QTTB · Q32 Bio Inc.

Represents shares of Issuer common stock underlying performance-based restricted stock units ("PSUs") granted on July 6, 2026, which vested on July 16, 2026 with respect to a performance-based condition, upon achievement of the closing of a financing of at least $100,000,000 in gross proceeds on or before December 31, 2026. Such PSUs are also subject to a time-based condition, which provides that the PSUs shall vest in equal quarterly installments over three years from July 1, 2026, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. Each PSU represents a contingent right to receive one share of Issuer common stock.

Represents shares of Issuer common stock underlying performance-based restricted stock units ("PSUs") granted on July 6, 2026, which vested on July 16, 2026 with respect to a performance-based condition, upon achievement of the closing of a financing of at least $100,000,000 in gross proceeds on or before December 31, 2026. Such PSUs are also subject to a time-based condition, which provides that the PSUs shall vest in equal quarterly installments over three years from July 1, 2026, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. Each PSU represents a contingent right to receive one share of Issuer common stock.

Represents shares of Issuer common stock underlying performance-based restricted stock units ("PSUs") granted on July 6, 2026, which vested on July 16, 2026 with respect to a performance-based condition, upon achievement of the closing of a financing of at least $100,000,000 in gross proceeds on or before December 31, 2026. Such PSUs are also subject to a time-based condition, which provides that the PSUs shall vest in equal quarterly installments over three years from July 1, 2026, subject to the Reporting Person's continued service to the Issuer through each applicable vesting date. Each PSU represents a contingent right to receive one share of Issuer common stock.

The shares underlying this option are fully vested and exercisable.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

This Form 4 amendment is being filed solely to amend the Form 4 filed on June 16, 2026 to correct the number of options awarded to the Reporting Person on June 12, 2026.

The shares underlying this option shall vest and become exercisable in full upon the earlier of (i) June 12, 2027 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.

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

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.

Each of the Reporting Person, OrbiMed Advisors, OrbiMed GP, and Genesis GP 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. 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.

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

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.

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.

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

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.

Each of the Reporting Person, OrbiMed Advisors, OrbiMed GP, and Genesis GP 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. 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.

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

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.

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.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $4.35 to $4.69. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, on request, full information regarding the number of shares sold at each separate price within the range set forth above.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $4.35 to $4.69. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, on request, full information regarding the number of shares sold at each separate price within the range set forth above.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $4.35 to $4.69. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, on request, full information regarding the number of shares sold at each separate price within the range set forth above.

The restricted stock units ("RSUs") vest in four equal installments, 25% shall vest 6 months from February 24, 2026 (the "Grant Date"), 25% shall vest 12 months from the Grant Date, 25% shall vest 24 months from the Grant Date, and 25% shall vest 36 months from Grant Date. Each RSU represents a contingent right to receive one share of Issuer common stock.

The restricted stock units ("RSUs") vest in four equal installments, 25% shall vest 6 months from February 24, 2026 (the "Grant Date"), 25% shall vest 12 months from the Grant Date, 25% shall vest 24 months from the Grant Date, and 25% shall vest 36 months from Grant Date. Each RSU represents a contingent right to receive one share of Issuer common stock.

The restricted stock units ("RSUs") vest in four equal installments, 25% shall vest 6 months from February 24, 2026 (the "Grant Date"), 25% shall vest 12 months from the Grant Date, 25% shall vest 24 months from the Grant Date, and 25% shall vest 36 months from Grant Date. Each RSU represents a contingent right to receive one share of Issuer common stock.

This option was granted to the Reporting Person, a director of the Issuer pursuant to the 2024 Stock Option and Incentive Plan and pursuant to the Issuer's non-employee director compensation policy. This option shall vest in four equal quarterly installments as of the last date of each calendar quarter subject to the Reporting Person's continued service through such date and represents the Reporting Person's election to receive stock options in lieu of cash retainer fees. Due to administrative oversight this option award initially was not reported.

This option was granted to the Reporting Person, a director of the Issuer pursuant to the 2024 Stock Option and Incentive Plan and pursuant to the Issuer's non-employee director compensation policy. This option shall vest in four equal quarterly installments as of the last date of each calendar quarter subject to the Reporting Person's continued service through such date and represents the Reporting Person's election to receive stock options in lieu of cash retainer fees. Due to administrative oversight this option award initially was not reported.

This option was granted to the Reporting Person, a director of the Issuer pursuant to the 2024 Stock Option and Incentive Plan and pursuant to the Issuer's non-employee director compensation policy. This option shall vest in four equal quarterly installments as of the last date of each calendar quarter subject to the Reporting Person's continued service through such date and represents the Reporting Person's election to receive stock options in lieu of cash retainer fees. Due to administrative oversight this option award initially was not reported.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

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.

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.

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.

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.

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.

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.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

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.

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.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported is a weighted average price. The securities were sold in multiple transactions over two consecutive trading days, at per share prices ranging from $1.81 to $1.96 and $1.73 to $1.83, respectively. The Reporting Person undertakes to provide upon request the SEC staff, the Issuer, or any shareholder of the Issuer, full information regarding the number of securities sold at each separate price within the ranges set forth in this footnote 2.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported is a weighted average price. The securities were sold in multiple transactions over two consecutive trading days, at per share prices ranging from $1.81 to $1.96 and $1.73 to $1.83, respectively. The Reporting Person undertakes to provide upon request the SEC staff, the Issuer, or any shareholder of the Issuer, full information regarding the number of securities sold at each separate price within the ranges set forth in this footnote 2.

Represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. These sales were automatic and not in the discretion of the Reporting Person.

The price reported is a weighted average price. The securities were sold in multiple transactions over two consecutive trading days, at per share prices ranging from $1.81 to $1.96 and $1.73 to $1.83, respectively. The Reporting Person undertakes to provide upon request the SEC staff, the Issuer, or any shareholder of the Issuer, full information regarding the number of securities sold at each separate price within the ranges set forth in this footnote 2.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

This option was granted to the Reporting Person, a director of the Issuer. The proceeds of any sale of shares of common stock issued to the Reporting Person upon exercise of this option will be transferred to Atlas Venture Life Science Advisors, LLC and as such, the Reporting Person disclaims ownership of such securities reported herein for purposes of Section 16 of the Securities Exchange Act of 1934, as amended, except to the extent of his pecuniary interest therein, if any.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

The exercise price of the option is $2.54 per share, representing the fair market value per share of the Issuer's Common Stock on the Repricing Date; provided that in the event (i) the option is exercised prior to the one-year anniversary of the Repricing Date, (ii) the Reporting Person's employment is terminated by the Company prior to the one-year anniversary of the Repricing Date due to Cause (as defined in the 2024 Plan) or (iii) the Reporting Person resigns for any reason prior to the one-year anniversary of the Repricing Date, the exercise price will be increased to the exercise price of the cancelled option in exchange for which this option was granted.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.

On February 24, 2025, the Issuer's board of directors approved an option repricing ("Repricing Date"). All of the other terms of the options remain unchanged. Such transactions were exempt pursuant to Rule 16b-6(d) and Rule 16b-3 of the Exchange Act, as applicable.

This stock option award was issued pursuant to the Q32 Bio Inc. 2017 Stock Option and Grant Plan (the "2017 Plan") or the Q32 Bio Inc. 2024 Stock Option and Incentive Plan (the "2024 Plan"), as applicable, and becomes exercisable in accordance with the vesting schedule specified in the award agreement and as previously reported on applicable Form 4, subject to the Reporting Person's continued service with the Issuer as of the applicable vesting date.