Regeneron Pharmaceuticals, Inc.

What does Regeneron own?
Regeneron owns and markets its internally developed medicines: Eylea and Eylea HD, Libtayo, Praluent, Kevzara, Arcalyst, Evkeeza, Veopoz, Inmazeb, and Lynozyfic, and shares Dupixent economics with Sanofi. It also owns the VelocImmune antibody platform and the Regeneron Genetics Center.

Is Regeneron publicly traded?
Yes. Regeneron Pharmaceuticals trades on Nasdaq under the ticker REGN and is a member of the S&P 500 index.

Who founded Regeneron?
Leonard Schleifer, a neurologist, founded the company in 1988. George Yancopoulos joined in 1989 and built its research organization. Both men still lead the company as CEO and President/Chief Scientific Officer respectively.

Does Sanofi own part of Regeneron?
No. Sanofi is a collaboration partner, not an owner. Sanofi books global Dupixent and Kevzara sales and shares profits with Regeneron under contract. Sanofi previously held a Regeneron equity stake but sold it in 2020.

Where is Regeneron headquartered?
Regeneron is headquartered in Tarrytown, New York, on the Hudson River north of New York City. Its main manufacturing campuses are in Rensselaer, New York, and Limerick, Ireland.

What is Regeneron's biggest product?
Dupixent is the largest by global sales at $17.8 billion in 2025, though Sanofi records those sales and shares the profit. The largest product Regeneron books directly is the Eylea retinal franchise at $7.9 billion in 2025 global sales.

Leonard Schleifer, a neurologist at Cornell University Medical College, founded Regeneron in 1988 in Tarrytown, New York, with backing that included an early investment from Amgen. George Yancopoulos, a molecular immunologist, joined in 1989 and became the company's scientific leader. The company's original focus was neurotrophic factors for degenerative diseases such as ALS, an effort that failed in the clinic in the 1990s and nearly ended the company.

The turning point came with a technology pivot. Regeneron developed the Trap platform for building fusion proteins, which produced its first approved drug, Arcalyst, in 2008, and then Eylea, approved in 2011 for wet age-related macular degeneration. In parallel, the VelocImmune mouse platform began generating fully human antibodies at industrial speed.

Eylea became the company's commercial foundation and its first blockbuster, while a collaboration with Sanofi produced Dupixent (approved 2017), Libtayo (2018), Praluent, and Kevzara. Dupixent grew into one of the best-selling drugs in the world, with 2025 global sales of $17.8 billion recorded by Sanofi.

In 2020, Regeneron used its antibody platform to develop the COVID-19 antibody cocktail REGEN-COV and gained FDA emergency authorization. In 2023, the FDA approved Eylea HD, an 8 mg formulation designed to extend dosing intervals and defend the retinal franchise against competition from Roche's Vabysmo and emerging biosimilars.

Regeneron and Sanofi restructured their antibody collaboration in 2022, with Regeneron taking back Libtayo's worldwide rights while Sanofi books global Dupixent sales and shares profits with Regeneron. In 2025 and 2026, the company's newer pipeline advanced: Lynozyfic (linvoseltamab) for multiple myeloma received approvals in Europe, and its obesity and genetic-disease programs moved into late-stage trials.

Regeneron publishes annual responsibility reporting covering environmental targets for its manufacturing campuses, clinical trial ethics, and patient access programs including its Regeneron Patient Assistance Foundation. The company is not a Certified B Corporation.

Its most recognized social program is the Regeneron Science Talent Search, the longstanding U.S. high school research competition it has sponsored since 2017, and its STEM education investments. Sustainability disclosures are largely self-reported rather than third-party certified.

Kickback settlement (2024): In 2024, Regeneron agreed to pay approximately $34 million to resolve U.S. Department of Justice allegations that it used a third-party foundation to channel copay assistance for Eylea in violation of the False Claims Act, without admitting wrongdoing.

Patent disputes: Regeneron has been involved in long-running patent litigation defending Eylea against biosimilar challengers, including a settlement framework that permits U.S. aflibercept biosimilar entry beginning in the late 2020s.