SECURITIES AND EXCHANGE COMMISSION
                              WASHINGTON, DC 20549


                                  SCHEDULE 13G
                                 (RULE 13D-102)


             INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT
           TO RULES 13D-1(B), (C) AND (D) AND AMENDMENTS THERETO FILED
                            PURSUANT TO RULE 13D-2(B)
                          (AMENDMENT NO. ____________)*


                         REGENERON PHARMACEUTICALS, INC.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                    Common Stock, par value $0.001 per share
--------------------------------------------------------------------------------
                         (Title of Class of Securities)

                                   75886F 10 7
--------------------------------------------------------------------------------
                                 (CUSIP Number)

                                 March 23, 2001
--------------------------------------------------------------------------------
             (Date of Event Which Requires Filing of this Statement)




Check  the appropriate box to designate the rule pursuant to which this Schedule
is  filed:


     [_]  Rule  13d-1(b)

     [X]  Rule  13d-1(c)

     [_]  Rule  13d-1(d)


     *The  remainder  of  this  cover  page  shall be filled out for a reporting
person's  initial  filing  on  this  form  with  respect to the subject class of
securities,  and for any subsequent amendment containing information which would
alter  the  disclosures  provided  in  a  prior  cover  page.

     The  information  required in the remainder of this cover page shall not be
deemed  to  be  "filed" for the purpose of Section 18 of the Securities Exchange
Act  of  1934 ("Act") or otherwise subject to the liabilities of that section of
the  Act,  but shall be subject to all other provisions of the Act (however, see
the  Notes).


                                                                    Page 1 of 16
                                                        Exhibit Index on Page 11

CUSIP NO. 75886F 10 7               13G     PAGE 2 --------- of ------- 16 PAGES
                                    ---

1             Names of Reporting Persons/I.R.S. Identification Nos. of Above
              Persons (Entities  Only)

              Feldon  Invest  SA
--------------------------------------------------------------------------------
2             Check the Appropriate Box if a Member of a Group    (a)  [ ]
              (See Instructions)                                  (b)  [ ]

--------------------------------------------------------------------------------
3             SEC  Use  Only

--------------------------------------------------------------------------------
4             Citizenship  or  Place  of  Organization

              Panama
--------------------------------------------------------------------------------
  Number of   5     Sole  Voting  Power
                    N/A
              ------------------------------------------------------------------
   Shares     6     Shared  Voting  Power
                    4,000,000
              ------------------------------------------------------------------
Beneficially  7     Sole  Dispositive  Power
                    N/A
              ------------------------------------------------------------------
  Owned by    8     Shared  Dispositive  Power
   Each
 Reporting          4,000,000
Person With
--------------------------------------------------------------------------------
9             Aggregate  Amount  Beneficially  Owned  by  Each Reporting Person

              4,000,000
--------------------------------------------------------------------------------
10            Check if the Aggregate Amount in Row (9) Excludes Certain
              Shares [ ] (See Instructions)

--------------------------------------------------------------------------------
11            Percent  of  Class  Represented  by  Amount  in  Row  (9)

              9.8%
--------------------------------------------------------------------------------
12            Type  of  Reporting  Person  (See  Instructions)

              CO
--------------------------------------------------------------------------------



CUSIP NO. 75886F 10 7               13G     PAGE 3 --------- of ------- 16 PAGES
                                    ---

1             Names of Reporting Persons/I.R.S. Identification Nos. of Above
              Persons (Entities  Only)

              Emfeld Ltd
--------------------------------------------------------------------------------
2             Check the Appropriate Box if a Member of a Group    (a)  [ ]
              (See Instructions)                                  (b)  [ ]

--------------------------------------------------------------------------------
3             SEC  Use  Only

--------------------------------------------------------------------------------
4             Citizenship  or  Place  of  Organization

              Cayman Islands
--------------------------------------------------------------------------------
  Number of   5     Sole  Voting  Power
                    N/A
              ------------------------------------------------------------------
   Shares     6     Shared  Voting  Power
                    4,000,000
              ------------------------------------------------------------------
Beneficially  7     Sole  Dispositive  Power
                    N/A
              ------------------------------------------------------------------
  Owned by    8     Shared  Dispositive  Power
   Each
 Reporting          4,000,000
Person With
--------------------------------------------------------------------------------
9             Aggregate  Amount  Beneficially  Owned  by  Each Reporting Person

              4,000,000
--------------------------------------------------------------------------------
10            Check if the Aggregate Amount in Row (9) Excludes Certain
              Shares [ ] (See Instructions)

--------------------------------------------------------------------------------
11            Percent  of  Class  Represented  by  Amount  in  Row  (9)

              9.8%
--------------------------------------------------------------------------------
12            Type  of  Reporting  Person  (See  Instructions)

              CO
--------------------------------------------------------------------------------



CUSIP NO. 75886F 10 7               13G     PAGE 4 --------- of ------- 16 PAGES
                                    ---

1             Names of Reporting Persons/I.R.S. Identification Nos. of Above
              Persons (Entities  Only)

              Bertarelli & Cie
--------------------------------------------------------------------------------
2             Check the Appropriate Box if a Member of a Group    (a)  [ ]
              (See Instructions)                                  (b)  [ ]

--------------------------------------------------------------------------------
3             SEC  Use  Only

--------------------------------------------------------------------------------
4             Citizenship  or  Place  of  Organization

              Switzerland
--------------------------------------------------------------------------------
  Number of   5     Sole  Voting  Power

                    N/A
              ------------------------------------------------------------------
   Shares     6     Shared  Voting  Power
                    4,000,000
              ------------------------------------------------------------------
Beneficially  7     Sole  Dispositive  Power
                    N/A
              ------------------------------------------------------------------
  Owned by    8     Shared  Dispositive  Power
   Each
 Reporting          4,000,000
Person With
--------------------------------------------------------------------------------
9             Aggregate  Amount  Beneficially  Owned  by  Each Reporting Person

              4,000,000
--------------------------------------------------------------------------------
10            Check if the Aggregate Amount in Row (9) Excludes Certain
              Shares [ ] (See Instructions)

--------------------------------------------------------------------------------
11            Percent  of  Class  Represented  by  Amount  in  Row  (9)

              9.8%
--------------------------------------------------------------------------------
12            Type  of  Reporting  Person  (See  Instructions)

              OO
--------------------------------------------------------------------------------



CUSIP NO. 75886F 10 7               13G     PAGE 5 --------- of ------- 16 PAGES
                                    ---

1             Names of Reporting Persons/I.R.S. Identification Nos. of Above
              Persons (Entities  Only)

              Ernesto Bertarelli
--------------------------------------------------------------------------------
2             Check the Appropriate Box if a Member of a Group    (a)  [ ]
              (See Instructions)                                  (b)  [ ]

--------------------------------------------------------------------------------
3             SEC  Use  Only

--------------------------------------------------------------------------------
4             Citizenship  or  Place  of  Organization

              Switzerland
--------------------------------------------------------------------------------
  Number of   5     Sole  Voting  Power
                    N/A
              ------------------------------------------------------------------
   Shares     6     Shared  Voting  Power
                    4,000,000
              ------------------------------------------------------------------
Beneficially  7     Sole  Dispositive  Power
                    N/A
              ------------------------------------------------------------------
  Owned by    8     Shared  Dispositive  Power
   Each
 Reporting          4,000,000
Person With
--------------------------------------------------------------------------------
9             Aggregate  Amount  Beneficially  Owned  by  Each Reporting Person

              4,000,000
--------------------------------------------------------------------------------
10            Check if the Aggregate Amount in Row (9) Excludes Certain
              Shares [ ] (See Instructions)

--------------------------------------------------------------------------------
11            Percent  of  Class  Represented  by  Amount  in  Row  (9)

              9.8%
--------------------------------------------------------------------------------
12            Type  of  Reporting  Person  (See  Instructions)

              IN
--------------------------------------------------------------------------------



CUSIP NO. 75886F 10 7               13G     PAGE 6 --------- of ------- 16 PAGES
                                    ---


ITEM  1(A).    NAME  OF  ISSUER:

               Regeneron  Pharmaceuticals,  Inc.

ITEM  1(B).    ADDRESS  OF  ISSUER'S  PRINCIPAL  EXECUTIVE  OFFICES:

               777  Old  Saw  Mill  River  Road
               Tarrytown,  New  York  10591-6707

ITEM  2(A).    NAMES  OF  PERSONS  FILING:

               This  statement  is  being  filed  jointly  by:

               (i)  Feldon  Invest SA, a Panamanian stock company, the holder of
                    an  aggregate  of  4,000,000  shares  of the issuer's common
                    stock,  par  value  $0.001;

               (ii) Emfeld  Ltd,  a  Cayman  Islands stock company, which is the
                    holder of all of the issued and outstanding capital stock of
                    Feldon  Invest  SA;

               (iii)Bertarelli  &  Cie,  a  societe  en  commandite  par actions
                    organized under the laws of Switzerland, which is the holder
                    of all of the issued and outstanding capital stock of Emfeld
                    Ltd;  and

               (iv) Ernesto  Bertarelli,  an  individual,  who,  as  President,
                    Managing  Director and controlling shareholder of Bertarelli
                    &  Cie,  controls  that  entity.

ITEM  2(B).    ADDRESS  OF  PRINCIPAL  BUSINESS  OFFICE OR, IF NONE, RESIDENCE:

               For  Feldon  Invest  SA:
               Urbanizacion  Obarrio
               Swiss  Bank  Building
               53rd  Street
               Panama  City,  Panama

               For  Emfeld  Ltd:
               One  Capital  Place
               Second  Floor
               P.O.  Box  1787
               George  Town,  Grand  Cayman,  Cayman  Islands

               For  Ernesto  Bertarelli  and  Bertarelli  &  Cie:
               c/o  Abacus  Conseil  et  Expertise  Comptable  SA
               2,  Chemin  des  Mines
               CH-1202  Geneva
               Switzerland

ITEM  2(C).    CITIZENSHIP:

               Feldon  Invest  SA:  A  stock company organized under the laws of
               Panama

               Emfeld  Ltd:  A  stock  company  organized  under the laws of the
               Cayman  Islands

               Bertarelli  & Cie:  A societe en commandite par actions organized
               under  the  laws  of  Switzerland



CUSIP NO. 75886F 10 7               13G     PAGE 7 --------- of ------- 16 PAGES
                                    ---

               Ernesto  Bertarelli:  Switzerland

ITEM  2(D).    TITLE  OF  CLASS  OF  SECURITIES:

               Common  Stock,  par  value  $0.001  per  share

ITEM  2(E).    CUSIP  NUMBER:

               75886F  10  7

ITEM  3.       IF THIS STATEMENT IS FILED PURSUANT TO RULE 13D-1(B), OR 13D-2(B)
               OR  (C),  CHECK  WHETHER  THE  PERSON  FILING  IS  A:

               Not  applicable.

ITEM  4.       OWNERSHIP.

     The  ownership  percentage set forth below is based on 40,787,624 shares of
common stock outstanding, as reported in the issuer's prospectus dated March 19,
2001.

     With respect  to  Feldon  Invest  SA:

               (a)  Amount  beneficially  owned:  4,000,000

               (b)  Percent  of  class:  9.8%

               (c)  Number  of  shares  as  to  which  the  person  has:

                    (i)  Sole  power  to  vote  or  to  direct  the  vote:  N/A

                    (ii) Shared  power  to vote or to direct the vote: 4,000,000

                    (iii)Sole power to dispose or to direct the disposition of:
                         N/A

                    (iv) Shared  power  to  dispose or to direct the disposition
                         of:  4,000,000

     With  respect  to  Emfeld  Ltd:

               (a)  Amount  beneficially  owned:  4,000,000

               (b)  Percent  of  class:  9.8%

               (c)  Number  of  shares  as  to  which  the  person  has:

                    (i)  Sole  power  to  vote  or  to  direct  the  vote:  N/A

                    (ii) Shared  power  to vote or to direct the vote: 4,000,000

                    (iii)Sole power to dispose or to direct the disposition of:
                         N/A

                    (iv) Shared  power  to  dispose or to direct the disposition
                         of:  4,000,000


CUSIP NO. 75886F 10 7               13G     PAGE 8 --------- of ------- 16 PAGES
                                    ---

     With  respect  to  Bertarelli  &  Cie:

               (a)  Amount  beneficially  owned:  4,000,000

               (b)  Percent  of  class:  9.8%

               (c)  Number  of  shares  as  to  which  the  person  has:

                    (i)  Sole  power  to  vote  or  to  direct  the  vote:  N/A

                    (ii) Shared  power  to vote or to direct the vote: 4,000,000

                    (iii)Sole power to dispose or to direct the disposition of:
                         N/A

                    (iv) Shared  power  to  dispose or to direct the disposition
                         of:  4,000,000

     With  respect  to  Ernesto  Bertarelli:

               (a)  Amount  beneficially  owned:  4,000,000

               (b)  Percent  of  class:  9.8%

               (c)  Number  of  shares  as  to  which  the  person  has:

                    (i)  Sole  power  to  vote  or  to  direct  the  vote:  N/A

                    (ii) Shared  power  to vote or to direct the vote: 4,000,000

                    (iii)Sole power to dispose or to direct the disposition of:
                         N/A

                    (iv) Shared  power  to  dispose or to direct the disposition
                         of:  4,000,000


CUSIP NO. 75886F 10 7               13G     PAGE 9 --------- of ------- 16 PAGES
                                    ---

ITEM  5.  OWNERSHIP  OF  FIVE  PERCENT  OR  LESS  OF  A  CLASS.

          Not  applicable.

ITEM  6.  OWNERSHIP  OF  MORE  THAN  FIVE  PERCENT  ON BEHALF OF ANOTHER PERSON.

          Not  applicable.

ITEM  7.  IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE
          SECURITY  BEING  REPORTED  ON BY THE PARENT HOLDING COMPANY OR CONTROL
          PERSON.

          Not  applicable.

ITEM  8.  IDENTIFICATION  AND  CLASSIFICATION  OF  MEMBERS  OF  THE  GROUP.

          Not  applicable.

ITEM  9.  NOTICE  OF  DISSOLUTION  OF  GROUP.

          Not  applicable.

ITEM 10.  CERTIFICATIONS.

          By  signing  below  I  certify  that,  to the best of my knowledge and
belief,  the securities referred to above were not acquired and are not held for
the  purpose of or with the effect of changing or influencing the control of the
issuer  of  the  securities and were not acquired and are not held in connection
with  or  as  a  participant  in  any transaction having that purpose or effect.



CUSIP NO. 75886F 10 7               13G     PAGE 10 -------- of ------- 16 PAGES
                                    ---

                                    SIGNATURE

     After  reasonable  inquiry  and to the best of our knowledge and belief, we
certify  that  the information set forth in this statement is true, complete and
correct.

Dated:  March  30,  2001

                                   FELDON  INVEST  SA


                                   /s/  Thomas  J.  Plotz
                                   ----------------------
                                   By:  Thomas  J.  Plotz
                                   Title:  Attorney-in-Fact



                                   EMFELD  LTD

                                   /s/  Thomas  J.  Plotz
                                   ------------------------
                                   By:  Thomas  J.  Plotz
                                   Title:  Attorney-in-Fact



                                   BERTARELLI  &  CIE


                                   /s/  Thomas  J.  Plotz
                                   -------------------------
                                   By:  Thomas  J.  Plotz
                                   Title:  Attorney-in-Fact



                                   /s/  Ernesto  Bertarelli*
                                   -------------------------
                                   Ernesto  Bertarelli


*  By:
     /s/ Thomas J. Plotz
     ---------------------------------
     Thomas J. Plotz, Attorney-in-Fact



CUSIP NO. 75886F 10 7               13G     PAGE 11 -------- of ------- 16 PAGES
                                    ---

                                    EXHIBITS

1.  Power  of  Attorney  of  Feldon  Invest  SA                          Page 12
2.  Power  of  Attorney  of  Emfeld  Ltd                                 Page 13
3.  Power  of  Attorney  of  Bertarelli  &  Cie                          Page 14
4.  Power  of  Attorney  of  Ernesto  Bertarelli                         Page 15
5.  Joint  Filing  Agreement  Pursuant to Rule 13d-1(k)(1)               Page 16