Flagship Ventures Fund IV, L.P.

SEC source: 0001104659-18-046534 · a4.xml · nonDerivative · entry 6

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.

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 5

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: 5,000,000

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

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 4

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: 5,000,000

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

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 3

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: 3,830,402

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.

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 · nonDerivative · entry 2

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: 15,323,593

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.

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: 0000899243-18-013014 · doc4.xml · derivative · entry 8

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 1,138,505 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · derivative · entry 7

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 4,562,664 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · derivative · entry 6

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 2,042,902 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · derivative · entry 5

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 1,327,939 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · derivative · entry 4

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 2,476,600 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · derivative · entry 3

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 3,073,533 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: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.exercise_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F7 · derivative.expiration_date: Upon closing of the Issuer's initial public offering, each share of preferred stock was automatically converted into the Issuer's common stock on a 0.2452-for-one basis.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · nonDerivative · entry 2

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 18,233,403

F6 · shares: Includes 35,156, 105,469, and 140,625 shares purchased by Nutritional Health Side Fund, Nutritional Innovation Fund, and Flagship Opportunities I, respectively, in connection with the Issuer's initial public offering.

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0000899243-18-013014 · doc4.xml · nonDerivative · entry 1

Flagship Ventures Fund IV General Partner LLC · CIK 0001508051 · 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

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 17,952,153

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

F1 · ownership.nature: Following the transactions reported herein, Flagship VentureLabs IV LLC ("VentureLabs IV") holds 684,372 shares of common stock, Flagship VentureLabs V LLC ("VentureLabs V") holds 2,645,637 shares of common stock, Flagship Ventures Fund IV L.P. ("Flagship Fund IV") holds 1,836,836 shares of common stock, Flagship Ventures Fund IV-Rx, L.P. ("Flagship Fund IV-Rx" and, together with VentureLabs IV and Flagship Fund IV, the "Flagship Fund IV Funds") holds 448,911 shares of common stock, Flagship Ventures Fund V, L.P. ("Flagship Fund V") holds 4,201,284 shares of common stock, Flagship V VentureLabs Rx Fund, L.P. ("VentureLabs Rx V") holds 1,609,871 shares of common stock, Nutritional Health Side Fund, L.P. ("Nutritional Health Side Fund") holds 795,950 shares of common stock,

F2 · ownership.nature: [Continued] Nutritional Health Disruptive Innovation Fund, L.P. ("Nutritional Innovation Fund" and, together with VentureLabs V, Flagship Fund V, VentureLabs Rx V and Nutritional Health Side Fund, the "Flagship Fund V Funds") holds 3,598,177 shares of common stock, and Flagship Ventures Opportunities Fund I, L.P. ("Flagship Opportunities I" and, together with the Flagship Fund IV Funds and Flagship Fund V Funds, the "Flagship Funds") holds 2,412,365 shares of common stock.

F3 · ownership.nature: Flagship Fund IV is a member of VentureLabs IV and also serves as its manager. Flagship Fund V is a member of VentureLabs V and also serves as its manager.

F4 · ownership.nature: The general partner of each of Flagship Fund IV and Flagship Fund IV-Rx is Flagship Ventures Fund IV General Partner LLC ("Flagship Fund IV GP"). The general partner of Flagship Fund V, VentureLabs Rx-V, Nutritional Innovation Fund and Nutritional Health Side Fund is Flagship Ventures Fund V General Partner LLC ("Flagship Fund V GP"). The general partner of Flagship Opportunities Fund I is Flagship Ventures Opportunities Fund I General Partner LLC ("Flagship Opportunities GP," and together with Flagship Fund IV GP and Flagship Fund V GP, the "Flagship General Partners").

F5 · ownership.nature: 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 Funds. Dr. Afeyan also serves as the managing member of the Flagship Fund V GP and Flagship Opportunities Fund GP and may be deemed to possess sole voting and investment control over the shares held by the Flagship Fund V Funds and Flagship Opportunities Fund I. Each of the Flagship General Partners, Dr. Afeyan and Mr. Kania disclaims beneficial ownership of any shares beneficially owned by the Flagship Funds except to the extent of its or his pecuniary interest therein.

SEC source: 0001012975-17-000639 · edgar.xml · nonDerivative · entry 3

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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

F1 · kind: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F1 · price: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F1 · balance_after: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F4 · ownership.nature: Held by Flagship IV LLC. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV LLC. Each of the filing persons other than Flagship IV LLC disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-17-000639 · edgar.xml · nonDerivative · entry 2

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: 612,442

F1 · kind: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F1 · price: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F3 · ownership.nature: Held by Flagship IV-Rx. Flagship IV LLC is the general partner of Flagship IV-Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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 other than Flagship IV-Rx disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-17-000639 · edgar.xml · nonDerivative · entry 1

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 2,378,663

F1 · kind: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F1 · price: On August 17, 2017, Flagship Ventures Fund IV, L.P. ("Flagship IV") and Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx") distributed to its limited partners and sole general partner, Flagship Ventures Fund IV General Partner, LLC ("Flagship IV LLC"), pro rata and without consideration, 1,295,997 shares and 306,222 shares, respectively, of the Issuer's common stock. Flagship IV LLC, in turn, distributed to its members, pro rata and without consideration, the 54,283 shares and 10 shares it received from Flagship IV and Flagship IV-Rx, respectively. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr., each a manager of Flagship IV LLC, each received 24,527 shares through Flagship IV LLC's distribution.

F2 · ownership.direct: Held by Flagship IV. Flagship IV LLC is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons other than Flagship IV disclaims beneficial ownership of the shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 8

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 106,787

F7 · price: The transactions were executed in multiple trades at prices ranging from $3.10 to $3.15. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 7

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 426,885

F7 · price: The transactions were executed in multiple trades at prices ranging from $3.10 to $3.15. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 6

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 117,080

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.16. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 5

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 468,063

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.16. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 4

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 120,198

F5 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.235. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 3

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 480,545

F5 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.235. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 2

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 167,288

F4 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.29. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001507 · edgar.xml · nonDerivative · entry 1

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 668,912

F4 · price: The transactions were executed in multiple trades at prices ranging from $3.15 to $3.29. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 6

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 195,451

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.45 to $4.23. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 5

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 781,643

F6 · price: The transactions were executed in multiple trades at prices ranging from $3.45 to $4.23. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 4

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 259,960

F5 · price: The transactions were executed in multiple trades at prices ranging from $3.32 to $3.49. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 3

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,039,857

F5 · price: The transactions were executed in multiple trades at prices ranging from $3.32 to $3.49. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 2

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 270,738

F4 · price: The transactions were executed in multiple trades at prices ranging from $3.30 to $3.37. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001505 · edgar.xml · nonDerivative · entry 1

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,082,996

F4 · price: The transactions were executed in multiple trades at prices ranging from $3.30 to $3.37. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001503 · edgar.xml · nonDerivative · entry 4

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 272,677

F5 · price: The transactions were executed in multiple trades at prices ranging from $4.15 to $4.18. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001503 · edgar.xml · nonDerivative · entry 3

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,090,757

F5 · price: The transactions were executed in multiple trades at prices ranging from $4.15 to $4.18. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001503 · edgar.xml · nonDerivative · entry 2

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 273,213

F4 · price: The transactions were executed in multiple trades at prices ranging from $4.15 to $4.24. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001503 · edgar.xml · nonDerivative · entry 1

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,092,902

F4 · price: The transactions were executed in multiple trades at prices ranging from $4.15 to $4.24. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 6

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 282,015

F5 · price: The transactions were executed in multiple trades at prices ranging from $4.50 to $4.56. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F3 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 5

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,128,111

F5 · price: The transactions were executed in multiple trades at prices ranging from $4.50 to $4.56. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 4

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,833,802

F5 · price: The transactions were executed in multiple trades at prices ranging from $4.50 to $4.56. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 LLC") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. Flagship 2007 LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the filing persons, other than Flagship 2007, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 3

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 290,160

F4 · price: The transactions were executed in multiple trades at prices ranging from $4.60 to $4.77. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F3 · ownership.direct: Held by Flagship Ventures Fund IV-Rx, L.P. ("Flagship IV-Rx"). Flagship IV LLC is the general partner of Flagship IV Rx. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC 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, other than Flagship IV-Rx, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 2

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,160,708

F4 · price: The transactions were executed in multiple trades at prices ranging from $4.60 to $4.77. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F2 · ownership.direct: Held by Flagship Ventures Fund IV, L.P. ("Flagship IV"). Flagship Ventures Fund IV General Partner LLC ("Flagship IV LLC") is the general partner of Flagship IV. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship IV LLC. Flagship IV LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship IV. Each of the filing persons, other than Flagship IV, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.

SEC source: 0001012975-16-001495 · edgar.xml · nonDerivative · entry 1

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

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

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

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

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

AFEYAN NOUBAR · CIK 0001222012 · 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: Direct

Disclosed balance after: 1,886,787

F4 · price: The transactions were executed in multiple trades at prices ranging from $4.60 to $4.77. The price above reflects the weighted average sales price. Detailed information regarding the number of shares sold at each separate price will be provided upon request by the Commission staff, the Issuer or a security holder of the Issuer.

F1 · ownership.direct: Held by Flagship Ventures Fund 2007, L.P. ("Flagship 2007"). Flagship Ventures 2007 General Partner LLC ("Flagship 2007 LLC") is the general partner of Flagship 2007. Noubar B. Afeyan, Ph.D. and Edwin M. Kania, Jr. are the managers of Flagship 2007 LLC. Flagship 2007 LLC and each of these individuals may be deemed to share voting and investment power with respect to all shares held by Flagship 2007. Each of the filing persons, other than Flagship 2007, disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.