UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                                  SCHEDULE 13G

                    Under the Securities Exchange Act of 1934

                               (Amendment No. 1 )*
                                ---------------

                               Nektar Therapeutics
--------------------------------------------------------------------------------
                                (Name of Issuer)

                                  Common Stock
--------------------------------------------------------------------------------
                         (Title of Class of Securities)


                                    640268108
                  ---------------------------------------------
                                 (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).



CUSIP No. 640268108                   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

    OWNED BY                     3,969,400
                      ----------------------------------------------------------
     EACH             7     SOLE DISPOSITIVE POWER

    REPORTING                    None
                      ----------------------------------------------------------
  PERSON WITH         8     SHARED DISPOSITIVE POWER

                                 3,969,400
--------------------------------------------------------------------------------
  9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            3,969,400
--------------------------------------------------------------------------------
 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

            7.1%
--------------------------------------------------------------------------------
 12     TYPE OF REPORTING PERSON*

            IA
--------------------------------------------------------------------------------



CUSIP No. 640268108                  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

    OWNED BY                     3,969,400
                      ----------------------------------------------------------
     EACH             7     SOLE DISPOSITIVE POWER

    REPORTING                    None
                      ----------------------------------------------------------
  PERSON WITH         8     SHARED DISPOSITIVE POWER

                                 3,969,400
--------------------------------------------------------------------------------
  9     AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

            3,969,400
--------------------------------------------------------------------------------
 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

            7.1%
--------------------------------------------------------------------------------
 12     TYPE OF REPORTING PERSON*

            CO
--------------------------------------------------------------------------------



Item 1(a)       Name of Issuer:

                      Nektar Therapeutics

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

                      150 Industrial Road
                      San Carlos, CA  94070

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 both 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:

                      640268108

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:

                           3,969,400

                      (b)  Percent of class:

                           7.1% (based on 56,122,809 shares outstanding as of
                           October 31, 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: 3,969,400
                            (iii) sole power to dispose or to direct the
                                  disposition of: none
                             (iv) shared power to dispose or to direct
                                  disposition of: 3,969,400

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