatitis, eosinophilic esophagitis, prurigo nodularis, chronic obstructive pulmonary disease, chronic spontaneous urticaria, bullous pemphigoid and allergic fungal rhinosinusitis.
Dupixent generated sales of €9.3 billion in the first half of 2026, up 28.6% year over year. Second-quarter sales jumped 37.6% to €5.2 billion, crossing the €5 billion quarterly threshold for the first time. Dupixent’s strong sales growth is being driven by demand across all geographies, newly approved indications and demographics. Sanofi expects Dupixent to achieve around €25 billion in sales in 2030.
While SNY records Dupixent sales, Regeneron registers its share of profits/losses in connection with the global sales of the drug.
New Medicines Strengthen Sanofi’s Portfolio
Besides Dupixent, Sanofi is also seeing a good uptake of its new medicines like novel recombinant factor VIII therapy, Altuviiio and cancer drugs, Ayvakit and Sarclisa. These drugs remain important for broadening the company’s growth base.
Sales of its new and acquired drugs rose 48.3% to €1.3 billion during the second quarter of 2026, led by Altuviiio, Ayvakit and Sarclisa. Beyfortus (in partnership with AstraZeneca [ AZN]) achieved blockbuster sales in its first full year of sales in 2024 and continues its expansion into new geographies. Altuviiio achieved blockbuster sales in 2025, and Ayvakit, added from the Blueprint Medicines acquisition, is expected to become the next blockbuster drug in 2026.
Sanofi expects its new and acquired products to generate approximately €10 billion in sales by 2030.
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