FULC

SEC source: 0000950170-24-074888 · ownership.xml · derivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2034-06-16

F1 · derivative.exercise_date: This option was granted on June 17, 2024 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-24-074885 · ownership.xml · derivative · entry 1

GERAGHTY JAMES A · CIK 0001239746 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2034-06-16

F1 · derivative.exercise_date: This option was granted on June 17, 2024 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-24-074884 · ownership.xml · derivative · entry 1

Dorton Katina · CIK 0001617541 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2034-06-16

F1 · derivative.exercise_date: This option was granted on June 17, 2024 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-24-074887 · ownership.xml · derivative · entry 1

Haviland Kate · CIK 0001663022 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2034-06-16

F1 · derivative.exercise_date: This option was granted on June 17, 2024 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-24-056947 · ownership.xml · nonDerivative · entry 1

Tourangeau Greg · CIK 0001916566 · Principal Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,571

F1 · kind: The sale reported on this Form 4 represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. The sale occurred automatically to satisfy the tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person.

SEC source: 0000950170-24-034177 · ownership.xml · derivative · entry 1

Horn Patrick Taylor · CIK 0001572002 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 400,000

Underlying: Common Stock · 400,000 shares

Expires 2034-03-17

F1 · derivative.exercise_date: This option was granted on March 18, 2024 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of March 18, 2024. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years until the fourth anniversary of the vesting commencement date, subject to continued service.

SEC source: 0000950170-24-028827 · ownership.xml · nonDerivative · entry 1

Tourangeau Greg · CIK 0001916566 · Vice President, Finance

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 11,807

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $11.71 to $11.74, inclusive. The reporting person undertakes to provide to Fulcrum Therapeutics, Inc., any security holder of Fulcrum Therapeutics, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (1) to this Form 4.

F2 · balance_after: Includes 699 shares acquired under the Issuer's employee stock purchase plan on May 13, 2022.

SEC source: 0000950170-24-025933 · ownership.xml · nonDerivative · entry 1

Sapir Alex · CIK 0001709415 · Director · See Remarks

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 43,360

F1 · price: The price reported in Column 4 is a weighted average price. These shares were purchased in multiple transactions at prices ranging from $10.96 to $11.50, inclusive. The reporting person undertakes to provide to Fulcrum Therapeutics, Inc., any security holder of Fulcrum Therapeutics, Inc. or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the range set forth in this footnote (1) to this Form 4.

SEC source: 0000950170-24-009094 · ownership.xml · derivative · entry 1

Musso Alan A · CIK 0001295830 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 100,000

Underlying: Common Stock · 100,000 shares

Expires 2034-01-25

F1 · derivative.exercise_date: This option was granted on January 26, 2024 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2024, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000950170-24-009096 · ownership.xml · derivative · entry 2

Tourangeau Greg · CIK 0001916566 · Vice President, Finance

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2034-01-25

F2 · derivative.exercise_date: This option was granted on January 26, 2024 and is scheduled to vest in equal yearly installments over two years beginning on the vesting commencement date of January 1, 2024, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000950170-24-009096 · ownership.xml · derivative · entry 1

Tourangeau Greg · CIK 0001916566 · Vice President, Finance

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 83,820

Underlying: Common Stock · 83,820 shares

Expires 2034-01-25

F1 · derivative.exercise_date: This option was granted on January 26, 2024 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2024, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000950170-24-009092 · ownership.xml · derivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · Chief Legal Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 150,000

Underlying: Common Stock · 150,000 shares

Expires 2034-01-25

F1 · derivative.exercise_date: This option was granted on January 26, 2024 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2024, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000950170-24-005790 · ownership.xml · derivative · entry 1

Musso Alan A · CIK 0001295830 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 61,822

Underlying: Common Stock · 61,822 shares

Expires 2033-08-06

F1 · balance_after: This performance-based stock option was granted on August 7, 2023 and is subject to the achievement of certain pre-defined performance objectives pertaining to financial and investor relations goals within six months from the grant date, and subject to Mr. Musso continuing to be an "eligible participant" (as defined in Fulcrum Therapeutics, Inc.'s 2022 Inducement Stock Incentive Plan) through the vesting date. All performance objectives were met on January 17, 2024.

SEC source: 0000950170-23-040615 · ownership.xml · derivative · entry 1

Musso Alan A · CIK 0001295830 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 432,800

Underlying: Common Stock · 432,800 shares

Expires 2033-08-06

F1 · derivative.exercise_date: This option was granted on August 7, 2023 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of August 7, 2023. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years until the fourth anniversary of the vesting commencement date, subject to continued service.

SEC source: 0000950170-23-030758 · ownership.xml · derivative · entry 1

Banks Sonja · CIK 0001896415 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030752 · ownership.xml · derivative · entry 1

Collins James J. · CIK 0001779269 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030755 · ownership.xml · derivative · entry 1

Ezekowitz Alan · CIK 0001780209 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030753 · ownership.xml · derivative · entry 1

Gould Robert J · CIK 0001577034 · Director · Interim President & CEO

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030765 · ownership.xml · derivative · entry 1

GERAGHTY JAMES A · CIK 0001239746 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030756 · ownership.xml · derivative · entry 1

Dorton Katina · CIK 0001617541 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 0 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-030757 · ownership.xml · derivative · entry 1

Haviland Kate · CIK 0001663022 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2033-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2023 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000950170-23-021245 · ownership.xml · nonDerivative · entry 1

Tourangeau Greg · CIK 0001916566 · Principal Accounting Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 15,992

F1 · kind: The sale reported on this Form 4 represents shares required to be sold by the Reporting Person to cover tax withholding obligations in connection with the vesting of restricted stock units. The sale occurred automatically to satisfy the tax withholding obligations to be funded by a "sell to cover" transaction and does not represent a discretionary trade by the Reporting Person.

SEC source: 0000950170-23-015824 · ownership.xml · derivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · Chief Legal Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 127,500

Underlying: Common Stock · 127,500 shares

Expires 2033-04-25

F1 · derivative.exercise_date: These stock options were granted to the reporting person under the Fulcrum 2019 Stock Incentive Plan (the "Plan") as part of an executive retention program and will vest 25% on the first anniversary of the grant date. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years, such that the options will be vested in full on the four-year anniversary of the grant date, and subject to the reporting person's continuing to be an "Eligible Participant" (as defined in the Plan) on each such vesting date.

SEC source: 0000950170-23-015832 · ownership.xml · derivative · entry 1

Hayes Melvin H. III · CIK 0001937148 · Chief Operating Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 115,000

Underlying: Common Stock · 115,000 shares

Expires 2033-04-25

F1 · derivative.exercise_date: These stock options were granted to the reporting person under the Fulcrum 2019 Stock Incentive Plan (the "Plan") as part of an executive retention program and will vest 25% on the first anniversary of the grant date. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years, such that the options will be vested in full on the four-year anniversary of the grant date, and subject to the reporting person's continuing to be an "Eligible Participant" (as defined in the Plan) on each such vesting date.

SEC source: 0000899243-23-004745 · doc4.xml · derivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · Chief Legal Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 150,000

Underlying: Common Stock · 150,000 shares

Expires 2033-02-08

F1 · derivative.exercise_date: This option was granted on February 9, 2023 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2023, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-23-004743 · doc4.xml · derivative · entry 1

Hayes Melvin H. III · CIK 0001937148 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 135,000

Underlying: Common Stock · 135,000 shares

Expires 2033-02-08

F1 · derivative.exercise_date: This option was granted on February 9, 2023 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2023, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-23-004742 · doc4.xml · derivative · entry 1

Rajavelu Esther · CIK 0001903716 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 160,000

Underlying: Common Stock · 160,000 shares

Expires 2033-02-08

F1 · derivative.exercise_date: This option was granted on February 9, 2023 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2023, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-23-004744 · doc4.xml · derivative · entry 1

Tourangeau Greg · CIK 0001916566 · Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,100

Underlying: Common Stock · 16,100 shares

Expires 2033-02-08

F1 · derivative.exercise_date: This option was granted on February 9, 2023 and is is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2023, subject to the reporting person's continued service on each such vesting date.

SEC source: 0001104659-23-006213 · tm234291-1_4seq1.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 11,609,704

F1 · balance_after: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F1 · ownership.nature: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F2 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0000899243-23-001803 · doc4.xml · nonDerivative · entry 1

Gould Robert J · CIK 0001577034 · Director · Interim President & CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 499,864

F1 · kind: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 7, 2022.

SEC source: 0001104659-23-001881 · tm232548-1_4seq1.xml · nonDerivative · entry 2

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 9,686,628

F3 · price: This transaction was executed in multiple trades at prices ranging from $7.64 to $8.00; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F4 · balance_after: Held directly by the Fund.

F4 · ownership.nature: Held directly by the Fund.

F5 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-23-001881 · tm232548-1_4seq1.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 9,628,259

F1 · price: This transaction was executed in multiple trades at prices ranging from $6.64 to $7.63; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F2 · balance_after: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F2 · ownership.nature: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F5 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-22-130982 · tm2233686-1_4seq1.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 9,505,925

F1 · price: This transaction was executed in multiple trades at prices ranging from $5.98 to $6.00; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F2 · balance_after: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F2 · ownership.nature: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-22-129121 · tm2233247-1_4.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 9,501,836

F1 · price: This transaction was executed in multiple trades at prices ranging from $5.79 to $6.00; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F2 · balance_after: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F2 · ownership.nature: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-22-127883 · tm2232930-1_4.xml · nonDerivative · entry 3

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 9,403,049

F4 · price: This transaction was executed in multiple trades at prices ranging from $5.25 to $5.69; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F5 · balance_after: Held directly by the Fund.

F5 · ownership.nature: Held directly by the Fund.

F6 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-22-127883 · tm2232930-1_4.xml · nonDerivative · entry 2

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 8,061,629

F2 · price: This transaction was executed in multiple trades at prices ranging from $5.35 to $5.50; the price reported above reflects the weighted average purchase price. The reporting person hereby undertakes, upon request, to provide full information to the staff of the Securities and Exchange Commission, the Issuer, or a security holder of the Issuer regarding the number of shares and prices at which these transactions, and all other transactions reported in this Form 4, were effected.

F3 · balance_after: Held directly by the Fund.

F3 · ownership.nature: Held directly by the Fund.

F6 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-22-127883 · tm2232930-1_4.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 10% owner

RA Capital Healthcare Fund LP · CIK 0001315082 · 10% owner

Kolchinsky Peter · CIK 0001384859 · 10% owner

Shah Rajeev M. · CIK 0001619841 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 7,824,600

F1 · balance_after: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F1 · ownership.nature: Held directly by RA Capital Healthcare Fund, L.P. (the "Fund").

F6 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund. The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. The Adviser, the Adviser GP, Dr. Kolchinsky and Mr. Shah disclaim beneficial ownership of any of the reported securities, except to the extent of their pecuniary interest therein.

SEC source: 0000899243-22-038602 · doc4.xml · nonDerivative · entry 1

Third Rock Ventures III, L.P. · CIK 0001569705 · 10% owner

Third Rock Ventures GP III, L.P. · CIK 0001637300 · 10% owner

TRV GP III, LLC · CIK 0001637299 · 10% owner

TEPPER ROBERT I · CIK 0001192595 · 10% owner

Joint disclosure: these amounts are not allocated separately to each reporting owner.

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,962,202

F1 · kind: On December 13, 2022, Third Rock Ventures III, L.P. ("TRV III") distributed for no consideration, 2,000,000 shares of Common Stock of the Issuer (the "Shares") to its limited partners and to Third Rock Ventures GP III, L.P. ("TRV GP III"), the general partner of TRV III, representing each such partner's pro rata interest in such Shares. On the same date, TRV GP III distributed, for no consideration, the Shares it received in the distribution by TRV III to its partners, representing each such partner's pro rata interest in such Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended.

F1 · price: On December 13, 2022, Third Rock Ventures III, L.P. ("TRV III") distributed for no consideration, 2,000,000 shares of Common Stock of the Issuer (the "Shares") to its limited partners and to Third Rock Ventures GP III, L.P. ("TRV GP III"), the general partner of TRV III, representing each such partner's pro rata interest in such Shares. On the same date, TRV GP III distributed, for no consideration, the Shares it received in the distribution by TRV III to its partners, representing each such partner's pro rata interest in such Shares. All of the aforementioned distributions were made in accordance with the exemptions afforded by Rules 16a-13 and 16a-9 of the Securities Exchange Act of 1934, as amended.

F2 · ownership.direct: These shares are directly held by TRV III. The general partner of TRV III is TRV GP III. The general partner of TRV GP III is TRV GP III, LLC ("TRV GP III LLC"). The individual manager of TRV GP III LLC is Dr. Robert Tepper ("Tepper"). Each of TRV GP III, TRV GP III LLC and Tepper disclaims beneficial ownership of the shares except to the extent of its or his pecuniary interest therein, if any, and this report shall not be deemed an admission that it or he is the beneficial owner of such shares.

SEC source: 0000899243-22-035434 · doc4.xml · derivative · entry 1

Arroyo Santiago · CIK 0001706857 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 400,000

Underlying: Common Stock · 400,000 shares

Expires 2032-11-06

F1 · derivative.exercise_date: This option was granted on November 7, 2022 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of November 7, 2022. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years until the fourth anniversary of the vesting commencement date, subject to continued service.

SEC source: 0000899243-22-028370 · doc4.xml · derivative · entry 1

Hayes Melvin H. III · CIK 0001937148 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 137,000

Underlying: Common Stock · 137,000 shares

Expires 2032-08-08

F1 · derivative.exercise_date: This option was granted on August 9, 2022 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of August 9, 2022. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years until the fourth anniversary of the vesting commencement date, subject to continued service.

SEC source: 0000899243-22-028368 · doc4.xml · derivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · Chief Legal Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 50,000

Underlying: Common Stock · 50,000 shares

Expires 2032-08-08

F1 · derivative.exercise_date: This option was granted on August 9, 2022 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of August 9, 2022. The remainder of the shares underlying the grant shall vest in equal quarterly installments over the following three years until the fourth anniversary of the vesting commencement date, subject to continued service

SEC source: 0000899243-22-026322 · doc4.xml · derivative · entry 1

Tourangeau Greg · CIK 0001916566 · Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,540

Underlying: Common Stock · 16,540 shares

Expires 2032-07-14

F1 · derivative.exercise_date: This option was granted on July 15, 2022 and is is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of July 1, 2022, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-22-024528 · doc4.xml · derivative · entry 2

Ezekowitz Alan · CIK 0001780209 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 14,500

Underlying: Common Stock · 500 shares

Expires 2030-12-02

F2 · derivative.exercise_date: No value was received for the cancellation of these stock options, which were originally granted on December 3, 2020.

SEC source: 0000899243-22-024523 · doc4.xml · derivative · entry 1

Banks Sonja · CIK 0001896415 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024522 · doc4.xml · derivative · entry 1

Collins James J. · CIK 0001779269 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024528 · doc4.xml · derivative · entry 1

Ezekowitz Alan · CIK 0001780209 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024527 · doc4.xml · derivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024524 · doc4.xml · derivative · entry 1

GERAGHTY JAMES A · CIK 0001239746 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024526 · doc4.xml · derivative · entry 1

Dorton Katina · CIK 0001617541 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.

SEC source: 0000899243-22-024525 · doc4.xml · derivative · entry 1

Haviland Kate · CIK 0001663022 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,000

Underlying: Common Stock · 19,000 shares

Expires 2032-06-26

F1 · derivative.exercise_date: This option was granted on June 27, 2022 and is scheduled to vest with respect to all shares on the first anniversary of the grant date or, if earlier, immediately prior to the first annual meeting of stockholders occurring after the grant date, subject to continued service.