UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D 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) Leo Kirby 667 Madison Avenue, 17th Floor New York, NY 10021 (212) 521-2418 -------------------------------------------------------------------------------- (Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications) February 14, 2007 ----------------------------------------------------------------------- (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-1(e), 13d-1(f) or 13d-1(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 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 (the "Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). Page 1 of 6 Pages SCHEDULE 13D ---------------------- ----------------- CUSIP No. 812578102 Page 2 of 6 Pages ---------------------- ----------------- --------- ---------------------------------------------------------------------- 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 --------- ---------------------------------------------------------------------- SOURCE OF FUNDS (See Instructions) 4 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 ------------------------ -------- ---------------------------------------------- 7 SOLE VOTING POWER 0 -------- ---------------------------------------------- NUMBER OF 8 SHARED VOTING POWER SHARES BENEFICIALLY 10,325,089 OWNED BY -------- ---------------------------------------------- EACH 9 SOLE DISPOSITIVE POWER REPORTING PERSON 0 WITH -------- ---------------------------------------------- 10 SHARED DISPOSITIVE POWER 10,325,089 --------- ---------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,325,089 --------- ---------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) X --------- ---------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 17.7% --------- ---------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON (See Instructions) IN --------- ---------------------------------------------------------------------- Page 2 of 6 Pages SCHEDULE 13D ---------------------- ----------------- CUSIP No. 812578102 Page 3 of 6 Pages ---------------------- ----------------- --------- ---------------------------------------------------------------------- 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 --------- ---------------------------------------------------------------------- SOURCE OF FUNDS (See Instructions) 4 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 ------------------------ -------- ---------------------------------------------- 7 SOLE VOTING POWER 20,000 -------- ---------------------------------------------- NUMBER OF 8 SHARED VOTING POWER SHARES BENEFICIALLY 10,325,089 OWNED BY -------- ---------------------------------------------- EACH 9 SOLE DISPOSITIVE POWER REPORTING PERSON 20,000 WITH -------- ---------------------------------------------- 10 SHARED DISPOSITIVE POWER 10,325,089 --------- ---------------------------------------------------------------------- 11 AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 10,345,089 --------- ---------------------------------------------------------------------- 12 CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES (See Instructions) X --------- ---------------------------------------------------------------------- 13 PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 17.7% --------- ---------------------------------------------------------------------- 14 TYPE OF REPORTING PERSON (See Instructions) IN --------- ---------------------------------------------------------------------- Page 3 of 6 Pages This Amendment No. 2 to Schedule 13D is being filed by Julian C. Baker and Felix J. Baker (the "Reporting Persons") to supplement the statements on Schedule 13D previously filed by them, as heretofore amended. Except as supplemented herein, such statements, as heretofore amended and supplemented, remain in full force and effect. Item 5. Interest in Securities of the Issuer. Set forth below is the aggregate number of shares of Common Stock held, including shares that maybe acquired upon conversion of Preferred Stock and shares that maybe acquired upon the exercise of Warrants and Options, as of the date hereof by each of the following, together with the percentage of outstanding shares of Common Stock that such number represents based upon 58,359,315 shares outstanding, according to The Company's SEC 10-Q Filing on November 7, 2006. Such percentage figures are calculated on the basis that the shares of Preferred Stock, Warrants and Options owned by the Reporting Persons are deemed converted into or exercised for shares of Common Stock but other outstanding shares of Preferred Stock, Warrants and Options are not deemed converted or exercised. Percent of class Name Number of Shares Outstanding -------------------------------------------------------------------------------- Baker Bros. Investments, L.P. 266,495 0.5% -------------------------------------------------------------------------------- Baker Bros. Investments II, L.P. 272,518 0.5% -------------------------------------------------------------------------------- Baker Biotech Fund I, L.P. 3,594,305 6.2% -------------------------------------------------------------------------------- Baker Brothers Life Sciences, L.P. 5,746,112 9.8% -------------------------------------------------------------------------------- 14159, L.P. 75,598 0.1% -------------------------------------------------------------------------------- Baker/Tisch Investments, L.P. 370,061 0.6% -------------------------------------------------------------------------------- Felix J. Baker 20,000 0.0% -------------------------------------------------------------------------------- Total 10,345,089 17.7% -------------------------------------------------------------------------------- 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, Julian C. Baker and Felix J. Baker may each be deemed to be beneficial owners of shares owned by such entities and may be deemed to have shared power to vote or direct the vote of and shared power to dispose or direct the disposition of such securities. The entities noted below are parties to a voting agreement contained in the Investors Rights Agreement referred to in Item 6 of the Schedule 13D previously filed on June 23, 2006. The parties to the voting agreement may be deemed to constitute a "group" for purposes of Section 13(d) of the Act. The Reporting Persons disclaim beneficial ownership of such shares held by such other persons, and such shares are excluded from the table above. The following transactions in Common Stock were effected by the entities noted below during the sixty days preceding the filing of this statement. None of the reporting Persons has effected any other transactions in Common Stock during this period. Page 4 of 6 Pages ------------------------------------------------------------------------------------------------ Price/ Name Date Number of Shares Transaction Share ------------------------------------------------------------------------------------------------ Baker Brothers Investments, L.P. 7/14/2007 74,127 Sale 8.76 ------------------------------------------------------------------------------------------------ Baker Brothers Investments II, L.P. 7/14/2007 75,803 Sale 8.76 ------------------------------------------------------------------------------------------------ Baker Brothers Life Sciences, L.P. 7/14/2007 1,599,792 Sale 8.76 ------------------------------------------------------------------------------------------------ Baker Biotech Fund I, L.P. 7/14/2007 999,782 Sale 8.76 ------------------------------------------------------------------------------------------------ Baker/ Tisch Investments, L.P. 7/14/2007 102,935 Sale 8.76 ------------------------------------------------------------------------------------------------ 14159, L.P. 7/14/2007 19,561 Sale 8.76 ------------------------------------------------------------------------------------------------ Exhibit 4. Agreement regarding the joint filing of this statement. 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. February 16, 2007 By: /s/ Julian C. Baker ------------------------------ Julian C. Baker By: /s/ Felix J. Baker ------------------------------ Felix J. Baker Page 5 of 6 Pages EXHIBIT 4 AGREEMENT In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree that this Statement on Schedule 13D relating to the Common Stock, $0.001 par value, of Seattle Genetics, Inc. is being filed with the Securities and Exchange Commission on behalf of each of them. February 15, 2007 By: /s/ Julian C. Baker ------------------------------ Julian C. Baker By: /s/ Felix J. Baker ------------------------------ Felix J. Baker Page 6 of 6 Pages