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


                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934

                           Epix Pharmaceuticals, Inc.
                                (Name of Issuer)

                     Common Stock, par value $0.01 per share
                         (Title of Class of Securities)

                                    26881Q309
                                 (CUSIP Number)

                                   May 7, 2009
             (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 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 11 Pages





CUSIP No. 26881Q309                    13G                   Page 2 of 11 Pages

-------------------------------------------------------------------------------
     (1)   NAMES OF REPORTING PERSONS

           Highbridge International LLC
-------------------------------------------------------------------------------
     (2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
           (see instructions)                                  (a) [X]
                                                               (b) [ ]
-------------------------------------------------------------------------------
     (3)   SEC USE ONLY
-------------------------------------------------------------------------------
     (4)   CITIZENSHIP OR PLACE OF ORGANIZATION

           Cayman Islands, British West Indies
-------------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ----------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    4,664,461 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ----------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
           BY EACH REPORTING PERSON
           4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (10)  CHECK BOX IF THE AGGREGATE AMOUNT
           IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions)
                                                                   [ ]
-------------------------------------------------------------------------------
     (11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
           6.24%
-------------------------------------------------------------------------------
     (12)  TYPE OF REPORTING PERSON (see instructions)
           OO
-------------------------------------------------------------------------------




CUSIP No. 26881Q309                    13G                   Page 3 of 11 Pages

-------------------------------------------------------------------------------

     (1)   NAMES OF REPORTING PERSONS

           Highbridge Capital Management, LLC
-------------------------------------------------------------------------------
     (2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
           (see instructions)                                  (a) [X]
                                                               (b) [ ]
-------------------------------------------------------------------------------
     (3)   SEC USE ONLY
-------------------------------------------------------------------------------
     (4)   CITIZENSHIP OR PLACE OF ORGANIZATION

           State of Delaware
-------------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ----------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    4,664,461 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ----------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
           BY EACH REPORTING PERSON
           4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (10)  CHECK BOX IF THE AGGREGATE AMOUNT
           IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions)
                                                                     [ ]
-------------------------------------------------------------------------------
     (11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
           6.24%
-------------------------------------------------------------------------------
     (12)  TYPE OF REPORTING PERSON (see instructions)
           OO
-------------------------------------------------------------------------------




CUSIP No. 26881Q309                    13G                   Page 4 of 11 Pages

-------------------------------------------------------------------------------

     (1)   NAMES OF REPORTING PERSONS

           Glenn Dubin
-------------------------------------------------------------------------------
     (2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
           (see instructions)                                  (a) [X]
                                                               (b) [ ]
-------------------------------------------------------------------------------
     (3)   SEC USE ONLY
-------------------------------------------------------------------------------
     (4)   CITIZENSHIP OR PLACE OF ORGANIZATION

           United States
-------------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ----------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    4,664,461 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ----------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
           BY EACH REPORTING PERSON
           4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (10)  CHECK BOX IF THE AGGREGATE AMOUNT
           IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions)
                                                                     [ ]
-------------------------------------------------------------------------------
     (11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
           6.24%
-------------------------------------------------------------------------------
     (12)  TYPE OF REPORTING PERSON (see instructions)
           IN
-------------------------------------------------------------------------------




CUSIP No. 26881Q309                    13G                   Page 5 of 11 Pages

-------------------------------------------------------------------------------

     (1)   NAMES OF REPORTING PERSONS

           Henry Swieca
-------------------------------------------------------------------------------
     (2)   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
           (see instructions)                                  (a) [X]
                                                               (b) [ ]
-------------------------------------------------------------------------------
     (3)   SEC USE ONLY
-------------------------------------------------------------------------------
     (4)   CITIZENSHIP OR PLACE OF ORGANIZATION

           United States
-------------------------------------------------------------------------------
NUMBER OF      (5)  SOLE VOTING POWER
                    0
SHARES         ----------------------------------------------------------------

BENEFICIALLY   (6)  SHARED VOTING POWER
                    4,664,461 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

EACH           (7)  SOLE DISPOSITIVE POWER
                    0
REPORTING      ----------------------------------------------------------------

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
           BY EACH REPORTING PERSON
           4,664,461 shares of Common Stock
-------------------------------------------------------------------------------
     (10)  CHECK BOX IF THE AGGREGATE AMOUNT
           IN ROW (9) EXCLUDES CERTAIN SHARES (see instructions)
                                                                     [ ]
-------------------------------------------------------------------------------
     (11)  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
           6.24%
-------------------------------------------------------------------------------
     (12)  TYPE OF REPORTING PERSON (see instructions)
           IN
-------------------------------------------------------------------------------




CUSIP No. 26881Q309                    13G                   Page 6 of 11 Pages

Item 1.

(a)  Name of Issuer

        Epix Pharmaceuticals, Inc. (the "Company")

(b)  Address of Issuer's Principal Executive Offices
        4 Maguire Road
        Lexington, Massachusetts 02421


Item 2(a).  Name of Person Filing
Item 2(b).  Address of Principal Business Office
Item 2(c).  Citizenship

        HIGHBRIDGE INTERNATIONAL LLC
        c/o Harmonic Fund Services
        The Cayman Corporate Centre, 4th Floor
        27 Hospital Road
        Grand Cayman, Cayman Islands, British West Indies
        Citizenship:  Cayman Islands, British West Indies

        HIGHBRIDGE CAPITAL MANAGEMENT, LLC
        9 West 57th Street, 27th Floor
        New York, New York  10019
        Citizenship:  State of Delaware

        GLENN DUBIN
        c/o Highbridge Capital Management, LLC
        9 West 57th Street, 27th Floor
        New York, New York 10019
        Citizenship:  United States

        HENRY SWIECA
        c/o Highbridge Capital Management, LLC
        9 West 57th Street, 27th Floor
        New York, New York 10019
        Citizenship:  United States


Item 2(d)  Title of Class of Securities

        Common Stock, $0.01 par value ("Common Stock")

Item 2(e)  CUSIP Number

        26881Q309


Item 3. If this statement is filed pursuant to Rules 13d-1(b), or 13d-2(b) or
 (c), check whether the person filing is a:

(a)  [ ] Broker or dealer registered under Section 15 of the Act (15 U.S.C.
     78o).

(b)  [ ] Bank as defined in Section 3(a)(6) of the Act (15 U.S.C. 78c).

(c)  [ ] Insurance company as defined in Section 3(a)(19) of the Act (15 U.S.C.
         78c).




CUSIP No. 26881Q309                    13G                   Page 7 of 11 Pages


(d)  [ ] Investment company registered under Section 8 of the Investment
         Company Act of 1940 (15 U.S.C. 80a-8).

(e)  [ ] An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

(f)  [ ] An employee benefit plan or endowment fund in accordance with Rule
         13d-1(b)(1)(ii)(F);

(g)  [ ] A parent holding company or control person in accordance with Rule
         13d-1(b)(1)(ii)(G);

(h)  [ ] A savings association as defined in Section 3(b) of the Federal
         Deposit Insurance Act (12 U.S.C. 1813);

(i)  [ ] A church plan that is excluded from the definition of an investment
         company under Section 3(c)(14) of the Investment Company Act of 1940
         (15 U.S.C. 80a-3);

(j)  [ ] Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

If this statement is filed pursuant to Rule 13d-1(c), check this box. [X]


Item 4.   Ownership

        Provide the following information regarding the aggregate number and
percentage of the class of securities of the issuer identified in Item 1.

        (a) Amount beneficially owned:

        As of the date of this filing, (i) Highbridge International LLC
beneficially owns 4,664,461 shares of Common Stock and (ii) each of Highbridge
Capital Management, LLC, Glenn Dubin and Henry Swieca may be deemed the
beneficial owner of the 4,664,461 shares of Common Stock beneficially owned by
Highbridge International LLC.

        Highbridge Capital Management, LLC is the trading manager of Highbridge
International LLC. Glenn Dubin is the Chief Executive Officer of Highbridge
Capital Management, LLC. Henry Swieca is the Chief Investment Officer of
Highbridge Capital Management, LLC. The foregoing should not be construed in and
of itself as an admission by any Reporting Person as to beneficial ownership of
shares of Common Stock owned by another Reporting Person. In addition, each of
Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca disclaims
beneficial ownership of shares of Common Stock held by Highbridge International
LLC.

        (b) Percent of class:

        The Company's current report on Form 8-K filed on May 7, 2009, indicates
that as of May 7, 2009, after giving effect to the issuance of the 32,828,421
shares of common stock in connection with the Company's exchange offer of
Common Stock, cash and contingent value rights in exchange for the Company's
existing 3% Convertible Senior Notes due 2024, there were 74,775,862 shares of
Common Stock issued and outstanding. Therefore, based on the Company's
outstanding shares of Common Stock (i) Highbridge International LLC may be
deemed to beneficially own 6.24% of the outstanding shares of Common Stock of
the Company and (ii) each of Highbridge Capital Management, LLC, Glenn Dubin and
Henry Swieca may be deemed to beneficially own 6.24% of the outstanding shares
of Common Stock of the Company. The foregoing should not be construed in and of
itself as an admission by any Reporting Person as to beneficial ownership of
shares of Common Stock owned by another Reporting Person.





CUSIP No. 26881Q309                    13G                   Page 8 of 11 Pages


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

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

                     0

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

                     See Item 4(a)

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

                     0

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

                     See Item 4(a)


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

        See Exhibit I.


Item 9.  Notice of Dissolution of Group

        Not applicable.


Item 10. Certification

        By signing below each of the undersigned certifies that, to the best of
its knowledge and belief, the securities referred to above were not acquired and





CUSIP No. 26881Q309                    13G                   Page 9 of 11 Pages

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.


Exhibits:

Exhibit I: Joint Filing Agreement, dated as of May 12, 2009, by and among
Highbridge International LLC, Highbridge Capital Management, LLC, Glenn Dubin
and Henry Swieca.





CUSIP No. 26881Q309                    13G                   Page 10 of 11 Pages

                                   SIGNATURES

        After reasonable inquiry and to the best of its knowledge and belief,
each of the undersigned certifies that the information with respect to it set
forth in this statement is true, complete, and correct.

Dated: May 12, 2009

HIGHBRIDGE CAPITAL MANAGEMENT, LLC       HIGHBRIDGE INTERNATIONAL LLC

                                         By: Highbridge Capital Management, LLC
                                             its Trading Manager

By: /s/ John Oliva
----------------------------
Name: John Oliva                         By: /s/ John Oliva
Title: Managing Director                     -------------------------------
                                             Name:  John Oliva
                                             Title: Managing Director



/s/ Henry Swieca                         /s/ Glenn Dubin
-----------------------------            ---------------------------
HENRY SWIECA                             GLENN DUBIN






CUSIP No. 26881Q309                    13G                   Page 11 of 11 Pages


                                    EXHIBIT I

                             JOINT FILING AGREEMENT

This will confirm the agreement by and among the undersigned that the Schedule
13G filed with the Securities and Exchange Commission on or about the date
hereof with respect to the beneficial ownership by the undersigned of the
shares of Common Stock, $0.01 par value, of Epix Pharmaceuticals, Inc., is being
filed, and all amendments thereto will be filed, on behalf of each of the
persons and entities named below in accordance with Rule 13d-1(k) under the
Securities Exchange Act of 1934, as amended. This Agreement may be executed in
two or more counterparts, each of which shall be deemed an original, but all of
which together shall constitute one and the same instrument.

Dated as of May 12, 2009


HIGHBRIDGE CAPITAL MANAGEMENT, LLC       HIGHBRIDGE INTERNATIONAL LLC

                                          By: Highbridge Capital Management, LLC
                                              its Trading Manager

By: /s/ John Oliva
    -----------------------------         By: /s/ John Oliva
Name: John Oliva                          --------------------------------
Title: Managing Director                  Name: John Oliva
                                          Title: Managing Director


/s/ Henry Swieca                         /s/ Glenn Dubin
--------------------------------         -----------------------------
HENRY SWIECA                             GLENN DUBIN