Filed pursuant to Rule No. 424(b)(3)
                                                           File Number 333-74464


                           PROSPECTUS SUPPLEMENT NO. 5
                         REGENERON PHARMACEUTICALS, INC.

                                  $200,000,000
              5.50% CONVERTIBLE SENIOR SUBORDINATED NOTES DUE 2008
        AND SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION OF THE NOTES


         This prospectus supplement supplements the prospectus dated January 24,
2002 of Regeneron Pharmaceuticals, Inc. relating to the sale by certain of our
securityholders (including their pledgees, donees, assignees, transferees,
successors and others who later hold any of the securityholders' interests) of
up to $200,000,000 principal amount at maturity of notes and the shares of
common stock issuable upon conversion of the notes. You should read this
prospectus supplement in conjunction with the prospectus, and this prospectus
supplement is qualified by reference to the prospectus, except to the extent
that the information in this prospectus supplement supersedes the information
contained in the prospectus.

         The table of selling securityholders contained in the prospectus is
hereby modified to add as follows:




                            Aggregate Principal                       Number of Shares    Percentage of
                                 Amount at          Percentage of     of Common Stock       Shares of
                           Maturity of the Notes        Notes            that may         Common Stock
Name                          that may be Sold       Outstanding        be Sold (1)      Outstanding (2)
- ----                       ---------------------    -------------     ----------------   ---------------
                                                                             

BMO Nesbitt Burns Inc.           4,500,000              2.25%             148,754               *


* Less than one percent (1%).

(1)  Assumes conversion of all of the holder's notes at a conversion rate of
     33.0565 shares of common stock per $1,000 principal amount at maturity of
     the notes. This conversion rate is subject to adjustment, however, as
     described under "Description of the Notes - Conversion of the Notes." As a
     result, the number of shares of common stock issuable upon conversion of
     the notes may increase or decrease in the future.

(2)  Calculated based on Rule 13d-3(d)(i) of the Exchange Act, using 43,826,969
     shares of common stock outstanding as of December 31, 2001. In calculating
     this amount for each holder, we treated as outstanding the number of shares
     of common stock issuable upon conversion of all that holder's notes, but we
     did not assume conversion of any other holder's notes.

         Investing in the notes or shares of common stock involves risks that
are described in the "Risk Factors" section beginning on page 5 of the
prospectus.

         NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED IF THIS
PROSPECTUS SUPPLEMENT IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.

         The date of this prospectus supplement is May 15, 2002.