Leonard Schleifer

Leonard Schleifer co-founded Regeneron Pharmaceuticals in 1988 with George Yancopoulos (now Chief Scientific Officer) and has served as President and CEO for over 35 years — one of the longest founder-CEO tenures in the pharmaceutical industry. A neurologist by training, Schleifer started Regeneron with $1 million from venture capital investors and endured years of preclinical and clinical development before the company's first commercial success. Regeneron's competitive advantage is its proprietary technology platforms, collectively called VelociSuite, which include VelocImmune (genetically engineered mice with humanized immune systems for antibody discovery), VelociGene (rapid gene modification), and VelociMab (high-throughput antibody screening). These platforms enable Regeneron to discover and develop fully human monoclonal antibodies significantly faster than traditional pharmaceutical approaches. The result has been an extraordinary pipeline productivity. The company's commercial portfolio includes multiple blockbusters: Eylea/Eylea HD (for wet age-related macular degeneration and diabetic eye disease — generating over $6 billion annually at peak), Dupixent (partnered with Sanofi, for atopic dermatitis, asthma, and other inflammatory conditions — rapidly approaching $15 billion in global sales), Libtayo (an immuno-oncology checkpoint inhibitor), and Kevzara (for rheumatoid arthritis). Key stock drivers include Dupixent's continued indication expansion, Eylea biosimilar competition, pipeline clinical readouts (particularly in oncology, obesity, and genetic medicines), and the sustainability of Regeneron's R&D productivity engine.