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

                          PROSPECTUS SUPPLEMENT NO. 4
                        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 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:

Name                            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
                                   that may be Sold        Outstanding               be sold (1)            Outstanding (2)
                                --------------------       ------------            ----------------         ----------------
 Bankgesellschaft Berlin AG         7,500,000                 3.75%                     247,923                   *
 Tribeca Investments LLC            2,000,000                 1.0%                       66,113                   *
* 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 26, 2002.