Diyong Xu - 23 Oct 2025 Form 4 Insider Report for Q32 Bio Inc. (QTTB)

Role: Director
Signature: /s/ Eric Bell, Attorney-in-Fact
Issuer symbol: QTTB
Transactions as of: 23 Oct 2025
Net transactions value: $0
Form type: 4
Filing time: 27 Oct 2025, 21:25:56 UTC
Previous filing: 26 Feb 2025
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Xu Diyong	Director	Q32 BIO INC., 830 WINTER STREET, WALTHAM	/s/ Eric Bell, Attorney-in-Fact	27 Oct 2025	0001995088

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	QTTB	Stock Option (Right to Buy)	Award	$0	+53,521		$0.000000	53,521	23 Oct 2025	Common Stock	53,521	$2.80	Direct	F1, F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) October 23, 2026 or (ii) the date of the Issuer's next annual meeting of stockholders, subject to the Reporting Person's continued service on such vesting date.
F2	Pursuant to an agreement with OrbiMed Advisors LLC and OrbiMed Capital GP VII LLC, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC and OrbiMed Capital GP VII LLC, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VII, LP.

Content

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) October 23, 2026 or (ii) the date of the Issuer's next annual meeting of stockholders, subject to the Reporting Person's continued service on such vesting date.

Pursuant to an agreement with OrbiMed Advisors LLC and OrbiMed Capital GP VII LLC, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC and OrbiMed Capital GP VII LLC, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VII, LP.