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* Foresite Capital Management V, LLC (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Theseus Pharmaceuticals, Inc. [ THRX ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 07/17/2023
	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

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	07/17/2023		P		523,450	A	$2.97	4,108,796	I	See Footnote(1)
Common Stock	07/17/2023		P		176,550	A	$2.97	1,385,825	I	See Footnote(2)

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* Foresite Capital Management V, LLC (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Foresite Capital Fund V, L.P. (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Foresite Capital Opportunity Fund V, L.P. (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Foresite Capital Opportunity Management V, LLC (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Tananbaum James B. (Last) (First) (Middle) 900 LARKSPUR LANDING CIRCLE SUITE 150 (Street) LARKSPUR CA 94939 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The shares are owned directly by Foresite Capital Fund V, L.P. ("Fund V"). Foresite Capital Management V, LLC ("FCM V") is the general partner of Fund V and may be deemed to have sole voting and dispositive power over these shares. James B. Tananbaum ("Dr. Tananbaum") is the sole managing member of FCM V and may be deemed to have sole voting and dispositive power over these shares. Each Reporting Person disclaims the existence of a "group." Each of FCM V and Dr. Tananbaum disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein, and the filing of this report is not an admission that FCM V or Dr. Tananbaum is the beneficial owner of these shares for purposes of Section 16 or any other purpose.

2. The shares are owned directly by Foresite Capital Opportunity Fund V, L.P. ("Opportunity Fund V"). Foresite Capital Opportunity Management V, LLC ("FCOM V") is the general partner of Opportunity Fund V and may be deemed to have sole voting and dispositive power over these shares. Dr. Tananbaum is the sole managing member of FCOM V and may be deemed to have sole voting and dispositive power over these shares. Each Reporting Person disclaims the existence of a "group." Each of FCOM V and Dr. Tananbaum disclaims beneficial ownership of these shares except to the extent of any pecuniary interest therein, and the filing of this report is not an admission that FCOM V or Dr. Tananbaum is the beneficial owner of these shares for purposes of Section 16 or any other purpose.

Remarks:

	FORESITE CAPITAL MANAGEMENT V, LLC, By: /s/ James B. Tananbaum, Managing Member	07/19/2023
	FORESITE CAPITAL FUND V, L.P., By: Foresite Capital Management V, LLC, Its: General Partner, By: /s/ James B. Tananbaum, Managing Member	07/19/2023
	FORESITE CAPITAL OPPORTUNITY FUND V, L.P., By: Foresite Capital Opportunity Management V, LLC, Its: General Partner, By: /s/ James B. Tananbaum, Managing Member	07/19/2023
	FORESITE CAPITAL OPPORTUNITY MANAGEMENT V, LLC, By: /s/ James B. Tananbaum, Managing Member	07/19/2023
	JAMES B. TANANBAUM /s/ James B. Tananbaum	07/19/2023
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
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