UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13G
                               (Amendment No. 1)*

                    Under the Securities Exchange Act of 1934

                           Arena Pharmaceuticals Inc.
                                (Name of Issuer)

                         Common Stock, $.0001 par value
                         (Title of Class of Securities)

                                    040047102
                                 (CUSIP Number)

                                November 30, 2003
             (Date of Event Which Requires Filing of this Statement)

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

      |X|   Rule 13d-1(b)

      |_|   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).


CUSIP No. 040047102                    13G                     Page 2 of 7 Pages


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Perry Corp.
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |_|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     New York
--------------------------------------------------------------------------------
  NUMBER OF    5.   SOLE VOTING POWER

   SHARES           2,806,154
               -----------------------------------------------------------------
BENEFICIALLY   6.   SHARED VOTING POWER

  OWNED BY          NONE
               -----------------------------------------------------------------
    EACH       7.   SOLE DISPOSITIVE POWER

  REPORTING         2,806,154
               -----------------------------------------------------------------
   PERSON      8.   SHARED DISPOSITIVE POWER

    WITH            NONE
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,806,154
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

                                                                          |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     10.96%*

*
Perry Corp and Richard C. Perry (collectively, the "Filers") are filing this
amendment to Schedule 13G to report an increase in the percentage of common
stock, par value $0.0001, of the Issuer (the "Common Stock") held by the Filers.
The increase in the percentage of Common Stock held by the Filers resulted from
one or more purchases by the Issuer of its Common Stock and was not occasioned
by the acquisition (or disposition) by the Filer of any shares of Common Stock.
The Form 10-Q filed by the Issuer on November 14, 2003 indicated that the total
issued and outstanding shares of Common Stock of the issuer decreased to
25,608,519 from 27,716,754 total issued and outstanding shares of Common Stock.

--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     IA, CO
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!


CUSIP No. 040047102                    13G                     Page 3 of 7 Pages


--------------------------------------------------------------------------------
1.   NAME OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY)

     Richard C. Perry
--------------------------------------------------------------------------------
2.   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP*

                                                                 (a)  |_|
                                                                 (b)  |_|
--------------------------------------------------------------------------------
3.   SEC USE ONLY


--------------------------------------------------------------------------------
4.   CITIZENSHIP OR PLACE OF ORGANIZATION

     United States
--------------------------------------------------------------------------------
  NUMBER OF    5.   SOLE VOTING POWER

   SHARES           2,806,154 (all shares beneficially owned by Perry Corp.)
               -----------------------------------------------------------------
BENEFICIALLY   6.   SHARED VOTING POWER

  OWNED BY          NONE
               -----------------------------------------------------------------
    EACH       7.   SOLE DISPOSITIVE POWER

  REPORTING         2,806,154 (all shares beneficially owned by Perry Corp.)
               -----------------------------------------------------------------
   PERSON      8.   SHARED DISPOSITIVE POWER

    WITH            NONE
--------------------------------------------------------------------------------
9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     2,806,154
--------------------------------------------------------------------------------
10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

                                                                          |_|
--------------------------------------------------------------------------------
11.  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)

     10.96%*

*
Perry Corp and Richard C. Perry (collectively, the "Filers") are filing this
amendment to Schedule 13G to report an increase in the percentage of common
stock, par value $0.0001, of the Issuer (the "Common Stock") held by the Filers.
The increase in the percentage of Common Stock held by the Filers resulted from
one or more purchases by the Issuer of its Common Stock and was not occasioned
by the acquisition (or disposition) by the Filer of any shares of Common Stock.
The Form 10-Q filed by the Issuer on November 14, 2003 indicated that the total
issued and outstanding shares of Common Stock of the issuer decreased to
25,608,519 from 27,716,754 total issued and outstanding shares of Common Stock.

--------------------------------------------------------------------------------
12.  TYPE OF REPORTING PERSON*

     IN, HC
--------------------------------------------------------------------------------
                     *SEE INSTRUCTIONS BEFORE FILLING OUT!



ITEM 1(a). NAME OF ISSUER:

      Arena Pharmaceuticals Inc.

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

      6166 Nancy Ridge Drive
      San Diego, CA 92121

ITEM 2(a). NAME OF PERSON FILING:

      This statement is filed on behalf of Perry Corp., a New York corporation,
and Richard C. Perry, an American citizen. Perry Corp. is a private investment
firm, and Richard C. Perry is the President and sole stockholder of Perry Corp.
Their agreement in writing to file this statement on behalf of each of them is
attached as Exhibit A hereto.

      This statement relates to shares held for the accounts of two or more
private investment funds for which Perry Corp. acts as general partner and/or
investment adviser.

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

      599 Lexington Avenue
      New York, NY 10022

ITEM 2(c). CITIZENSHIP:

      Perry Corp. is a New York corporation, and Richard C. Perry is a citizen
      of the United States.

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

      Common Stock, $0.0001 par value

ITEM 2(e). CUSIP NUMBER:

      040047102

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

      Perry Corp. is an investment adviser registered under Section 203 of the
Investment Advisers Act of 1940, and Richard C. Perry is a control person of
Perry Corp.



ITEM 4. OWNERSHIP:

      (a)   AMOUNT BENEFICIALLY OWNED:

            2,806,154

      (b)   PERCENT OF CLASS:

            10.96%*

*Perry Corp and Richard C. Perry (collectively, the "Filers") are filing this
amendment to Schedule 13G to report an increase in the percentage of common
stock, par value $0.0001, of the Issuer (the "Common Stock") held by the Filers.
The increase in the percentage of Common Stock held by the Filers resulted from
one or more purchases by the Issuer of its Common Stock and was not occasioned
by the acquisition (or disposition) by the Filer of any shares of Common Stock.
The Form 10-Q filed by the Issuer on November 14, 2003 indicated that the total
issued and outstanding shares of Common Stock of the issuer decreased to
25,608,519 from 27,716,754 total issued and outstanding shares of Common Stock.

      (c)   NUMBER OF SHARES AS TO WHICH SUCH PERSON HAS:

            (i)   Sole power to vote or to direct the vote:

                  2,806,154 shares

            (ii)  Shared power to vote or to direct the vote:

                  NONE

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

                  2,806,154

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

                  NONE

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

      If this statement is being filed to report the fact that as of the date
      hereof the reporting person has ceased to be the beneficial owner of more
      than 5 percent of the class of securities, check the following [ ]

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

      The limited partners of (or investors in) each of two or more private
      investment funds for which Perry Corp. acts as general partner and/or
      investment adviser have the right to participate in the receipt of
      dividends from, or proceeds from the sale of, the shares held for the
      accounts of their respective funds in accordance with their respective
      limited partnership interest (or investment percentages) in their
      respective funds.

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

      See Exhibit B

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

      Not Applicable

ITEM 9. NOTICE OF DISSOLUTION OF THE GROUP:

      Not Applicable

ITEM 10. CERTIFICATION:

      By signing below I certify that, to the best of my knowledge and belief,
      the securities referred to above were acquired and are held in the
      ordinary course of business and 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.



                                    SIGNATURE

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

                                            PERRY CORP.


Dated: December 29, 2003
       New York, New York                   By: /s/ Richard C. Perry
                                                -----------------------------
                                                Name: Richard C. Perry
                                                Title: President


Dated: December 29, 2003
       New York, New York                       /s/ Richard C. Perry
                                                -----------------------------
                                                Richard C. Perry



                                                                       EXHIBIT A

                                    AGREEMENT

                          JOINT FILING OF SCHEDULE 13G

            The undersigned hereby agree to jointly prepare and file with
regulatory authorities a Schedule 13G and any future amendments thereto
reporting each of the undersigned's ownership of securities of Arena
Pharmaceuticals Inc., and hereby affirm that such Schedule 13G is being filed on
behalf of each of the undersigned pursuant to and in accordance with the
provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934. The
undersigned acknowledge that each shall be responsible for the timely filing of
such amendments, and for the completeness and accuracy of the information
concerning him or it contained therein, but shall not be responsible for the
completeness and accuracy of the information concerning the other, except to the
extent that he or it knows or has reason to believe that such information is
inaccurate.

                                            PERRY CORP.


Dated: December 29, 2003
       New York, New York                   By: /s/ Richard C. Perry
                                                -----------------------------
                                                Name: Richard C. Perry
                                                Title: President


Dated: December 29, 2003
       New York, New York                       /s/ Richard C. Perry
                                                -----------------------------
                                                Richard C. Perry



                                                                       EXHIBIT B

                                     ITEM 7

Perry Corp. is the relevant entity for which Richard C. Perry may be considered
a control person.

Perry Corp. is an investment adviser registered under the Investment Advisers
Act of 1940.