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

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                         (Amendment No. ____________)*

                           Enzon Pharmaceuticals, Inc.
                                (Name of Issuer)

                                  Common Stock
                         (Title of Class of Securities)

                                    293904108
                                 (CUSIP Number)

                                December 31, 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).

                                Page 1 of 9 pages




- -------------------                                           ------------------
CUSIP No. 293904108                    13G                    Page 2 of 9 Pages
- -------------------                                           ------------------

- --------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

          Columbia Wanger Asset Management, L.P. 36-3820584

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

          Not Applicable                                                  (a)[ ]
                                                                          (b)[ ]

- --------------------------------------------------------------------------------
3    SEC USE ONLY

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

          Delaware

- --------------------------------------------------------------------------------
 NUMBER OF      5    SOLE VOTING POWER

  SHARES               None

               -----------------------------------------------------------------
BENEFICIALLY   6    SHARED VOTING POWER

                       2,558,400
 OWNED BY
               -----------------------------------------------------------------
               7    SOLE DISPOSITIVE POWER
  EACH
                       None

 REPORTING    -----------------------------------------------------------------
               8    SHARED DISPOSITIVE POWER

PERSON WITH            2,558,400

- --------------------------------------------------------------------------------
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          2,558,400

- --------------------------------------------------------------------------------
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

          Not Applicable                                                     [ ]

- --------------------------------------------------------------------------------
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

          5.9 %

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

          IA

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



- -------------------                                           ------------------
CUSIP No. 293904108                    13G                    Page 3 of 9 Pages
- -------------------                                           ------------------

- --------------------------------------------------------------------------------
1    NAME OF REPORTING PERSON
     S.S. or I.R.S. IDENTIFICATION NO. OF ABOVE PERSON

          WAM Acquisition GP, Inc.

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

          Not Applicable                                                  (a)[ ]
                                                                          (b)[ ]

- --------------------------------------------------------------------------------
3    SEC USE ONLY

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

          Delaware

- --------------------------------------------------------------------------------
 NUMBER OF     5    SOLE VOTING POWER

  SHARES               None

               -----------------------------------------------------------------
BENEFICIALLY   6    SHARED VOTING POWER

                       2,558,400
 OWNED BY
               -----------------------------------------------------------------
               7    SOLE DISPOSITIVE POWER
  EACH
                       None

 REPORTING    -----------------------------------------------------------------
               8    SHARED DISPOSITIVE POWER

PERSON WITH            2,558,400

- --------------------------------------------------------------------------------
9    AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

          2,558,400

- --------------------------------------------------------------------------------
10   CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES*

          Not Applicable                                                     [ ]

- --------------------------------------------------------------------------------
11   PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

          5.9 %

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

          CO

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



Item 1(a) Name of Issuer:

               Enzon Pharmaceuticals, Inc.

Item 1(b) Address of Issuer's Principal Executive Offices:

               685 Route 202/206
               Bridgewater, New Jersey 08807

Item 2(a) Name of Person Filing:

               Columbia Wanger Asset Management, L.P. ("WAM")
               WAM Acquisition GP, Inc., the general partner of WAM
               ("WAM GP")

Item 2(b) Address of Principal Business Office:

               WAM and WAM GP are located at:

               227 West Monroe Street, Suite 3000
               Chicago, Illinois 60606

Item 2(c) Citizenship:

               WAM is a Delaware limited partnership and WAM GP is a Delaware
               corporation.

Item 2(d) Title of Class of Securities:

               Common Stock

Item 2(e) CUSIP Number:

               293904108

Item 3    Type of Person:

               (e)  WAM is an Investment Adviser registered under section 203 of
                    the Investment Advisers Act of 1940; WAM GP is the General
                    Partner of the Investment Adviser.

                               Page 4 of 9 pages



Item 4    Ownership (at December 31, 2003):

               (a)  Amount owned "beneficially" within the meaning of rule
                    13d-3:

                    2,558,400

               (b)  Percent of class:

                    5.9 % (based on 43,520,896 shares outstanding as of November
                    12, 2003)

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

                         (i)   sole power to vote or to direct the vote: none

                         (ii)  shared power to vote or to direct the vote:
                               2,558,400

                         (iii) sole power to dispose or to direct the
                               disposition of: none

                         (iv)  shared power to dispose or to direct disposition
                               of: 2,558,400

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:

               The shares reported herein have been acquired on behalf of
               discretionary clients of WAM. Persons other than WAM and WAM GP
               are entitled to receive all dividends from, and proceeds from the
               sale of, those shares.

Item 7    Identification and Classification of the Subsidiary Which Acquired the
          Security Being Reported on by the Parent Holding Company:

               Not Applicable

Item 8    Identification and Classification of Members of the Group:

               Not Applicable

Item 9    Notice of Dissolution of Group:

               Not Applicable

                                Page 5 of 9 pages



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.

                               Page 6 of 9 pages



                                    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.

Date: February 13, 2004

               The undersigned corporation, on the date above written, agrees
               and consents to the joint filing on its behalf of this Schedule
               13G in connection with its beneficial ownership of the security
               reported herein.

                                     WAM Acquisition GP, Inc.
                                         for itself and as general partner of
                                         COLUMBIA WANGER ASSET MANAGEMENT, L.P.


                                     By: /s/ Bruce H. Lauer
                                         ---------------------------------------
                                             Bruce H. Lauer
                                             Senior Vice President and Secretary

                                Page 7 of 9 pages



                                  Exhibit Index

Exhibit 1 Joint Filing Agreement dated as of February 13, 2004 by and among
          Columbia Wanger Asset Management, L.P. and WAM Acquisition GP, Inc.

                               Page 8 of 9 pages



                                                                       EXHIBIT 1

                             JOINT FILING AGREEMENT

     The undersigned hereby agree to the joint filing of the Schedule 13G to
which this Agreement is attached.

               Dated: February 13, 2004

                                     WAM Acquisition GP, Inc.
                                         for itself and as general partner of
                                         COLUMBIA WANGER ASSET MANAGEMENT, L.P.


                                     By: /s/ Bruce H. Lauer
                                         ---------------------------------------
                                             Bruce H. Lauer
                                             Senior Vice President and Secretary

                               Page 9 of 9 pages