Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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 *
Baker Bros. Capital (GP), LLC
   2. Issuer Name and Ticker or Trading Symbol
SEATTLE GENETICS INC /WA [SGEN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
667 MADISON AVENUE 21ST FLOOR		 3. Date of Earliest Transaction (Month/Day/Year)
12/30/2011
(Street)

NEW YORK, NY US 10065		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock (1) (2) 12/30/2011   X   68,006 (3) A $ 6.25 539,130 I Through Partnership (4)

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Common Stock Warrants (right to buy) $ 6.25 12/30/2011   X     68,006 (3) 07/08/2003 12/31/2011 Common Stock 68,006 $ 0 0 I Through Partnership

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Baker Bros. Capital (GP), LLC
667 MADISON AVENUE 21ST FLOOR
NEW YORK, NY US 10065		   X   X    
BAKER JULIAN
667 MADISON AVENUE, 21ST FLOOR
NEW YORK, NY US 10065		   X   X    
BAKER FELIX
667 MADISON AVENUE, 21ST FLOOR
NEW YORK, NY US 10065		   X   X    

Signatures

 /s/ Julian C. Baker, as Managing Member of Baker Bros. Capital (GP), LLC   01/04/2012
**Signature of Reporting Person Date
 /s/ Julian C. Baker   01/04/2012
**Signature of Reporting Person Date
 /s/ Felix J. Baker   01/04/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) In addition to Baker Bros. Capital (GP), LLC, this Form 4 is being filed jointly by Felix J. Baker and Julian C. Baker, each of whom has the same business address as Baker Bros. Capital (GP), LLC and may be deemed to have a pecuniary interest in securities owned by it. Felix J. Baker is a director of the Issuer. Because of certain relationships with other security holders of the Issuer, the Reporting Persons are filing solely for informational purposes as if they were members of a group with such security holders. (Continued in footnote 2).
(2) However, the Reporting Persons disclaim that they and any other person or persons, in fact constitute a "group" for purposes of Section 13(d)(3) of the Securities Exchange Act of 1934, as amended, or Rule 13d-5 thereunder or that they are the beneficial owners of securities owned by any such other persons, and each of them disclaims beneficial ownership of securities reported herein except to the extent of their pecuniary interest, if any, therein.
(3) Represents 33,475 warrants exercised by Baker Bros. Investments I, L.P. and 34,531 warrants exercised by Baker Bros. Investmenets II, L.P.
(4) Represents shares 266,495 shares owned directly by Baker Bros. Investments, L.P. and 272,635 shares owned directly by Baker Bros. Investments II, L.P., limited partnerships of which the sole general partner is Baker Bros. Capital, L.P., a limited partnership of which the sole general partner is Baker Bros. Capital (GP), LLC. Felix J. Baker and Julian C. Baker are controlling members of Baker Bros. Capital (GP), LLC.

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