SEC Filing | Enzon Pharmaceuticals

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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 ---------------------- SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* Enzon Pharmaceuticals, Inc. (Name of Issuer) Common Stock, par value $0.01 per share (Title of Class of Securities) 293904108 (CUSIP Number) December 31, 2006 (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 18 Pages

CUSIP No. 293904108 13G/A Page 2 of 18 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 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 3 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge Convertible Arbitrage Master Fund, L.P. - -------------------------------------------------------------------------------- (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 4.0% Convertible Senior Notes, due 2013, convertible into 1,047,120 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 1,047,120 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 1,047,120 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) 2.33% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 4 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge Capital Corporation - -------------------------------------------------------------------------------- (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 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY -------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING -------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 5 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge Capital L.P. - -------------------------------------------------------------------------------- (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 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 6 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge Master L.P. - -------------------------------------------------------------------------------- (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 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** PN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 7 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge GP, Ltd. - -------------------------------------------------------------------------------- (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 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 8 of 18 Pages - -------------------------------------------------------------------------------- (1) NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS Highbridge GP, 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 State of Delaware - -------------------------------------------------------------------------------- NUMBER OF (5) SOLE VOTING POWER 0 SHARES ----------------------------------------------------------------- BENEFICIALLY (6) SHARED VOTING POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 3,979,056 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) 8.31% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 9 of 18 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 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 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) 10.27% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** OO - Limited Liability Company - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 10 of 18 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 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 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) 10.27% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** IN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 11 of 18 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 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock OWNED BY ----------------------------------------------------------------- EACH (7) SOLE DISPOSITIVE POWER 0 REPORTING ----------------------------------------------------------------- PERSON WITH (8) SHARED DISPOSITIVE POWER 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 shares of Common Stock - -------------------------------------------------------------------------------- (9) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4.0% Convertible Senior Notes, due 2013, convertible into 5,026,176 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) 10.27% - -------------------------------------------------------------------------------- (12) TYPE OF REPORTING PERSON ** IN - -------------------------------------------------------------------------------- ** SEE INSTRUCTIONS BEFORE FILLING OUT!

CUSIP No. 293904108 13G/A Page 12 of 18 Pages This Amendment No. 1 (this "Amendment") amends the statement on Schedule 13G filed on May 26, 2006 (as amended, the "Schedule 13G") with respect to shares of common stock (the "Common Stock") of Enzon Pharmaceuticals, Inc., a Delaware corporation (the "Company"). Capitalized terms used herein and not otherwise defined in this Amendment have the meanings set forth in the Schedule 13G. This Amendment amends and restates Items 2(a), 2(b), 2(c), 4 and 8 in their entirety as set forth below. 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 CONVERTIBLE ARBITRAGE MASTER FUND, L.P. c/o Highbridge Capital Manangement, LLC 9 West 57th Street, 27th Floor New York, New York 10019 Citizenship: Cayman Islands, British West Indies HIGHBRIDGE CAPITAL CORPORATION 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 MASTER L.P. 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 L.P. c/o Highbridge Capital Management, LLC 9 West 57th Street, 27th Floor New York, New York 10019 Citizenship: State of Delaware HIGHBRIDGE GP, LTD. 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 GP, LLC c/o Highbridge Capital Management, LLC 9 West 57th Street, 27th Floor New York, New York 10019 Citizenship: State of Delaware

CUSIP No. 293904108 13G/A Page 13 of 18 Pages HIGHBRIDGE CAPITAL MANAGEMENT, LLC IRS #: 20-1901985 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 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, Highbridge Master L.P., Highbridge Capital Corporation, Highbridge Capital L.P., Highbridge GP Ltd., Highbridge GP LLC, Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca may be deemed the beneficial owner of 4.0% Convertible Senior Notes due 2013 convertible into 3,979,056 shares of Common Stock issuable to Highbridge International LLC. In addition, Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca may be deemed the beneficial owner of 4.0% Convertible Senior Notes due 2013 convertible into 1,047,120 shares of Common Stock issuable to Highbridge Convertible Arbitrage Master Fund, L.P. Highbridge International LLC is a subsidiary of Highbridge Master L.P. Highbridge Capital Corporation and Highbridge Capital L.P. are limited partners of Highbridge Master L.P. Highbridge GP, Ltd. is the General Partner of Highbridge Master L.P. Highbridge GP, LLC is the General Partner of Highbridge Capital L.P. Highbridge Capital Management, LLC is the trading manager of Highbridge Capital Corporation, Highbridge Capital L.P., Highbridge Convertible Arbitrage Master Fund, L.P. and Highbridge Master L.P. 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 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 Master L.P., Highbridge Capital Corporation, Highbridge Capital L.P., Highbridge GP, Ltd., Highbridge GP, LLC, Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca disclaims beneficial ownership of shares of Common Stock owned by Highbridge International LLC. (b) Percent of class: Based on the Company's Prospectus filed on Form S-3/A on November 3, 2006, there were 43,897,988 shares of Common Stock outstanding as of October 31, 2006. Therefore, based on the Company's outstanding shares of Common Stock and the Common Stock issuable upon the conversion of the 4.0% Convertible Senior Notes due 2013, issued by the Company, (i) Highbridge International LLC, Highbridge Master L.P., Highbridge Capital Corporation, Highbridge Capital L.P., Highbridge GP Ltd., Highbridge GP LLC may be deemed to beneficially own approximately 8.31% of the outstanding shares of Common Stock of the Company, (ii) Highbridge Convertible Arbitrage Master Fund, L.P. may be deemed to beneficially own approximately 2.33% of the outstanding shares of Common Stock of the Company, (iii) Highbridge Capital Management, LLC may be deemed to beneficially own approximately 10.27% 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. 293904108 13G/A Page 14 of 18 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 8. Identification and Classification of Members of the Group See Exhibit I. Exhibits: Exhibit I: Joint Filing Agreement, dated as of February 14, 2007, by and among Highbridge International LLC, Highbridge Convertible Arbitrage Master Fund, L.P., Highbridge Capital Corporation, Highbridge Capital L.P., Highbridge Master L.P., Highbridge GP, Ltd., Highbridge GP, LLC, Highbridge Capital Management, LLC, Glenn Dubin and Henry Swieca.

CUSIP No. 293904108 13G/A Page 15 of 18 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: February 14, 2007 HIGHBRIDGE INTERNATIONAL LLC HIGHBRIDGE CAPITAL L.P. By: Highbridge Capital Management, LLC By: Highbridge GP, LLC its Trading Manager its General Partner By: /s/ Carolyn Rubin By: /s/ Clive Harris ------------------------------ ------------------------------ Name: Carolyn Rubin Name: Clive Harris Title: Managing Director Title: Director HIGHBRIDGE CAPITAL CORPORATION HIGHBRIDGE GP, LTD. By: Highbridge Capital Management, LLC its Trading Manager By: /s/ Clive Harris ------------------------------ Name: Clive Harris Title: Director By: /s/ Carolyn Rubin ------------------------------ Name: Carolyn Rubin Title: Managing Director HIGHBRIDGE MASTER L.P. HIGHBRIDGE CAPITAL MANAGEMENT, LLC By: Highbridge GP, Ltd. By: /s/ Carolyn Rubin its General Partner ------------------------------ Name: Carolyn Rubin Title: Managing Director By: /s/ Clive Harris ------------------------------ Name: Clive Harris Title: Director HIGHBRIDGE GP, LLC By: /s/ Clive Harris /s/ Henry Swieca ------------------------------ ------------------------------ Name: Clive Harris HENRY SWIECA Title: Director

CUSIP No. 293904108 13G/A Page 16 of 18 Pages HIGHBRIDGE CONVERTIBLE ARBITRAGE MASTER FUND, L.P. By: Highbridge Capital Management, LLC /s/ Glenn Dubin its Trading Manager - ---------------------------------- GLENN DUBIN By: /s/ Carolyn Rubin ------------------------------ Name: Carolyn Rubin Title: Managing Director

CUSIP No. 293904108 13G/A Page 17 of 18 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 Stock, $0.01 par value, of Enzon 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 February 14, 2006 HIGHBRIDGE INTERNATIONAL LLC HIGHBRIDGE CAPITAL L.P. By: Highbridge Capital Management, LLC By: Highbridge GP, LLC its Trading Manager its General Partner By: /s/ Carolyn Rubin By: /s/ Clive Harris ------------------------------ ------------------------------ Name: Carolyn Rubin Name: Clive Harris Title: Managing Director Title: Director HIGHBRIDGE CAPITAL CORPORATION HIGHBRIDGE GP, LTD. By: Highbridge Capital Management, LLC its Trading Manager By: /s/ Clive Harris ------------------------------ Name: Clive Harris Title: Director By: /s/ Carolyn Rubin ------------------------------ Name: Carolyn Rubin Title: Managing Director HIGHBRIDGE MASTER L.P. HIGHBRIDGE CAPITAL MANAGEMENT, LLC By: Highbridge GP, Ltd. By: /s/ Carolyn Rubin its General Partner ------------------------------ Name: Carolyn Rubin Title: Managing Director By: /s/ Clive Harris ------------------------------ Name: Clive Harris Title: Director HIGHBRIDGE GP, LLC By: /s/ Clive Harris /s/ Henry Swieca ------------------------------ ------------------------------ Name: Clive Harris HENRY SWIECA Title: Director

CUSIP No. 293904108 13G/A Page 18 of 18 Pages HIGHBRIDGE CONVERTIBLE ARBITRAGE MASTER FUND, L.P. By: Highbridge Capital Management, LLC /s/ Glenn Dubin its Trading Manager - ---------------------------------- GLENN DUBIN By: /s/ Carolyn Rubin ------------------------------ Name: Carolyn Rubin Title: Managing Director