KANGO SUJAY

SEC source: 0001336503-26-000002 · ownership.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 6,090

Underlying: Common Stock · 6,090 shares

Expires 2036-05-21

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award will vest in full on the date that is the earlier of (i) the first anniversary of the grant date or (ii) the Issuer's 2027 Annual Meeting of Stockholders, subject to the Reporting Person's continued service to the Issuer through the vesting date.

SEC source: 0000950170-25-033808 · ownership.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 25,000

Underlying: Common Stock · 25,000 shares

Expires 2035-03-04

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award will vest as to one-third of the shares subject to the option on each of the first, second and third anniversaries of the date of grant, subject to the Reporting Person's continued service to the Issuer on each such vesting date.

SEC source: 0000929638-23-002768 · form4.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2033-09-29

F1 · derivative.exercise_date: Such option shall vest as follows: 16.66666% shall be vested on the date of grant, and the remaining shares subject to the option shall vest in equal monthly amounts beginning October 1, 2023 and continuing on the first day of each calendar month following such date and continuing through July 1, 2024.

SEC source: 0001567619-22-013789 · doc1.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 87,500

Underlying: Common Stock · 87,500 shares

Expires 2032-07-05

F1 · derivative.exercise_date: The options will vest in equal monthly installments over twelve months.

SEC source: 0001140361-22-012388 · form4.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 90,000

Underlying: Common Stock · 90,000 shares

Expires 2032-03-29

F1 · derivative.exercise_date: The option vests as to 1/8th of the total number of shares on March 31, 2022 and as to 1/8th of the total number of shares at the end of each calendar quarter thereafter, provided that the Reporting Person continues to serve as a Director of the Issuer.

SEC source: 0001567619-21-021035 · doc1.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 58,334

Underlying: Common Stock · 58,334 shares

Expires 2031-11-22

F1 · derivative.exercise_date: 25,000 options will vest in equal monthly installments over thirty-six months from November 22, 2021 and 33,334 options shall vest in equal monthly installments over twelve months from November 22, 2021.

SEC source: 0001104659-21-142269 · tm2133601-4_4seq1.xml · derivative · entry 5

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 20,896 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142269 · tm2133601-4_4seq1.xml · derivative · entry 4

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 24,334 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142269 · tm2133601-4_4seq1.xml · derivative · entry 3

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 25,500 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142269 · tm2133601-4_4seq1.xml · derivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 25,000 shares

Expires not disclosed

F2 · price: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.exercise_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

F2 · derivative.expiration_date: Pursuant to the terms of the Merger Agreement, at the Effective Time, each option to purchase Shares granted under an Issuer equity plan (each, a "Company Stock Option") that was outstanding and unvested immediately prior to the Effective Time vested in full. As of the Effective Time, each Company Stock Option that was outstanding immediately prior to the Effective Time was cancelled, and, in exchange therefor, the holder of such cancelled Company Stock Option was entitled to receive (without interest), in consideration of the cancellation of such Company Stock Option, an amount in cash (less applicable tax withholdings) equal to the product of (x) the total number of Shares subject to such Company Stock Option immediately prior to the Effective Time multiplied by (y) the excess, if any, of the Offer Price over the applicable exercise price per Share under such Company Stock Option.

SEC source: 0001104659-21-142269 · tm2133601-4_4seq1.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

F1 · kind: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

F1 · shares: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

F1 · price: This Form 4 reports securities disposed of pursuant to the terms of the Agreement and Plan of Merger (the "Merger Agreement"), dated as of September 29, 2021, by and among the Issuer, Merck Sharp & Dohme Corp. ("Parent"), and Astros Merger Sub, Inc., a direct wholly owned subsidiary of Parent ("Merger Sub"), pursuant to which Merger Sub completed a tender offer for shares of common stock of the Issuer (each, a "Share") and thereafter merged with and into the Issuer (the "Merger") effective as of November 19, 2021 (the "Effective Time"). At the Effective Time, each issued and outstanding Share was cancelled and converted into the right to receive $180.00 in cash (the "Offer Price") without interest and subject to applicable withholding taxes.

SEC source: 0001179110-21-008949 · edgar.xml · derivative · entry 3

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 25,000

Underlying: Common Stock · 5,000 shares

Expires 2028-03-01

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F2 · derivative.exercise_date: The shares of common stock underlying this stock option award vested as to 25% of the shares on the first anniversary of February 12, 2018 and the remaining shares vest in equal quarterly installments over the following three years thereafter.

SEC source: 0001179110-21-008949 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,509

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

SEC source: 0001179110-21-008949 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 23,509

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

SEC source: 0001179110-21-008894 · edgar.xml · derivative · entry 3

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 30,000

Underlying: Common Stock · 5,000 shares

Expires 2028-03-01

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F3 · derivative.exercise_date: The shares of common stock underlying this stock option award vested as to 25% of the shares on the first anniversary of February 12, 2018 and the remaining shares vest in equal quarterly installments over the following three years thereafter.

SEC source: 0001179110-21-008894 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,509

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $150.00 to $150.45 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001179110-21-008894 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 23,509

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

SEC source: 0001179110-21-002883 · edgar.xml · derivative · entry 6

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 35,000

Underlying: Common Stock · 5,000 shares

Expires 2028-03-01

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F5 · derivative.exercise_date: The shares of common stock underlying this stock option award vested as to 25% of the shares on the first anniversary of February 12, 2018 and the remaining shares vest in equal quarterly installments over the following three years thereafter.

SEC source: 0001179110-21-002883 · edgar.xml · nonDerivative · entry 5

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,396

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

SEC source: 0001179110-21-002883 · edgar.xml · nonDerivative · entry 4

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,596

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $137.02 to $137.60 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (4) to this Form 4.

SEC source: 0001179110-21-002883 · edgar.xml · nonDerivative · entry 3

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 20,196

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $135.90 to $136.46 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (3) to this Form 4.

SEC source: 0001179110-21-002883 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 21,697

F1 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $134.80 to $135.78 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001179110-21-002883 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 24,396

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 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

SEC source: 0001179110-21-006494 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 18,509

SEC source: 0001179110-21-001119 · edgar.xml · derivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 20,896

Underlying: Common Stock · 20,896 shares

Expires 2031-01-29

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest in equal quarterly installments over the four years after January 1, 2021.

SEC source: 0001179110-21-001119 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 19,396

SEC source: 0001179110-21-000372 · edgar.xml · nonDerivative · entry 4

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 3,987

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

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $125.66 to $126.61 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (4) to this Form 4.

SEC source: 0001179110-21-000372 · edgar.xml · nonDerivative · entry 3

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 8,611

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

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $124.64 to $125.63 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (3) to this Form 4.

SEC source: 0001179110-21-000372 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 12,040

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

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $123.50 to $124.46 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001179110-21-000372 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,987

SEC source: 0001179110-21-001118 · edgar.xml · derivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 40,000

Underlying: Common Stock · 10,000 shares

Expires 2028-03-01

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 · security: This Form 4 amendment is being filed to report the exercise of an option to purchase common stock that was inadvertently omitted from the original Form 4 filed on January 6, 2021.

F2 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F4 · derivative.exercise_date: The shares of common stock underlying this stock option award vested as to 25% of the shares on the first anniversary of February 12, 2018 and the remaining shares vest in equal quarterly installments over the following three years thereafter.

SEC source: 0001179110-21-001118 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,987

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 · security: This Form 4 amendment is being filed to report the exercise of an option to purchase common stock that was inadvertently omitted from the original Form 4 filed on January 6, 2021.

F2 · kind: The reported transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person.

F3 · balance_after: Reflects the holdings of the reporting person as of the date of the original Form 4 filed on January 6, 2021, taking into account the transactions set forth in such original Form 4 and the transaction set forth in this amendment.

SEC source: 0001179110-20-001641 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 15,344

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

SEC source: 0001179110-20-001641 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · EVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 15,349

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

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $93.76 to $94.44 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001179110-20-000769 · edgar.xml · derivative · entry 2

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 24,334

Underlying: Common Stock · 24,334 shares

Expires 2030-01-22

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest in equal quarterly installments over the four years after January 1, 2020.

SEC source: 0001179110-20-000769 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 15,939

SEC source: 0001179110-20-000276 · edgar.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 9,570

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

SEC source: 0001179110-20-000276 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 9,581

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

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $50.90 to $51.74 inclusive. The reporting person undertakes to provide Acceleron Pharma Inc., any security holder of Acceleron Pharma Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote (2) to this Form 4.

SEC source: 0001179110-19-001056 · edgar.xml · derivative · entry 2

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 25,500

Underlying: Common Stock · 25,500 shares

Expires 2029-01-25

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest in equal quarterly installments over the four years after January 1, 2019.

SEC source: 0001179110-19-001056 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 10,050

SEC source: 0001179110-18-003496 · edgar.xml · derivative · entry 1

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 50,000

Underlying: Common Stock · 50,000 shares

Expires 2028-03-01

F1 · derivative.exercise_date: The shares of common stock underlying this stock option award vest as to 25% of the shares on the first anniversary of February 12, 2018 and the remaining shares vest in equal quarterly installments over the following three years thereafter.

SEC source: 0001179110-18-002019 · edgar.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · SVP, Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 6,000

SEC source: 0000899243-16-035555 · doc4.xml · nonDerivative · entry 4

KANGO SUJAY · CIK 0001336503 · Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 599

F3 · kind: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $1.25 to $1.255, inclusive. The reporting person undertakes to provide to Infinity Pharmaceuticals, Inc., any security holder of Infinity Pharmaceuticals, Inc. 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 this footnote 3.

SEC source: 0000899243-16-035555 · doc4.xml · nonDerivative · entry 3

KANGO SUJAY · CIK 0001336503 · Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 8,275

F2 · kind: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $1.26 to $1.285, inclusive. The reporting person undertakes to provide to Infinity Pharmaceuticals, Inc., any security holder of Infinity Pharmaceuticals, Inc. 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 this footnote 2.

SEC source: 0000899243-16-035555 · doc4.xml · nonDerivative · entry 2

KANGO SUJAY · CIK 0001336503 · Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 50,292

SEC source: 0000899243-16-035555 · doc4.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 50,590

F1 · kind: The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $1.30 to $1.31, inclusive. The reporting person undertakes to provide to Infinity Pharmaceuticals, Inc., any security holder of Infinity Pharmaceuticals, Inc. 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 this footnote 1.

SEC source: 0000899243-16-032623 · doc4.xml · nonDerivative · entry 1

KANGO SUJAY · CIK 0001336503 · Chief Commercial Officer

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 75,599

F1 · shares: Represents shares from a grant of performance-based restricted stock on July 22, 2016. Upon the determination by the Compensation Committee of our Board of Directors, such shares vested in full on October 31, 2016.