ALEC

SEC source: 0001209191-21-005750 · doc4.xml · nonDerivative · entry 5

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 241,027

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

SEC source: 0001209191-21-005750 · doc4.xml · nonDerivative · entry 4

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 236,861

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

SEC source: 0001209191-21-005750 · doc4.xml · derivative · entry 8

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 66,667

Underlying: Common Stock · 2,084 shares

Expires 2028-11-06

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_date: One-fourth (1/4th) of the shares subject to the option vested on November 1, 2019 and one forty-eighth (1/48th) of the shares vest monthly thereafter.

SEC source: 0001209191-21-005750 · doc4.xml · derivative · entry 7

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 257,683

Underlying: Common Stock · 27,916 shares

Expires 2028-07-02

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_date: One forty-eighth (1/48th) of the shares subject to the option vested on August 2, 2018, and one forty-eighth (1/48th) of the shares subject to the option vest monthly thereafter.

SEC source: 0001209191-21-005750 · doc4.xml · nonDerivative · entry 3

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 213,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on May 28, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to $18.16, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (3) to this Form 4.

SEC source: 0001209191-21-005750 · doc4.xml · nonDerivative · entry 2

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 243,719

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

SEC source: 0001209191-21-005750 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 241,635

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

SEC source: 0001209191-21-004742 · doc4.xml · derivative · entry 10

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 68,751

Underlying: Common Stock · 2,083 shares

Expires 2028-11-06

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_date: One-fourth (1/4th) of the shares subject to the option vested on November 1, 2019 and one forty-eighth (1/48th) of the shares vest monthly thereafter.

SEC source: 0001209191-21-004742 · doc4.xml · derivative · entry 9

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 285,599

Underlying: Common Stock · 6,484 shares

Expires 2028-07-02

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_date: One forty-eighth (1/48th) of the shares subject to the option vested on August 2, 2018, and one forty-eighth (1/48th) of the shares subject to the option vest monthly thereafter.

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 6

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 213,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on May 28, 2020.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to $18.01, inclusive.

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 5

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 222,286

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

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 4

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 220,203

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

SEC source: 0001209191-21-004742 · doc4.xml · derivative · entry 8

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 70,834

Underlying: Common Stock · 2,083 shares

Expires 2028-11-06

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_date: One-fourth (1/4th) of the shares subject to the option vested on November 1, 2019 and one forty-eighth (1/48th) of the shares vest monthly thereafter.

SEC source: 0001209191-21-004742 · doc4.xml · derivative · entry 7

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 292,083

Underlying: Common Stock · 27,917 shares

Expires 2028-07-02

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_date: One forty-eighth (1/48th) of the shares subject to the option vested on August 2, 2018, and one forty-eighth (1/48th) of the shares subject to the option vest monthly thereafter.

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 3

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 213,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on May 28, 2020.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.00 to $18.50, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (3) to this Form 4.

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 2

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 243,719

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

SEC source: 0001209191-21-004742 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 241,636

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

SEC source: 0001209191-20-053597 · doc4.xml · derivative · entry 1

Rosenthal Arnon · CIK 0001757770 · Director · Chief Executive Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 457,038

Underlying: Common Stock · 457,038 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-053614 · doc4.xml · derivative · entry 1

Yu Calvin · CIK 0001757799 · Vice President, Finance

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 67,526

Underlying: Common Stock · 67,526 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-053605 · doc4.xml · derivative · entry 1

King Robert · CIK 0001635264 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 123,400

Underlying: Common Stock · 123,400 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-053612 · doc4.xml · derivative · entry 1

Oney Sabah · CIK 0001757776 · Chief Business Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 109,689

Underlying: Common Stock · 109,689 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-053606 · doc4.xml · derivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 109,689

Underlying: Common Stock · 109,689 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-053599 · doc4.xml · derivative · entry 1

SULIMAN SHEHNAAZ · CIK 0001713070 · President and COO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 189,213

Underlying: Common Stock · 189,213 shares

Expires 2030-09-30

F1 · derivative.exercise_date: One forty-eighth (1/48th) of the shares subject to the option shall vest on the one month anniversary of October 1, 2020 (the "Vesting Commencement Date"), and one forty-eighth (1/48th) of the shares shall vest each month thereafter on the same day of the month as the Vesting Commencement Date (and if there is no corresponding day, on the last day of the month), subject to the Reporting Person continuing to be a service provider to the Issuer through each such date.

SEC source: 0001209191-20-042869 · doc4.xml · nonDerivative · entry 2

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 213,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F3 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $23.56 to $23.61 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-042869 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 214,097

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $22.54 to $23.50 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0000899243-20-017687 · doc4.xml · nonDerivative · entry 1

MCGUIRE TERRANCE · CIK 0001117003 · Director · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 12,853,817

F1 · shares: 242 shares were sold by Polaris Venture Partners Founders' Fund VI, L.P ("PVPFF VI"), 3,153 shares were sold by Polaris Venture Partners VI (AIV), L.P. ("PVP VI AIV") and 982 shares were sold by PVP VI (AIV) Feeder Corp. Holding Partnership, L.P. ("PVP VI Feeder" and, together with PVP VI AIV, PVPFF VI, and Polaris Venture Partners VI, L.P. ("PVP VI"), the "Polaris Funds"). The general partner of each of the Polaris Funds is Polaris Venture Management Co. VI, L.L.C. ("PVM"). Each of Amir Nashat, Brian Chee, David Barrett, Bryce Youngren, Jonathan Flint, and the Reporting Person, a member of the Issuer's board of directors, are managing members of PVM (collectively, the "Managing Members") and may be deemed to have shared power to vote and dispose of the shares held by the Polaris Funds.

F2 · shares: (continued from footnote 1) Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.50 to $31.61, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4.

F4 · ownership.nature: 709,675 shares are held by PVPFF VI, 9,347,724 shares are held by PVP VI AIV, 2,297,950 shares are held by PVP VI Feeder and 498,468 shares are held by PVP VI. Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.

SEC source: 0000899243-20-017680 · doc4.xml · nonDerivative · entry 1

Polaris Venture Management Co. VI, L.L.C. · CIK 0001665594 · 10% owner

Polaris Venture Partners VI (AIV), L.P. · CIK 0001767127 · 10% owner

Polaris Venture Partners Founders' Fund VI, L.P. · CIK 0001575691 · 10% owner

Polaris Venture Partners VI, L.P. · CIK 0001493463 · 10% owner

PVP VI (AIV) Feeder Corp. Holding Partnership, L.P. · CIK 0001767130 · 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: 12,853,817

F1 · shares: 242 shares were sold by Polaris Venture Partners Founders' Fund VI, L.P ("PVPFF VI"), 3,153 shares were sold by Polaris Venture Partners VI (AIV), L.P. ("PVP VI AIV") and 982 shares were sold by PVP VI (AIV) Feeder Corp. Holding Partnership, L.P. ("PVP VI Feeder" and, together with PVP VI AIV, PVPFF VI, and Polaris Venture Partners VI, L.P. ("PVP VI"), the "Polaris Funds"). The general partner of each of the Polaris Funds is Polaris Venture Management Co. VI, L.L.C. ("PVM"). Each of Amir Nashat, Brian Chee, David Barrett, Bryce Youngren, Jonathan Flint, and Terrance McGuire, a member of the Issuer's board of directors, are managing members of PVM (collectively, the "Managing Members") and may be deemed to have shared power to vote and dispose of the shares held by the Polaris Funds.

F2 · shares: (Continued from footnote 1) Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.50 to $31.61, inclusive. The Reporting Persons undertake to provide to the Issuer, any security holder of the Issuer or the staff of the Securities Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote (3) to this Form 4.

F4 · ownership.nature: 709,675 shares are held by PVPFF VI, 9,347,724 shares are held by PVP VI AIV, 2,297,950 shares are held by PVP VI Feeder and 498,468 shares are held by PVP VI. Each of the Managing Members and PVM disclaims beneficial ownership of the securities held by the Polaris Funds, and this report shall not be deemed an admission that any of them is the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their respective pecuniary interest therein.

SEC source: 0001209191-20-037254 · doc4.xml · nonDerivative · entry 2

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 223,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F3 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $29.76 to $30.14 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-037254 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 227,628

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $28.76 to $29.74 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-034702 · doc4.xml · nonDerivative · entry 2

Yu Calvin · CIK 0001757799 · Vice President, Finance

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 110,686

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan. Consists of 1,343 shares acquired on May 29, 2020 at a price of $15.8270 per share under the Issuer's 2019 Employee Stock Purchase Plan.

F3 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $31.95 to $32.06 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-034702 · doc4.xml · nonDerivative · entry 1

Yu Calvin · CIK 0001757799 · Vice President, Finance

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 110,986

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan. Consists of 1,343 shares acquired on May 29, 2020 at a price of $15.8270 per share under the Issuer's 2019 Employee Stock Purchase Plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $30.59 to $31.42 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030601 · doc4.xml · nonDerivative · entry 3

King Robert · CIK 0001635264 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 477,317

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F4 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $27.63 to $28.00 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030601 · doc4.xml · nonDerivative · entry 2

King Robert · CIK 0001635264 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 480,320

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F3 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $26.62 to $27.61 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030601 · doc4.xml · nonDerivative · entry 1

King Robert · CIK 0001635264 · Chief Development Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 488,952

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $25.59 to $26.58 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030604 · doc4.xml · nonDerivative · entry 3

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 233,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F4 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $27.61 to $27.99 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030604 · doc4.xml · nonDerivative · entry 2

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 235,823

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F3 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $26.60 to $27.59 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-030604 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 241,819

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $25.57 to $26.53 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0001209191-20-028993 · doc4.xml · derivative · entry 1

MCGUIRE TERRANCE · CIK 0001117003 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0001209191-20-028986 · doc4.xml · derivative · entry 1

Gerngross Tillman U. · CIK 0001722061 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0001209191-20-028991 · doc4.xml · derivative · entry 1

LAVIGNE LOUIS J JR · CIK 0001214127 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0001209191-20-028995 · doc4.xml · derivative · entry 1

SCHELLER RICHARD H · CIK 0001214133 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0001209191-20-028997 · doc4.xml · derivative · entry 1

Wehner David M. · CIK 0001534965 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0001209191-20-029004 · doc4.xml · derivative · entry 1

Yaffe Kristine · CIK 0001783895 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,274

Underlying: Common Stock · 19,274 shares

Expires 2030-05-11

F1 · derivative.exercise_date: The shares subject to the option vest in 12 equal monthly installments beginning on June 11, 2020 and vest in full on the earlier of the date of the Issuer's next annual meeting of stockholders or May 11, 2021.

SEC source: 0000947871-20-000388 · ownership.xml · nonDerivative · entry 4

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,906,718

F5 · price: These shares of the Issuer's common stock ("Shares") were sold in a block order at a price of $23.53.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

F4 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL (Feeder), LP ("OrbiMed IV-AL (Feeder)"). OrbiMed GP is the general partner of OrbiMed IV-AL (Feeder). OrbiMed Advisors is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL (Feeder) and as a result may be deemed to have beneficial ownership over such securities.

SEC source: 0000947871-20-000388 · ownership.xml · nonDerivative · entry 3

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 5,955,674

F5 · price: These shares of the Issuer's common stock ("Shares") were sold in a block order at a price of $23.53.

F2 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL, LP ("OrbiMed IV-AL"). OrbiMed Capital GP IV LLC ("OrbiMed GP"), is the general partner of OrbiMed IV-AL. OrbiMed Advisors LLC ("OrbiMed Advisors"), a registered investment adviser under the Investment Advisers Act of 1940, as amended (the "Investment Advisers Act"), is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL and as a result may be deemed to have beneficial ownership over such securities.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0001209191-20-024871 · doc4.xml · nonDerivative · entry 1

Paul Robert · CIK 0001757964 · Chief Medical Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 243,719

F1 · kind: The sales reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan.

F2 · price: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares purchased ranging from $21.86 to $22.64 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

SEC source: 0000947871-20-000388 · ownership.xml · nonDerivative · entry 2

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,921,804

F1 · price: These shares of the Issuer's common stock ("Shares") were sold in a block order at a price of $23.52.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

F4 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL (Feeder), LP ("OrbiMed IV-AL (Feeder)"). OrbiMed GP is the general partner of OrbiMed IV-AL (Feeder). OrbiMed Advisors is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL (Feeder) and as a result may be deemed to have beneficial ownership over such securities.

SEC source: 0000947871-20-000388 · ownership.xml · nonDerivative · entry 1

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 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: 6,002,771

F1 · price: These shares of the Issuer's common stock ("Shares") were sold in a block order at a price of $23.52.

F2 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL, LP ("OrbiMed IV-AL"). OrbiMed Capital GP IV LLC ("OrbiMed GP"), is the general partner of OrbiMed IV-AL. OrbiMed Advisors LLC ("OrbiMed Advisors"), a registered investment adviser under the Investment Advisers Act of 1940, as amended (the "Investment Advisers Act"), is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL and as a result may be deemed to have beneficial ownership over such securities.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

SEC source: 0000947871-20-000371 · ownership.xml · nonDerivative · entry 6

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 1,927,440

F6 · price: These Shares were sold in a block order at a price of $23.79.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.

F4 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL (Feeder), LP ("OrbiMed IV-AL (Feeder)"). OrbiMed GP is the general partner of OrbiMed IV-AL (Feeder). OrbiMed Advisors is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL (Feeder) and as a result may be deemed to have beneficial ownership over such securities.

SEC source: 0000947871-20-000371 · ownership.xml · nonDerivative · entry 5

ORBIMED ADVISORS LLC · CIK 0001055951 · 10% owner

OrbiMed Capital GP IV LLC · CIK 0001502240 · 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: 6,020,366

F6 · price: These Shares were sold in a block order at a price of $23.79.

F2 · ownership.nature: The Shares are held of record by OrbiMed Private Investments IV-AL, LP ("OrbiMed IV-AL"). OrbiMed Capital GP IV LLC ("OrbiMed GP"), is the general partner of OrbiMed IV-AL. OrbiMed Advisors LLC ("OrbiMed Advisors"), a registered adviser under the Investment Advisers Act of 1940, as amended (the "Investment Advisers Act"), is the managing member of OrbiMed GP. By virtue of such relationships, OrbiMed GP and OrbiMed Advisors may be deemed to have voting and investment power over the securities held by OrbiMed IV-AL and as a result may be deemed to have beneficial ownership over such securities.

F3 · ownership.nature: Each of OrbiMed GP and OrbiMed Advisors disclaims beneficial ownership of the securities reported herein for purposes of Rule 16a-1(a) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), except to the extent of its pecuniary interest therein, if any. This report on Form 4 shall not be deemed an admission that any of the Reporting Persons is a beneficial owner of such securities for the purpose of Section 16 of the Exchange Act, or for any other purpose.