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

                          PROSPECTUS SUPPLEMENT NO. 7
                        Regeneron Pharmaceuticals, Inc.

              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 pledges, 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:

Name               Aggregate Principal                       Number of Shares    Percentage of
-----                  Amount at          Percentage of      of Common Stock       Shares of
                    Maturity of Notes        Notes             that may           Common Stock
                    that may be Sold      Outstanding         be Sold (1)        Outstanding (2)
                    -----------------     -----------         -----------        ---------------
JP Morgan
  Securities, Inc.      1,505,000              *                49,750                 *

* 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 April 9, 2003