Regeneron Pharmaceuticals, Inc.
Leadership History
3 leaders · Full leadership timeline
Leonard S. Schleifer is the CEO of Regeneron, in the role since 1988.
| Name | Role | From | To | Years in role |
|---|---|---|---|---|
| George D. Yancopoulos, M.D., Ph.D. | Co-Founder, Board co-Chair, President and Chief Scientific Officer | 1989 | Present | 37 |
| Leonard S. Schleifer, M.D., Ph.D. | Founder, Board co-Chair, President and CEO | 1988 | Present | 38 |
| Christopher Fenimore | Executive Vice President, Finance and Chief Financial Officer | — | Present | — |
Regeneron is a Tarrytown, New York biotech that discovers, develops and manufactures its own biologic medicines. Its best-known products are EYLEA and EYLEA HD for retinal disease, Dupixent (with Sanofi) for eczema, asthma, COPD and other Type 2 inflammatory conditions, and Libtayo for cancer. Co-founders Leonard Schleifer (CEO) and George Yancopoulos (Chief Scientific Officer) still lead the company, which had about 15,400 employees at the end of 2025. Regeneron was founded in 1988 in New York City by Dr. Leonard Schleifer and Dr. George Yancopoulos, establishing its primary laboratories in Tarrytown, New York, and pioneering the proprietary VelociSuite genetics platform to build one of the world’s most scientifically productive biopharmaceutical giants.
Regeneron makes money three ways. First, it records U.S. net product sales of its own medicines, mainly EYLEA HD and EYLEA for retinal disease, Libtayo in oncology, and smaller rare-disease products. Second, it earns collaboration revenue from Sanofi on Dupixent and Kevzara: Sanofi books global sales and the two companies share profits. Third, it shares ex-U.S. EYLEA profits with Bayer, which sells the drug outside the United States. The discovery engine behind all of this is VelociSuite, including VelocImmune mice that produce fully human antibodies.
Co-Founder, Board co-Chair, President and Chief Scientific Officer
1989 – Present
37 years (current)
Built VelociSuite and led discovery of EYLEA and Dupixent.
Runs Regeneron Research and the scientific portfolio.
Founder, Board co-Chair, President and CEO
1988 – Present
38 years (current)
Has led Regeneron since 1988, from platform research to a company with $14.34 billion in FY2025 revenue.
Executive Vice President, Finance and Chief Financial Officer
Oversees finance and capital allocation, including share repurchases and the dividend.
Regeneron's biggest challenges are EYLEA biosimilar and branded competition, product concentration, payer pricing pressure, high R&D spend, clinical trial risk, and the difficulty of turning newer modalities into approved medicines.
Schleifer, an M.D./Ph.D. neurologist from the University of Virginia who taught at Cornell, founded Regeneron in 1988 and has been CEO for 38 years. He is also President and Board co-Chair.
Dr. George D. Yancopoulos joined Regeneron in 1989 as founding Chief Scientific Officer, later becoming President and Board Co-Chair. An elected member of the National Academy of Sciences and one of the most cited scientists in history, Yancopoulos is the principal inventor of the VelociSuite technologies and all of Regeneron's FDA-approved drugs.
Schleifer and Yancopoulos have run Regeneron together since 1989, an unusually long founder partnership at a large public biotech.
P. Roy Vagelos, former Chairman and CEO of Merck, served as Regeneron's board chairman for many years and was an important adviser to Schleifer and Yancopoulos.
In the 1990s, Regeneron suffered high-profile clinical trial failures for its early neurotrophic factors (BDNF, CNTF) in ALS and obesity. Rather than giving up, Schleifer and Yancopoulos pivoted the company to invent the VelociSuite genetic technologies and target vascular biology and immunology, leading to the breakthrough creation of EYLEA and Dupixent.
Both founders have received business and scientific recognition; Yancopoulos is a member of the National Academy of Sciences.
Regeneron's culture is guided by its motto 'Doing Well by Doing Good', prioritizing uncompromised scientific truth, fearless biological experimentation, teamwork, and a profound commitment to saving human lives.
Growing Dupixent and EYLEA HD, winning approval for pipeline assets such as cemdisiran, and advancing bispecific antibodies, obesity programs and genetic medicines.
Dr. Leonard S. Schleifer, M.D., Ph.D., is the Founder, President, and Chief Executive Officer of Regeneron, having led the company continuously since founding it in 1988.
Dr. Schleifer earned his M.D. and Ph.D. in pharmacology from the University of Virginia and worked as an assistant professor of neurology and practicing clinician at Cornell University Medical College / New York Hospital before launching Regeneron.
Dr. George D. Yancopoulos, M.D., Ph.D., is the Co-Founder, Board Co-Chair, President, and Chief Scientific Officer of Regeneron; joining in 1989, he is inducted into the National Academy of Sciences and is one of the most cited research scientists in biomedical history.
Schleifer and Yancopoulos operate in an iconic 35+ year partnership: Schleifer focuses on corporate strategy, commercialization, finance, and government relations, while Yancopoulos directs research, preclinical biology, and clinical trial strategy.
Regeneron became the title sponsor of the prestigious Regeneron Science Talent Search (formerly Westinghouse/Intel) and the International Science and Engineering Fair (ISEF), committing over $100 million to inspire the next generation of American scientists.
Schleifer, Yancopoulos, and long-standing scientific board members (including Nobel laureates like Dr. Michael Brown and Dr. Joseph Goldstein) maintain significant voting control, insulating Regeneron from short-term Wall Street activist pressures.
Regeneron is headquartered in Tarrytown, New York, operating a world-class 150-acre corporate science and technology campus in Westchester County.
Regeneron’s culture is defined by "Doing Well by Doing Good"—relentless scientific integrity, putting patient outcomes and rigorous biology ahead of commercial shortcuts, and fostering an environment of fearless scientific debate.
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