Regeneron Announces Staff Additions.

TARRYTOWN, NY--(BUSINESS WIRE)--May 13, 1999--

Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) announced the appointment of William G. Roberts, M.D., as Vice President, Regulatory Development.

Prior to joining Regeneron, Dr. Roberts was Director, Regulatory Affairs at Merck & Co., Inc., where he had been employed since 1993. At Merck, Dr. Roberts most recently had primary regulatory responsibility for pulmonary, oncologic, ophthalmic, and anti-infective drugs. Previously at Merck, he was Associate Director, Gastroenterology Clinical Research. Dr. Roberts received his M.D. in 1983 from the Columbia University College of Physicians & Surgeons, where he also completed his residency in internal medicine and a fellowship in gastroenterology.

"Dr. Roberts will have two immediate and important areas of involvement," said Leonard S. Schleifer, M.D., Ph.D., President and Chief Executive Officer of Regeneron. "Leveraging his extensive background in gastroenterology and regulatory development, Bill will play a key role in our clinical development of two products that are currently in clinical trials: AXOKINE(R) second generation ciliary neurotrophic factor, which is being developed initially for the treatment of Type II diabetes in obese patients in collaboration with The Procter & Gamble Company, and neurotrophin-3, which is being developed for constipating conditions in collaboration with Amgen Inc. The addition of Dr. Roberts to our management group will also help advance our other development programs as they move to clinical studies."

Regeneron also announced that Richard X. Horne had joined the Company as Staff Vice President, Human Resources. Prior to joining Regeneron, Mr. Horne held the position of Vice President, Human Resources, at the Braintree Hospital Rehabilitation Network and at Serono Laboratories. Commented Dr. Schleifer, "With the rapid growth of our scientific and technical staff to support Regeneron's research, clinical, and manufacturing activities, we are pleased to be able to draw on Rick's broad experience in all areas of Human Resources administration."

Regeneron also announced that Gail M. Kempler, Ph.D., had resigned her position as Vice President, Intellectual Property and Associate General Counsel, but continues to serve as Acting Patent Counsel for the Company.

Regeneron is a leader in the application of molecular and cell biology to the search for novel human therapeutics. Regeneron uses its expertise in growth factors and their mechanisms of action to discover and develop protein-based and small molecule drugs. Regeneron is currently conducting a clinical trial, in collaboration with The Procter & Gamble Company, of AXOKINE second generation ciliary neurotrophic factor for the treatment of Type II diabetes in obese patients and uncomplicated obesity. Regeneron is also conducting clinical trials, in partnership with Amgen Inc., of brain-derived neurotrophic factor for the treatment of amyotrophic lateral sclerosis and of neurotrophin-3 for the treatment of constipation associated with spinal cord injury and other medical conditions.

This news release discusses historical information and includes forward looking statements about Regeneron's products, programs, finances, and business, all of which involve a number of risks and uncertainties, such as risks associated with preclinical and clinical development of drugs and biologics, determinations by regulatory and administrative governmental authorities, competitive factors, technological developments, the availability and cost of capital, the costs of developing, producing, and selling products, the potential for any collaboration agreement to be canceled or to terminate without any product success, and other material risks. A more complete description of these risks can be found in Regeneron's Form 10-K for the year ended December 31, 1998, a copy of which should be read before making any investment decision regarding Regeneron common stock.

Additional information about Regeneron and recent news releases are available on Regeneron's Worldwide Web Home Page at www.regeneron.com. Fax copies of news releases can be obtained from Regeneron's News-on-Demand Service by dialing [phone].