Flagship Ventures Fund IV General Partner LLC

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 13

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 132,817 shares

Expires not disclosed

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

F3 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 12

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 128,845 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 11

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 171,428 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 10

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 359,276 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 283,460 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 400,000 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · derivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 0

Underlying: Common Stock · 571,428 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.exercise_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · derivative.expiration_date: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 1,061,102

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

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F3 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, each outstanding share of Series B-1 preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms, determined by dividing the original issue price of $3.416 per share by a conversion price of $12.365, and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 1,469,173

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

F2 · kind: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F2 · price: The Preferred Stock reported herein is preferred stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Merger Agreement, such Series C, D and F preferred stock of TransMedics, Inc. was converted into shares of common stock of the Issuer based on (i) the one-for-one ratio on which such shares of preferred stock of TransMedics Inc. were convertible into shares of common stock of TransMedics Inc. according to their terms and (ii) the 3.5-for-one ratio on which shares of common stock of TransMedics, Inc. were converted into shares of common stock of the Issuer. The Preferred Stock has no expiration date.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 268,736

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 3

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 2007, L.P.

Disclosed balance after: 0

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F5 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship Fund 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship Fund 2007 GP") is the general partner of Flagship Fund 2007. Dr. Afeyan is a manager of Flagship Fund 2007 GP and, for purposes of Flagship Fund 2007's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 214,285

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-012303 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 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 IV, L.P.

Disclosed balance after: 0

F1 · kind: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F1 · price: The Common Stock reported herein being disposed of is common stock of TransMedics, Inc. Immediately prior to the closing of the Issuer's initial public offering, pursuant to the Agreement and Plan of Merger and Reorganization by and among the Issuer, TransMedics, Inc. and TMDX, Inc., dated April 15, 2019 (the "Merger Agreement") such common stock of TransMedics, Inc. was converted into shares of common stock of the Issuer on a 3.5-for-one basis.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. is a manager of Flagship Fund IV GP and, for purposes of Flagship Fund IV's investment in the Issuer, Dr. Afeyan may be deemed to have voting and investment power with respect to all shares held by Flagship Fund IV. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent, if any, of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 281,203 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.

F6 · derivative.exercise_price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.exercise_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.expiration_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 173,586 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.

F6 · derivative.exercise_price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.exercise_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F6 · derivative.expiration_date: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 GP") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. While Mr. Kania is retired from Flagship Pioneering, Inc., he continue to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · derivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 665,908 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.

F4 · derivative.exercise_price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · derivative.exercise_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F4 · derivative.expiration_date: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 947,111

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

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 216,451

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

F6 · price: Each share of Series A-1 Preferred Stock converted into shares of the Issuer's Common Stock on a one-for-two basis upon the closing of the Issuer's initial public offering.

F1 · ownership.nature: Shares held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 GP") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. While Mr. Kania is retired from Flagship Pioneering, Inc., he continue to serve as a manager of Flagship 2007 GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the reporting persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-19-006452 · doc4.xml · nonDerivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures 2007 General Partner LLC · CIK 0001508053 · 10% owner

Flagship Ventures Fund 2007, L.P. · CIK 0001508052 · 10% owner

Cadena LLC · CIK 0001768776 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 665,908

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.

F4 · price: Each share of Series A Preferred Stock converted into shares of the Issuer's common stock, par value $0.001 ("Common Stock"), on a one-for-two basis upon the closing of the Issuer's initial public offering.

F5 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc., he continues to serve as a manager of Flagship Fund IV GP. Each of these individuals and entities may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 18

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 0

Underlying: Common Stock · 21,496 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.

F8 · derivative.exercise_price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · derivative.exercise_date: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · derivative.expiration_date: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 17

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 0

Underlying: Common Stock · 85,989 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.

F8 · derivative.exercise_price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · derivative.exercise_date: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F8 · derivative.expiration_date: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 16

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 0

Underlying: Common Stock · 1,428,432 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.

F7 · derivative.exercise_price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · derivative.exercise_date: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · derivative.expiration_date: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 15

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 0

Underlying: Common Stock · 5,713,739 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.

F7 · derivative.exercise_price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · derivative.exercise_date: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F7 · derivative.expiration_date: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 14

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 0

Underlying: Common Stock · 6,195,632 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.

F6 · derivative.exercise_price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · derivative.exercise_date: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · derivative.expiration_date: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 13

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 0

Underlying: Common Stock · 24,782,551 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.

F6 · derivative.exercise_price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · derivative.exercise_date: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F6 · derivative.expiration_date: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 12

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 0

Underlying: Common Stock · 1,823,036 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: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · price: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · derivative.exercise_date: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · derivative.expiration_date: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · derivative · entry 11

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 0

Underlying: Common Stock · 7,292,145 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: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · price: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · derivative.exercise_date: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F5 · derivative.expiration_date: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 8

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 9,468,596

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.

F8 · price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 7

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 37,874,424

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.

F8 · price: The Series D Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45854 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series D Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 6

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 9,447,100

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.

F7 · price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 5

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 37,788,435

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.

F7 · price: The Series C Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45853 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series C Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 4

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 8,018,668

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

F6 · price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 3

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 32,074,696

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

F6 · price: The Series B Preferred Stock converted into Common Stock based on an applicable conversion ratio of 0.45457 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series B Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 2

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV-Rx, LP

Disclosed balance after: 1,823,036

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 · price: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F2 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship Fund IV-Rx. While Mr. Kania is retired from Pioneering he continues to serve as a manager of the Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV-Rx disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0000899243-18-030859 · doc4.xml · nonDerivative · entry 1

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 10% owner

Flagship Pioneering Inc. · CIK 0001400240 · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 IV, LP

Disclosed balance after: 7,292,145

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 · price: The Series A Preferred Stock converted into shares of the Issuer's common stock, $0.0001 par value per share ("Common Stock") based on an applicable conversion ratio of 0.45576 upon the closing of the Issuer's initial public offering on December 11, 2018. The Series A Preferred Stock had no expiration date.

F1 · ownership.nature: Shares held by Flagship Ventures Fund IV, L.P. ("Flagship Fund IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP") is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. While Mr. Kania is retired from Flagship Pioneering, Inc. ("Pioneering"), he continues to serve as a manager of Flagship Fund IV GP. Each of the reporting persons except for Flagship Fund IV disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 21

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 781,860 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F7 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 20

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 195,466 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F6 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by VentureLabs Rx V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 19

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 195,466 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F5 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Fund V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 18

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 1,781,843 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F7 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 17

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 593,948 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F6 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by VentureLabs Rx V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 16

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 593,948 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F5 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Fund V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 15

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 5,000,000 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F6 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by VentureLabs Rx V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 14

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 5,000,000 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F5 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Fund V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 13

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 3,830,402 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F4 · ownership.nature: Shares held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx"). Flagship Fund IV GP is the general partner of Flagship IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP. Flagship Fund IV GP and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV-Rx. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · derivative · entry 12

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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 · 15,323,593 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.exercise_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F2 · derivative.expiration_date: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F3 · ownership.nature: Shares held by Flagship Fund IV. Flagship Fund IV GP is the general partner of Flagship Fund IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship Fund IV GP and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship Fund IV. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 11

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,563,703

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

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F7 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 10

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 5,789,414

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

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F6 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by VentureLabs Rx V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 9

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 5,789,414

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

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F5 · ownership.nature: Shares held by Flagship Ventures Fund V, L.P. ("Flagship Fund V"). Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP") is the general partner of Flagship Fund V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Fund V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,781,843

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

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F7 · ownership.nature: Shares held by Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities Fund I"). Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP") is the general partner of Flagship Opportunities I. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Opportunities GP and may be deemed to possess sole voting and investment power with respect to all shares held by Flagship Opportunities I. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · Director · 10% owner

Flagship VentureLabs IV, LLC · CIK 0001642578 · 10% owner

Flagship Ventures Fund IV, L.P. · CIK 0001503559 · 10% owner

Flagship Ventures Fund IV-Rx, L.P. · CIK 0001590973 · 10% owner

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

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

Flagship Ventures Opportunities Fund I, L.P. · CIK 0001677345 · 10% owner

AFEYAN NOUBAR · CIK 0001222012 · Director · 10% owner

KANIA EDWIN M JR · CIK 0001255927 · 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: 5,593,948

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

F2 · price: The preferred stock is convertible into the Issuer's common stock on a one-for-one basis at the holder's election and has no expiration date. The preferred stock automatically convert into common stock upon the closing of the Issuer's initial public offering held on July 20, 2018.

F6 · ownership.nature: Shares held by Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V"). Flagship Fund V GP is the general partner of VentureLabs Rx V. Noubar B. Afeyan, Ph.D. is the sole manager of Flagship Fund V GP and may be deemed to possess sole voting and investment power with respect to all shares held by VentureLabs Rx V. Each of the filing persons disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.