SC 13G 1 p24-3090sc13g.htm LEXEO THERAPEUTICS, INC.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
______________________

SCHEDULE 13G

Under the Securities Exchange Act of 1934
(Amendment No. )*

Lexeo Therapeutics, Inc.
(Name of Issuer)

Common Stock, par value $0.0001 per share
(Title of Class of Securities)

52886X107
(CUSIP Number)

September 30, 2024
(Date of Event Which Requires Filing of This Statement)


Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

ý	Rule 13d-1(b)
¨	Rule 13d-1(c)
¨	Rule 13d-1(d)

(Page 1 of 8 Pages)

______________________________

*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 the disclosures provided in a prior cover page.

The information required in 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. 52886X107

13G

Page 2 of 8 Pages

1	NAME OF REPORTING PERSON Adage Capital Management, L.P.
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ¨ (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION Delaware
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 2,597,736
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 2,597,736
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,597,736
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 7.86%
12	TYPE OF REPORTING PERSON PN, IA

CUSIP No. 52886X107

13G

Page 3 of 8 Pages

1	NAME OF REPORTING PERSON Robert Atchinson
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ¨ (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 2,597,736
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 2,597,736
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,597,736
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 7.86%
12	TYPE OF REPORTING PERSON IN; HC

CUSIP No. 52886X107

13G

Page 4 of 8 Pages

1	NAME OF REPORTING PERSON Phillip Gross
2	CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP		(a) ¨ (b) ¨
3	SEC USE ONLY
4	CITIZENSHIP OR PLACE OF ORGANIZATION United States
NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:	5	SOLE VOTING POWER 0
	6	SHARED VOTING POWER 2,597,736
	7	SOLE DISPOSITIVE POWER 0
	8	SHARED DISPOSITIVE POWER 2,597,736
9	AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 2,597,736
10	CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES			¨
11	PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9) 7.86%
12	TYPE OF REPORTING PERSON IN; HC

CUSIP No. 52886X107

13G

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Item 1(a).	NAME OF ISSUER

	The name of the issuer is Lexeo Therapeutics, Inc. (the “Company”).

Item 1(b).	ADDRESS OF ISSUER’S PRINCIPAL EXECUTIVE OFFICES

	The Company’s principal executive offices are located at 345 Park Avenue South, Floor 6, New York, NY 10010.

Item 2(a).	NAME OF PERSON FILING

	This statement is filed by:

	(i)	Adage Capital Management, L.P., a Delaware limited partnership (“ACM”), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership (“ACP”), with respect to the shares of Common Stock directly held by ACP;

	(ii)	Robert Atchinson (“Mr. Atchinson”), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware (“ACA”), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware (“ACPGP”), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company (“ACPLLC”), general partner of ACM, with respect to the shares of Common Stock directly held by ACP; and

	(iii)	Phillip Gross (“Mr. Gross”), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the shares of Common Stock directly held by ACP.

	The foregoing persons are hereinafter sometimes collectively referred to as the “Reporting Persons.” Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.

	The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein.

Item 2(b).	ADDRESS OF PRINCIPAL BUSINESS OFFICE OR, IF NONE, RESIDENCE

	The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.

Item 2(c).	CITIZENSHIP

	ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.

Item 2(d).	TITLE OF CLASS OF SECURITIES

	Common Stock, par value $0.0001 per share (the “Common Stock”).

CUSIP No. 52886X107

13G

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Item 2(e).	CUSIP NUMBER

	52886X107

Item 3.	IF THIS STATEMENT IS FILED PURSUANT TO Rules 13d-1(b), OR 13d-2(b) OR (c), CHECK WHETHER THE PERSON FILING IS A:

	(a)	¨	Broker or dealer registered under Section 15 of the Act;

	(b)	¨	Bank as defined in Section 3(a)(6) of the Act;

	(c)	¨	Insurance company as defined in Section 3(a)(19) of the Act;

	(d)	¨	Investment company registered under Section 8 of the Investment Company Act of 1940;

	(e)	þ	An investment adviser in accordance with Rule 13d-1(b)(1)(ii)(E);

	(f)	¨	An employee benefit plan or endowment fund in accordance with Rule 13d-1(b)(1)(ii)(F);

	(g)	þ	A parent holding company or control person in accordance with Rule 13d-1(b)(1)(ii)(G);

	(h)	¨	A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act;

	(i)	¨	A church plan that is excluded from the definition of an investment company under Section 3(c)(14) of the Investment Company Act;

	(j)	¨	A non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J);

	(k)	¨	Group, in accordance with Rule 13d-1(b)(1)(ii)(K).

	If filing as a non-U.S. institution in accordance with Rule 13d-1(b)(1)(ii)(J), please specify the type of institution: Not applicable.______________________________

Item 4.	OWNERSHIP

	The information required by Items 4(a) – (c) is set forth in Rows (5) – (11) of the cover page for each Reporting Person hereto and is incorporated herein by reference for each such Reporting Person.

	The percentage set forth in this Schedule 13G is calculated based upon 33,061,004 shares of Common Stock outstanding as of August 8, 2024, as reported in the Company’s Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2024, filed with the Securities and Exchange Commission on August 12, 2024.

Item 5.	OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS

	Not applicable.

CUSIP No. 52886X107

13G

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Item 6.	OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON

	See Item 2(a).

Item 7.	IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT HOLDING COMPANY OR CONTROL PERSON

	Not applicable.

Item 8.	IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP

	Not applicable.

Item 9.	NOTICE OF DISSOLUTION OF GROUP

	Not applicable.

Item 10.	CERTIFICATION

	Each of the Reporting Persons hereby makes the following certification:

	By signing below each Reporting Person certifies that, to the best of his or its knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect.

CUSIP No. 52886X107

13G

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SIGNATURES

After reasonable inquiry and to the best of his or its knowledge and belief, each of the undersigned certifies that the information set forth in this statement is true, complete and correct.

DATE: November 12, 2024

ADAGE CAPITAL MANAGEMENT, L.P.
By: Adage Capital Partners LLC,
its general partner

/s/ Robert Atchinson
Name: Robert Atchinson
Title: Managing Member

/s/ Robert Atchinson
ROBERT ATCHINSON, individually

/s/ Phillip Gross
PHILLIP GROSS, individually