FULC

SEC source: 0000899243-22-021530 · doc4.xml · derivative · entry 3

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 86,523

Underlying: Common Stock · 71,435 shares

Expires 2022-06-30

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F3 · derivative.exercise_date: This option was granted on January 22, 2019 under the 2016 Stock Incentive Plan (the "2016 Plan") and was to vest in equal quarterly installments from January 1, 2019 through December 31, 2022, subject to the reporting person's continuous service on each such vesting date and thus ceased on March 31, 2022 when the reporting person's continuous service ceased upon termination of his consulting agreement. Per terms of the award agreement under the 2016 Plan governing such option, the right to exercise this option will terminate June 30, 2022.

SEC source: 0000899243-22-021530 · doc4.xml · nonDerivative · entry 2

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.90 to $8.35, 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 (2) to this Form 4.

SEC source: 0000899243-22-021530 · doc4.xml · nonDerivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 578,065

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-021250 · doc4.xml · derivative · entry 9

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 157,958

Underlying: Common Stock · 24,382 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 under the 2016 Stock Incentive Plan (the "2016 Plan") and was to vest in equal quarterly installments from January 1, 2019 through December 31, 2022, subject to the reporting person's continuous service on each such vesting date and thus ceased on March 31, 2022 when the reporting person's continuous service ceased upon termination of his consulting agreement. Per terms of the award agreement under the 2016 Plan governing such option, the right to exercise this option will terminate June 30, 2022.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 6

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.90 to $8.59, 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 (4) to this Form 4.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 5

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 531,012

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-021250 · doc4.xml · derivative · entry 8

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 182,340

Underlying: Common Stock · 25,551 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 under the 2016 Stock Incentive Plan (the "2016 Plan") and was to vest in equal quarterly installments from January 1, 2019 through December 31, 2022, subject to the reporting person's continuous service on each such vesting date and thus ceased on March 31, 2022 when the reporting person's continuous service ceased upon termination of his consulting agreement. Per terms of the award agreement under the 2016 Plan governing such option, the right to exercise this option will terminate June 30, 2022.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 4

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.90 to $8.08, 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 (3) to this Form 4.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 3

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 532,181

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-021250 · doc4.xml · derivative · entry 7

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 207,891

Underlying: Common Stock · 16,689 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 under the 2016 Stock Incentive Plan (the "2016 Plan") and was to vest in equal quarterly installments from January 1, 2019 through December 31, 2022, subject to the reporting person's continuous service on each such vesting date and thus ceased on March 31, 2022 when the reporting person's continuous service ceased upon termination of his consulting agreement. Per terms of the award agreement under the 2016 Plan governing such option, the right to exercise this option will terminate June 30, 2022.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 2

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $7.90 to $7.95, 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 (2) to this Form 4.

SEC source: 0000899243-22-021250 · doc4.xml · nonDerivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 523,319

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-017416 · doc4.xml · derivative · entry 2

Tourangeau Greg · CIK 0001916566 · Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,500

Underlying: Common Stock · 6,500 shares

Expires 2032-05-05

F2 · derivative.exercise_date: This option was granted on May 6, 2022 and is subject to time-based vesting, with (i) 25% of the options vesting on May 6, 2023, (ii) 25% of the options vesting on May 6, 2024, and (iii) 50% of the options vesting on May 6, 2025, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-22-017416 · doc4.xml · nonDerivative · entry 1

Tourangeau Greg · CIK 0001916566 · Controller

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 16,202

F1 · price: These shares represent restricted stock unit (RSU) awards granted on May 6, 2022, with each RSU representing a right to receive one share of common stock. The RSU is subject to time-based vesting with (i) 25% of the shares vesting on May 6, 2023, (ii) 25% of the shares vesting on May 6, 2024, and (iii) 50% of the shares vesting on May 6, 2025, subject to the reporting person's continued service on each such vesting date.

SEC source: 0000899243-22-014438 · doc4.xml · derivative · entry 3

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 224,580

Underlying: Common Stock · 5,631 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F3 · derivative.exercise_date: This option was granted on January 22, 2019 and is scheduled to vest in equal quarterly installments from January 1, 2019 through December 31, 2022.

SEC source: 0000899243-22-014438 · doc4.xml · nonDerivative · entry 2

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.00 to $24.09, 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 (2) to this Form 4.

SEC source: 0000899243-22-014438 · doc4.xml · nonDerivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 512,261

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-013881 · doc4.xml · derivative · entry 9

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 230,211

Underlying: Common Stock · 52,552 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 and is scheduled to vest in equal quarterly installments from January 1, 2019 through December 31, 2022.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 6

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.00 to $24.75, 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 (4) to this Form 4.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 5

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 559,182

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-013881 · doc4.xml · derivative · entry 8

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 282,763

Underlying: Common Stock · 7,235 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 and is scheduled to vest in equal quarterly installments from January 1, 2019 through December 31, 2022.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 4

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.00 to $24.05, 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 (3) to this Form 4.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 3

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 513,865

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-013881 · doc4.xml · derivative · entry 7

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 289,998

Underlying: Common Stock · 34,464 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

F5 · derivative.exercise_date: This option was granted on January 22, 2019 and is scheduled to vest in equal quarterly installments from January 1, 2019 through December 31, 2022.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 2

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 506,630

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 15, 2021.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.00 to $24.17, 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 (2) to this Form 4.

SEC source: 0000899243-22-013881 · doc4.xml · nonDerivative · entry 1

Gould Robert J · CIK 0001577034 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 541,094

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 15, 2021.

SEC source: 0000899243-22-002880 · doc4.xml · derivative · entry 1

Dunn Judith · CIK 0001811904 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 140,890

Underlying: Common Stock · 140,890 shares

Expires 2032-01-18

F1 · derivative.exercise_date: This option was granted on January 19, 2022 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2022, subject to continued service.

SEC source: 0000899243-22-002881 · doc4.xml · derivative · entry 1

Thomson Peter G. · CIK 0001779120 · VP Finance & Accounting

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 40,000

Underlying: Common Stock · 40,000 shares

Expires 2032-01-18

F1 · derivative.exercise_date: This option was granted on January 19, 2022 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2022, subject to continued service.

SEC source: 0000899243-22-002879 · doc4.xml · derivative · entry 1

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 340,000

Underlying: Common Stock · 340,000 shares

Expires 2032-01-18

F1 · derivative.exercise_date: This option was granted on January 19, 2022 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2022, subject to continued service.

SEC source: 0000899243-22-002878 · doc4.xml · derivative · entry 1

Morabito Christopher · CIK 0001859284 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 59,744

Underlying: Common Stock · 59,744 shares

Expires 2032-01-18

F1 · derivative.exercise_date: This option was granted on January 19, 2022 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2022, subject to continued service.

SEC source: 0000899243-22-002877 · doc4.xml · derivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · SVP, General Counsel

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 60,000

Underlying: Common Stock · 60,000 shares

Expires 2032-01-18

F1 · derivative.exercise_date: This option was granted on January 19, 2022 and is scheduled to vest in equal quarterly installments over four years beginning on the vesting commencement date of January 1, 2022, subject to continued service.

SEC source: 0000899243-22-001475 · doc4.xml · derivative · entry 1

Rajavelu Esther · CIK 0001903716 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 200,000

Underlying: Common Stock · 200,000 shares

Expires 2032-01-02

F1 · derivative.exercise_date: This option was granted on January 3, 2022 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of January 3, 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: 0000899243-22-001356 · doc5.xml · nonDerivative · entry 1

Oltmans Curtis Gale · CIK 0001714982 · SVP, General Counsel

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,248

F1 · balance_after: Consists of 1,248 shares acquired under the Issuer's 2019 Employee Stock Purchase Plan on November 12, 2021.

SEC source: 0000899243-21-047542 · doc4.xml · derivative · entry 1

Banks Sonja · CIK 0001896415 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 30,000 shares

Expires 2031-12-07

F1 · derivative.exercise_date: This option was granted on December 8, 2021 and is scheduled to vest in equal monthly installments until December 8, 2024, subject to continued service.

SEC source: 0000899243-21-044427 · doc4.xml · nonDerivative · entry 1

LEVIN MARK J · CIK 0001180428 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 3,962,202

F1 · kind: Pursuant to a 10b5-1 trading plan adopted on September 8, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on November 10, 2021, 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: Pursuant to a 10b5-1 trading plan adopted on September 8, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on November 10, 2021, 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 · balance_after: Pursuant to a 10b5-1 trading plan adopted on September 8, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on November 10, 2021, 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.nature: The Reporting Person is a partner of TRV GP III, which is the general partner of TRV III. The Reporting Person disclaims beneficial ownership over the shares held by TRV III, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares.

SEC source: 0000899243-21-044424 · 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

STARR KEVIN P · CIK 0001192603 · 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: 3,962,202

F1 · kind: Pursuant to a 10b5-1 trading plan adopted on September 8, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on November 10, 2021, 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: Pursuant to a 10b5-1 trading plan adopted on September 8, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on November 10, 2021, 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 managers of TRV GP III LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper"). Each of TRV GP III, TRV GP III LLC, Levin, Starr 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: 0000899243-21-037615 · doc4.xml · nonDerivative · entry 1

LEVIN MARK J · CIK 0001180428 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 4,962,202

F1 · kind: Pursuant to a 10b5-1 trading plan adopted on March 30, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on September 22, 2021, 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: Pursuant to a 10b5-1 trading plan adopted on March 30, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on September 22, 2021, 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 · balance_after: Pursuant to a 10b5-1 trading plan adopted on March 30, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on September 22, 2021, 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.nature: The Reporting Person is a partner of TRV GP III, which is the general partner of TRV III. The Reporting Person disclaims beneficial ownership over the shares held by TRV III, except to the extent of his pecuniary interest therein, if any, and this report shall not be deemed an admission that he is the beneficial owner of such shares.

SEC source: 0000899243-21-037614 · 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

STARR KEVIN P · CIK 0001192603 · 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: 4,962,202

F1 · kind: Pursuant to a 10b5-1 trading plan adopted on March 30, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on September 22, 2021, 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: Pursuant to a 10b5-1 trading plan adopted on March 30, 2021 by Third Rock Ventures III, L.P. ("TRV III"), TRV III distributed for no consideration, 1,000,000 shares of Common Stock of the Issuer (the "Shares") on September 22, 2021, 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 managers of TRV GP III LLC are Mark Levin ("Levin"), Kevin Starr ("Starr") and Dr. Robert Tepper ("Tepper"). Each of TRV GP III, TRV GP III LLC, Levin, Starr 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: 0000899243-21-032753 · doc4.xml · derivative · entry 6

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 243,571

Underlying: Common Stock · 28,000 shares

Expires 2028-12-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 29, 2020.

F2 · derivative.exercise_date: This option was granted on December 18, 2018 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of December 18, 2018. 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: 0000899243-21-032753 · doc4.xml · nonDerivative · entry 4

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

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 December 29, 2020.

SEC source: 0000899243-21-032753 · doc4.xml · nonDerivative · entry 3

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 28,000

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 29, 2020.

SEC source: 0000899243-21-032753 · doc4.xml · derivative · entry 5

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 271,571

Underlying: Common Stock · 32,000 shares

Expires 2028-12-17

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 29, 2020.

F2 · derivative.exercise_date: This option was granted on December 18, 2018 and is scheduled to vest 25% on the first anniversary of the vesting commencement date of December 18, 2018. 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: 0000899243-21-032753 · doc4.xml · nonDerivative · entry 2

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

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 December 29, 2020.

SEC source: 0000899243-21-032753 · doc4.xml · nonDerivative · entry 1

Stuart Bryan · CIK 0001619846 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 32,000

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 29, 2020.

SEC source: 0000899243-21-032755 · doc4.xml · derivative · entry 6

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 72,501

Underlying: Common Stock · 31,071 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · kind: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 28, 2021.

F3 · derivative.exercise_date: The shares underlying the option are scheduled to vest 25% on the first anniversary of the vesting commencement date of January 22, 2020. 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: 0000899243-21-032755 · doc4.xml · derivative · entry 5

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 103,572

Underlying: Common Stock · 20,714 shares

Expires 2029-01-21

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 10, 2020.

F3 · derivative.exercise_date: The shares underlying the option are scheduled to vest 25% on the first anniversary of the vesting commencement date of January 22, 2020. 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: 0000899243-21-032755 · doc4.xml · nonDerivative · entry 4

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F2 · kind: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 28, 2021.

SEC source: 0000899243-21-032755 · doc4.xml · nonDerivative · entry 3

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 31,071

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

F2 · kind: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 28, 2021.

SEC source: 0000899243-21-032755 · doc4.xml · nonDerivative · entry 2

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

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 December 10, 2020.

SEC source: 0000899243-21-032755 · doc4.xml · nonDerivative · entry 1

Moxham Christopher · CIK 0001843784 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 20,714

Exercise/conversion can include RSU settlement. Transaction price and option strike are different fields; a missing price is not zero. Derivative and underlying rows can describe the same event.

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 December 10, 2020.