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

                                  SCHEDULE 13G

                   Under the Securities Exchange Act of 1934

                      Oscient Pharmaceuticals Corporation
                                (Name of Issuer)

                    Common Stock, par value $0.10 per share
                         (Title of Class of Securities)

                                   68812R303
                                 (CUSIP Number)

                                 April 26, 2007
            (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. 68812R303                    13G                   Page 2 of 11 Pages

-------------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS
            I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

            Highbridge International LLC
-------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (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
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **
                                                                    [ ]
-------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            11.15%
-------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON **
            OO
-------------------------------------------------------------------------------

                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 68812R303                    13G                   Page 3 of 11 Pages

-------------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS
            I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

            Highbridge Capital Management, LLC                    20-1901985
-------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (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
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **
                                                                     []
-------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            11.15%
-------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON **
            OO
-------------------------------------------------------------------------------
                    ** SEE INSTRUCTIONS BEFORE FILLING OUT!



CUSIP No. 68812R303                    13G                   Page 4 of 11 Pages


-------------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS
            I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

            Glenn Dubin
-------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (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
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **
                                                                    []
-------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            11.15%
-------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON **
            IN
-------------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 68812R303                    13G                   Page 5 of 11 Pages

-------------------------------------------------------------------------------
     (1)    NAMES OF REPORTING PERSONS
            I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS

            Henry Swieca
-------------------------------------------------------------------------------
     (2)    CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP **
                                                                    (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
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
OWNED BY       ----------------------------------------------------------------

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

PERSON WITH    (8)  SHARED DISPOSITIVE POWER
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (9)    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                    7,421 shares of Common Stock

                    3.50% Convertible Senior Notes due 2011
                    convertible into 1,718,310 shares of Common Stock
-------------------------------------------------------------------------------
     (10)   CHECK BOX IF THE AGGREGATE AMOUNT
            IN ROW (9) EXCLUDES CERTAIN SHARES **
                                                                    []
-------------------------------------------------------------------------------
     (11)   PERCENT OF CLASS REPRESENTED
            BY AMOUNT IN ROW (9)
            11.15%
-------------------------------------------------------------------------------
     (12)   TYPE OF REPORTING PERSON **
            IN
-------------------------------------------------------------------------------
                     ** SEE INSTRUCTIONS BEFORE FILLING OUT!




CUSIP No. 68812R303                    13G                   Page 6 of 11 Pages


This statement on Schedule 13G (this "Statement") relates to the 7,421 shares
(the "Owned Shares") of common stock, par value $0.10 per share (the "Common
Stock"), of Oscient Pharmaceuticals Corporation, a Massachusetts corporation
(the "Company"), held by Highbridge International LLC and the 1,718,310 shares
of Common Stock of the Company issuable to Highbridge International LLC upon
conversion of the 3.50% Convertible Senior Notes due 2011 of the Company (the
"Notes" and together with the Owned Shares, the "Common Shares"). In addition to
the Common Shares, the Reporting Persons (as defined below) may be deemed to
beneficially own 161,917 shares of Common Stock issuable to Highbridge
International LLC and 83,891 shares of Common Stock issuable to Smithfield
Fiduciary LLC, a wholly-owned subsidiary of Highbridge International LLC, upon
the exercise of warrants to purchase shares of Common Stock. However, pursuant
to the terms of these warrants, the warrants cannot be exercised until such time
as its holders would not beneficially own after such exercise more than 4.99% of
the outstanding shares of Common Stock.

Item 1.

(a)  Name of Issuer

        Oscient Pharmaceuticals Corporation (the "Company").

(b)  Address of Issuer's Principal Executive Offices

        1000 Winter Street, Suite 2200
        Waltham, Massachusetts 02451

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 IRS #: 20-1901985
        9 West 57th Street, 27th Floor
        New York, New York 10019
        Citizenship: 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



CUSIP No. 68812R303                    13G                   Page 7 of 11 Pages


Item 2(d)  Title of Class of Securities

        Shares of Common Stock, $0.10 par value

Item 2(e)   CUSIP Number

        68812R303

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).

(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, each of the Reporting Persons is the
beneficial owner of (i) 7,421 shares of Common Stock held by Highbridge
International LLC and (ii) 1,718,310 shares of Common Stock issuable to
Highbridge International LLC upon conversion of the Notes.

        Highbridge Capital Management, LLC is the trading manager of Highbridge
International LLC. Glenn Dubin is a Co-Chief Executive Officer of Highbridge
Capital Management, LLC. Henry Swieca is a Co-Chief Executive Officer of
Highbridge Capital Management, LLC. The foregoing should not be construed in




CUSIP No. 68812R303                    13G                   Page 8 of 11 Pages


and of itself as an admission by any Reporting Person as to beneficial ownership
of Common Shares owned by another Reporting Person. In addition, each of
Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca disclaims
beneficial ownership of Common Shares owned by Highbridge International LLC.


        (b) Percent of class:

            The Company's Quarterly Report on Form 10-Q that was filed on May
10, 2007, indicates there were 13,764,113 shares of Common Stock outstanding as
of May 2, 2007. Therefore, based on the Company's outstanding shares of Common
Stock and the shares of Common Stock issuable upon the conversion of the Notes,
each of Highbridge International LLC, Highbridge Capital Management LLC, Glenn
Dubin and Henry Swieca may be deemed to beneficially own 11.15% 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 Shares owned by another Reporting
Person.

        (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




CUSIP No. 68812R303                    13G                   Page 9 of 11 Pages

        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
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 15, 2007, by and among
Highbridge International LLC, Highbridge Capital Management, LLC, Glenn Dubin
and Henry Swieca.



CUSIP No. 68812R303                    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 15, 2007

HIGHBRIDGE INTERNATIONAL LLC                HIGHBRIDGE CAPITAL MANAGEMENT, LLC

By: Highbridge Capital Management, LLC
    its Trading Manager

                                            By: /s/ Carolyn Rubin
By: /s/ Carolyn Rubin                          -------------------------
    ---------------------------             Name:  Carolyn Rubin
Name:  Carolyn Rubin                        Title: Managing Director
Title: Managing Director



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





CUSIP No. 68812R303                    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 Common
Shares, $0.10 par value, of Oscient Pharmaceuticals Corporation, 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 15, 2007



HIGHBRIDGE INTERNATIONAL LLC                HIGHBRIDGE CAPITAL MANAGEMENT, LLC

By: Highbridge Capital Management, LLC
    its Trading Manager

                                            By: /s/ Carolyn Rubin
By: /s/ Carolyn Rubin                           -------------------------
    ---------------------------             Name:  Carolyn Rubin
Name:  Carolyn Rubin                        Title: Managing Director
Title: Managing Director



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