Edgar Filing: SEATTLE GENETICS INC /WA

Ownership Submission

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person ^*

Â Baker Brothers Life Sciences LP

2. Date of Event Requiring Statement (Month/Day/Year)
05/17/2013

3. Issuer Name and Ticker or Trading Symbol
SEATTLE GENETICS INC /WA [SGEN]

(Last)

(First)

(Middle)

667 MADISON AVENUE, 21ST FLOOR

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

__X__ Director	_____ 10% Owner
_____ Officer (give title below)	_____ Other (specify below)

5. If Amendment, Date Original Filed(Month/Day/Year)

(Street)

NEW YORK,Â NYÂ US 10065

6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

(City)

(State)

(Zip)

Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	15,131,223 ⁽¹⁾	D	Â

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security		6. Nature of Indirect Beneficial Ownership (Instr. 5)
Non-Qualified Stock Options (right to buy)	05/17/2004	05/17/2014	Common Stock	10,000	$ 7.26	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/13/2005	05/12/2015	Common Stock	10,000	$ 5.11	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/19/2006	05/18/2016	Common Stock	10,000	$ 4.18	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/25/2007	05/25/2017	Common Stock	10,000	$ 10.2	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/16/2008	05/16/2018	Common Stock	10,000	$ 10.08	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/15/2009	05/15/2019	Common Stock	10,000	$ 8.38	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/21/2010	05/21/2020	Common Stock	17,500	$ 12.76	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/20/2011	05/20/2021	Common Stock	17,500	$ 19.02	I	See footnote ⁽²⁾
Non-Qualified Stock Options (right to buy)	05/18/2012	05/17/2022	Common Stock	17,500	$ 20.06	I	See footnote ⁽²⁾

Reporting Owners

Reporting Owner Name / Address	Relationships
Reporting Owner Name / Address	Director	10% Owner	Officer	Other
Baker Brothers Life Sciences LP 667 MADISON AVENUE, 21ST FLOOR NEW YORK,Â NYÂ US 10065	Â X	Â	Â	Â

Signatures

Baker Bros. Advisors, LLC, Mgmt. Co. and Inv. Adviser to BAKER BROTHERS LIFE SCIENCES, L.P., pursuant to authority granted by Baker Brothers Life Sciences Capital, L.P., GP to Baker Brothers Life Sciences, L.P Name:Scott L. Lessing, Title: President /s/		05/21/2013
^**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	The shares of common stock of Seattle Genetics, Inc. reported herein are held directly by Baker Brothers Life Sciences, L.P. ("Life Sciences"), a limited partnership the sole general partner of which is Baker Brothers Life Sciences Capital, L.P., a limited partnership the sole general partner of which is Baker Brothers Life Sciences Capital (GP), LLC. Julian C. Baker and Felix J. Baker are the controlling members of Baker Brothers Life Sciences Capital (GP), LLC. Baker Bros. Advisors, LLC (the "Adviser") serves as the Investment Adviser to Life Sciences. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest. On April 12, 2012, the Adviser, Life Sciences and the general partner of Life Sciences entered into an amended and restated management agreement which gave the Adviser complete and unlimited discretion and authority with respect to Life Sciences' investments and voting power over investments. The general partner of Life Sciences relinquished all discretion and authority with respect to Life Sciences' investments and voting power over investments. Julian C. Baker and Felix J. Baker each may be deemed to control the Adviser and to indirectly beneficially own the shares beneficially owned by it. Julian C. Baker and Felix J. Baker disclaim beneficial ownership of these securities, except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that Felix J. Baker or Julian C. Baker is the beneficial owner of the above referenced securities for purposes of Section 16 or for any other purpose. The shares reported herein have been previously reported by Felix J. Baker, Julian C. Baker and the Adviser in their own Section 16 reports. In the future, Life Sciences may jointly file Section 16 reports with Julian C. Baker, Felix J. Baker and the Adviser.
(2)	These stock options were issued to Felix J. Baker in his capacity as director of Seattle Genetics, Inc. Felix J. Baker serves on the Issuer's Board of Directors (the "Board") as a representative of Life Sciences. Felix J. Baker, pursuant to the policies of the Adviser, did not have any right to the pecuniary interest in the stock options issued for his service on the Board. Life Sciences, with 667, L.P. and 14159, L.P., owns an indirect proportionate pecuniary interest in the options issued in connection with Felix J. Baker's service on the Board. Solely as a result of their ownership interest in the general partners of the general partners of the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the options issued to Felix J. Baker (i.e. no direct pecuniary interest). The stock options reported herein have been previously reported by Felix J. Baker.
Â Remarks: Remarks: FelixÂ J.Â BakerÂ isÂ aÂ directorÂ ofÂ SeattleÂ Genetics,Â Inc.Â (theÂ "Issuer").Â ForÂ purposesÂ ofÂ SectionÂ 16Â ofÂ theÂ SecuritiesÂ ExchangeÂ ActÂ ofÂ 1934,Â asÂ amended,Â BakerÂ BrothersÂ LifeÂ Sciences,Â L.P.Â isÂ deemedÂ aÂ directorÂ byÂ deputizationÂ byÂ virtueÂ ofÂ itsÂ representationÂ onÂ theÂ BoardÂ ofÂ theÂ Issuer.

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