SEC FORM 4

SEC FORM 4SEC 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

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

ORBIMED ADVISORS LLC

(Last)

(First)

(Middle)

601 LEXINGTON AVENUE

54TH FLOOR

(Street)

NEW YORK

10022

(City)

(State)

(Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Adicet Bio, Inc. [ ACET ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

Director	X	10% Owner
Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
04/07/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common Stock	04/07/2026		S		29,319	D	$6.53	34,923	I	See footnotes⁽¹⁾⁽⁶⁾
Common Stock	04/07/2026		S		2,400	D	$6.38	32,523	I	See footnotes⁽¹⁾⁽⁶⁾
Common Stock	04/08/2026		S		32,523	D	$6.29	0	I	See footnotes⁽¹⁾⁽⁶⁾
Common Stock	04/08/2026		S		40,416	D	$6.52	0	I	See footnotes⁽²⁾⁽⁶⁾
Common Stock								78,499	I	See footnotes⁽³⁾⁽⁶⁾
Common Stock								564,147	I	See footnotes⁽⁴⁾⁽⁶⁾
Common Stock								280,640	I	See footnotes⁽⁵⁾⁽⁶⁾

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

1. Name and Address of Reporting Person^*

ORBIMED ADVISORS LLC

(Last)

(First)

(Middle)

601 LEXINGTON AVENUE

54TH FLOOR

(Street)

NEW YORK

10022

(City)

(State)

(Zip)

UNITED STATES

(Country)

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^*

OrbiMed Capital GP V LLC

(Last)

(First)

(Middle)

601 LEXINGTON AVENUE

54TH FLOOR

(Street)

NEW YORK

10022

(City)

(State)

(Zip)

UNITED STATES

(Country)

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^*

OrbiMed Capital GP VI LLC

(Last)

(First)

(Middle)

601 LEXINGTON AVENUE, 54TH FLOOR

(Street)

NEW YORK

10022

(City)

(State)

(Zip)

UNITED STATES

(Country)

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^*

OrbiMed Genesis GP LLC

(Last)

(First)

(Middle)

601 LEXINGTON AVENUE, 54TH FLOOR

(Street)

NEW YORK

10022

(City)

(State)

(Zip)

UNITED STATES

(Country)

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^*

OrbiMed Advisors Israel II Ltd

(Last)

(First)

(Middle)

5 HAHOSHLIM STREET, BUILDING B

1ST FLOOR

(Street)

HERZLIYA

PITUACH

(City)

(State)

(Zip)

ISRAEL

(Country)

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^*

OrbiMed Israel GP II, L.P.

(Last)

(First)

(Middle)

5 HAHOSHLIM STREET, BUILDING B

1ST FLOOR

(Street)

HERZLIYA

PITUACH

(City)

(State)

(Zip)

ISRAEL

(Country)

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^*

OrbiMed Israel GP Ltd.

(Last)

(First)

(Middle)

5 HAHOSHLIM STREET, BUILDING B

1ST FLOOR

(Street)

HERZLIYA

PITUACH

(City)

(State)

(Zip)

ISRAEL

(Country)

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^*

OrbiMed Israel BioFund GP Limited Partnership

(Last)

(First)

(Middle)

5 HAHOSHLIM STREET, BUILDING B

1ST FLOOR

(Street)

HERZLIYA

PITUACH

(City)

(State)

(Zip)

ISRAEL

(Country)

Relationship of Reporting Person(s) to Issuer

Director	X	10% Owner
Officer (give title below)		Other (specify below)

Explanation of Responses:

1. These securities are held of record by OrbiMed Israel Partners Limited Partnership ("OIP"). OrbiMed Israel BioFund GP Limited Partnership ("OrbiMed BioFund") is the general partner of OIP, and OrbiMed Israel GP Ltd. ("OrbiMed Israel GP") is the general partner of OrbiMed BioFund. By virtue of such relationships, OrbiMed BioFund and OrbiMed Israel GP may be deemed to have voting and investment power over the shares of common stock held by OIP and, as a result, may be deemed to have beneficial ownership over such shares of common stock. OrbiMed Israel GP exercises this investment and voting power through an investment committee comprised of Carl L. Gordon and Erez Chimovits, each of whom disclaims beneficial ownership over the shares of common stock held by OIP.

2. These securities are held of record by OrbiMed Israel Partners II, L.P. ("OIP II"). OrbiMed Israel GP II, L.P. ("OrbiMed Israel GP II") is the general partner of OIP II, and OrbiMed Advisors Israel II Limited ("OrbiMed Israel II") is the general partner of OrbiMed Israel GP II. By virtue of such relationships, OrbiMed Israel GP II and OrbiMed Israel II may be deemed to have voting and investment power over the shares of common stock held by OIP II and, as a result, may be deemed to have beneficial ownership over such shares of common stock. OrbiMed Israel II exercises this investment and voting power through an investment committee comprised of Carl L. Gordon, David Bonita, and Erez Chimovits, each of whom disclaims beneficial ownership over the shares of common stock held by OIP II.

3. These securities are held of record by OrbiMed Genesis Master Fund, L.P. ("Genesis"). OrbiMed Genesis GP LLC ("Genesis GP") is the general partner of Genesis, and OrbiMed Advisors LLC ("OrbiMed Advisors"), a registered investment adviser under the Investment Advisors Act of 1940, as amended, is the managing member of Genesis. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting and investment power over the shares of common stock held by Genesis and, as a result, may be deemed to have beneficial ownership over such shares of common stock. OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership over the shares of common stock held by Genesis.

4. These securities are held of record by OrbiMed Private Investments V, LP ("OPI V"). OrbiMed Capital GP V LLC ("GP V") is the general partner of OPI V, and OrbiMed Advisors is the managing member of GP V. By virtue of such relationships, GP V and OrbiMed Advisors may be deemed to have voting and investment power over the shares of common stock held by OPI V and, as a result, may be deemed to have beneficial ownership over such shares of common stock. OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership over the shares of common stock held by OPI V.

5. These securities are held of record by OrbiMed Private Investments VI, LP ("OPI VI"). OrbiMed Capital GP VI LLC ("GP VI") is the general partner of OPI VI, and OrbiMed Advisors is the managing member of GP VI. By virtue of such relationships, GP VI and OrbiMed Advisors may be deemed to have voting and investment power over the shares of common stock held by OPI VI and, as a result, may be deemed to have beneficial ownership over such shares of common stock. OrbiMed Advisors exercises this investment and voting power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership over the shares of common stock held by OPI VI.

6. Each of OrbiMed Advisors, OrbiMed BioFund, OrbiMed Israel GP, OrbiMed Israel GP II, OrbiMed Israel II, Genesis GP, GP V, and GP VI disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of his or its pecuniary interest therein, if any. This report shall not be deemed an admission that any such person or entity is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

	/s/ Carl L. Gordon, Member of OrbiMed Advisors LLC	04/09/2026
	/s/ Carl L. Gordon, Member of OrbiMed Capital GP V LLC	04/09/2026
	/s/ Carl L. Gordon, Member of OrbiMed Capital GP VI LLC	04/09/2026
	/s/ Carl L. Gordon, Member of OrbiMed Genesis GP LLC	04/09/2026
	/s/ Carl L. Gordon, Director of OrbiMed Israel GP Ltd.	04/09/2026
	/s/ Carl L. Gordon, Director of OrbiMed Advisors Israel II Ltd.	04/09/2026
	/s/ Carl L. Gordon, Director of OrbiMed Israel GP II, L.P.	04/09/2026
	/s/ Carl L. Gordon, Director of OrbiMed Israel BioFund GP Limited Partnership	04/09/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

SEC Form 4 filed by Orbimed Advisors Llc