ORBIMED ADVISORS LLC - 28 May 2026 Form 4 Insider Report for Q32 Bio Inc. (QTTB)

Reporting relationship: Director, 10%+ Owner
Issuer ticker: QTTB
Reported as of: 28 May 2026
Net transaction value: +$15,000,000
SEC form: 4
Accepted by SEC: 01 Jun 2026, 21:13:02 UTC
Prior SEC filing: 29 May 2026
Next SEC filing: 09 Jun 2026
Source filing: View source filing
Reporting owner signature: /s/ Carl L. Gordon, Member of OrbiMed Advisors LLC

Key filing fact

ORBIMED ADVISORS LLC filed Form 4 for Q32 Bio Inc. (QTTB) on 01 Jun 2026.

Key facts

This page summarizes ORBIMED ADVISORS LLC's Form 4 filing for Q32 Bio Inc. (QTTB).
2 reported transactions and 0 derivative rows are listed below.
Accepted by SEC: 01 Jun 2026, 21:13.

Change

Previous filing in this sequence was filed on 29 May 2026.
Current net transaction value: +$15,000,000.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (3)

CIK 0001055951 Primary reporting owner

ORBIMED ADVISORS LLC

Relationship: Director, 10%+ Owner
Address: 601 LEXINGTON AVENUE, 54TH FLOOR, NEW YORK
Signature: /s/ Carl L. Gordon, Member of OrbiMed Advisors LLC
Signature date: 01 Jun 2026

CIK 0001760648

OrbiMed Capital GP VII LLC

Relationship: Director, 10%+ Owner
Address: 601 LEXINGTON AVENUE, 54TH FLOOR, NEW YORK
Signature: /s/ Carl L. Gordon, Member of OrbiMed Capital GP VII LLC
Signature date: 01 Jun 2026

CIK 0001808744

OrbiMed Genesis GP LLC

Relationship: Director, 10%+ Owner
Address: 601 LEXINGTON AVENUE, 54TH FLOOR, NEW YORK
Signature: /s/ Carl L. Gordon, Member of OrbiMed Genesis GP LLC
Signature date: 01 Jun 2026

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

QTTB transaction

Common Stock

Purchase

Transaction value: $10,000,000
Shares: +1,250,000
Change %: +55%
Price: $8.00
Shares after: 3,502,987
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F2, F4

QTTB transaction

Common Stock

Purchase

Transaction value: $10,000,000
Shares: +1,250,000
Change %: +55%
Price: $8.00
Shares after: 3,502,987
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F2, F4

QTTB transaction

Common Stock

Purchase

Transaction value: $10,000,000
Shares: +1,250,000
Change %: +55%
Price: $8.00
Shares after: 3,502,987
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F2, F4

QTTB transaction

Common Stock

Purchase

Transaction value: $5,000,000
Shares: +625,000
Change %
Price: $8.00
Shares after: 625,000
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F3, F4

QTTB transaction

Common Stock

Purchase

Transaction value: $5,000,000
Shares: +625,000
Change %
Price: $8.00
Shares after: 625,000
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F3, F4

QTTB transaction

Common Stock

Purchase

Transaction value: $5,000,000
Shares: +625,000
Change %
Price: $8.00
Shares after: 625,000
Date: 28 May 2026
Ownership: See footnotes
Footnotes: F1, F3, F4

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 4 footnotes

Footnote F1

These shares of the Issuer's common stock were purchased from the Issuer in a private placement.

Footnote F2

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

Footnote F3

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 is the managing member of Genesis GP. By virtue of such relationships, Genesis GP and OrbiMed Advisors may be deemed to have voting power and investment power over the securities held by Genesis and as a result, may be deemed to have beneficial ownership over such securities. OrbiMed Advisors exercises voting and investment power through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares held by Genesis.

Footnote F4

This report on Form 4 is jointly filed by OrbiMed Advisors, OrbiMed GP, and Genesis GP. Each of the Reporting Persons 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 its pecuniary interest therein, if any. The Reporting Persons have designated a representative, Diyong Xu, an employee of OrbiMed Advisors, to serve on the Issuer's board of directors. This report shall not be deemed an admission that any such person or entity, including the Reporting Persons, is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.