SEC Form SC 13D/A filed by Theseus Pharmaceuticals Inc. (Amendment)

11/24/23 4:23:24 PM ET

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Biotechnology: Pharmaceutical Preparations

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SC 13D/A 1 eh230423669_13da4-thrx.htm AMENDMENT NO. 4

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 4)*

Theseus Pharmaceuticals, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

88369M101

(CUSIP Number)

Dennis Ryan

Foresite Capital Management, LLC

900 Larkspur Landing Circle, Suite 150, Larkspur, CA 94939

(415) 877-4887

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

November 22, 2023

(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 §§240.13d-1(e), 240.13d-1(f) or 240.13d-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 (“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).

CUSIP No. 88369M101

SCHEDULE 13D

Page 2 of 9

1	NAME OF REPORTING PERSON Foresite Capital Fund V, L.P. (“FCF V”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ☐ (b) ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS 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 Delaware

NUMBER OF

BENEFICIALLY

OWNED BY EACH

REPORTING PERSON

WITH

SOLE VOTING POWER

4,108,796 shares, except that Foresite Capital Management V, LLC (“FCM V”), the general partner of FCF V, may be deemed to have sole power to vote these shares, and James B. Tananbaum (“Tananbaum”), the managing member of FCM V, may be deemed to have sole power to vote these shares.

SHARED VOTING POWER

See response to row 7.

SOLE DISPOSITIVE POWER

4,108,796 shares, except that FCM V, the general partner of FCF V, may be deemed to have sole power to dispose of these shares, and Tananbaum, the managing member of FCM V, may be deemed to have sole power to dispose of these shares.

SHARED DISPOSITIVE POWER

See response to row 9.

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,108,796
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.3%*
14	TYPE OF REPORTING PERSON PN

*	This percentage is calculated based upon 44,230,135 shares of common stock outstanding of Theseus Pharmaceuticals, Inc. (the “Issuer”) as of November 10, 2023, as set forth in the Issuer’s Form 10-Q filed with the Securities and Exchange Commission on November 17, 2023 (the “Form 10-Q”).

CUSIP No. 88369M101

SCHEDULE 13D

Page 3 of 9

1	NAME OF REPORTING PERSON Foresite Capital Management V, LLC (“FCM V”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ☐ (b) ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF

BENEFICIALLY

OWNED BY EACH

REPORTING PERSON

WITH

SOLE VOTING POWER

4,108,796 shares, all of which are directly owned by FCF V. FCM V, the general partner of FCF V, may be deemed to have sole power to vote these shares, and Tananbaum, the managing member of FCM V, may be deemed to have sole power to vote these shares.

SHARED VOTING POWER

See response to row 7.

SOLE DISPOSITIVE POWER

4,108,796 shares, all of which are directly owned by FCF V. FCM V, the general partner of FCF V, may be deemed to have sole power to dispose of these shares, and Tananbaum, the managing member of FCM V, may be deemed to have sole power to dispose of these shares.

SHARED DISPOSITIVE POWER

See response to row 9.

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 4,108,796
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 9.3%*
14	TYPE OF REPORTING PERSON OO

*	This percentage is calculated based upon 44,230,135 shares of common stock outstanding of the Issuer as of November 10, 2023, as set forth in the Issuer’s Form 10-Q.

CUSIP No. 88369M101

SCHEDULE 13D

Page 4 of 9

1	NAME OF REPORTING PERSON Foresite Capital Opportunity Fund V, L.P. (“FCOF V”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ☐ (b) ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS 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 Delaware

NUMBER OF

BENEFICIALLY

OWNED BY EACH

REPORTING PERSON

WITH

SOLE VOTING POWER

1,385,825 shares, except that Foresite Capital Opportunity Management V, LLC (“FCOM V”), the general partner of FCOF V, may be deemed to have sole power to vote these shares, and James B. Tananbaum (“Tananbaum”), the managing member of FCOM V, may be deemed to have sole power to vote these shares.

SHARED VOTING POWER

See response to row 7.

SOLE DISPOSITIVE POWER

1,385,825 shares, except that FCOM V, the general partner of FCOF V, may be deemed to have sole power to dispose of these shares, and Tananbaum, the managing member of FCOM V, may be deemed to have sole power to dispose of these shares.

SHARED DISPOSITIVE POWER

See response to row 9.

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,385,825
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 3.1%*
14	TYPE OF REPORTING PERSON PN

*	This percentage is calculated based upon 44,230,135 shares of common stock outstanding of the Issuer as of November 10, 2023, as set forth in the Issuer’s Form 10-Q.

CUSIP No. 88369M101

SCHEDULE 13D

Page 5 of 9

1	NAME OF REPORTING PERSON Foresite Capital Opportunity Management V, LLC (“FCOM V”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ☐ (b) ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware

NUMBER OF

BENEFICIALLY

OWNED BY EACH

REPORTING PERSON

WITH

SOLE VOTING POWER

1,385,825 shares, all of which are directly owned by FCOF V. FCOM V, the general partner of FCOF V, may be deemed to have sole power to vote these shares, and Tananbaum, the managing member of FCOM V, may be deemed to have sole power to vote these shares.

SHARED VOTING POWER

See response to row 7.

SOLE DISPOSITIVE POWER

1,385,825 shares, all of which are directly owned by FCOF V. FCOM V, the general partner of FCOF V, may be deemed to have sole power to dispose of these shares, and Tananbaum, the managing member of FCOM V, may be deemed to have sole power to dispose of these shares.

SHARED DISPOSITIVE POWER

See response to row 9.

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 1,385,825
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 3.1%*
14	TYPE OF REPORTING PERSON OO

*	This percentage is calculated based upon 44,230,135 shares of common stock outstanding of the Issuer as of November 10, 2023, as set forth in the Issuer’s Form 10-Q.

CUSIP No. 88369M101

SCHEDULE 13D

Page 6 of 9

1	NAME OF REPORTING PERSON James B. Tananbaum (“Tananbaum”)
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP	(a) ☐ (b) ☒
3	SEC USE ONLY
4	SOURCE OF FUNDS AF
5	CHECK BOX IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT TO ITEMS 2(d) or 2(e)	☐
6	CITIZENSHIP OR PLACE OF ORGANIZATION U.S. Citizen

NUMBER OF

BENEFICIALLY

OWNED BY EACH

REPORTING PERSON

WITH

SOLE VOTING POWER

5,494,621 shares, of which 4,108,796 shares are directly owned by Foresite Capital Fund V, L.P. (“FCF V”) and 1,385,825 shares are directly owned by Foresite Capital Opportunity Fund V, L.P. (“FCOF V”). Tananbaum is the managing member of each of Foresite Capital Management V, LLC (“FCM V”), which is the general partner of FCF V; and Foresite Capital Opportunity Management V, LLC (“FCOM V”), which is the general partner of FCOF V. Tananbaum may be deemed to have sole power to vote these shares.

SHARED VOTING POWER

See response to row 7.

SOLE DISPOSITIVE POWER

5,494,621 shares, of which 4,108,796 shares are directly owned by FCF V and 1,385,825 shares are directly owned by FCOF V. Tananbaum is the managing member of each of FCM V, which is the general partner of FCF V; and FCOM V, which is the general partner of FCOF V. Tananbaum may be deemed to have sole power to dispose of these shares.

SHARED DISPOSITIVE POWER

See response to row 9.

11	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 5,494,621
12	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN SHARES	☐
13	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11) 12.4%*
14	TYPE OF REPORTING PERSON IN

*	This percentage is calculated based upon 44,230,135 shares of common stock outstanding of the Issuer as of November 10, 2023, as set forth in the Issuer’s Form 10-Q.

CUSIP No. 88369M101

SCHEDULE 13D

Page 7 of 9

Statement on Schedule 13D

This Amendment No. 4 (“Amendment No. 4”) amends and restates the Statement on Schedule 13D initially filed on October 18, 2021 (the “Original Schedule 13D”), as amended and restated by Amendment No. 1 filed with the Securities and Exchange Commission (“SEC”) on June 13, 2022 (“Amendment No. 1”), Amendment No. 2 filed on January 3, 2023 (“Amendment No. 2”) and Amendment No. 3 filed on July 19, 2023 (“Amendment No. 3” and, together with the Original Schedule 13D, Amendment No. 1, Amendment No. 2 and this Amendment No. 4, the “Schedule 13D”). This Schedule 13D relates to the beneficial ownership of common stock, par value $0.0001 per share (the “Common Stock”), of Theseus Pharmaceuticals, Inc., a corporation organized under the laws of the state of Delaware (“Issuer”). This Schedule 13D is being filed by Foresite Capital Fund V, L.P. (“FCF V”), Foresite Capital Management V, LLC (“FCM V”), Foresite Capital Opportunity Fund V, L.P. (“FCOF V”), Foresite Capital Opportunity Management V, LLC (“FCOM V”), and James B. Tananbaum (“Tananbaum” and together with FCF V, FCM V, FCOF V and FCOM V, the “Reporting Persons”).

Except as provided herein, this Amendment No. 4 does not modify any of the information previously reported on the Schedule 13D.

ITEM 4.

PURPOSE OF TRANSACTION.

Item 4 of the Schedule 13D is hereby amended and supplemented by adding the following:

On November 22, 2023 (i) FCF V and FCOF V (collectively, “Foresite”) and (ii) OrbiMed Private Investments VII, LP and OrbiMed Genesis Master Fund, L.P. (collectively, “OrbiMed”, and together with Foresite, the “Investors”) submitted to the board of directors of the Issuer (the “Board”) a non-binding expression of interest letter (the “Letter”) setting forth an intent to explore and evaluate a potential acquisition of all of the outstanding shares of Common Stock that are not owned by the Investors or their affiliates in a going-private transaction. A copy of the Letter is filed as Exhibit 1 to this Amendment No. 4, and the information set forth in the Letter is incorporated by reference herein.

The Letter may result in one or more of the transactions, events or actions specified in clauses (a) through (j) of Item 4 of Schedule 13D, including, without limitation, an acquisition of additional securities of the Issuer, an extraordinary corporate transaction (such as a merger) involving the Issuer, delisting of its Common Stock from the Nasdaq Global Select Market and other material changes in the Issuer’s business or corporate structure.

The Letter stated that any transaction, once structured and agreed upon, would be conditioned upon, among other things, the (x) approval of the transaction by a properly constituted special committee composed of independent and disinterested directors of the Issuer appointed by the Board, with assistance from legal and financial advisors and (y) approval of the stockholders holding at least a majority of all the issued and outstanding shares of Common Stock not held by the Investors or their affiliates.

The Letter is non-binding in nature and does not obligate in any way the Investors or the Issuer to negotiate or enter into definitive documentation with respect to a transaction or otherwise complete a transaction.

The foregoing description of the Letter does not purport to be complete and is qualified in its entirety by reference to the full text of the Letter. Neither the Letter nor this Schedule 13D is meant to be, nor should be construed as, an offer to buy or the solicitation of an offer to sell any of the Issuer’s securities.

The Reporting Persons intend to review their investment in the Issuer on a continuing basis and may from time to time and at any time in the future depending on various factors, including, without limitation, the outcome of any discussions referenced in this Schedule 13D, as may be amended from time to time, the Issuer’s financial position and strategic direction, actions taken by the Board, price levels of the Issuer’s securities, other investment opportunities available to the Reporting Persons, conditions in the securities market and general economic and industry conditions, take such actions with respect to the investment in the Issuer as they deem appropriate.

CUSIP No. 88369M101

SCHEDULE 13D

Page 8 of 9

ITEM 5.

INTEREST IN SECURITIES OF THE ISSUER.

Item 5 of the Schedule 13D is hereby amended and supplemented by adding the following:

Based on the events and transactions described above, the Reporting Persons may be deemed to constitute a “group” (within the meaning of Section 13(d) of the Act) with OrbiMed and its affiliated investment funds and persons that hold shares of Common Stock of the Issuer but do not affirm the existence of any such “group.” The following table sets forth the beneficial ownership of shares of Common Stock held by OrbiMed and certain of its affiliates listed below (each, an “OrbiMed Holder” and, collectively, the “OrbiMed Holders”) based on a Schedule 13D/A filed by the OrbiMed Holders with the SEC on July 19, 2023. The Reporting Persons expressly disclaim beneficial ownership of any shares of Common Stock held or which may be acquired by any OrbiMed Holder.

OrbiMed Holder	Amount beneficially owned		Percent of total⁽¹⁾			Sole voting power		Shared Voting power		Sole dispositive power		Shared dispositive power
OrbiMed Advisors LLC		17,713,600		40	%		—		17,713,600		—		17,713,600
OrbiMed Capital GP VII LLC		17,063,000		38.6	%		—		17,063,000		—		17,063,000
OrbiMed Genesis GP LLC		650,600		1.5	%		—		650,600		—		650,600

(1) This percentage is calculated based upon 44,230,135 shares of common stock outstanding of the Issuer as of November 10, 2023, as set forth in the Issuer’s Form 10-Q.

ITEM 6.

CONTRACTS, ARRANGEMENTS, UNDERSTANDINGS OR RELATIONSHIPS WITH RESPECT TO SECURITIES OF THE ISSUER.

The information set forth in Item 4 hereof is hereby incorporated by reference into this Item 6, as applicable.

ITEM 7.

MATERIAL TO BE FILED AS EXHIBITS.

Exhibit No.		Description
1		Letter, dated November 22, 2023, from the Investors to the Board

CUSIP No. 88369M101

SCHEDULE 13D

Page 9 of 9

SIGNATURES

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.

Date: November 24, 2023

	FORESITE CAPITAL FUND V, L.P.

	By:	Foresite Capital Management V, LLC
	Its:	General Partner

	By:	/s/ James B. Tananbaum
		James B. Tananbaum
		Managing Member

	FORESITE CAPITAL MANAGEMENT V, LLC

	By:	/s/ James B. Tananbaum
		James B. Tananbaum
		Managing Member

	FORESITE CAPITAL OPPORTUNITY FUND V, L.P.

	By:	Foresite Capital Opportunity Management V, LLC
	Its:	General Partner

	By:	/s/ James B. Tananbaum
		James B. Tananbaum
		Managing Member

	FORESITE CAPITAL OPPORTUNITY MANAGEMENT V, LLC

	By:	/s/ James B. Tananbaum
		James B. Tananbaum
		Managing Member

	JAMES B. TANANBAUM

	/s/ James B. Tananbaum

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Date	Price Target	Rating	Analyst
7/14/2023		Buy → Hold	Needham
3/16/2023	$24.00	Buy	Stifel
12/14/2022	$22.00	Buy	Needham
6/30/2022	$22.00	Buy	H.C. Wainwright
11/1/2021	$25.00	Overweight	Cantor Fitzgerald
11/1/2021	$24.00	Outperform	Wedbush
11/1/2021	$28.00	Outperform	SVB Leerink
11/1/2021	$23.00	Buy	Jefferies

SEC Form SC 13D/A filed by Theseus Pharmaceuticals Inc. (Amendment)

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