KYMR

SEC source: 0000899243-21-048614 · doc4.xml · nonDerivative · entry 1

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 472,199

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.

SEC source: 0000899243-21-046845 · doc4.xml · derivative · entry 5

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 189,899

Underlying: Common Stock · 10,000 shares

Expires 2029-08-28

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.

F6 · derivative.exercise_date: Twenty-five percent (25%) of the shares underlying this stock option vested on July 1, 2020 and the remaining shares shall vest in equal monthly installments over the remaining thirty-six (36) months, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-046845 · doc4.xml · nonDerivative · entry 4

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,514

F2 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 6, 2020.

F5 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $54.96 to $55.12. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-046845 · doc4.xml · nonDerivative · entry 3

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,814

F2 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 6, 2020.

F4 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $53.92 to $54.74. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-046845 · doc4.xml · nonDerivative · entry 2

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,801

F2 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 6, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $52.91 to $53.88. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-046845 · doc4.xml · nonDerivative · entry 1

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 27,514

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 · balance_after: This number includes 258 shares acquired under the Registrant's employee stock purchase plan on November 30, 2021.

SEC source: 0000899243-21-045803 · doc4.xml · derivative · entry 2

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 199,899

Underlying: Common Stock · 10,000 shares

Expires 2029-08-28

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 · derivative.exercise_date: Twenty-five percent (25%) of the shares underlying this stock option vested on July 1, 2020 and the remaining shares shall vest in equal monthly installments over the remaining thirty-six (36) months, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-045803 · doc4.xml · nonDerivative · entry 1

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,256

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.

SEC source: 0000899243-21-042437 · doc4.xml · derivative · entry 13

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 118,812

Underlying: Common Stock · 14,996 shares

Expires 2029-05-22

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.

F10 · derivative.exercise_date: The shares underlying this stock option shall vest in forty-eight (48) equal monthly installments following the vesting commencement date of February 7, 2019, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 10

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 24,657

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F8 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $64.13 to $64.48. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 9

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 25,859

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F7 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $63.13 to $64.09. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 8

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 31,139

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F6 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $62.13 to $63.12. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 7

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 39,653

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.

SEC source: 0000899243-21-042437 · doc4.xml · derivative · entry 12

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 133,808

Underlying: Common Stock · 4,607 shares

Expires 2029-05-22

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.

F10 · derivative.exercise_date: The shares underlying this stock option shall vest in forty-eight (48) equal monthly installments following the vesting commencement date of February 7, 2019, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-042437 · doc4.xml · derivative · entry 11

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 40,007

Underlying: Common Stock · 20,000 shares

Expires 2028-10-31

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.

F9 · derivative.exercise_date: Twenty-five percent (25%) of the shares underlying this stock option vested on September 12, 2019 and the remaining shall vest in equal monthly installments over the remaining thirty-six (36) months, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 6

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 24,657

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F5 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $63.03 to $63.57. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 5

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 28,722

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F4 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $62.03 to $63.01. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 4

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 44,633

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $61.01 to $62.00. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 3

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 59,767

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $60.00 to $60.98. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 2

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 67,154

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.

SEC source: 0000899243-21-042437 · doc4.xml · nonDerivative · entry 1

Gollob Jared · CIK 0001821198 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 62,547

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.

SEC source: 0000899243-21-039857 · doc4.xml · derivative · entry 12

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 28,725

Underlying: Common Stock · 6,456 shares

Expires 2029-11-13

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.

F9 · derivative.exercise_date: The shares underlying this stock option shall vest upon the achievement of specified performance-based milestones.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 10

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 464,199

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F8 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $54.28 to $54.60. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 9

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 464,943

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F7 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $53.19 to $54.16. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 8

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 470,655

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.

SEC source: 0000899243-21-039857 · doc4.xml · derivative · entry 11

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,181

Underlying: Common Stock · 41,544 shares

Expires 2029-11-13

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.

F9 · derivative.exercise_date: The shares underlying this stock option shall vest upon the achievement of specified performance-based milestones.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 7

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 464,199

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 6

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 464,470

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F6 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $59.91 to $60.61. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 5

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 465,140

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F5 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $58.90 to $59.81. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 4

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 473,060

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F4 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $57.20 to $58.14. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 3

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 475,138

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $56.19 to $57.185. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 2

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 484,507

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $55.10 to $56.09. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-039857 · doc4.xml · nonDerivative · entry 1

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 505,743

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.

SEC source: 0000899243-21-035158 · doc4.xml · derivative · entry 4

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 209,899

Underlying: Common Stock · 10,000 shares

Expires 2029-08-28

F4 · derivative.exercise_date: Twenty-five percent (25%) of the shares underlying this stock option vested on July 1, 2020 and the remaining shares shall vest in equal monthly installments over the remaining thirty-six (36) months, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-035158 · doc4.xml · nonDerivative · entry 3

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 7,256

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 6, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $60.42 to $60.59. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-035158 · doc4.xml · nonDerivative · entry 2

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 8,756

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on November 6, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $59.41 to $60.35. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-035158 · doc4.xml · nonDerivative · entry 1

Jacobs Bruce N. · CIK 0001821074 · Chief Financial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 17,256

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.

SEC source: 0001209191-21-053642 · doc4.xml · derivative · entry 3

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 263,340

Underlying: Common Stock · 33,779 shares

Expires 2030-08-19

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.

F3 · derivative.exercise_date: Twenty-five percent (25%) of the shares subject to this option vested and became exercisable on August 17, 2021, and the remainder of the shares shall vest in equal monthly installments for a period of thirty-six (36) months thereafter.

SEC source: 0001209191-21-053642 · doc4.xml · nonDerivative · entry 2

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $59.99 to $60.69. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0001209191-21-053642 · doc4.xml · nonDerivative · entry 1

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 33,779

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.

SEC source: 0000899243-21-033636 · doc4.xml · derivative · entry 2

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 84,424

Underlying: Common Stock · 12,000 shares

Expires 2029-05-22

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 · derivative.exercise_date: The shares underlying this stock option shall vest in forty-eight (48) equal monthly installments following the vesting commencement date of February 7, 2019, subject to the reporting person's continued employment through each vesting date.

SEC source: 0000899243-21-033636 · doc4.xml · nonDerivative · entry 1

Mainolfi Nello · CIK 0001821189 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 464,199

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.

SEC source: 0000899243-21-033638 · doc4.xml · derivative · entry 6

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 297,119

Underlying: Common Stock · 54,000 shares

Expires 2030-08-19

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.

F6 · derivative.exercise_date: Twenty-five percent (25%) of the shares subject to this option vested and became exercisable on August 17, 2021, and the remainder of the shares shall vest in equal monthly installments for a period of thirty-six (36) months thereafter.

SEC source: 0000899243-21-033638 · doc4.xml · nonDerivative · entry 5

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F5 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $52.06 to $52.16. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-033638 · doc4.xml · nonDerivative · entry 4

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 288

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F4 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $51.05 to $52.00. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-033638 · doc4.xml · nonDerivative · entry 3

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 3,216

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $50.04 to $51.02. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-033638 · doc4.xml · nonDerivative · entry 2

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 45,191

F1 · kind: This sale was effected pursuant to a Rule 10b5-1 trading plan adopted on November 6, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $49.04 to $50.03. Full information regarding the number of shares sold at each separate price can be furnished to the SEC staff upon request.

SEC source: 0000899243-21-033638 · doc4.xml · nonDerivative · entry 1

Chesworth Richard · CIK 0001821188 · Chief Scientific Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 54,000

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.

SEC source: 0001209191-21-051016 · doc4.xml · nonDerivative · entry 1

Booth Bruce · CIK 0001451612 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

F1 · shares: The shares reported herein give effect to the pro rata distribution of shares by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"), on May 18, 2021, for no additional consideration to its limited partners and its general partner, Atlas Venture Associates X, L.P. ("AVA X LP"), subsequent to the Reporting Person's last Section 16 filing reporting ownership of the Issuer's Common Stock. As the distribution of such shares constituted only a change in the form of the Reporting Person's indirect ownership in such shares, the Reporting Person was not required to report the distribution pursuant to Section 16.

F2 · ownership.nature: These shares are held directly by AVA X LP. Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. The Reporting Person is a member of AVA X LLC and disclaims Section 16 beneficial ownership of such securities held by AVA X LP, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-21-051015 · doc4.xml · nonDerivative · entry 1

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F1 · shares: The shares reported herein give effect to the pro rata distribution of shares by Atlas Venture Fund X, L.P. ("Atlas Venture Fund X"), on May 18, 2021, for no additional consideration to its limited partners and its general partner, Atlas Venture Associates X, L.P. ("AVA X LP"), subsequent to the Reporting Persons' last Section 16 filing reporting ownership of the Issuer's Common Stock. As the distribution of such shares constituted only a change in the form of the Reporting Persons' ownership in such shares, the Reporting Persons were not required to report the distribution pursuant to Section 16.

F2 · ownership.direct: The shares are held directly by AVA X LP. Atlas Venture Associates X, LLC ("AVA X LLC") is the general partner of AVA X LP. AVA X LLC disclaims Section 16 beneficial ownership of the securities held by AVA X LP except to the extent of its pecuniary interest therein, if any.