DYN

SEC source: 0000899243-20-026186 · doc4.xml · derivative · entry 2

Forbion Capital Fund IV Cooperatief U.A. · CIK 0001823747 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 4,522,293 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.direct: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. Each of the Partners disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026186 · doc4.xml · nonDerivative · entry 1

Forbion Capital Fund IV Cooperatief U.A. · CIK 0001823747 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,131,079

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.direct: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. Each of the Partners disclaims beneficial ownership of such shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026184 · doc4.xml · derivative · entry 2

CureDuchenne Ventures, LLC · CIK 0001824590 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 602,972 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026184 · doc4.xml · nonDerivative · entry 1

CureDuchenne Ventures, LLC · CIK 0001824590 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 602,972

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026183 · doc4.xml · derivative · entry 5

Klein Lawrence Otto · CIK 0001762583 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 10,725 shares

Expires not disclosed

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_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026183 · doc4.xml · nonDerivative · entry 1

Klein Lawrence Otto · CIK 0001762583 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,725

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 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026179 · doc4.xml · derivative · entry 5

Stehman-Breen Catherine · CIK 0001702233 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 10,725 shares

Expires not disclosed

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_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026179 · doc4.xml · nonDerivative · entry 1

Stehman-Breen Catherine · CIK 0001702233 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 115,713

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 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026177 · doc4.xml · derivative · entry 4

Rhodes Jason P · CIK 0001577014 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 1,608,785 shares

Expires not disclosed

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_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. The reporting person is a member of AVAO I LLC and disclaims beneficial ownership of such securities held by Atlas Venture Opportunity Fund I, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026177 · doc4.xml · derivative · entry 3

Rhodes Jason P · CIK 0001577014 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 6,029,726 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. The reporting person is a member of AVA XI LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund XI, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026177 · doc4.xml · nonDerivative · entry 2

Rhodes Jason P · CIK 0001577014 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 1,608,785

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 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. The reporting person is a member of AVAO I LLC and disclaims beneficial ownership of such securities held by Atlas Venture Opportunity Fund I, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026177 · doc4.xml · nonDerivative · entry 1

Rhodes Jason P · CIK 0001577014 · Director

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 8,140,130

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. The reporting person is a member of AVA XI LLC and disclaims beneficial ownership of such securities held by Atlas Venture Fund XI, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026175 · doc4.xml · derivative · entry 5

Kersten Dirk · CIK 0001823682 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 1,608,786 shares

Expires not disclosed

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 · derivative.exercise_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. The Reporting Person is a partner of Forbion Management and a member of the investment committee of Forbion Management. The Reporting Person disclaims beneficial ownership of the shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026175 · doc4.xml · derivative · entry 4

Kersten Dirk · CIK 0001823682 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 4,522,293 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. The Reporting Person is a partner of Forbion Management and a member of the investment committee of Forbion Management. The Reporting Person disclaims beneficial ownership of the shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026175 · doc4.xml · nonDerivative · entry 1

Kersten Dirk · CIK 0001823682 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 6,131,079

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. The Reporting Person is a partner of Forbion Management and a member of the investment committee of Forbion Management. The Reporting Person disclaims beneficial ownership of the shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026172 · doc4.xml · derivative · entry 2

Wellington Biomedical Innovation Master Investors (Cayman) I L.P. · CIK 0001787092 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 1,608,785 shares

Expires not disclosed

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_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026172 · doc4.xml · nonDerivative · entry 1

Wellington Biomedical Innovation Master Investors (Cayman) I L.P. · CIK 0001787092 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 1,608,785

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 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026171 · doc4.xml · derivative · entry 4

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Associates XI, L.P. · CIK 0001780068 · 10% owner

Atlas Venture Associates XI, LLC · CIK 0001780067 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 1,608,785 shares

Expires not disclosed

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_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

SEC source: 0000899243-20-026171 · doc4.xml · derivative · entry 3

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Associates XI, L.P. · CIK 0001780068 · 10% owner

Atlas Venture Associates XI, LLC · CIK 0001780067 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 6,029,726 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

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

SEC source: 0000899243-20-026171 · doc4.xml · nonDerivative · entry 2

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Associates XI, L.P. · CIK 0001780068 · 10% owner

Atlas Venture Associates XI, LLC · CIK 0001780067 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 1,608,785

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 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

SEC source: 0000899243-20-026171 · doc4.xml · nonDerivative · entry 1

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Associates XI, L.P. · CIK 0001780068 · 10% owner

Atlas Venture Associates XI, LLC · CIK 0001780067 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 8,140,130

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

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

SEC source: 0001104659-20-107953 · tm2031638-1_4.xml · derivative · entry 3

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 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 footnote

Disclosed balance after: 0

Underlying: Common Stock · 2,145,045 shares

Expires not disclosed

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_price: The Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: The Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: The Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.underlying_shares: Includes (a) 1,458,068 shares held by RA Capital Healthcare Fund L.P. (the "Fund"), (b) 150,716 shares held in a separately managed account (the "Account") and (c) 536,261 shares held by RA Capital Nexus Fund, L.P. (the "Nexus Fund").

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, the Nexus Fund and the Account. 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 may be deemed indirect beneficial owners of the reported securities for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the "Act").

F4 · ownership.nature: They disclaim beneficial ownership of any of the reported securities for the purpose of determining whether they are subject to Section 16 of the Act, however, in reliance on Rule 16a-1(a)(1)(v) and (vii). To the extent that they might be deemed subject to Section 16, they disclaim beneficial ownership of securities held by the Fund and the Nexus Fund for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein, and disclaim any pecuniary interest in securities held in the Account for purposes of Rule 16a-1(a)(2).

SEC source: 0001104659-20-107953 · tm2031638-1_4.xml · nonDerivative · entry 2

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 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 footnote

Disclosed balance after: 2,805,045

F5 · shares: Includes (a) 570,747 shares held by the Fund, (b) 57,453 shares held by the Account, and (c) 31,800 shares held by the Nexus Fund, in each case acquired in the Issuer's initial public offering.

F6 · balance_after: Includes (a) 2,028,815 shares held by the Fund, (b) 208,169 shares held by the Account, and (c) 568,061 shares held by the Nexus Fund.

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, the Nexus Fund and the Account. 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 may be deemed indirect beneficial owners of the reported securities for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the "Act").

F4 · ownership.nature: They disclaim beneficial ownership of any of the reported securities for the purpose of determining whether they are subject to Section 16 of the Act, however, in reliance on Rule 16a-1(a)(1)(v) and (vii). To the extent that they might be deemed subject to Section 16, they disclaim beneficial ownership of securities held by the Fund and the Nexus Fund for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein, and disclaim any pecuniary interest in securities held in the Account for purposes of Rule 16a-1(a)(2).

SEC source: 0001104659-20-107953 · tm2031638-1_4.xml · nonDerivative · entry 1

RA CAPITAL MANAGEMENT, L.P. · CIK 0001346824 · 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 footnote

Disclosed balance after: 2,145,045

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 · price: The Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · balance_after: Includes (a) 1,458,068 shares held by RA Capital Healthcare Fund L.P. (the "Fund"), (b) 150,716 shares held in a separately managed account (the "Account") and (c) 536,261 shares held by RA Capital Nexus Fund, L.P. (the "Nexus Fund").

F3 · ownership.nature: RA Capital Management, L.P. (the "Adviser") is the investment manager for the Fund, the Nexus Fund and the Account. 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 may be deemed indirect beneficial owners of the reported securities for purposes of Section 13(d) of the Securities Exchange Act of 1934 (the "Act").

F4 · ownership.nature: They disclaim beneficial ownership of any of the reported securities for the purpose of determining whether they are subject to Section 16 of the Act, however, in reliance on Rule 16a-1(a)(1)(v) and (vii). To the extent that they might be deemed subject to Section 16, they disclaim beneficial ownership of securities held by the Fund and the Nexus Fund for purposes of Rule 16a-1(a)(2), except to the extent of their pecuniary interest therein, and disclaim any pecuniary interest in securities held in the Account for purposes of Rule 16a-1(a)(2).

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 15

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 7,893 shares

Expires not disclosed

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 · derivative.exercise_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · ownership.nature: The shares are held directly by MPM Asset Management Investors BV2018 LLC ("MPM Asset Management"). The manager of MPM Asset Management is BV 2018 LLC. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by MPM Asset Management, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 14

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 21,254 shares

Expires not disclosed

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 · derivative.exercise_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"). The general partner of BV 2018(B) is BV 2018 GP. BV 2018 LLC is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018(B), except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 13

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 399,867 shares

Expires not disclosed

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 · derivative.exercise_price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.exercise_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · derivative.expiration_date: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by MPM BioVentures 2018, L.P. ("BV 2018"). The general partner of BV 2018 is MPM BioVentures 2018 GP LLC ("BV 2018 GP"). MPM BioVentures 2018 LLC ("BV 2018 LLC") is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 12

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 83,188 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · ownership.nature: The shares are held directly by MPM Asset Management Investors BV2018 LLC ("MPM Asset Management"). The manager of MPM Asset Management is BV 2018 LLC. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by MPM Asset Management, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 11

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 224,025 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"). The general partner of BV 2018(B) is BV 2018 GP. BV 2018 LLC is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018(B), except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 10

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 4,215,076 shares

Expires not disclosed

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_price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.exercise_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F1 · derivative.expiration_date: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by MPM BioVentures 2018, L.P. ("BV 2018"). The general partner of BV 2018 is MPM BioVentures 2018 GP LLC ("BV 2018 GP"). MPM BioVentures 2018 LLC ("BV 2018 LLC") is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · nonDerivative · entry 3

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 91,081

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · ownership.nature: The shares are held directly by MPM Asset Management Investors BV2018 LLC ("MPM Asset Management"). The manager of MPM Asset Management is BV 2018 LLC. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by MPM Asset Management, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · nonDerivative · entry 2

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 245,279

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · ownership.nature: The shares are held directly by MPM BioVentures 2018 (B), L.P. ("BV 2018(B)"). The general partner of BV 2018(B) is BV 2018 GP. BV 2018 LLC is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018(B), except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-026170 · doc4.xml · nonDerivative · entry 1

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 4,614,943

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 · price: On September 21, 2020, the Series A Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F2 · price: On September 21, 2020, the Series B Preferred Stock automatically converted into Common Stock on a 3.3169-for-one basis without payment of further consideration upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by MPM BioVentures 2018, L.P. ("BV 2018"). The general partner of BV 2018 is MPM BioVentures 2018 GP LLC ("BV 2018 GP"). MPM BioVentures 2018 LLC ("BV 2018 LLC") is the managing member of BV 2018 GP. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by BV 2018, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000899243-20-025741 · doc4.xml · nonDerivative · entry 1

Beskrovnaya Oxana · CIK 0001824542 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,289

F1 · shares: Consists of shares of Common Stock issuable under 19,289 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025742 · doc4.xml · nonDerivative · entry 1

HIGH SUSANNA GATTI · CIK 0001691005 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,904

F1 · shares: Consists of shares of Common Stock issuable under 35,904 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025739 · doc4.xml · nonDerivative · entry 1

Subramanian Romesh · CIK 0001824655 · Chief Scientific Officer · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 566,249

F1 · shares: Consists of shares of Common Stock issuable under 41,309 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025737 · doc4.xml · nonDerivative · entry 1

McNeill Jonathan · CIK 0001824673 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 36,910

F1 · shares: Consists of shares of Common Stock issuable under 17,012 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025736 · doc4.xml · nonDerivative · entry 1

Brumm Joshua T · CIK 0001528826 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 107,027

F1 · shares: Consists of shares of Common Stock issuable under 107,027 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025735 · doc4.xml · nonDerivative · entry 1

Scalzo Richard William · CIK 0001789545 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 11,465

F1 · shares: Consists of shares of Common Stock issuable under 11,465 restricted stock units ("RSUs"). Each RSU represents the right to receive one share of Common Stock upon vesting. These RSUs are scheduled to vest in equal annual installments over four years with the first installment vesting on September 17, 2021.

SEC source: 0000899243-20-025741 · doc4.xml · derivative · entry 2

Beskrovnaya Oxana · CIK 0001824542 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 59,857

Underlying: Common Stock · 59,857 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-025742 · doc4.xml · derivative · entry 2

HIGH SUSANNA GATTI · CIK 0001691005 · Chief Operating Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 111,405

Underlying: Common Stock · 111,405 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-025739 · doc4.xml · derivative · entry 2

Subramanian Romesh · CIK 0001824655 · Chief Scientific Officer · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 128,185

Underlying: Common Stock · 128,185 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-025737 · doc4.xml · derivative · entry 2

McNeill Jonathan · CIK 0001824673 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 52,787

Underlying: Common Stock · 52,787 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-025736 · doc4.xml · derivative · entry 2

Brumm Joshua T · CIK 0001528826 · Director · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 320,781

Underlying: Common Stock · 320,781 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-025735 · doc4.xml · derivative · entry 2

Scalzo Richard William · CIK 0001789545 · See Remarks

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,575

Underlying: Common Stock · 35,575 shares

Expires 2030-09-15

F2 · derivative.exercise_date: This option was granted on September 16, 2020. The shares underlying the option are scheduled to vest over four years in equal monthly installments through September 16, 2024.

SEC source: 0000899243-20-026192 · doc4.xml · derivative · entry 4

Lubner David Charles · CIK 0001572000 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 177,872

Underlying: Common Stock · 53,625 shares

Expires not disclosed

F4 · derivative.exercise_price: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.exercise_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.expiration_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026183 · doc4.xml · derivative · entry 4

Klein Lawrence Otto · CIK 0001762583 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,574

Underlying: Common Stock · 10,725 shares

Expires not disclosed

F4 · derivative.exercise_price: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.exercise_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.expiration_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026179 · doc4.xml · derivative · entry 4

Stehman-Breen Catherine · CIK 0001702233 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,574

Underlying: Common Stock · 10,725 shares

Expires not disclosed

F4 · derivative.exercise_price: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.exercise_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F4 · derivative.expiration_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

SEC source: 0000899243-20-026175 · doc4.xml · derivative · entry 3

Kersten Dirk · CIK 0001823682 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 5,336,179

Underlying: Common Stock · 1,608,786 shares

Expires not disclosed

F5 · derivative.exercise_price: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · derivative.exercise_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · derivative.expiration_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F3 · ownership.nature: The shares are held directly by Forbion Capital Fund IV Cooperatief U.A ("FCF IV"). Forbion IV Management B.V. ("Forbion Management") the director of FCF IV, may be deemed to have voting and dispositive power over the shares held by FCF IV. Investment decisions with respect to the shares held by FCF IV can be made by FCPM III Services B.V., the director of Forbion Management, which may delegate such powers to its investment committee which may delegate such powers to the authorized representatives of Forbion Management. Messrs. Slootweg, van Osch, Mulder, van Houten, Reithinger and Boorsma (the "Partners") are partners of FCPM III Services B.V., which acts as the investment advisor to the directors of FCF IV. The Reporting Person is a partner of Forbion Management and a member of the investment committee of Forbion Management. The Reporting Person disclaims beneficial ownership of the shares, except to the extent of his pecuniary interest therein.

SEC source: 0000899243-20-026170 · doc4.xml · derivative · entry 9

HURWITZ EDWARD · CIK 0001211840 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 26,176

Underlying: Common Stock · 7,893 shares

Expires not disclosed

F7 · derivative.exercise_price: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F7 · derivative.exercise_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F7 · derivative.expiration_date: The Series B Preferred Stock was convertible into common stock on a 3.3169-for-one basis into the number of shares of common stock shown in Column 7 without payment of further consideration at the holder's election or upon closing of the initial public offering of the Issuer's common stock. The shares had no expiration date.

F5 · ownership.nature: The shares are held directly by MPM Asset Management Investors BV2018 LLC ("MPM Asset Management"). The manager of MPM Asset Management is BV 2018 LLC. The Reporting Person, Luke Evnin, Ansbert Gadicke, and Todd Foley are the Managing Directors of BV 2018 LLC. The Reporting Person disclaims Section 16 beneficial ownership of the securities held by MPM Asset Management, except to the extent of his pecuniary interest therein, if any.