Flagship V VentureLabs Rx Fund, L.P.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 6

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Pioneering Fund VI General Partner LLC

Disclosed balance after: 0

F7 · kind: On September 13, 2023, Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI") distributed in-kind to its limited partners and sole general partner, Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP"), pro rata and without consideration, 2,431,281 shares of the Issuer's common stock. Flagship Fund VI GP, in turn, distributed in-kind to its members, pro rata and without consideration, the 70,813 shares it received from Flagship Fund VI. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F7 · price: On September 13, 2023, Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI") distributed in-kind to its limited partners and sole general partner, Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP"), pro rata and without consideration, 2,431,281 shares of the Issuer's common stock. Flagship Fund VI GP, in turn, distributed in-kind to its members, pro rata and without consideration, the 70,813 shares it received from Flagship Fund VI. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F9 · ownership.nature: Represents shares held directly by Flagship Fund VI GP. Each of the reporting persons except Flagship Fund VI GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 5

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Pioneering Fund VI, L.P.

Disclosed balance after: 7,293,841

F7 · kind: On September 13, 2023, Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI") distributed in-kind to its limited partners and sole general partner, Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP"), pro rata and without consideration, 2,431,281 shares of the Issuer's common stock. Flagship Fund VI GP, in turn, distributed in-kind to its members, pro rata and without consideration, the 70,813 shares it received from Flagship Fund VI. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F7 · price: On September 13, 2023, Flagship Pioneering Fund VI, L.P. ("Flagship Fund VI") distributed in-kind to its limited partners and sole general partner, Flagship Pioneering Fund VI General Partner LLC ("Flagship Fund VI GP"), pro rata and without consideration, 2,431,281 shares of the Issuer's common stock. Flagship Fund VI GP, in turn, distributed in-kind to its members, pro rata and without consideration, the 70,813 shares it received from Flagship Fund VI. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F8 · ownership.nature: Represents shares held directly by Flagship Fund VI. Flagship Fund VI GP is the general partner of Flagship Fund VI. Flagship Pioneering is the manager of Flagship Fund VI GP. Each of the reporting persons except Flagship Fund VI disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 4

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V General Partner LLC

Disclosed balance after: 0

F3 · kind: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · price: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F6 · ownership.nature: Represents shares held directly by Flagship Fund V GP. Each of the reporting persons except Flagship Fund V GP disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 3

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,035,208

F3 · kind: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · price: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F5 · ownership.nature: Represents shares held directly by Flagship Fund V Rx. Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 2

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 8,057,470

F3 · kind: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F3 · price: On September 13, 2023, Flagship Ventures Fund V, L.P. ("Flagship Fund V") and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") distributed in-kind to their respective limited partners and sole general partner, Flagship Ventures Fund V General Partner, LLC ("Flagship Fund V GP"), pro rata and without consideration, 4,926,378 shares and 345,069 shares, respectively, of the Issuer's common stock. Flagship Fund V GP, in turn, distributed in-kind to its members, pro rata and without consideration, the aggregate of 1,181,745 shares it received from Flagship Fund V and Flagship Fund V Rx. The aforementioned distributions were made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F4 · balance_after: Represents shares held directly by Flagship Fund V. Includes 2,240,555 shares received in the distribution-in-kind from VentureLabs V described in footnote (1) above. Flagship V GP is the general partner of Flagship Fund V. Dr. Afeyan is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

F4 · ownership.nature: Represents shares held directly by Flagship Fund V. Includes 2,240,555 shares received in the distribution-in-kind from VentureLabs V described in footnote (1) above. Flagship V GP is the general partner of Flagship Fund V. Dr. Afeyan is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-019165 · doc4.xml · nonDerivative · entry 1

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship VentureLabs V, LLC

Disclosed balance after: 8,615,337

F1 · kind: On September 13, 2023, Flagship VentureLabs V LLC ("VentureLabs V") distributed in-kind to its members, pro rata and without consideration, 2,825,989 shares of the Issuer's common stock. The aforementioned distribution was made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F1 · price: On September 13, 2023, Flagship VentureLabs V LLC ("VentureLabs V") distributed in-kind to its members, pro rata and without consideration, 2,825,989 shares of the Issuer's common stock. The aforementioned distribution was made in accordance with the exemptions afforded by Rule 16a-13 and Rule 16a-9 of the Securities Exchange Act of 1934, as amended.

F2 · ownership.nature: Represents shares held directly by VentureLabs V. Flagship VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. Dr. Afeyan is the CEO and sole stockholder of Flagship Pioneering. Each of the reporting persons except VentureLabs V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-014953 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,380,277

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.20 to $6.36, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-014953 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 10,743,293

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.20 to $6.36, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-014953 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,403,037

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.30 to $6.415, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-014953 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 10,920,533

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.30 to $6.415, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,425,334

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.08 to $6.43, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 11,101,994

F5 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.08 to $6.43, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,434,664

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.30 to $6.56, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 11,174,664

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.30 to $6.56, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,447,791

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.50 to $6.99, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F3 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Each of the reporting persons except Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-23-013992 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 11,276,909

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $6.50 to $6.99, inclusive. The reporting persons undertake to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range.

F2 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein, if any.

SEC source: 0000899243-22-031404 · doc4.xml · derivative · entry 5

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 210,743

Underlying: Common Stock · 210,743 shares

Expires 2027-09-15

F1 · kind: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F1 · price: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F3 · ownership.nature: Shares held by Flagship Fund V Rx. Flagship V GP is the general partner of Flagship Fund V Rx. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-22-031404 · doc4.xml · derivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 722,590

Underlying: Common Stock · 722,590 shares

Expires 2027-09-15

F1 · kind: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F1 · price: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F2 · ownership.nature: Shares held by Flagship Fund V. Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-22-031404 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship V VentureLabs Rx Fund, L.P.

Disclosed balance after: 1,188,920

F1 · kind: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F1 · price: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F3 · ownership.nature: Shares held by Flagship Fund V Rx. Flagship V GP is the general partner of Flagship Fund V Rx. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-22-031404 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · By Flagship Ventures Fund V, L.P.

Disclosed balance after: 1,865,767

F1 · kind: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F1 · price: On September 15, 2022, pursuant to an underwritten public offering by the Issuer (the "Offering"), Flagship Ventures Fund V, L.P. ("Flagship Fund V") acquired 722,590 shares of Common Stock and accompanying warrants to purchase 722,590 shares of Common Stock, and Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx") acquired 210,743 shares of Common Stock and accompanying warrants to purchase 210,743 shares of Common Stock. The combined purchase price in the Offering was $1.50 per share of Common Stock and accompanying warrant.

F2 · ownership.nature: Shares held by Flagship Fund V. Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 21

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 441,176 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F7 · ownership.nature: Represents shares held directly by FPN, L.P. ("FPN Fund").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 20

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 1,323,530 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Represents shares held directly by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II")

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 19

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 441,176 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 18

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 882,353 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F7 · ownership.nature: Represents shares held directly by FPN, L.P. ("FPN Fund").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 17

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 3,529,413 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Represents shares held directly by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II")

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 16

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 176,470 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Represents shares held directly by Nutritional Health LTP Fund, L.P. ("Nutritional LTP").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 15

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 705,882 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 14

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 794,118 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Represents shares held directly by Nutritional Health LTP Fund, L.P. ("Nutritional LTP").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 13

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 7,249,767 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 12

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 5,896,386 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F3 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · derivative · entry 11

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 1,088,470 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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · price: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F1 · derivative.expiration_date: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F2 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 9

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,617,646

F7 · ownership.nature: Represents shares held directly by FPN, L.P. ("FPN Fund").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 8

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,323,529

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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F7 · ownership.nature: Represents shares held directly by FPN, L.P. ("FPN Fund").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 7

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 5,514,707

F6 · ownership.nature: Represents shares held directly by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II")

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 6

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 4,852,943

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: The shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F6 · ownership.nature: Represents shares held directly by Flagship Pioneering Special Opportunities Fund II, L.P. ("Flagship Opportunities Fund II")

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 5

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 970,588

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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Represents shares held directly by Nutritional Health LTP Fund, L.P. ("Nutritional LTP").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 4

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 8,617,413

F4 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 3

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 8,396,825

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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F4 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 2

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 5,896,386

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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F3 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-031797 · doc4.xml · nonDerivative · entry 1

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,088,470

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 shares of Issuer's preferred stock have no expiration date and are convertible at the holder's election into Issuer's common stock at a conversion ratio of 1-to-0.264706. The preferred stock will automatically convert into shares of the Issuer's common stock, for no additional consideration, upon the closing of the Issuer's initial public offering.

F2 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx").

F9 · ownership.nature: Flagship Fund V is a member of VentureLabs V. VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP"). The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The General Partner of Flagship Opportunities Fund II is Flagship Pioneering Special Opportunities Fund II General Partner LLC ("Flagship Opportunities Fund II GP").

F10 · ownership.nature: (continued from above) The general partner of FPN Fund is FPN General Partner LLC ("FPN GP"). The manager of Flagship Pioneering VI GP, Flagship Opportunities Fund II GP, and FPN GP is Flagship Pioneering. The general partner of Nutritional LTP is Nutritional Health LTP Fund General Partner LLC ("Nutritional LTP GP" and, together with VentureLabs V Manager, Flagship Pioneering, Flagship V GP, Flagship Pioneering VI GP, Flagship Opportunities Fund II GP and FPN GP, the "Flagship General Partners").

F11 · ownership.nature: (continued from above) Noubar B. Afeyan, Ph.D. ("Dr. Afeyan") is the sole director of Flagship Pioneering and may be deemed to have beneficial ownership of all the shares held by VentureLabs V, Flagship Pioneering VI, Flagship Opportunities Fund II and FPN Fund. In addition, Dr. Afeyan serves as the sole manager of Flagship V GP and is the sole member and manager of Nutritional LTP GP and may be deemed to have beneficial ownership of all the shares held by Flagship Fund V, Flagship Fund V Rx and Nutritional LTP. None of the Flagship General Partners nor Dr. Afeyan directly own any of the shares held by the Reporting Persons, and each of the Flagship General Partners and Dr. Afeyan disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · derivative · entry 8

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 11,585,199 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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F8 · derivative.expiration_date: The expiration date is not relevant to the conversion of these securities.

F5 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V" and together with Flagship Fund V Rx, Flagship Pioneering VI, and VentureLabs V, the "Flagship Pioneering Funds").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · derivative · entry 7

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 11,441,326 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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F8 · derivative.expiration_date: The expiration date is not relevant to the conversion of these securities.

F4 · ownership.nature: Represents shares held directly by Flagship VentureLabs V LLC. ("VentureLabs V").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · derivative · entry 6

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 9,725,122 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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F8 · derivative.expiration_date: The expiration date is not relevant to the conversion of these securities.

F3 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · derivative · entry 5

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 1,487,371 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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F1 · derivative.exercise_date: The shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F8 · derivative.expiration_date: The expiration date is not relevant to the conversion of these securities.

F2 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 11,585,199

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.

F1 · price: The shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F5 · ownership.nature: Represents shares held directly by Flagship Ventures Fund V, L.P. ("Flagship Fund V" and together with Flagship Fund V Rx, Flagship Pioneering VI, and VentureLabs V, the "Flagship Pioneering Funds").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 11,441,326

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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F4 · ownership.nature: Represents shares held directly by Flagship VentureLabs V LLC. ("VentureLabs V").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 9,725,122

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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F3 · ownership.nature: Represents shares held directly by Flagship Pioneering Fund VI, L.P. ("Flagship Pioneering VI").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-21-005747 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship Pioneering Fund VI General Partner LLC · CIK 0001724957 · 10% owner

Flagship Pioneering Fund VI, L.P. · CIK 0001716926 · 10% owner

Flagship VentureLabs V Manager LLC · CIK 0001768987 · 10% owner

Flagship VentureLabs V LLC · CIK 0001724959 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 1,487,371

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 shares of Issuer's Preferred Stock automatically convert into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering.

F2 · ownership.nature: Represents shares held directly by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx").

F6 · ownership.nature: VentureLabs V Manager LLC ("VentureLabs V Manager") is the manager of VentureLabs V. Flagship Pioneering, Inc. ("Flagship Pioneering") is the manager of VentureLabs V Manager. The General Partner of Flagship Pioneering VI is Flagship Pioneering Fund VI General Partner LLC ("Flagship Pioneering VI GP"). The manager of Flagship Pioneering VI GP is Flagship Pioneering. The General Partner of Flagship Fund V and Flagship Fund V Rx is Flagship Ventures Fund V General Partner LLC ("Flagship V GP" and, together with VentureLabs V Manager, Flagship Pioneering, and Flagship Pioneering VI GP, the "Flagship General Partners").

F7 · ownership.nature: (continued from footnote 6) Noubar B. Afeyan, Ph.D. is the sole Director of Flagship Pioneering and may be deemed to have sole voting and investment control over all the shares held by VentureLabs V and Flagship Fund VI. In addition, Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP and may be deemed to possess sole voting and investment control over all the shares held by Flagship Fund V and Flagship Fund V Rx. None of the Flagship General Partners nor Noubar B. Afeyan, Ph.D. directly own any of the shares held by the Flagship Pioneering Funds, and each of the Flagship General Partners and Noubar Afeyan, Ph.D. disclaims beneficial ownership of such shares except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-20-028807 · doc4.xml · derivative · entry 14

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 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 · 95,861 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.

F5 · derivative.exercise_price: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · price: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · derivative.exercise_date: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · derivative.expiration_date: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F3 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("Flagship Fund V Rx"). Flagship V GP is the general partner of Flagship Fund V Rx. Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-20-028807 · doc4.xml · derivative · entry 13

Flagship Ventures Fund V General Partner LLC · CIK 0001724575 · 10% owner

Flagship Ventures Fund V, L.P. · CIK 0001627639 · 10% owner

Flagship V VentureLabs Rx Fund, L.P. · CIK 0001724939 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · 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 · 95,861 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.

F5 · derivative.exercise_price: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · price: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · derivative.exercise_date: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F5 · derivative.expiration_date: Each share of Series C Preferred Stock automatically converted into the Issuer's Common Stock on a 1-for-6.8855 basis upon the closing of the Issuer's initial public offering on October 16, 2020 and had no expiration date. The reporting person previously reported shares of common stock into which the Series C Preferred Stock was convertible based on a 1-for-6.8758 conversion ratio estimated at pricing of the Issuer's initial public offering, which reflected a fixed conversion price plus an estimated adjustment based on the issuance of shares in the Issuer's initial public offering.

F2 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. serves as the sole manager of Flagship V GP. Each of the reporting persons except for Flagship Fund V disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.