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FOR IMMEDIATE RELEASE
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                  REGENERON ANNOUNCES OFFERING OF CONVERTIBLE
                  SENIOR SUBORDINATED NOTES IN A 144A OFFERING

Tarrytown, NY - (October 12, 2001) -- Regeneron Pharmaceuticals, Inc. (NASDAQ:
REGN) announced today that subject to market and other conditions, it intends to
offer approximately $150 million of seven-year convertible senior subordinated
notes. These notes will be convertible into shares of Regeneron common stock.
The offering will be made by means of an offering memorandum to qualified
institutional buyers pursuant to Rule 144A of the Securities Act of 1933, as
amended. The offering is expected to close on or about October 17, 2001.
Regeneron expects to use the net proceeds from this offering for preclinical and
clinical development, expansion of manufacturing facilities, research, working
capital, and general corporate purposes.

The notes and the common stock issuable upon conversion of the notes have not
been registered under the Securities Act or applicable state securities laws,
and may not be offered or sold absent registration under the Securities Act and
applicable state securities laws or applicable exemptions from registration
requirements. Regeneron will file a registration statement for the resale of the
notes and the shares of common stock issuable upon conversion of the notes
within 90 days after the closing of the offering.

This press release shall not constitute an offer to sell or the solicitation of
an offer to buy the notes, nor shall there be any sale of the notes in any state
in which such offer, solicitation or sale would be unlawful prior to
registration or qualification under the securities laws of such state. The press
release is being issued pursuant to and in accordance with Rule 135(c) of the
Securities Act.
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Regeneron is a biopharmaceutical company that discovers, develops, and intends
to commercialize therapeutic drugs for the treatment of serious medical
conditions. Regeneron's platform technologies include Targeted Genomics(TM),
Functionomics(TM), and Designer Protein Therapeutics(TM). Regeneron has drugs in
clinical trials for the potential treatment of obesity and rheumatoid arthritis,
and has preclinical development programs in cancer, asthma, allergies, and 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, 2000. 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.

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Contact:    Charles Poole
            Vice President, Investor Relations
            Regeneron Pharmaceuticals, Inc.
            charles.poole@regn.com
            (914) 345-7641
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Additional information about Regeneron and recent news releases are available on
Regeneron's Worldwide Web Home Page at www.regn.com. Fax copies of news releases
can be obtained from Regeneron's News-on-Demand Service by dialing (800)
311-0841.