SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* BAKER BROS. ADVISORS LP (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Seagen Inc. [ SGEN ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 05/31/2023
	4. If Amendment, Date of 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
	Rule 10b5-1(c) Transaction Indication Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

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								23,280(1)	D
Common Stock								23,277(2)	D
Common Stock	05/31/2023		A		2,044	A	$0.00	1,731,202	I	See footnotes(3)(4)(5)(6)(7)(8)(9)(10)
Common Stock	05/31/2023		A		2,044	A	$0.00	42,977,301	I	See footnotes(4)(5)(6)(7)(8)(9)(10)(11)

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 Securities Underlying Derivative Security (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: 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

1. Name and Address of Reporting Person* BAKER BROS. ADVISORS LP (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Baker Brothers Life Sciences LP (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* 667, L.P. (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* BAKER JULIAN (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* BAKER FELIX (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Baker Bros. Advisors (GP) LLC (Last) (First) (Middle) 860 WASHINGTON STREET, 3RD FLOOR (Street) NEW YORK NY 10014 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. Reflects shares of common stock ("Common Stock") of Seagen Inc. (the "Issuer") held directly by Felix J. Baker.

2. Reflects Common Stock held directly by Julian C. Baker.

3. After giving effect to the transactions reported herein and as a result of their ownership interest in (i) Baker Biotech Capital, L.P. and (ii) 667, L.P. ("667"), Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I directly held by 667, a limited partnership of which the sole general partner is Baker Biotech Capital, L.P., a limited partnership of which the sole general partner is Baker Biotech Capital (GP), LLC, due to their interest in 667 and Baker Biotech Capital, L.P.'s right to receive an allocation of a portion of the profits from 667.

4. Pursuant to the policies of the Adviser, Felix J. Baker does not have a right to any of the Issuer's securities issued in lieu of director retainer fees and the Funds are entitled to an indirect proportionate pecuniary interest in the securities. 667 and Baker Brothers Life Sciences, L.P. ("Life Sciences", and together with 667, the "Funds") each own an indirect proportionate pecuniary interest in the shares of Common Stock. Solely as a result of their ownership interest in (i) the general partners of the Funds and (ii) the Funds, Felix J. Baker and Julian C. Baker may be deemed to have an indirect pecuniary interest in the shares of Common Stock issued in lieu of director retainer fees, non-qualified options to purchase Common Stock ("Stock Options"), Common Stock issued upon exercise of Stock Options, restricted stock units (each an "RSU") payable solely in Common Stock and Common Stock received upon vesting of RSUs (i.e. no direct pecuniary interest).

5. Includes beneficial ownership of 29,003 previously issued RSUs payable solely in Common Stock issued to Felix Baker in his capacity as a director of the Issuer pursuant to the Amended and Restated 2007 Equity Incentive Plan of which the Funds may be deemed to own a portion and 121,250 previously issued shares from exercise of 121,250 Stock Options of the Issuer that were issued to Felix J. Baker in his capacity as a director of the Issuer, of which the Funds may be deemed to own a portion. The policy of the Funds and the Adviser does not permit full-time employees of the Adviser or managing members of the Adviser GP to receive compensation for serving as a director of the Issuer.

6. Pursuant to agreements between Felix J. Baker and the Adviser, the Adviser has voting and dispositive power over the Stock Options, RSUs and any Common Stock received as a result of the exercise of Stock Options or vesting of RSUs.

7. The Adviser serves as the investment adviser to the Funds. In connection with the services provided by the Adviser, the Adviser receives an asset-based management fee that does not confer any pecuniary interest in the securities held by the Funds. Baker Bros. Advisors (GP) LLC (the "Adviser GP") is the Adviser's sole general partner. Julian C. Baker and Felix J. Baker are managing members of the Adviser GP. The Adviser has complete and unlimited discretion and authority with respect to the investment and voting power of the securities held by the Funds. The general partners of the Funds relinquished to the Adviser all discretion and authority with respect to the investment and voting power of the securities held by the Funds.

8. Julian C. Baker, Felix J. Baker, the Adviser GP and the Adviser disclaim beneficial ownership of the securities held directly by the Funds except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that any of Julian C. Baker, Felix J. Baker, the Adviser GP or the Adviser is a beneficial owner of such securities for purposes of Section 16 or any other purpose.

9. RSUs granted to Felix J. Baker on May 31, 2023, pursuant to the Amended and Restated 2007 Equity Incentive Plan of the Issuer. The RSUs fully vest on May 31, 2024.

10. The disclosure of the grant of RSUs reported on this form is a single grant of 2,044 RSUs. The grant of 2,044 RSUs is reported for each of the Funds as each has an indirect pecuniary interest in such securities.

11. After giving effect to the transaction reported herein and as a result of their ownership interest in (i) Baker Brothers Life Sciences Capital, L.P. and (ii) Life Sciences, Julian C. Baker and Felix J. Baker each may be deemed to have an indirect pecuniary interest in Common Stock reported in column 5 of Table I directly held by Life Sciences, a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital, L.P., a limited partnership of which the sole general partner is Baker Brothers Life Sciences Capital (GP), LLC, due to their interest in Life Sciences and Baker Brothers Life Sciences Capital, L.P.'s right to receive an allocation of a portion of the profits from Life Sciences.

Remarks:

Felix J. Baker is a director of Seagen Inc. (the "Issuer"). By virtue of their representation on the Board of Directors of the Issuer, for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, the reporting persons other than Felix J. Baker are deemed directors by deputization of the Issuer.

	By: Baker Bros. Advisors LP, Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing	06/02/2023
	Baker Bros. Advisors LP, 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/	06/02/2023
	Baker Bros. Advisors LP, Mgmt. Co. and Inv. Adviser to 667, L.P., pursuant to authority granted by Baker Biotech Capital, L.P., GP to 667, L.P. Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing	06/02/2023
	Julian C. Baker	06/02/2023
	Felix J. Baker	06/02/2023
	By: Baker Bros. Advisors (GP) LLC, Name: Scott L. Lessing, Title: President /s/ Scott L. Lessing	06/02/2023
	** Signature of Reporting Person	Date
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