Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 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 that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES 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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(Print or Type Responses)

1. Name and Address of Reporting Person * Kynam Global Healthcare Master Fund, LP 2. Issuer Name and Ticker or Trading Symbol 2seventy bio, Inc. [TSVT] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O OGIER GLOBAL (CAYMAN) LIMITED, 89 NEXUS WAY, CAMANA BAY 3. Date of Earliest Transaction (Month/Day/Year) 03/11/2025 (Street) GRAND CAYMAN, E9 KY1-9009 4. If Amendment, Date 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 (City) (State) (Zip) 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, par value $0.0001 per share 03/11/2025 S 5,953,825 D $4.93 0 I See Footnote(1) Common Stock, par value $0.0001 per share 03/11/2025 S 5,142,111 D $4.93 0 D(2) Common Stock, par value $0.0001 per share 03/11/2025 S 5,142,111 D $4.93 0 I See Footnote(3)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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 Underlying Securities (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 of Derivative Security: 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

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Kynam Global Healthcare Master Fund, LP C/O OGIER GLOBAL (CAYMAN) LIMITED 89 NEXUS WAY, CAMANA BAY GRAND CAYMAN, E9 KY1-9009		X
Kynam Fund GP, LLC 221 ELM ROAD PRINCETON, NJ 08540		X
Kynam Capital Management GP, LLC 221 ELM ROAD PRINCETON, NJ 08540		X
Kynam Capital Management, LP 221 ELM ROAD PRINCETON, NJ 08540		X
Tang Yue C/O KYNAM CAPITAL MANAGEMENT, LP 221 ELM ROAD PRINCETON, NJ 08540		X

Signatures

KYNAM GLOBAL HEALTHCARE MASTER FUND, LP, By: KYNAM FUND GP, LLC, By: /s/ Yue Tang, Yue Tang, Managing Member		03/13/2025
**Signature of Reporting Person		Date
KYNAM FUND GP, LLC, By: /s/ Yue Tang, Yue Tang, Managing Member		03/13/2025
**Signature of Reporting Person		Date
KYNAM CAPITAL MANAGEMENT GP, LLC, By: /s/ Yue Tang, Yue Tang, Managing Member		03/13/2025
**Signature of Reporting Person		Date
KYNAM CAPITAL MANAGEMENT, LP, By: KYNAM CAPITAL MANAGEMENT GP, LLC, By: /s/ Yue Tang, Yue Tang, Managing Member		03/13/2025
**Signature of Reporting Person		Date
YUE TANG, /s/ Yue Tang		03/13/2025
**Signature of Reporting Person		Date

Explanation of Responses:

*	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).
(1)	The reported securities are owned directly by Kynam Global Healthcare Master Fund, LP (the "Master Fund"), a private investment fund managed by Kynam Capital Management, LP (the "Adviser"), and separately managed account clients of the Adviser and may be deemed to be indirectly beneficially owned by (i) the Adviser, (ii) Kynam Capital Management GP, LLC (the "Adviser GP"), the general partner of the Adviser and (iii) Yue Tang, the managing member of the Adviser GP. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.
(2)	The reported securities are directly owned by the Master Fund. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.
(3)	The reported securities are owned directly by the Master Fund and may be deemed to be indirectly beneficially owned by Kynam Fund GP, LLC, the general partner of the Master Fund. The Reporting Persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the Reporting Persons are the beneficial owners of the securities for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, or for any other purpose.

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