Schedule 13D
Cusip No. 812578102
                                                   -----------------------------
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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                  SCHEDULE 13D
                                 (Rule 13d-101)

                    Under the Securities Exchange Act of 1934
                                (Amendment No. 2)

                             Seattle Genetics, Inc.
--------------------------------------------------------------------------------
                                (Name of Issuer)

                    Common Stock, par value $0.001 per share
                    ----------------------------------------
                         (Title of Class of Securities)

                                    812578102
                           ---------------------------
                                 (CUSIP Number)


                               Phillip Isom, Esq.
                              O'Melveny & Myers LLP
                                 7 Times Square
                               New York, NY 10036
                            Telephone: (212) 408-2418
--------------------------------------------------------------------------------
            (Name, Address and Telephone Number of Person Authorized
                     to Receive Notices and Communications)


                                 March 30, 2005
                       ----------------------------------
             (Date of Event which Requires Filing of this Statement)

      If the filing person has previously filed a statement on Schedule 13G to
report the acquisition that is the subject of this Schedule 13D, and is filing
this schedule because of Rule 13d-l(e), 13d-l(f) or 13d-l(g), check the
following box |_|

      Note: Schedules filed in paper format shall include a signed original and
five copies of the schedule, including all exhibits. See Rule 13d-7 for other
parties to whom copies are to be sent. 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 disclosures provided in a prior cover page. The
information required on this cover page shall not be deemed to be "filed" for
the purpose of Section 18 of the Securities Exchange Act of 1934 ("Exchange
Act") or otherwise subject to the liabilities of that section of the Exchange
Act but shall be subject to all other provisions of the Exchange Act (however,
see the Notes)

                                  Page 1 of 28




Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners (BHCA), L.P.
         13-3371826
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             5,417,325 (includes shares of Series A
           WITH              Convertible Preferred Stock and Warrant to Purchase
                             601,925 shares of common stock)

                             8        SHARED VOTING POWER
                                              0

                             9       SOLE DISPOSITIVE POWER
                                     5,417,325 (includes shares of Series A
                             Convertible Preferred Stock and Warrant to Purchase
                             601,925 shares of common stock)

                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         5,417,325 (includes shares of Series A Convertible Preferred Stock and
         Warrant to Purchase 601,925 shares of common stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(1)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           11.4 %
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------
(1) The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                  Page 2 of 28




Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners Global Investors, L.P.
         13-4197054
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             912,791 (includes shares of Series A
           WITH              Convertible Preferred Stock and warrant to purchase
                             101,421 shares of Common Stock)
                             ---------------------------------------------------
                             8        SHARED VOTING POWER
                                              0
                             ---------------------------------------------------
                             9        SOLE DISPOSITIVE POWER
                                      912,791 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             101,421 shares of Common Stock)
                             ---------------------------------------------------
                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  912,791 (includes shares of Series A Convertible Preferred
         Stock and warrant to purchase 101,421 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(2)                                               |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           2.1%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------
(2) The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.
                                  Page 3 of 28




Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners Global Investors A, L.P.
         26-0032493
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             124,436 (includes shares of Series A
           WITH              Convertible Preferred Stock and warrant to purchase
                             13,826 shares of Common Stock)
                             ---------------------------------------------------
                             8        SHARED VOTING POWER
                                              0
                             ---------------------------------------------------
                             9        SOLE DISPOSITIVE POWER
                                      124,436 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             13,826 shares of Common Stock)
                             ---------------------------------------------------
                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         124,436 (includes shares of Series A Convertible Preferred Stock and
         warrant to purchase 13,826 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(3)                                             |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           0.3 %
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------

3 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.
                                  Page 4 of 28




Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners Global Investors (Cayman), L.P.
         13-4197057
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Cayman Islands
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             463,298 (includes shares of Series A
           WITH              Convertible Preferred Stock and warrant to purchase
                             51,478 shares of Common Stock)

                             8        SHARED VOTING POWER
                                              0

                             9       SOLE DISPOSITIVE POWER
                                      463,298 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             51,478 shares of common stock)

                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         463,298 (includes shares of Series A Convertible Preferred Stock and
         warrant to purchase 51,478 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(4)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           1.1%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------

4 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                  Page 5 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners Global Investors (Cayman) II, L.P.
         26-0005546
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Cayman Islands
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             51,626 (includes shares of Series A
           WITH              Convertible Preferred Stock and warrant to purchase
                             5,736 shares of Common Stock)

                             8        SHARED VOTING POWER
                                              0

                             9       SOLE DISPOSITIVE POWER
                                      51,626 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             5,736 shares of Common Stock)

                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         51,626 (includes shares of Series A Convertible Preferred Stock and
         warrant to purchase 5,736 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(5)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           0.1%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------

5 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                  Page 6 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         J.P. Morgan Partners Global Investors (Selldown), L.P.
         56-2489868
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Cayman Islands
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON             343,024 (includes shares of Series A
           WITH              Convertible Preferred Stock and warrant to purchase
                             38,114 shares of Common Stock)

                             8        SHARED VOTING POWER
                                              0

                             9       SOLE DISPOSITIVE POWER
                                      343,024 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             38,114 shares of Common Stock)

                             10       SHARED DISPOSITIVE POWER
                                              0
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         343,024 (includes shares of Series A Convertible Preferred Stock and
         warrant to purchase 38,114 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(6)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           0.8%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------

6 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.
                                  Page 7 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS

                 Julian C. Baker
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP See
         Instructions)
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS (See Instructions)
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
         United States
--------------------------------------------------------------------------------
NUMBER OF SHARES             7        SOLE VOTING POWER
BENEFICIALLY                                 0
OWNED BY EACH
REPORTING PERSON
WITH
                             8        SHARED VOTING POWER
                                         8,175,684 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             812,500 shares of Common Stock)

                             9       SOLE DISPOSITIVE POWER
                                              0

                             10       SHARED DISPOSITIVE POWER
                                         8,175,684 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             812,500 shares of Common Stock)
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
              8,175,684 (includes shares of Series A Convertible Preferred Stock
         and warrant to purchase 812,500 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES (See Instructions)(7)                             |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           16.5%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  IN
--------------------------------------------------------------------------------

----------

7 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                  Page 8 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS

                 Felix J. Baker
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP See
         Instructions)
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS (See Instructions)
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
         United States
--------------------------------------------------------------------------------
NUMBER OF SHARES             7        SOLE VOTING POWER
BENEFICIALLY                                 0
OWNED BY EACH
REPORTING PERSON
WITH
                             8        SHARED VOTING POWER
                                         8,175,684 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             812,500 shares of Common Stock)

                             9       SOLE DISPOSITIVE POWER
                                              0

                             10       SHARED DISPOSITIVE POWER
                                         8,175,684 (includes shares of Series A
                             Convertible Preferred Stock and warrant to purchase
                             812,500 shares of Common Stock)
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
              8,175,684 (includes shares of Series A Convertible Preferred Stock
         and warrant to purchase 812,500 shares of Common Stock)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES (8)                             |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           16.5%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  IN
--------------------------------------------------------------------------------

----------

8 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                  Page 9 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         Delphi Ventures VI, L.P.
         42-1561726
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON                     0
           WITH
                             8        SHARED VOTING POWER
                                      2,227,725 (includes 1,980,200 shares of
                                      Common Stock issuable upon conversion of
                                      the Series A Convertible Preferred Stock
                                      and 247,525 shares of Common Stock
                                      issuable upon exercise of the Warrants)

                             9       SOLE DISPOSITIVE POWER
                                              0

                             10       SHARED DISPOSITIVE POWER
                                      2,227,725 (includes 1,980,200 shares of
                                      Common Stock issuable upon conversion of
                                      the Series A Convertible Preferred Stock
                                      and 247,525 shares of Common Stock
                                      issuable upon exercise of the Warrants)
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         2,227,725 (includes 1,980,200 shares of Common Stock issuable upon
         conversion of the Series A Convertible Preferred Stock and 247,525
         shares of Common Stock issuable upon exercise of the Warrants)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(9)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           5.0%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------

9 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                 Page 10 of 28



Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         Delphi BioInvestments VI, L.P.
         04-3760672
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON                     0
           WITH
                             8        SHARED VOTING POWER
                                      22,275 includes 19,800 shares of Common
                                      Stock issuable upon conversion of the
                                      Series A Convertible Preferred Stock and
                                      2,475 shares of Common Stock issuable
                                      upon exercise of the Warrants)

                             9       SOLE DISPOSITIVE POWER
                                              0

                             10       SHARED DISPOSITIVE POWER
                                      22,275 (includes 19,800 shares of
                                      Common Stock issuable upon conversion of
                                      the Series A Convertible Preferred Stock
                                      and 2,475 shares of Common Stock issuable
                                      upon exercise of the Warrants)
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         22,275 (includes 19,800 shares of Common Stock issuable upon conversion
         of the Series A Convertible Preferred Stock and 2,475 shares of Common
         Stock issuable upon exercise of the Warrants)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(10)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           0%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  PN
--------------------------------------------------------------------------------

----------
10 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                 Page 11 of 28





Schedule 13D
Cusip No. 812578102

--------------------------------------------------------------------------------
1        NAMES OF REPORTING PERSONS
         I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)

         Delphi Management Partners VI, L.L.C.
--------------------------------------------------------------------------------
2        CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
                                                                    (a) |_|
                                                                    (b) |X|
--------------------------------------------------------------------------------
3        SEC USE ONLY
--------------------------------------------------------------------------------
4        SOURCE OF FUNDS
                  WC
--------------------------------------------------------------------------------
5        CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED
         PURSUANT TO ITEMS 2(d) or 2(e)                                 |_|
--------------------------------------------------------------------------------
6        CITIZENSHIP OR PLACE OF ORGANIZATION
                  Delaware
--------------------------------------------------------------------------------
SHARES BENEFICIALLY OWNED    7        SOLE VOTING POWER
 BY EACH REPORTING PERSON                     0
           WITH
                             8        SHARED VOTING POWER
                                      2,250,000 includes 2,000,000 shares of
                                      Common Stock issuable upon conversion of
                                      the Series A Convertible Preferred Stock
                                      and 250,000 shares of Common Stock
                                      issuable upon exercise of the Warrants)

                             9       SOLE DISPOSITIVE POWER
                                              0

                             10       SHARED DISPOSITIVE POWER
                                      2,250,000 includes 2,000,000 shares of
                                      Common Stock issuable upon conversion of
                                      the Series A Convertible Preferred Stock
                                      and 250,000 shares of Common Stock
                                      issuable upon exercise of the Warrants)
--------------------------------------------------------------------------------
11       AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
         2,250,000 includes 2,000,000 shares of Common Stock issuable upon
         conversion of the Series A Convertible Preferred Stock and 250,000
         shares of Common Stock issuable upon exercise of the Warrants)
--------------------------------------------------------------------------------
12       CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES
         CERTAIN SHARES(11)                                              |X|
--------------------------------------------------------------------------------
13       PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                           5.1%
--------------------------------------------------------------------------------
14       TYPE OF REPORTING PERSON
                  OO
--------------------------------------------------------------------------------

----------
11 The Reporting Person above is party to a voting agreement contained in the
Investors Rights Agreement described herein. As a result, the parties to the
Investors Rights Agreement may be deemed to constitute a "group" for purposes of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended (the "Act")
with respect to 17,738,184 shares of Common Stock (defined herein), representing
30.1% of the outstanding voting power of the Issuer. The Reporting Person above
disclaims beneficial ownership of any securities held by any other Reporting
Person and the filing of this Statement on Schedule 13D shall not be deemed an
admission that the Reporting Person above and any other person or persons
constitute a "group" for purposes of Section 13(d)(3) of the Act or Rule 13d-5
thereunder.

                                 Page 12 of 28



Preliminary Statement: This Schedule 13D is being amended to reflect the
purchase by the Baker Reporting Persons of 863,179 shares of the Issuer's Common
Stock in open market purchases in 2004 and 2005 as well as to amend a
typographical error in the shares reported for the JPMP Reporting Persons.

Item 1. Security and Issuer.

            The class of equity securities to which this statement (this
            "Statement") relates is the Common Stock, par value $0.001 per share
            (the "Common Stock") of Seattle Genetics, Inc., a Delaware
            corporation (the "Issuer" or "Company"). The Issuer's principal
            executive offices are located at 21823 -- 30th Drive S.E., Bothell,
            WA 98021.

Item 2.    Identity and Background.

            JPMP Reporting Persons

            This Statement is being filed by: (i) J.P. Morgan Partners (BHCA),
            L.P., a limited partnership organized under the laws of Delaware
            ("JPMP (BHCA)"), whose principal office is located at 1221 Avenue of
            the Americas, New York, NY 10020, (ii) J.P. Morgan Partners Global
            Investors, L.P., a limited partnership organized under the laws of
            Delaware ("JPMP Global"), whose principal office is located at the
            same address as JPMP (BHCA), (iii) J.P. Morgan Partners Global
            Investors A, L.P., a limited partnership organized under the laws of
            Delaware ("JPMP Global A"), whose principal office is located at the
            same address as JPMP (BHCA), (iv) J.P. Morgan Partners Global
            Investors (Cayman), L.P., a limited partnership organized under the
            laws of the Cayman Islands ("JPMP Cayman"), whose principal office
            is located at the same address as JPMP (BHCA), (v) J.P. Morgan
            Partners Global Investors (Cayman) II, L.P. a limited partnership
            organized under the laws of the Cayman Islands ("JPMP Cayman II"),
            whose principal address is located at the same address as JPMP
            (BHCA) and (vi) J.P. Morgan Partners Global Investors (Selldown),
            L.P., a Delaware Limited Partnership ("JPMP Selldown" and
            collectively with JPMP (BHCA), JPMP Global, JPMP Global A and JPMP
            Cayman, the "JPMP Reporting Persons"), whose principal office is
            located at the same address as JPMP (BHCA).

            JPMP (BHCA) is engaged in the venture capital, private equity and
            leveraged buyout business. The general partner of JPMP (BHCA) is
            JPMP Master Fund Manager, L.P., a Delaware limited partnership
            ("JPMP Master Fund"), whose principal business office is located at
            the same address as JPMP (BHCA), and is also engaged directly and
            indirectly (through affiliates) in the venture capital, private
            equity and leveraged buyout business.

                                 Page 13 of 28



            JPMP Global, JPMP Global A, JPMP Cayman, JPMP Cayman II and JPMP
            Selldown (collectively, the "Global Fund Entities") are also engaged
            in the venture capital, private equity and leveraged buyout
            business. The general partner of each of the Global Fund Entities is
            J.P. Morgan Partners Global Investors, L.P., a Delaware limited
            partnership ("JPMP Investors"), whose principal place of business is
            located at the same address as JPMP (BHCA). JPMP Investors is
            engaged indirectly in the venture capital, private equity and
            leveraged buyout business as general partner of each of the Global
            Fund Entities.

            The general partner of each of JPMP Master Fund and JPMP Investors
            is JPMP Capital Corp., a New York corporation ("JPMP Capital
            Corp."), whose principal business office is located at the same
            address as JPMP (BHCA), and is also engaged directly and indirectly
            (through affiliates) in the venture capital, private equity and
            leveraged buyout business. Set forth in Schedule A hereto and
            incorporated herein by reference are the names, business addresses,
            principal occupations and employments of each executive officer and
            director of JPMP Capital Corp.

            JPMP Capital Corp. is a wholly owned subsidiary of JPMorgan Chase &
            Co., a Delaware Corporation ("JPMorgan Chase") which is engaged
            (primarily through subsidiaries) in the commercial banking business
            with its principal office located at 270 Park Avenue, New York, NY
            10018. Set forth in Schedule B hereto and incorporated herein by
            reference are the names, business addresses, principal occupations
            and employments of each executive officer and director of JPMorgan
            Chase.

            Baker Reporting Persons

            This Statement is also being filed by: (i) Julian C. Baker and (ii)
            Felix J. Baker, each of whom is a United States citizen whose
            principal office is located at 667 Madison Avenue, New York, NY
            10021 (collectively, the "Baker Reporting Persons"). Set forth below
            is certain information with respect to the Baker Reporting Persons:


           Name                   Present Principal Occupation

           Julian C. Baker        Managing Member, Baker Bros. Advisors, LLC
                                  (an entity engaged in investment activities)

           Felix J. Baker         Managing Member, Baker Bros. Advisors, LLC
                                  (an entity engaged in investment activities)

            Delphi Reporting Persons

            This Statement is also being filed by: (i) Delphi Ventures VI, L.P.,
            a limited partnership organized under the laws of Delaware ("Delphi
            Ventures"), whose principal office is located at 3000 Sand Hill
            Road, Building 1, Suite 135, Menlo Park, CA 94025, (ii) Delphi
            BioInvestments VI, L.P., a limited partnership organized under the
            laws of Delaware ("Delphi BioInvestments"), whose principal office
            is located at the same address as Delphi Ventures, and (iii) Delphi
            Management Partners VI, L.L.C., a Delaware limited liability company
            ("Delphi Management", and together with Delphi Ventures and Delphi
            BioInvestments, the "Delphi Reporting Persons") whose principal
            office is located at the same address as Delphi Ventures.

                                 Page 14 of 28


           The Delphi Reporting Persons are engaged in the venture capital
           business. The general partner of each of Delphi Ventures and Delphi
           BioInvestments is Delphi Management. Delphi Management is also
           engaged indirectly (through affiliates) in the venture capital
           business. Set forth in Schedule C hereto and incorporated herein by
           reference are the names, business addresses, principal occupations
           and employments of each managing member of Delphi Management.

            The Delphi Reporting Persons, the JPMP Reporting Persons and the
            Baker Reporting Persons are collectively referred to herein as the
            "Reporting Persons".

            During the last five years, none of the Reporting Persons have been
            convicted in any criminal proceeding (excluding traffic violations
            or similar misdemeanors) or have been a party to a civil proceeding
            of a judicial or administrative body of competent jurisdiction
            resulting in their being subject to a judgment, decree or final
            order enjoining future violations of, or prohibiting or mandating
            activities subject to, federal or state securities laws, or finding
            any violations with respect to such laws.

Item 3.    Source and Amount of Funds or Other Consideration.

           JPMP Reporting Persons:

           The funds provided by JPMP (BHCA) and the Global Fund Entities for
           the purchase of the securities reported in Item 5 below were obtained
           from the contributed capital and available working capital of JPMP
           (BHCA) and the Global Fund Entities, which includes funds that are
           held available for such purpose.

           Baker Reporting Persons:

           The funds used by the limited partnerships controlled by Julian C.
           Baker and Felix J. Baker to purchase the securities reported in Item
           5 below were provided from the available working capital of such
           limited partnerships.

           Delphi Reporting Persons:

           The funds provided by Delphi Ventures and Delphi BioInvestments for
           the purchase of the securities reported in Item 5 below were obtained
           from the contributed capital and available working capital of Delphi
           Ventures and Delphi BioInvestments respectively, which includes funds
           that are held available for such purpose.

                                 Page 15 of 28


Item 4.    Purpose of Transactions.

           The securities referred to in Item 5 below (other than the Open
           Market Purchases (defined below) by the Baker Reporting Persons) were
           acquired pursuant to the Securities Purchase Agreement referred to in
           Item 6 below solely for investment purposes. The Open Market
           Purchases by the Baker Reporting Persons were acquired pursuant to
           open market transactions for investment purposes only.

           The transactions described in Item 6 below are incorporated in their
           entirety herein by reference.

           Subject to the rights of the Reporting Persons set forth in the
           Securities  Purchase Agreement and the Investors Rights Agreement
           referred to in Item 6 below, except as set forth in this Item 4, none
           of the JPMP Reporting Persons, the Baker Reporting Persons, or the
           Delphi Reporting Persons have a present plan or proposal that relates
           to or would result in any of the actions specified in clauses (a)
           through (j) of Item 4 of Schedule 13D. However, each of the JPMP
           Reporting Persons, the Baker Reporting Persons and the Delphi
           Reporting Persons reserves the right to propose or participate in
           future transactions which may result in one or more of such actions,
           including but not limited to, an extraordinary corporate
           transaction, such as a merger, reorganization or liquidation, sale
           of a material amount of assets of the Issuer or its subsidiaries, or
           other transactions which might have the effect of causing the
           Issuer's Common Stock to cease to be listed on the NASDAQ National
           Market System or causing the Common Stock to become eligible for
           termination of registration, under section 12(g) of the Securities
           Exchange Act of 1934, as amended (the "Act").

Item 5.    Interest in Securities of the Issuer.

           The percentages of outstanding shares of the Issuer reported in this
           Item 5 are based on 42,140,428 shares of Common Stock outstanding as
           of March 9, 2005 as reported by the Issuer's Form 10K for fiscal year
           ended December 31, 2004.

           JPMP Reporting Persons

           JPMP (BHCA) beneficially owns 5,417,325 shares of the Issuer's Common
           Stock, which represents 11.4% of the Issuer's Common Stock. JPMP
           Global beneficially owns 912,791 shares of the Issuer's Common
           Stock, which represents 2.1% of the Issuer's Common Stock. JPMP
           Global A beneficially owns 124,436 shares of the Issuer's Common
           Stock, which represents 0.3% of the Issuer's Common Stock. JPMP
           Cayman beneficially owns 463,298 shares of the Issuer's Common Stock,
           which represents 1.1% of the Issuer's Common Stock. JPMP Cayman II
           beneficially owns 51,626 shares of the Issuer's Common Stock, which
           represents 0.1% of the Issuer's Common Stock. JPMP Selldown
           beneficially owns 343,024 shares of the Issuer's Common Stock, which
           represents 8% the Issuer's Common Stock.

                                 Page 16 of 28


           JPMP Master Fund, as the General Partner of JPMP (BHCA), may be
           deemed to beneficially own the shares beneficially owned by JPMP
           (BHCA).

           JPMP Investors, as the General Partner of each of the Global Fund
           Entities, may be deemed to beneficially own the shares beneficially
           owned by each of the Global Fund Entities.

           JPMP Capital Corp., as the General Partner of each of JPMP Master
           Fund and JPMP Investors, may be deemed to beneficially own the shares
           beneficially owned by JPMP (BHCA) and each of the Global Fund
           Entities.

           JPMP Capital Corp. is a wholly owned subsidiary of JPMorgan Chase &
           Co., a publicly traded company.

           The foregoing shall not be an admission that JPMP Master Fund, JPMP
           Investors or JPMP Capital Corp. are the beneficial owners of the
           shares held by JPMP (BHCA) and/or the Global Fund Entities.

           Baker Reporting Persons:

           Set forth in the table below is the aggregate number of shares of
           Common Stock beneficially owned as of the date hereof by each of the
           limited partnerships controlled by the Baker Reporting Persons,
           together with the percentage of outstanding shares of Common Stock
           that such ownership represents based upon shares of Common Stock
           outstanding as of March 9, 2005, in each case taking into account the
           shares of Common Stock that can be acquired upon conversion of Series
           A Convertible Preferred Stock and exercise of the Warrants to
           purchase shares of Common Stock:


                                            Number of           Percent of Class
              Name                            Shares               Outstanding
  ----------------------------              ---------           ----------------
  Baker/Tisch Investments, L.P.              463,913                    1.1%
  Baker Bros. Investments, L.P.              330,820                    0.8%
  Baker Bros. Investments II, L.P.           338,909                    0.8%
  Baker Biotech Fund I, L.P.                 3,350,091                  7.4%
  Baker Biotech Fund II, L.P.                3,074,235                  6.8%
  Baker Biotech Fund II (Z), L.P.            424,148                    1.0%
  Baker Biotech Fund III, L.P.               151,797                    0.4%
  Baker Biotech Fund III (Z), L.P.           29,134                     0.1%
  14159, L.P.                                12,637                     .03%
  Total                                      8,175,684                  16.5%

                                 Page 17 of 28


           By virtue of their ownership of entities that have the power to
           control the investment decisions of the limited partnerships listed
           in the table above (collectively, the "Baker Entities"), Julian C.
           Baker and Felix J. Baker may each be deemed to be beneficial owners
           of securities owned by the Baker Entities and may be deemed to have
           shared power to vote or direct the vote and to dispose or direct the
           disposition of such securities, although such entities have the sole
           right to receive and power to direct the receipt of dividends from,
           and the proceeds from the sale of, securities owned by them.

           Additionally, Felix J. Baker is a director of the Issuer.

           Delphi Reporting Persons

           Delphi Ventures beneficially owns 2,227,725 shares of the Issuer's
           Common Stock, which represents 5.0% of the Issuer's Common Stock.
           Delphi BioInvestments beneficially owns 22,275 shares of the Issuer's
           Common Stock, which represents 0.0001% of the Issuer's Common Stock.

           As the general partner of Delphi Ventures and Delphi BioInvestments,
           Delphi Management may be deemed to beneficially own the shares
           beneficially owned by each of Delphi Ventures and Delphi
           BioInvestments.

           The foregoing shall not be an admission that Delphi Management is the
           beneficial owner of the shares held by Delphi Ventures and/or Delphi
           BioInvestments.

           The Reporting Persons are party to a voting agreement contained in
           the Investors Rights Agreement referred to in Item 6 below. The JPMP
           Reporting Persons, the Baker Reporting Persons, and the Delphi
           Reporting Persons together may be deemed to constitute a "group" for
           purposes of Section 13(d)(3) of the Act, with respect to 17,738,184
           shares of Common Stock, representing 30.1% of the outstanding voting
           power of the Issuer.

           Each of the Reporting Persons, however, disclaims beneficial
           ownership of any of the securities owned by any other Reporting
           Person and disclaims that it is a member of a "group" with any other
           persons either for purposes of Section 13(d)(3) of the Act or Rule
           13d-5 thereunder or this Statement or for any other purpose related
           to its beneficial ownership of the Issuer's securities. The filing of
           this Statement shall not be construed as an admission that the
           Reporting Person is the beneficial owner of such shares or that the
           Reporting Person and any of such other stockholders' constitute for
           purposes of Section 13(d) of the Act, a "group." Each Reporting
           Person is not responsible for the accuracy of any information filed
           in this Statement relating to any Reporting Person other than itself
           and its related persons or entities.

           There have been no transactions involving the Issuer's Common Stock
           during the past sixty days which are required to be reported in this
           Statement.

                                 Page 18 of 28


           No person other than the JPMP Reporting Persons, the Baker Reporting
           Persons and the Delphi Reporting Persons has the right to receive or
           the power to direct the receipt of dividends from or the proceeds
           from the sale of the Issuer's Common Stock owned beneficially by the
           JPMP Reporting Persons, the Baker Reporting Persons and the Delphi
           Reporting Persons.

Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to
Securities of the Issuer.

            On May 12, 2003 the Company entered into the Securities Purchase
            Agreement (as amended by Amendment No. 1 dated as of May 14, 2003
            and Amendment No. 2 dated as of June 2, 2003) (the "SPA"), with JPMP
            (BHCA), the Global Fund Entities, the Baker Entities, Delphi
            Ventures, Delphi BioInvestments, entities affiliated with BA Venture
            Partners and T. Rowe Price Health Sciences Fund, Inc. (collectively,
            the "Series A Investors"). Both the SPA and all exhibits thereto are
            attached as Exhibit A hereto and are incorporated herein in their
            entirety by reference.

            Pursuant to the SPA, the Issuer issued in a private placement (a)
            1,640,000 shares of the Company's Series A Convertible Preferred
            Stock (the "Preferred Stock") to the Series A Investors, as well as
            the reservation for issuance of 16,400,000 shares of the Company's
            Common Stock upon conversion of the Preferred Stock, and (b)
            warrants (the "Warrants") to purchase 2,050,000 shares of the
            Company's Common Stock and the reservation for issuance of 2,050,000
            shares of the Company's Common Stock upon the exercise of such
            Warrants (together, the "Preferred Stock Financing"). The Preferred
            Stock has the rights, preferences and privileges set forth in the
            Certificate of Designations of Series A Convertible Preferred Stock
            as filed with the Secretary of State of the State of Delaware. The
            purchase price for the Preferred Stock was $25.00 per share. Each
            share of Preferred Stock is initially convertible into 10 shares of
            Common Stock at a fixed conversion price of $2.50 per share (subject
            to adjustment upon the occurrence of certain events including stock
            subdivisions, combinations, splits, stock dividends, capital
            reorganizations, or capital reclassifications of the Common Stock),
            at such holder's option at any time after the first anniversary of
            the closing of the Investors Rights Agreement among the Company, the
            Reporting Persons and the other investors named therein, dated as of
            July 8, 2003, a copy of which is attached hereto as Exhibit B and is
            incorporated herein in its entirety by reference (the "Investors
            Rights Agreement").

            The Warrants are immediately exercisable at a fixed purchase price
            of $6.25 per share of Common Stock and expire on December 31, 2011.

            Pursuant to the Certificate of Designations and the Investors Rights
            Agreement, the Series A Investors, voting together as a separate
            class, have the right to designate two members of the Company's
            Board of Directors so long as at least 37.5% of the shares of
            Preferred Stock issued at the closing of the Preferred Stock
            Financing remain outstanding. If between 18.75% and 37.5% of the
            shares of Preferred Stock issued at the closing of the Preferred
            Stock Financing are outstanding, the Series A Investors, voting
            together as a separate class, have the right to designate one member
            of the Company's Board of Directors. If less than 18.75% of the
            shares of Preferred Stock issued at the closing of the Preferred
            Stock Financing are outstanding, the rights of the Series A
            Investors to vote separately for the election of directors shall
            terminate.

                                 Page 19 of 28


            Pursuant to the terms of the Investors Rights Agreement, one
            director will be designated by the JPMP Reporting Persons and one
            director will be designated by the Baker Entities. The right of the
            JPMP Reporting Persons and the Baker Entities, as applicable, to
            designate a director terminates if the JPMP Reporting Persons or the
            Baker Entities, as applicable, hold less than 50% of the Preferred
            Stock (or Common Stock issued upon conversion thereof) purchased by
            it at the closing of the Preferred Stock Financing. Pursuant to
            these rights, the JPMP Reporting Persons designated Srinivas
            Akkaraju, M.D., Ph.D. as its representative on the Company's Board
            of Directors and the Baker Entities designated Felix Baker, Ph.D. as
            its representative on the Company's Board of Directors upon the
            closing of the Preferred Stock Financing. The Series A Investors do
            not have the right to vote on members of the Company's Board of
            Directors other than the nominees they designate.

            Each of JPMP (BHCA) and the Global Fund Entities is a party to the
            Regulatory Sideletter, dated as of July 8, 2003, by and among the
            Company, JPMP (BHCA) and each of the Global Fund Entities, a copy of
            which is attached as Exhibit C hereto and is incorporated herein in
            its entirety by reference.

            In August 2004, the Baker Entities acquired 230,166 shares of Common
            Stock, in the aggregate, pursuant to open market purchases (the
            "August Open Market Purchases") on dates, in amounts and for a
            purchase price set forth below:




Baker Entity                 Purchased    Shares    of  Date of Purchase           Purchase Price per Share
                             Common Stock
---------------------------- -------------------------- -------------------------- --------------------------
                                                                         
Baker Bros. Investment,      116                        8/2/04                     $5.89
L.P.                         933                        8/2/04                     $5.9796
                             1,356                      8/3/04                     $5.7122
                             1,643                      8/4/04                     $5.5788
                             1,745                      8/5/04                     $5.5412
                             441                        8/6/04                     $5.5
                             1,145                      8/10/04                    $5.3179
                             94                         8/11/04                    $5.49
                             451                        8/11/04                    $5.4191
                             2,821                      8/12/04                    $5.5783

Baker Bros. Investments      106                        8/2/04                     $5.89
II, L.P.                     855                        8/2/04                     $5.9796
                             1,242                      8/3/04                     $5.7122
                             1,505                      8/4/04                     $5.5788
                             1,619                      8/5/04                     $5.5412
                             408                        8/6/04                     $5.5
                             1,061                      8/10/04                    $5.3179
                             86                         8/11/04                    $5.49
                             418                        8/11/04                    $5.4191
                             2,613                      8/12/04                    $5.5783



                                 Page 20 of 28




                                                                         
Baker Biotech Fund I, L.P.   1,109                      8/2/04                     $5.89
                             8,910                      8/2/04                     $5.9796
                             12,952                     8/3/04                     $5.7122
                             15,692                     8/4/04                     $5.5788
                             16,558                     8/5/04                     $5.5412
                             4,176                      8/6/04                     $5.5
                             10,858                     8/10/04                    $5.3179
                             885                        8/11/04                    $5.49
                             4,242                      8/11/04                    $5.4191
                             26,535                     8/12/04                    $5.5783
---------------------------- -------------------------- -------------------------- --------------------------
Baker Biotech Fund II, L.P.  1,023                      8/2/04                     $5.89
                             8,225                      8/2/04                     $5.9796
                             11,955                     8/3/04                     $5.7122
                             14,485                     8/4/04                     $5.5788
                             15,284                     8/5/04                     $5.5412
                             3,855                      8/6/04                     $5.5
                             10,022                     8/10/04                    $5.3179
                             816                        8/11/04                    $5.49
                             3,912                      8/11/04                    $5.4191
                             24,472                     8/12/04                    $5.5783
---------------------------- -------------------------- -------------------------- --------------------------
Baker Biotech Fund II (z),   146                        8/2/04                     $5.89
L.P.                         1,177                      8/2/04                     $5.9796
                             1,710                      8/3/04                     $5.7122
                             2,072                      8/4/04                     $5.5788
                             2,196                      8/5/04                     $5.5412
                             554                        8/6/04                     $5.5
                             1,440                      8/10/04                    $5.3179
                             119                        8/11/04                    $5.49
                             569                        8/11/04                    $5.4191
                             3,559                      8/12/04                    $5.5783
---------------------------- -------------------------- -------------------------- --------------------------



            In March 2005, the Baker Entities acquired 633,013 shares of Common
            Stock, in the aggregate, pursuant to open market purchases (the
            "March Open Market Purchases" and together with the August Open
            Market Purchases, the "Open Market Purchases") on dates, in amounts
            and for a purchase price set forth in the table below:


                                 Page 21 of 28





Baker Entity                 Purchased    Shares    of  Date of Purchase           Purchase Price per Share
                             Common Stock
---------------------------- -------------------------- -------------------------- --------------------------
                                                                         
Baker/Tisch Investments,     547                        3/22/05                    $4.879
L.P.                         7,749                      3/22/05                    $5.03669
                             5                          3/23/05                    $4.99
                             7,442                      3/23/05                    $4.9595
                             85                         3/28/05                    $4.9
                             261                        3/29/05                    $4.8138
                             622                        3/29/05                    $4.8992
                             1,134                      3/30/05                    $4.9625

Baker Bros. Investments,     576                        3/22/05                    $4.879
L.P.                         8,167                      3/22/05                    $5.03669
                             6                          3/23/05                    $4.99
                             7,843                      3/23/05                    $4.9595
                             89                         3/28/05                    $4.9
                             274                        3/29/05                    $4.8138
                             654                        3/29/05                    $4.8992
                             1,191                      3/30/05                    $4.9625

Baker Bros. Investment II,   559                        3/22/05                    $4.879
L.P.                         7,914                      3/22/05                    $5.03669
                             5                          3/23/05                    $4.99
                             7,600                      3/23/05                    $4.9595
                             86                         3/28/05                    $4.9
                             265                        3/29/05                    $4.8138
                             633                        3/29/05                    $4.8992
                             1,153                      3/30/05                    $4.9625

Baker Biotech Fund I, L.P.   5,828                      3/22/05                    $4.879
                             82,580                     3/22/05                    $5.03669
                             57                         3/23/05                    $4.99
                             79,308                     3/23/05                    $4.9595
                             901                        3/28/05                    $4.9
                             2,767                      3/29/05                    $4.8138
                             6,605                      3/29/05                    $4.8992
                             12,040                     3/30/05                    $4.9625

Baker Biotech Fund II, L.P.  5,234                      3/22/05                    $4.879
                             74,167                     3/22/05                    $5.03669
                             51                         3/23/05                    $4.99
                             71,227                     3/23/05                    $4.9595
                             809                        3/28/05                    $4.9
                             2,486                      3/29/05                    $4.8138
                             5,934                      3/29/05                    $4.8992
                             10,816                     3/30/05                    $4.9625

Baker Biotech Fund II (Z),   729                        3/22/05                    $4.879
L.P.                         10,329                     3/22/05                    $5.03669
                             7                          3/23/05                    $4.99
                             9,919                      3/23/05                    $4.9595
                             113                        3/28/05                    $4.9
                             346                        3/29/05                    $4.8138
                             826                        3/29/05                    $4.8992
                             1,506                      3/30/05                    $4.9625

Baker Biotech Fund III,      4,654                      3/22/05                    $4.879
L.P.                         65,945                     3/22/05                    $5.03669
                             46                         3/23/05                    $4.99
                             63,330                     3/23/05                    $4.9595
                             719                        3/28/05                    $4.9
                             2,210                      3/29/05                    $4.8138
                             5,276                      3/29/05                    $4.8992
                             9,617                      3/30/05                    $4.9625
Baker Biotech Fund III       893                        3/22/05                    $4.879
(Z), L.P.                    12,659                     3/22/05                    $5.03669
                             9                          3/23/05                    $4.99
                             12,157                     3/23/05                    $4.9595
                             138                        3/28/05                    $4.9
                             424                        3/29/05                    $4.8138
                             1,011                      3/29/05                    $4.8992
                             1,843                      3/30/05                    $4.9625

14159, L.P.                  387                        3/22/05                    $4.879
                             5,490                      3/22/05                    $5.03669
                             4                          3/23/05                    $4.99
                             5,274                      3/23/05                    $4.9595
                             60                         3/28/05                    $4.9
                             183                        3/29/05                    $4.8138
                             439                        3/29/05                    $4.8992
                             800                        3/30/05                    $4.9625




                                 Page 22 of 28


Item 7.    Material to be Filed as Exhibits.

            SCHEDULE A

            Item 2 information for executive officers and directors of JPMP
            Capital Corp.12

            SCHEDULE B

            Item 2 information for executive officers and directors of JPMorgan
            Chase.*

            SCHEDULE C

            Item 2 information for managing members of Delphi Management.*

            EXHIBIT A

            Securities Purchase Agreement dated as of May 12, 2003, by and among
            the Issuer and the Series A Investors incorporated by reference to
            Exhibit 10.1 of the Form 8-K filed with the Commission on May 15,
            2003.*

            EXHIBIT B

            Investors Rights Agreement dated as of July 8, 2003, by and among
            the Company and the Investors named therein incorporated by
            reference to Exhibit 4.2 of the Form 8-K filed with the Commission
            on May 15, 2003.*

            EXHIBIT C

            Regulatory Sideletter dated as of July 8, 2003, by and among the
            Company, JPMP (BHCA) and each of the Global Fund Entities.13

---------------
* Filed previously

                                 Page 23 of 28


            EXHIBIT D

            Joint Filing Agreement dated as of May 17, 2004 among the JPMP
            Entities, the Bakers and the Delphi Entities.*



---------------
* Filed previously


                                 Page 24 of 28


                                    SIGNATURE

      After reasonable inquiry and to the best of our knowledge and belief, we
certify that the information set forth in this Statement is true, complete and
correct.

Dated: April 8, 2005


                                J.P. MORGAN PARTNERS (BHCA), L.P.

                                By: JPMP Master Fund Manager, L.P.,
                                    its general partner

                                By: JPMP Capital Corp.,
                                    its general partner

                                By: /s/ Jeffrey  C. Walker
                                    ----------------------
                                    Name:  Jeffrey C. Walker
                                    Title:  President

                                J.P. MORGAN PARTNERS GLOBAL INVESTORS, L.P.

                                By: JPMP Global Investors, L.P.,
                                    its general partner

                                By: JPMP Capital Corp.,
                                    its general partner

                                By: /s/ Jeffrey  C. Walker
                                    ----------------------
                                    Name:  Jeffrey C. Walker
                                    Title:  President


                                J.P. MORGAN PARTNERS GLOBAL
                                INVESTORS (CAYMAN), L.P.

                                By: JPMP Global Investors, L.P.,
                                    its general partner

                                By: JPMP Capital Corp.,
                                    its general partner

                                By: /s/ Jeffrey  C. Walker
                                    ----------------------
                                    Name:  Jeffrey C. Walker
                                    Title:  President


                                 Page 25 of 28


                                J.P. MORGAN PARTNERS GLOBAL
                                INVESTORS A, L.P.

                                By: JPMP Global Investors, L.P.,
                                    its general partner

                                By: JPMP Capital Corp.,
                                    its general partner

                                By: /s/ Jeffrey  C. Walker
                                    ----------------------
                                    Name:  Jeffrey C. Walker
                                    Title:  President

                                J.P. MORGAN PARTNERS GLOBAL
                                INVESTORS (SELLDOWN), L.P.

                                By: JPMP Global Investors, L.P.,
                                    its general partner

                                By: JPMP Capital Corp.,
                                    its general partner

                                By: /s/ Jeffrey  C. Walker
                                    ----------------------
                                    Name:  Jeffrey C. Walker
                                    Title:  President


                                 Page 26 of 28


                                    SIGNATURE

      After reasonable inquiry and to the best of our knowledge and belief, we
certify that the information set forth in this Statement is true, complete and
correct.

Dated: April 8, 2005



                                JULIAN C. BAKER

                                By:   /s/  Julian C. Baker
                                      --------------------
                                        Julian C. Baker

                                FELIX J. BAKER

                                By:   /s/  Felix J. Baker
                                      --------------------
                                        Felix J. Baker



                                 Page 27 of 28


                                    SIGNATURE

      After reasonable inquiry and to the best of our knowledge and belief, we
certify that the information set forth in this Statement is true, complete and
correct.

Dated: April 8, 2005


                                DELPHI VENTURES VI, L.P.

                                By: Delphi Management Partners VI,
                                    L.L.C., its general partner


                                By: /s/ John F. Maroney
                                    --------------------------
                                    John F. Maroney
                                    Managing Member


                                DELPHI BIOINVESTMENTS VI, L.P.

                                By: Delphi Management Partners VI,
                                    L.L.C., its general partner


                                By: /s/ John F. Maroney
                                    --------------------------
                                    John F. Maroney
                                    Managing Member


                                DELPHI MANAGEMENT PARTNERS
                                VI, L.L.C.

                                By: /s/ John F. Maroney
                                    --------------------------
                                    John F. Maroney
                                    Managing Member


                                 Page 28 of 28