SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 January 21, 2003 (January 7, 2003) ---------------------------------- Date of Report (Date of earliest event reported) REGENERON PHARMACEUTICALS, INC. ------------------------------------------------------ (Exact name of registrant as specified in its charter) NEW YORK 0-19034 No. 13-3444607 - ---------------------------- ----------- ------------- (State or other jurisdiction (Commission (IRS Employer of incorporation) File Number) Identification No.) 777 OLD SAW MILL RIVER ROAD, TARRYTOWN, NY 10591-6707 -------------------------------------------------------------- (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code (914) 347-7000 NOT APPLICABLE -------------- (Former name or former address, if changed since last report) Page 1 of 8

INFORMATION TO BE INCLUDED IN REPORT ITEM 5. OTHER EVENTS. On January 7, 2003, the Company issued two press releases, copies of which are included as exhibits to this filing. On January 17, 2003, the Company issued a press release, a copy of which is included as an exhibit to this filing. ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS. (c) Exhibits 99(a) Press Release dated January 7, 2003. 99(b) Press Release dated January 7, 2003. 99(c) Press Release dated January 17, 2003. -2-

SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized. REGENERON PHARMACEUTICALS, INC. By: /s/ Stuart Kolinski ------------------------------------ Stuart Kolinski Vice President & General Counsel Date: January 21, 2003 -3-

EXHIBIT 99(a) FOR IMMEDIATE RELEASE REGENERON COMPLETES 12-MONTH EFFICACY PHASE OF AXOKINE(R) PHASE III PIVOTAL TRIAL FOR THE TREATMENT OF OBESITY Tarrytown, NY (January 7, 2003) - Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced today at the JP Morgan Healthcare Conference that the last study participant has completed the 12-month placebo-controlled portion of its Phase III pivotal trial designed to assess the efficacy and safety of AXOKINE(R) for weight loss in overweight and obese subjects. This pivotal trial included nearly 2,000 people at 65 study sites across the United States. "This is an important milestone in the AXOKINE pivotal trial and overall in the Phase III development program," noted Steven P. Weinstein, M.D., Ph.D., Regeneron's Executive Director of Endocrinology. "We note that approximately 65 percent of all study subjects completed the 12-month placebo-controlled phase of the trial, and the average treatment period for participants in this trial is now more than 14 months." THE AXOKINE PHASE III PROGRAM The Company initiated its Phase III AXOKINE program in July 2001 and began treating people in the pivotal trial in September 2001. This pivotal trial includes two phases. The recently completed first phase was designed to measure weight change in a 12-month double-blind treatment period, in which participants gave themselves daily subcutaneous injections of placebo or AXOKINE. This phase was overseen by an independent Data Safety Monitoring Board, which reviewed the safety data. The co-primary end-points of the study are change in body weight and proportion of subjects who lose 5 percent or more of their body weight over the 12-month treatment period. Data collection for this first phase of the pivotal study and finalization of the database for statistical analysis are currently underway. The double-blind, placebo-controlled treatment period is being followed by a 12-month open-label safety extension phase, during which all trial participants receive AXOKINE. To be included in the study, patients must not have been diabetic and must have had a body mass index (BMI) of 30 to 55 if they had no obesity-related risk factors or 27 to 55 if they had obesity-related risk factors, such as elevated blood pressure or increased blood lipids. People are classified -4-

as overweight if they have a BMI between 25 and 30, and obese if they have a BMI of 30 or greater. BMI is a medical measure of obesity. It measures weight in relation to height and is calculated as weight in kilograms divided by height measured in meters, squared. For example, a person 5'8" tall weighing 174 pounds would have a BMI of 27 and be considered overweight. The same 5'8" adult weighing 258 pounds would have a BMI of 40 and be considered extremely obese. The entire AXOKINE program has been designed to include approximately 4,000 participants. As part of the overall Phase III program, Regeneron has initiated 4 clinical studies that are currently underway and has planned additional confirmatory and ancillary studies of AXOKINE(R) in obese and obese diabetic subjects. ABOUT REGENERON Regeneron is a biopharmaceutical company that discovers, develops, and intends to commercialize therapeutic medicines for the treatment of serious medical conditions. Regeneron has therapeutic candidates for the potential treatment of obesity, rheumatoid arthritis, cancer, and asthma and has preclinical programs in other diseases and disorders. This news release discusses historical information and includes forward-looking statements about Regeneron and its 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 filings with the United States Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2001 and the Form 10-Q for the quarter ended September 30, 2002. Regeneron does not undertake any obligation to update publicly any forward-looking statement, whether as a result of new information, future events, or otherwise, unless required by law. -5-

EXHIBIT 99(b) FOR IMMEDIATE RELEASE REGENERON RECEIVES FAST TRACK DESIGNATION FROM U.S. FOOD AND DRUG ADMINISTRATION FOR ASPECT OF AXOKINE(R) OBESITY DEVELOPMENT PROGRAM Tarrytown, NY - January 7, 2003 - Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced today at the JP Morgan Healthcare Conference that the U.S. Food and Drug Administration (FDA) has granted Fast Track designation to an important component of the development program of AXOKINE(R) for obesity. The designation covers treatment of severely obese people who are unresponsive to, intolerant of, or unsuitable candidates for certain FDA approved medicines for long-term treatment of obesity. As part of its ongoing development program for AXOKINE, Regeneron plans to study the use of AXOKINE in this patient population. The FDA grants Fast Track designation to a therapeutic development program that the agency determines has the potential to address an unmet medical need in treating serious or life-threatening disease conditions. Under the FDA Modernization Act of 1997, the FDA may take actions to expedite the development and review of an application for approval to market a therapeutic candidate that has been granted Fast Track designation. AXOKINE is being evaluated for the treatment of obesity in a wide range of treatment paradigms in a comprehensive Phase III program that includes overweight, obese and severely obese people. "Practicing physicians and medical researchers have become increasingly concerned about the serious medical consequences, limited therapeutic options, and rising prevalence of obesity in this country," remarked Leonard S. Schleifer, M.D., Ph.D., Regeneron's President and Chief Executive Officer. "Obesity has been shown to be a major cause of diabetes, heart attacks, stroke, hypertension, and other life-threatening medical problems. AXOKINE, if proved to be safe and effective, will provide a new therapeutic approach to the treatment of this serious disease." ABOUT AXOKINE AXOKINE is a genetically re-engineered version of a naturally occurring human protein known as ciliary neurotrophic factor (CNTF). Preclinical studies have shown that injected AXOKINE travels -6-

through the bloodstream to reach the hypothalamus, a critical area of the brain that regulates body weight. AXOKINE is believed to bind to specific receptors and activate signaling pathways in the hypothalamus that suppress appetite. Both the site of the AXOKINE receptor and the mechanism of action of AXOKINE are similar to those of leptin, a natural hormone regulator of body weight that is released by fat cells. Ongoing Phase III trials are studying the safety and efficacy of AXOKINE. ABOUT REGENERON Regeneron is a biopharmaceutical company that discovers, develops, and intends to commercialize therapeutic medicines for the treatment of serious medical conditions. Regeneron has therapeutic candidates for the potential treatment of obesity, rheumatoid arthritis, cancer, and asthma and has preclinical programs in other diseases and disorders. This news release discusses historical information and includes forward-looking statements about Regeneron and its 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 filings with the United States Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2001 and the Form 10-Q for the quarter ended September 30, 2002. Regeneron does not undertake any obligation to update publicly any forward-looking statement, whether as a result of new information, future events, or otherwise, unless required by law. -7-

EXHIBIT 99(c) FOR IMMEDIATE RELEASE ARTHUR F. RYAN ELECTED TO REGENERON'S BOARD OF DIRECTORS Tarrytown, NY (January 17, 2003) - Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced today that it has elected Arthur F. Ryan to fill a new seat on its expanded Board of Directors. Mr. Ryan is Chairman, Chief Executive Officer, and President of Prudential Financial, Inc., one of the largest diversified financial institutions in the world. "Art brings extraordinarily important strategic and financial leadership skills to our Board," noted P. Roy Vagelos, M.D., Chairman of Regeneron's Board of Directors. "With our broad therapeutic pipeline and emerging opportunities for several product candidates, we'll benefit from Art's significant experience in managing complex businesses. He'll help us plan Regeneron's business growth. We're delighted to have Art join our Board." Mr. Ryan joined Prudential in December 1994, and he led the company's strategic conversion from a mutual to a publicly traded company in 2001. Prior to joining Prudential in December 1994, he had been President and Chief Operating Officer of Chase Manhattan Bank since 1990. Mr. Ryan ran Chase's worldwide retail bank between 1984 and 1990. Regeneron is a biopharmaceutical company that discovers, develops, and intends to commercialize therapeutic medicines for the treatment of serious medical conditions. Regeneron has therapeutic candidates for the potential treatment of obesity, rheumatoid arthritis, cancer, and asthma and has preclinical programs in other diseases and disorders. This news release discusses historical information and includes forward-looking statements about Regeneron and its 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 filings with the United States Securities and Exchange Commission, including its Form 10-K for the year ended December 31, 2001 and the Form 10-Q for the quarter ended September 30, 2002. Regeneron does not undertake any obligation to update publicly any forward-looking statement, whether as a result of new information, future events, or otherwise, unless required by law. -8-