# EDGAR Filing Document

**Accession Number:** 0001661998
**File Stem:** 0000947871-26-000245
**Filing Date:** 2026-3
**Character Count:** 17152
**Document Hash:** 8e60df38004d09e3849d4d6ff5890a97
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000947871-26-000245.hdr.sgml**: 20260312

**ACCESSION NUMBER**: 0000947871-26-000245

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260312

**DATE AS OF CHANGE**: 20260312

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Q32 Bio Inc.
- **CENTRAL INDEX KEY:** 0001661998
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 473468154
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-90433
- **FILM NUMBER:** 26748898

**BUSINESS ADDRESS:**
- **STREET 1:** 830 WINTER STREET
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
- **BUSINESS PHONE:** 781-999-0232

**MAIL ADDRESS:**
- **STREET 1:** 830 WINTER STREET
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Homology Medicines, Inc.
- **DATE OF NAME CHANGE:** 20151228
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ORBIMED ADVISORS LLC
- **CENTRAL INDEX KEY:** 0001055951

**ORGANIZATION NAME:**
- **EIN:** 133976876
- **STATE OF INCORPORATION:** DE

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 601 LEXINGTON AVENUE
- **STREET 2:** 54TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** (212) 739-6400

**MAIL ADDRESS:**
- **STREET 1:** 601 LEXINGTON AVENUE
- **STREET 2:** 54TH FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022

## Exhibit 99.1

**<u>Exhibit 1</u>**

JOINT FILING AGREEMENT

The undersigned hereby agree that Amendment No. 1 to the Statement on Schedule 13D, dated February 18, 2026, with respect to the common stock, par value $0.0001 per share, of Q32 Bio Inc. is filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. Each of the undersigned agrees to be responsible for the timely filing of this Statement, and for the completeness and accuracy of the information concerning itself contained therein. This Joint Filing Agreement may be executed in any number of counterparts, all of which taken together shall constitute one and the same instrument.

IN WITNESS WHEREOF, the undersigned have executed this Joint Filing Agreement as of the 12th day of March 2026.

---

| | |
|:---|:---|
| ORBIMED ADVISORS LLC | ORBIMED ADVISORS LLC |
| By: | <u>/s/ Carl L. Gordon</u> |
|  | Name: Carl L. Gordon |
|  | Title: Member |
| ORBIMED CAPITAL GP VII LLC | ORBIMED CAPITAL GP VII LLC |
| By: | ORBIMED ADVISORS LLC, its managing member |
| By: | <u>/s/ Carl L. Gordon</u> |
|  | Name: Carl L. Gordon |
|  | Title: Member of OrbiMed Advisors LLC |

---

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**Q32 Bio Inc.**

*(Name of Issuer)*

**COMMON STOCK**

*(Title of Class of Securities)*

**746964105**

*(CUSIP Number)*

**OrbiMed Advisors LLC**<br>601 Lexington Avenue, 54th Floor<br>New York NY 10022<br>(212) 739-6400

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**02/18/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **746964105** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**ORBIMED ADVISORS LLC** | Name of reporting person<br>**ORBIMED ADVISORS LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**2252987.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**2252987.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2252987.00** | Aggregate amount beneficially owned by each reporting person<br>**2252987.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**15.4%** | Percent of class represented by amount in Row (11)<br>**15.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IA** | Type of Reporting Person (See Instructions)<br>**IA** | |

---

| **CUSIP No.** | **746964105** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**ORBIMED CAPITAL GP VII LLC** | Name of reporting person<br>**ORBIMED CAPITAL GP VII LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**AF** | Source of funds (See Instructions)<br>**AF** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**2252987.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**2252987.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2252987.00** | Aggregate amount beneficially owned by each reporting person<br>**2252987.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**15.4%** | Percent of class represented by amount in Row (11)<br>**15.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
COMMON STOCK

**(b) Name of Issuer:**
Q32 Bio Inc.

**(c) Address of Issuer's Principal Executive Offices:**
830 Winter Street, Waltham, MA, 02451

This Amendment No. 1 ("Amendment No. 1") to Schedule 13D supplements and amends the Statement on Schedule 13D of OrbiMed Advisors LLC ("OrbiMed Advisors") and OrbiMed Capital GP VII LLC, ("OrbiMed GP") (collectively, the "Reporting Persons") originally filed with the Securities and Exchange Commission (the "SEC") on March 28, 2024. This Amendment No. 1 is being filed to report that the beneficial ownership of the outstanding Shares held by the Reporting Persons decreased by more than 1% as a result of an increase in the number of Shares outstanding.

**Item 4. Purpose of Transaction**

The Reporting Persons from time to time intend to review their investment in the Issuer on the basis of various factors, including the Issuer's business, financial condition, results of operations and prospects, general economic and industry conditions, the securities markets in general and those for the Issuer's Shares in particular, as well as other developments and other investment opportunities. Based upon such review, the Reporting Persons will take such actions in the future as the Reporting Persons may deem appropriate in light of the circumstances existing from time to time. If the Reporting Persons believe that further investment in the Issuer is attractive, whether because of the market price of Shares or otherwise, they may acquire Shares or other securities of the Issuer either in the open market or in privately negotiated transactions. Similarly, depending on market and other factors, the Reporting Persons may determine to dispose of some or all of the Shares currently owned by the Reporting Persons or otherwise acquired by the Reporting Persons either in the open market or in privately negotiated transactions.

Except as set forth in this Schedule 13D, the Reporting Persons have not formulated any plans or proposals which relate to or would result in:  (a) the acquisition by any person of additional securities of the Issuer or the disposition of securities of the Issuer, (b) an extraordinary corporate transaction, such as a merger, reorganization or liquidation, involving the Issuer or any of its subsidiaries, (c) a sale or transfer of a material amount of the assets of the Issuer or any of its subsidiaries, (d) any change in the present Board of Directors or management of the Issuer, including any plans or proposals to change the number or term of directors or to fill any existing vacancies on the board, (e) any material change in the Issuer's capitalization or dividend policy of the Issuer, (f) any other material change in the Issuer's business or corporate structure, (g) any change in the Issuer's charter or bylaws or other instrument corresponding thereto or other action which may impede the acquisition of control of the Issuer by any person, (h) causing a class of the Issuer's securities to be deregistered or delisted from a national securities exchange or to cease to be authorized to be quoted in an inter-dealer quotation system of a registered national securities association, (i) a class of equity securities of the Issuer becoming eligible for termination of registration pursuant to Section 12(g)(4) of the Act or (j) any action similar to any of those enumerated above.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The following disclosure is based upon 14,629,463 outstanding Shares, as set forth in the Issuer's Annual Report on Form 10-K filed with the SEC on March 1, 2026.

As of the date of this filing, OrbiMed Private Investments VII, LP ("OPI VII"), a limited partnership organized under the laws of Delaware, holds 2,252,987 Shares constituting approximately 15.4% of the issued and outstanding Shares. OrbiMed GP is the general partner of OPI VII pursuant to the terms of the limited partnership agreement of OPI VII, and OrbiMed Advisors is the managing member of OrbiMed GP pursuant to the terms of the limited liability company agreement of OrbiMed GP. As a result, OrbiMed Advisors and OrbiMed GP share power to direct the vote and disposition of the Shares held by OPI VII and may be deemed directly or indirectly, including by reason of their mutual affiliation, to be the beneficial owners of the Shares held by OPI VII. 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 of the Shares held by OPI VII.

In addition, OrbiMed Advisors and OrbiMed GP, pursuant to their authority under the limited partnership agreements of OPI VII, caused OPI VII to enter into the agreements referred to in Item 6 below.

**(b)**
Item 5(a) is incorporated by reference herein.

**(c)**
Not applicable.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

In addition to the relationships between the Reporting Persons described in Items 2 and 5 above, OrbiMed GP is the general partner of OPI VII pursuant to the terms of the limited partnership agreement of OPI VII. Pursuant to this agreement and relationship, OrbiMed GP has discretionary investment management authority with respect to the assets of OPI VII. Such authority includes the power to vote and otherwise dispose of securities held by OPI VII. The number of outstanding Shares of the Issuer attributable to OPI VII is 2,252,987. OrbiMed GP, pursuant to its authority under the limited partnership agreement of OPI VII, may be considered to hold indirectly 2,252,987 Shares.

OrbiMed Advisors is the managing member of OrbiMed GP pursuant to the terms of the limited liability company agreement of OrbiMed GP. Pursuant to this agreement and relationship, OrbiMed Advisors and OrbiMed GP have discretionary investment management authority with respect to the assets of OPI VII. Such authority includes the power of OrbiMed GP to vote and otherwise dispose of securities held by OPI VII. The number of outstanding Shares attributable to OPI VII is 2,252,987 Shares. OrbiMed Advisors, pursuant to its authority under the terms of the limited liability company agreement of OrbiMed GP, may also be considered to hold indirectly 2,252,987 Shares.

Diyong Xu ("Xu"), an employee of OrbiMed Advisors, is a member of the Board of Directors of the Issuer and, accordingly, OrbiMed Advisors and OrbiMed GP may have the ability to affect and influence control of the Issuer. From time to time, Xu may receive stock options or other awards of equity-based compensation pursuant to the Issuer's compensation arrangements for non-employee directors. Pursuant to an agreement with OrbiMed Advisors and OrbiMed GP, Xu is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors and OrbiMed GP, which will in turn ensure that such securities or economic benefits are provided to OPI VII.

Registration Rights Agreement

Pursuant to the Subscription Agreement OPI VII entered into with Admirx, Inc. ("Legacy Q32" and such Subscription Agreement, the "Subscription Agreement"), on March 25, 2024, Legacy Q32 and the investors in the transaction resulting in OVI VII's purchase of 8,852,000 Shares immediately prior to the consummation of the Merger pursuant to the Subscription Agreement (the "Pre-Closing Financing"), including OPI VII entered into a registration rights agreement (the "Registration Rights Agreement"). Pursuant to the Registration Rights Agreement, among other things, Legacy Q32 agreed to register for resale certain shares of its common stock held by such investors from time to time, including Shares issued in the Issuer's merger  with Homology Medicines, Inc. (the "Merger") in exchange for the shares of Legacy Q32 common stock issued in the Pre-Closing Financing.

Pursuant to the Registration Rights Agreement, the Issuer is obligated to prepare and file a shelf registration statement covering the resale of covered Shares within 45 calendar days following the closing of the Merger, subject to certain exceptions, pursuant to Rule 415 of the Securities Act of 1933, as amended (the "Securities Act"). The Issuer also agreed to use its reasonable best efforts to keep such registration statement continuously effective under the Securities Act until the earlier of the date that all registrable securities covered by such registration statement (i) have been sold, thereunder or pursuant to Rule 144 of the Securities Act or (ii) may be sold without volume or manner-of-sale restrictions pursuant to Rule 144 of the Securities Act and without the requirement for the Issuer to be in compliance with the current public information requirement under Rule 144 of the Securities Act. The Registration Rights Agreement also provides that the Issuer will pay certain expenses of the securityholders and indemnify the applicable securityholders against certain liabilities.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** ORBIMED ADVISORS LLC

**Signature:** /s/ Carl L. Gordon

**Name/Title:** Carl L. Gordon/Member

**Date:** 03/12/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** ORBIMED CAPITAL GP VII LLC

**Signature:** /s/ Carl L. Gordon

**Name/Title:** Carl L. Gordon/Member of OrbiMed Advisors LLC

**Date:** 03/12/2026