Billionaire Profile
Leonard Schleifer
Global Rank
#1546

Image: Unknown photographer | Public domain | via Wikimedia Commons

Leonard Schleifer

CEO, Pharmaceuticals
UNITED STATES
Real-Time Net Worth
$2.756B
Estimated based on Pharmaceuticals stock value as of April 20, 2026
0% (24h)
Age
73
Source
Pharmaceuticals
Industry
Healthcare
Citizenship
UNITED STATES

Biography

Leonard Schleifer, a leading figure in the biopharmaceutical industry, is the co-founder and CEO of Regeneron Pharmaceuticals. Born in Queens, New York, Schleifer, with a net worth of $2.9 billion, has dedicated his career to transforming scientific discoveries into life-changing medicines. His career began with a passion for science and a desire to address unmet medical needs, particularly in neurology. Schleifer's achievements include building Regeneron into a global biotechnology company with a market cap of approximately $40 billion, overseeing the development and approval of 12 FDA-approved medicines.

Fact Checked
Verified by Editorial Team
Live Data
Updated 4/20/2026

Wealth Over Time

In-Depth Profile

Early Life

Leonard Schleifer was born in Queens, New York, to a Jewish family. His father was a sweater manufacturer and a World War II codebreaker. Schleifer attended Cornell University on scholarship and earned a B.S. degree. He then obtained his M.D. and Ph.D. in pharmacology from the University of Virginia, where he trained under future Nobel Laureate Alfred G. Gilman. While working as a practicing neurologist and professor at Cornell Medical School, Schleifer was frustrated by the lack of effective treatments for neurodegenerative diseases, which inspired him to enter the biotechnology field.

Rise to Success

In 1988, Schleifer founded Regeneron Pharmaceuticals with George Yancopoulos. Initially focused on neurotrophic factors, the company later shifted its focus to monoclonal antibodies, a decision that reshaped its trajectory. Under Schleifer's leadership, Regeneron developed groundbreaking treatments for various diseases, including Eylea for age-related macular degeneration, which became a blockbuster drug. He took Regeneron public in 1991. The company's success is also marked by its innovative VelociSuite of technologies, which accelerate the development of fully human monoclonal antibodies.

Key Business Strategies

Schleifer's leadership has been pivotal in Regeneron's success. Key strategies include a strong commitment to research and development, fostering a culture of scientific excellence, and forming strategic collaborations. He emphasized a focus on drugs with well-understood biology and the importance of human testing. Regeneron's ability to develop product candidates is enhanced by proprietary technology platforms, known as the VelociSuite of technologies.

Philanthropy

Schleifer and his wife Harriet have been involved in philanthropy. They have supported research and initiatives related to rare diseases and the advancement of scientific research. Schleifer's company supports STEM (Science, Technology, Engineering, and Math) education and fosters the future of biomedicine.

Career Milestones

1988

Founded Regeneron Pharmaceuticals

Co-founded Regeneron Pharmaceuticals with George Yancopoulos, which has become a leading biotechnology company.

1991

Regeneron went public

Took Regeneron public on the NASDAQ.

2011

Eylea Approval

Oversaw the approval of Eylea, a successful treatment for age-related macular degeneration, which became a blockbuster drug.

2020

COVID-19 Response

Led the development of an antibody cocktail for the treatment and prevention of COVID-19.

2025

Biotechnology Heritage Award

Received the Biotechnology Heritage Award from the Science History Institute and Biotechnology Innovation Organization.

Philanthropy & Social Impact

Medical Research

Yale Transketolase Deficiency Program

Undisclosed

Supporting the establishment of a program at Yale to advance research on rare diseases.

Education

STEM Education

Undisclosed

Supporting STEM education through Regeneron's initiatives, including the Regeneron Science Talent Search.

Business Philosophy & Leadership

Notable Quotes

"Most people, they lose their edge. We just push the edge further forward."

Leadership Principles

Commitment to Science

A strong focus on scientific research and innovation to drive the development of new medicines.

Patient-Centric Approach

A dedication to creating medicines that help patients with serious diseases.

Fostering a Culture of Excellence

Building a company culture that values scientific excellence and encourages innovation.

Controversies & Challenges

2017

Praluent Patent Infringement

A court ruling determined that Regeneron's cholesterol-lowering drug Praluent infringed on a rival's patents, leading to a drop in the company's share price.

2020

COVID-19 Treatment Criticism

Regeneron's apparent privileged access to its experimental COVID-19 therapeutic for Donald Trump and members of the Trump Administration drew criticism over ethical concerns.