XLO

SEC source: 0001415889-23-009742 · form4-06132023_040625.xml · derivative · entry 1

Xu Yuan · CIK 0001858214 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2033-06-11

F1 · derivative.exercise_date: The option was granted on June 12, 2023 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 12, 2024 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service to the Issuer through the vesting date.

SEC source: 0001415889-23-005764 · form4-04032023_080434.xml · derivative · entry 1

Brennan Kevin M. · CIK 0001971303 · SVP, FINANCE AND ACCOUNTING

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,000

Underlying: Common Stock · 55,000 shares

Expires 2033-03-31

F1 · derivative.exercise_date: The option was granted on April 1, 2023 and shall vest on March 30, 2024 with respect to 25% of the shares of common stock underlying the stock option, and the remaining 75% of the shares of common stock underlying the stock option shall continue to vest in 36 equal monthly installments thereafter until March 30, 2027.

SEC source: 0001415889-23-000282 · form4-01042023_090144.xml · derivative · entry 1

English Edward C · CIK 0001302600 · PRINCIPAL ACCOUNTING OFFICER

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 24,000

Underlying: Common Stock · 24,000 shares

Expires 2032-12-31

F1 · derivative.exercise_date: The option award was granted on January 1, 2023 and shall vest on February 1, 2023 with respect to 1/48th of the shares of common stock underlying the stock option and shall continue to vest in equal monthly installments thereafter until January 1, 2027.

SEC source: 0001415889-23-000289 · form4-01042023_090139.xml · derivative · entry 1

Huber Martin H. Jr. · CIK 0001653276 · PRESIDENT AND HEAD OF R&D

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 136,500

Underlying: Common Stock · 136,500 shares

Expires 2032-12-31

F1 · derivative.exercise_date: The option award was granted on January 1, 2023 and shall vest on February 1, 2023 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until January 1, 2027.

SEC source: 0001415889-23-000291 · form4-01042023_090151.xml · derivative · entry 1

Russo Rene · CIK 0001722066 · Director · CEO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 350,000

Underlying: Common Stock · 350,000 shares

Expires 2032-12-31

F1 · derivative.exercise_date: The option award was granted on January 1, 2023 and shall vest on February 1, 2023 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until January 1, 2027.

SEC source: 0001415889-22-009708 · form4-09162022_040901.xml · derivative · entry 1

Heyman Tomas J. · CIK 0001814673 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 26,400

Underlying: Common Stock · 26,400 shares

Expires 2032-09-14

F1 · derivative.exercise_date: The option award was granted on September 15, 2022 and will vest in three equal installments on September 15, 2023, September 15, 2024 and September 15, 2025, subject to the Reporting Person's continued service as a director of the Issuer through the applicable vesting date.

SEC source: 0001415889-22-006744 · form4-06172022_040611.xml · derivative · entry 1

Clancy Paul J · CIK 0001409601 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 15, 2023 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service as a director of the Issuer through the vesting date.

SEC source: 0001415889-22-006746 · form4-06172022_040630.xml · derivative · entry 1

Ross Michael Jay · CIK 0001254452 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 15, 2023 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service as a director of the Issuer through the vesting date.

SEC source: 0001415889-22-006742 · form4-06172022_040601.xml · derivative · entry 1

Bonstein Sara · CIK 0001604019 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 15, 2023 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service to as a director of the Issuer through the vesting date.

SEC source: 0001415889-22-006747 · form4-06172022_040644.xml · derivative · entry 1

Huber Martin H. Jr. · CIK 0001653276 · PRESIDENT AND HEAD OF R&D

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 20,000

Underlying: Common Stock · 20,000 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest in equal monthly installments until June 15, 2026, subject to the Reporting Person's continued service through the applicable vesting date.

SEC source: 0001415889-22-006704 · form4-06172022_010602.xml · derivative · entry 1

ROSS ROBERT W. · CIK 0001733077 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 26,400

Underlying: Common Stock · 26,400 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest in three equal installments on June 15, 2023, June 15, 2024 and June 15, 2025.

SEC source: 0001415889-22-006745 · form4-06172022_040617.xml · derivative · entry 1

Rossi Christina · CIK 0001756941 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 15, 2023 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service as a director of the Issuer through the vesting date.

SEC source: 0001415889-22-006743 · form4-06172022_040606.xml · derivative · entry 1

Xu Yuan · CIK 0001858214 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 13,200

Underlying: Common Stock · 13,200 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and will vest as to 100% of the shares underlying the option on the earlier of (i) June 15, 2023 and (ii) the Issuer's next annual meeting of stockholders following the grant date, subject to the Reporting Person's continued service as a director of the Issuer through the vesting date.

SEC source: 0001415889-22-006908 · form4a-06232022_070602.xml · derivative · entry 1

Huber Martin H. Jr. · CIK 0001653276 · PRESIDENT AND HEAD OF R&D

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 20,000

Underlying: Common Stock · 20,000 shares

Expires 2032-06-14

F1 · derivative.exercise_date: The option award was granted on June 15, 2022 and shall vest on July 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until June 1, 2026.

SEC source: 0001415889-22-001792 · form4-02242022_050208.xml · derivative · entry 1

Huber Martin H. Jr. · CIK 0001653276 · PRESIDENT OF R&D AND CMO

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 65,000

Underlying: Common Stock · 65,000 shares

Expires 2032-02-21

F1 · derivative.exercise_date: The option award was granted on February 22, 2022 and shall vest on March 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until February 1, 2026.

SEC source: 0001415889-22-001791 · form4-02242022_050201.xml · derivative · entry 1

Russo Rene · CIK 0001722066 · Director · CEO AND PRESIDENT

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 150,000

Underlying: Common Stock · 150,000 shares

Expires 2032-02-21

F1 · derivative.exercise_date: The option award was granted on February 22, 2022 and shall vest on March 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until February 1, 2026.

SEC source: 0001415889-22-001793 · form4-02242022_050215.xml · derivative · entry 1

Giovine Salvatore · CIK 0001887790 · CHIEF FINANCIAL OFFICER

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 49,500

Underlying: Common Stock · 49,500 shares

Expires 2032-02-21

F1 · derivative.exercise_date: The option award was granted on February 22, 2022 and shall vest on March 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until February 1, 2026.

SEC source: 0001415889-22-000439 · form4-01062022_030116.xml · derivative · entry 1

Xu Yuan · CIK 0001858214 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 26,400

Underlying: Common Stock · 26,400 shares

Expires 2032-01-03

F1 · derivative.exercise_date: The option award was granted on January 4, 2022 and will vest in three equal installments on January 4, 2023, January 4, 2024 and January 4, 2025.

SEC source: 0001415889-21-006215 · form4-12232021_041229.xml · derivative · entry 1

Russo Rene · CIK 0001722066 · Director · CEO AND PRESIDENT

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 100,000

Underlying: Common Stock · 100,000 shares

Expires 2031-12-21

F1 · derivative.exercise_date: The option award was granted on December 22, 2021 and shall vest on January 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until December 1, 2026.

SEC source: 0001415889-22-000247 · form4a-01042022_020119.xml · derivative · entry 1

Russo Rene · CIK 0001722066 · Director · CEO AND PRESIDENT

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 100,000

Underlying: Common Stock · 100,000 shares

Expires 2031-12-21

F1 · derivative.exercise_date: The option award was granted on December 22, 2021 and shall vest on January 1, 2022 with respect to 1/48th of the shares of common stock underlying the stock option and continue to vest in equal monthly installments thereafter until December 1, 2025.

F2 · derivative.exercise_date: On December 23, 2021, the reporting person filed a Form 4 that inadvertently reported that the stock option shall continue to vest until December 1, 2026. This amendment is being filed solely to correct such date to December 1, 2025, as set forth in footnote 1.

SEC source: 0000899243-21-047829 · doc4.xml · nonDerivative · entry 4

Bain Capital Life Sciences Investors, LLC · CIK 0001703031 · 10% owner

Bain Capital Life Sciences Fund II, L.P. · CIK 0001773187 · 10% owner

Bain Capital Life Sciences Investors II, LLC · CIK 0001796155 · 10% owner

BCLS II Investco, LP · CIK 0001818893 · 10% owner

BCLS II Investo (GP), LLC · CIK 0001819101 · 10% owner

BCIP Life Sciences Associates, LP · CIK 0001702921 · 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: 2,805,413

F1 · kind: On December 8, 2021, December 9, 2021 and December 10, 2021, BCLS II Investco, LP ("BCLS II Investco") purchased 13,458, 4,011 and 25,000 shares of the Issuer's common stock, respectively.

F5 · price: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $10.13 to $10.25, inclusive.

F6 · ownership.nature: Represents shares of the Issuer's common stock held by Bain Capital Life Sciences Fund II, L.P. ("BCLS II"), BCLS II Investco and BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS II and BCLS II Investco, the "Bain Capital Life Sciences Entities"). Following the completion of the transactions reported in footnote (1) to this Form 4, BCLS II, BCLS II Investco and BCIPLS each holds 1,348,682, 1,292,469 and 164,262 shares of the Issuer's common stock, respectively.

F7 · ownership.nature: Bain Capital Life Sciences Investors II, LLC ("BCLSI II") is the general partner of BCLS II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F8 · ownership.nature: BCLS II Investco (GP), LLC ("BCLS II Investco GP"), whose manager is BCLS II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F9 · ownership.nature: Boylston Coinvestors, LLC is the general partner of BCIPLS.

F10 · ownership.nature: Bain Capital Life Sciences Investors, LLC ("BCLSI") is the manager of BCLSI II and governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

SEC source: 0000899243-21-047829 · doc4.xml · nonDerivative · entry 3

Bain Capital Life Sciences Investors, LLC · CIK 0001703031 · 10% owner

Bain Capital Life Sciences Fund II, L.P. · CIK 0001773187 · 10% owner

Bain Capital Life Sciences Investors II, LLC · CIK 0001796155 · 10% owner

BCLS II Investco, LP · CIK 0001818893 · 10% owner

BCLS II Investo (GP), LLC · CIK 0001819101 · 10% owner

BCIP Life Sciences Associates, LP · CIK 0001702921 · 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: 2,802,225

F1 · kind: On December 8, 2021, December 9, 2021 and December 10, 2021, BCLS II Investco, LP ("BCLS II Investco") purchased 13,458, 4,011 and 25,000 shares of the Issuer's common stock, respectively.

F4 · price: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.07 to $10.00, inclusive.

F6 · ownership.nature: Represents shares of the Issuer's common stock held by Bain Capital Life Sciences Fund II, L.P. ("BCLS II"), BCLS II Investco and BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS II and BCLS II Investco, the "Bain Capital Life Sciences Entities"). Following the completion of the transactions reported in footnote (1) to this Form 4, BCLS II, BCLS II Investco and BCIPLS each holds 1,348,682, 1,292,469 and 164,262 shares of the Issuer's common stock, respectively.

F7 · ownership.nature: Bain Capital Life Sciences Investors II, LLC ("BCLSI II") is the general partner of BCLS II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F8 · ownership.nature: BCLS II Investco (GP), LLC ("BCLS II Investco GP"), whose manager is BCLS II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F9 · ownership.nature: Boylston Coinvestors, LLC is the general partner of BCIPLS.

F10 · ownership.nature: Bain Capital Life Sciences Investors, LLC ("BCLSI") is the manager of BCLSI II and governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

SEC source: 0000899243-21-047829 · doc4.xml · nonDerivative · entry 2

Bain Capital Life Sciences Investors, LLC · CIK 0001703031 · 10% owner

Bain Capital Life Sciences Fund II, L.P. · CIK 0001773187 · 10% owner

Bain Capital Life Sciences Investors II, LLC · CIK 0001796155 · 10% owner

BCLS II Investco, LP · CIK 0001818893 · 10% owner

BCLS II Investo (GP), LLC · CIK 0001819101 · 10% owner

BCIP Life Sciences Associates, LP · CIK 0001702921 · 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: 2,780,413

F1 · kind: On December 8, 2021, December 9, 2021 and December 10, 2021, BCLS II Investco, LP ("BCLS II Investco") purchased 13,458, 4,011 and 25,000 shares of the Issuer's common stock, respectively.

F3 · price: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.53 to $10.00, inclusive.

F6 · ownership.nature: Represents shares of the Issuer's common stock held by Bain Capital Life Sciences Fund II, L.P. ("BCLS II"), BCLS II Investco and BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS II and BCLS II Investco, the "Bain Capital Life Sciences Entities"). Following the completion of the transactions reported in footnote (1) to this Form 4, BCLS II, BCLS II Investco and BCIPLS each holds 1,348,682, 1,292,469 and 164,262 shares of the Issuer's common stock, respectively.

F7 · ownership.nature: Bain Capital Life Sciences Investors II, LLC ("BCLSI II") is the general partner of BCLS II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F8 · ownership.nature: BCLS II Investco (GP), LLC ("BCLS II Investco GP"), whose manager is BCLS II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F9 · ownership.nature: Boylston Coinvestors, LLC is the general partner of BCIPLS.

F10 · ownership.nature: Bain Capital Life Sciences Investors, LLC ("BCLSI") is the manager of BCLSI II and governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

SEC source: 0000899243-21-047829 · doc4.xml · nonDerivative · entry 1

Bain Capital Life Sciences Investors, LLC · CIK 0001703031 · 10% owner

Bain Capital Life Sciences Fund II, L.P. · CIK 0001773187 · 10% owner

Bain Capital Life Sciences Investors II, LLC · CIK 0001796155 · 10% owner

BCLS II Investco, LP · CIK 0001818893 · 10% owner

BCLS II Investo (GP), LLC · CIK 0001819101 · 10% owner

BCIP Life Sciences Associates, LP · CIK 0001702921 · 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: 2,776,402

F1 · kind: On December 8, 2021, December 9, 2021 and December 10, 2021, BCLS II Investco, LP ("BCLS II Investco") purchased 13,458, 4,011 and 25,000 shares of the Issuer's common stock, respectively.

F2 · price: The price reported in Column 4 is a weighted average price. The shares were purchased in multiple transactions at prices ranging from $9.41 to $9.75, inclusive. The reporting persons undertake to provide to the Issuer, any securityholder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each separate price within the ranges set forth in footnotes (2) through (5) to this Form 4.

F6 · ownership.nature: Represents shares of the Issuer's common stock held by Bain Capital Life Sciences Fund II, L.P. ("BCLS II"), BCLS II Investco and BCIP Life Sciences Associates, LP ("BCIPLS" and, together with BCLS II and BCLS II Investco, the "Bain Capital Life Sciences Entities"). Following the completion of the transactions reported in footnote (1) to this Form 4, BCLS II, BCLS II Investco and BCIPLS each holds 1,348,682, 1,292,469 and 164,262 shares of the Issuer's common stock, respectively.

F7 · ownership.nature: Bain Capital Life Sciences Investors II, LLC ("BCLSI II") is the general partner of BCLS II. As a result, BCLSI II may be deemed to share voting and dispositive power with respect to the securities held by BCLS II. BCLSI II disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F8 · ownership.nature: BCLS II Investco (GP), LLC ("BCLS II Investco GP"), whose manager is BCLS II, is the general partner of BCLS II Investco. As a result, each of BCLSI II, BCLS II and BCLS II Investco GP may be deemed to share voting and dispositive power with respect to the securities held by BCLS II Investco. Each of BCLSI II, BCLS II and BCLS II Investco GP disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

F9 · ownership.nature: Boylston Coinvestors, LLC is the general partner of BCIPLS.

F10 · ownership.nature: Bain Capital Life Sciences Investors, LLC ("BCLSI") is the manager of BCLSI II and governs the investment strategy and decision-making process with respect to investments held by BCIPLS. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Bain Capital Life Sciences Entities. BCLSI disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · derivative · entry 7

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 548,442 shares

Expires not disclosed

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

F4 · derivative.exercise_price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F4 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F4 · derivative.exercise_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F4 · derivative.expiration_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F5 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · derivative · entry 6

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 624,089 shares

Expires not disclosed

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

F3 · derivative.exercise_price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date.

F3 · price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date.

F3 · derivative.exercise_date: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date.

F3 · derivative.expiration_date: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. Each of AVA XI LP and AVA XI LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund XI, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · derivative · entry 5

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 0

Underlying: Common Stock · 1,372,998 shares

Expires not disclosed

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

F1 · derivative.exercise_price: The Series A1 Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series A1 Preferred Stock had no expiration date.

F1 · price: The Series A1 Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series A1 Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series A1 Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series A1 Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series A1 Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series A1 Preferred Stock had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. Each of AVA XI LP and AVA XI LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund XI, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · nonDerivative · entry 4

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 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: 735,942

F5 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · nonDerivative · entry 3

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 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: 548,442

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

F4 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F5 · ownership.nature: The shares are held directly by Atlas Venture Opportunity Fund I, L.P. ("Atlas Venture Opportunity Fund I"). The general partner of Atlas Venture Opportunity Fund I is Atlas Venture Associates Opportunity I, L.P. ("AVAO I LP"). Atlas Venture Associates Opportunity I, LLC ("AVAO I LLC") is the general partner of AVAO I LP. Each of AVAO I LP and AVAO I LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Opportunity Fund I, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · nonDerivative · entry 2

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 2,023,402

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.

F3 · price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series B Preferred Stock had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. Each of AVA XI LP and AVA XI LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund XI, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130026 · tm2130646-24_4seq1.xml · nonDerivative · entry 1

Atlas Venture Fund XI, L.P. · CIK 0001708269 · 10% owner

Atlas Venture Opportunity Fund I, L.P. · CIK 0001759241 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnote

Disclosed balance after: 1,399,313

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

F1 · price: The Series A1 Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series A1 Preferred Stock had no expiration date.

F2 · ownership.nature: The shares are held directly by Atlas Venture Fund XI, L.P. ("Atlas Venture Fund XI"). The general partner of Atlas Venture Fund XI is Atlas Venture Associates XI, L.P. ("AVA XI LP"). Atlas Venture Associates XI, LLC ("AVA XI LLC") is the general partner of AVA XI LP. Each of AVA XI LP and AVA XI LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Venture Fund XI, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001104659-21-130022 · tm2130646-19_4seq1.xml · derivative · entry 2

Clancy Paul J · CIK 0001409601 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 65,528

Underlying: Common Stock · 65,528 shares

Expires 2021-03-10

F2 · derivative.exercise_date: On March 11, 2021, the reporting person was granted an option to purchase 65,528 shares of common stock of the Company, the vesting of which was contingent upon the closing of the Company's IPO. The Company's IPO closed as of October 26, 2021. On October 26, 2021, 20,477 shares underlying the option vested and the remainder will vest in equal monthly installments until July 16, 2024.

SEC source: 0001104659-21-130022 · tm2130646-19_4seq1.xml · derivative · entry 1

Clancy Paul J · CIK 0001409601 · Director

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 44,033

Underlying: Common Stock · 44,033 shares

Expires 2030-07-22

F1 · derivative.exercise_date: On July 23, 2020, the reporting person was granted an option to purchase 44,033 shares of common stock of the Company, the vesting of which was contingent upon the closing of the Company's initial public offering ("IPO"). The Company's IPO closed as of October 26, 2021. On October 26, 2021, 13,760 shares underlying the award vested and the remainder will vest in equal monthly installments until July 16, 2024.

SEC source: 0001104659-21-130027 · tm2130646-25_4seq1.xml · derivative · entry 5

BAY CITY CAPITAL LLC · CIK 0001288452 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 151,294 shares

Expires not disclosed

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

F2 · derivative.exercise_price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F2 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F2 · derivative.exercise_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F2 · derivative.expiration_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: Bay City Capital LLC, a Delaware limited liability company (BCC), Bay City Capital JV Management I LLC, a Delaware limited liability company (Management I), Bay City Capital GF XINDE Investment Management Co., a Cayman Islands company (Management Co.), and Bay City Capital GF Xinde International Life Sciences USD Fund, L.P., a Cayman Islands exempt limited partnership (USD Fund) are deemed to be a group for the purposes of Section 13(d) under the Securities Exchange Act of 1934. Management Co. is the general partner of USD Fund and has voting and dispositive power with respect to the securities held by USD Fund. BCC is the manager of, and an advisor to, Management I, and Management I holds an equity interest in Management Co.

F4 · ownership.nature: Represent securities held by USD Fund, including indirect interests of BCC, Management I, and Management Co. BCC, Management I and Management Co. each disclaims beneficial ownership with respect to these securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-21-130027 · tm2130646-25_4seq1.xml · derivative · entry 4

BAY CITY CAPITAL LLC · CIK 0001288452 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 0

Underlying: Common Stock · 665,696 shares

Expires not disclosed

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

F1 · derivative.exercise_price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: Bay City Capital LLC, a Delaware limited liability company (BCC), Bay City Capital JV Management I LLC, a Delaware limited liability company (Management I), Bay City Capital GF XINDE Investment Management Co., a Cayman Islands company (Management Co.), and Bay City Capital GF Xinde International Life Sciences USD Fund, L.P., a Cayman Islands exempt limited partnership (USD Fund) are deemed to be a group for the purposes of Section 13(d) under the Securities Exchange Act of 1934. Management Co. is the general partner of USD Fund and has voting and dispositive power with respect to the securities held by USD Fund. BCC is the manager of, and an advisor to, Management I, and Management I holds an equity interest in Management Co.

F4 · ownership.nature: Represent securities held by USD Fund, including indirect interests of BCC, Management I, and Management Co. BCC, Management I and Management Co. each disclaims beneficial ownership with respect to these securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-21-130027 · tm2130646-25_4seq1.xml · nonDerivative · entry 3

BAY CITY CAPITAL LLC · CIK 0001288452 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 1,129,490

F3 · ownership.nature: Bay City Capital LLC, a Delaware limited liability company (BCC), Bay City Capital JV Management I LLC, a Delaware limited liability company (Management I), Bay City Capital GF XINDE Investment Management Co., a Cayman Islands company (Management Co.), and Bay City Capital GF Xinde International Life Sciences USD Fund, L.P., a Cayman Islands exempt limited partnership (USD Fund) are deemed to be a group for the purposes of Section 13(d) under the Securities Exchange Act of 1934. Management Co. is the general partner of USD Fund and has voting and dispositive power with respect to the securities held by USD Fund. BCC is the manager of, and an advisor to, Management I, and Management I holds an equity interest in Management Co.

F4 · ownership.nature: Represent securities held by USD Fund, including indirect interests of BCC, Management I, and Management Co. BCC, Management I and Management Co. each disclaims beneficial ownership with respect to these securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-21-130027 · tm2130646-25_4seq1.xml · nonDerivative · entry 2

BAY CITY CAPITAL LLC · CIK 0001288452 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 816,990

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 Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: Bay City Capital LLC, a Delaware limited liability company (BCC), Bay City Capital JV Management I LLC, a Delaware limited liability company (Management I), Bay City Capital GF XINDE Investment Management Co., a Cayman Islands company (Management Co.), and Bay City Capital GF Xinde International Life Sciences USD Fund, L.P., a Cayman Islands exempt limited partnership (USD Fund) are deemed to be a group for the purposes of Section 13(d) under the Securities Exchange Act of 1934. Management Co. is the general partner of USD Fund and has voting and dispositive power with respect to the securities held by USD Fund. BCC is the manager of, and an advisor to, Management I, and Management I holds an equity interest in Management Co.

F4 · ownership.nature: Represent securities held by USD Fund, including indirect interests of BCC, Management I, and Management Co. BCC, Management I and Management Co. each disclaims beneficial ownership with respect to these securities, except to the extent of their pecuniary interest therein.

SEC source: 0001104659-21-130027 · tm2130646-25_4seq1.xml · nonDerivative · entry 1

BAY CITY CAPITAL LLC · CIK 0001288452 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnotes

Disclosed balance after: 665,696

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

F1 · price: The Series B Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: Bay City Capital LLC, a Delaware limited liability company (BCC), Bay City Capital JV Management I LLC, a Delaware limited liability company (Management I), Bay City Capital GF XINDE Investment Management Co., a Cayman Islands company (Management Co.), and Bay City Capital GF Xinde International Life Sciences USD Fund, L.P., a Cayman Islands exempt limited partnership (USD Fund) are deemed to be a group for the purposes of Section 13(d) under the Securities Exchange Act of 1934. Management Co. is the general partner of USD Fund and has voting and dispositive power with respect to the securities held by USD Fund. BCC is the manager of, and an advisor to, Management I, and Management I holds an equity interest in Management Co.

F4 · ownership.nature: Represent securities held by USD Fund, including indirect interests of BCC, Management I, and Management Co. BCC, Management I and Management Co. each disclaims beneficial ownership with respect to these securities, except to the extent of their pecuniary interest therein.

SEC source: 0001395064-21-000216 · wf-form4_163529469670062.xml · derivative · entry 3

TAKEDA PHARMACEUTICAL CO LTD · CIK 0001395064 · 10% owner

Takeda Ventures, Inc. · CIK 0001771657 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See explanation

Disclosed balance after: 0

Underlying: Common Stock · 226,941 shares

Expires not disclosed

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

F1 · derivative.exercise_price: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F2 · ownership.nature: This statement is being filed jointly by Takeda Pharmaceutical Company Limited and Takeda Ventures, Inc.

F3 · ownership.nature: The reportable securities are owned directly by Takeda Ventures, Inc. Takeda Pharmaceutical Company Limiteds beneficial ownership of these securities is comprised of the reportable securities owned by Takeda Ventures, Inc. Takeda Ventures, Inc., is a direct, wholly owned subsidiary of Takeda Pharmaceuticals U.S.A. Inc., which is a direct subsidiary of Takeda Pharmaceutical Company Limited (72.70%) and Takeda Pharmaceuticals International AG (27.3%). Takeda Pharmaceuticals International AG is a direct, wholly owned subsidiary of Takeda Pharmaceutical Company Limited.

SEC source: 0001395064-21-000216 · wf-form4_163529469670062.xml · derivative · entry 2

TAKEDA PHARMACEUTICAL CO LTD · CIK 0001395064 · 10% owner

Takeda Ventures, Inc. · CIK 0001771657 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See explanation

Disclosed balance after: 0

Underlying: Common Stock · 1,248,180 shares

Expires not disclosed

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

F1 · derivative.exercise_price: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F1 · derivative.exercise_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F1 · derivative.expiration_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F2 · ownership.nature: This statement is being filed jointly by Takeda Pharmaceutical Company Limited and Takeda Ventures, Inc.

F3 · ownership.nature: The reportable securities are owned directly by Takeda Ventures, Inc. Takeda Pharmaceutical Company Limiteds beneficial ownership of these securities is comprised of the reportable securities owned by Takeda Ventures, Inc. Takeda Ventures, Inc., is a direct, wholly owned subsidiary of Takeda Pharmaceuticals U.S.A. Inc., which is a direct subsidiary of Takeda Pharmaceutical Company Limited (72.70%) and Takeda Pharmaceuticals International AG (27.3%). Takeda Pharmaceuticals International AG is a direct, wholly owned subsidiary of Takeda Pharmaceutical Company Limited.

SEC source: 0001395064-21-000216 · wf-form4_163529469670062.xml · nonDerivative · entry 1

TAKEDA PHARMACEUTICAL CO LTD · CIK 0001395064 · 10% owner

Takeda Ventures, Inc. · CIK 0001771657 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See explanation

Disclosed balance after: 1,475,121

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

F1 · price: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F1 · ownership.nature: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into shares of the Issuers Common Stock on a one-for-one basis immediately prior to the completion of the Issuers initial public offering for no additional consideration. The Preferred Stock had no expiration date.

F2 · ownership.nature: This statement is being filed jointly by Takeda Pharmaceutical Company Limited and Takeda Ventures, Inc.

F3 · ownership.nature: The reportable securities are owned directly by Takeda Ventures, Inc. Takeda Pharmaceutical Company Limiteds beneficial ownership of these securities is comprised of the reportable securities owned by Takeda Ventures, Inc. Takeda Ventures, Inc., is a direct, wholly owned subsidiary of Takeda Pharmaceuticals U.S.A. Inc., which is a direct subsidiary of Takeda Pharmaceutical Company Limited (72.70%) and Takeda Pharmaceuticals International AG (27.3%). Takeda Pharmaceuticals International AG is a direct, wholly owned subsidiary of Takeda Pharmaceutical Company Limited.

SEC source: 0001104659-21-130031 · tm2130646-27_4seq1.xml · derivative · entry 5

Rock Springs Capital Management LP · CIK 0001595725 · 10% owner

Rock Springs Capital LLC · CIK 0001735397 · 10% owner

Rock Springs Capital Master Fund LP · CIK 0001735393 · 10% owner

Four Pines Master Fund LP · CIK 0001888685 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 151,294 shares

Expires not disclosed

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

F1 · derivative.exercise_price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: The securities reported herein are held of record by Four Pines Master Fund LP ("Four Pines"). RSC is the general partner of RSCM which is the investment manager to Four Pines. RSC and RSCM may therefore be deemed to have or share beneficial ownership of the shares held directly by Four Pines.

SEC source: 0001104659-21-130031 · tm2130646-27_4seq1.xml · derivative · entry 4

Rock Springs Capital Management LP · CIK 0001595725 · 10% owner

Rock Springs Capital LLC · CIK 0001735397 · 10% owner

Rock Springs Capital Master Fund LP · CIK 0001735393 · 10% owner

Four Pines Master Fund LP · CIK 0001888685 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 0

Underlying: Common Stock · 756,472 shares

Expires not disclosed

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

F1 · derivative.exercise_price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.exercise_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F1 · derivative.expiration_date: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F2 · ownership.nature: The securities reported herein are held of record by Rock Springs Capital Master Fund LP ("Master Fund"). Rock Springs Capital LLC ("RSC") is the general partner of Rock Springs Capital Management LP ("RSCM") which is the investment manager to Master Fund. RSC and RSCM may therefore be deemed to have or share beneficial ownership of the shares held directly by Master Fund.

SEC source: 0001104659-21-130031 · tm2130646-27_4seq1.xml · nonDerivative · entry 3

Rock Springs Capital Management LP · CIK 0001595725 · 10% owner

Rock Springs Capital LLC · CIK 0001735397 · 10% owner

Rock Springs Capital Master Fund LP · CIK 0001735393 · 10% owner

Four Pines Master Fund LP · CIK 0001888685 · 10% owner

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

10b5-1 filing: Not disclosed

Ownership: Indirect · See footnote

Disclosed balance after: 1,256,472

F2 · ownership.nature: The securities reported herein are held of record by Rock Springs Capital Master Fund LP ("Master Fund"). Rock Springs Capital LLC ("RSC") is the general partner of Rock Springs Capital Management LP ("RSCM") which is the investment manager to Master Fund. RSC and RSCM may therefore be deemed to have or share beneficial ownership of the shares held directly by Master Fund.

SEC source: 0001104659-21-130031 · tm2130646-27_4seq1.xml · nonDerivative · entry 2

Rock Springs Capital Management LP · CIK 0001595725 · 10% owner

Rock Springs Capital LLC · CIK 0001735397 · 10% owner

Rock Springs Capital Master Fund LP · CIK 0001735393 · 10% owner

Four Pines Master Fund LP · CIK 0001888685 · 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: 151,294

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

F1 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F3 · ownership.nature: The securities reported herein are held of record by Four Pines Master Fund LP ("Four Pines"). RSC is the general partner of RSCM which is the investment manager to Four Pines. RSC and RSCM may therefore be deemed to have or share beneficial ownership of the shares held directly by Four Pines.

SEC source: 0001104659-21-130031 · tm2130646-27_4seq1.xml · nonDerivative · entry 1

Rock Springs Capital Management LP · CIK 0001595725 · 10% owner

Rock Springs Capital LLC · CIK 0001735397 · 10% owner

Rock Springs Capital Master Fund LP · CIK 0001735393 · 10% owner

Four Pines Master Fund LP · CIK 0001888685 · 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: 756,472

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

F1 · price: The Series C Preferred Stock converted into shares of the Issuer's common stock, $0.001 par value, on a 9.5:1 basis automatically immediately prior to the closing of the Issuer's initial public offering. The Series C Preferred Stock had no expiration date.

F2 · ownership.nature: The securities reported herein are held of record by Rock Springs Capital Master Fund LP ("Master Fund"). Rock Springs Capital LLC ("RSC") is the general partner of Rock Springs Capital Management LP ("RSCM") which is the investment manager to Master Fund. RSC and RSCM may therefore be deemed to have or share beneficial ownership of the shares held directly by Master Fund.

SEC source: 0001722024-21-000012 · wf-form4_163528147482023.xml · derivative · entry 2

Alexandria Venture Investments, LLC · CIK 0001722024 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 0

Underlying: Common stock · 166,423 shares

Expires not disclosed

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

F1 · derivative.exercise_price: Each share of preferred stock automatically converted into the Issuer's common stock at a ratio of 9.5 shares of preferred stock to 1 share of common stock upon closing of the Issuer's initial public offering on October 22, 2021, for no additional consideration. The shares had no expiration date.

F2 · price: Not applicable.

F1 · derivative.exercise_date: Each share of preferred stock automatically converted into the Issuer's common stock at a ratio of 9.5 shares of preferred stock to 1 share of common stock upon closing of the Issuer's initial public offering on October 22, 2021, for no additional consideration. The shares had no expiration date.

F1 · derivative.expiration_date: Each share of preferred stock automatically converted into the Issuer's common stock at a ratio of 9.5 shares of preferred stock to 1 share of common stock upon closing of the Issuer's initial public offering on October 22, 2021, for no additional consideration. The shares had no expiration date.

SEC source: 0001722024-21-000012 · wf-form4_163528147482023.xml · nonDerivative · entry 1

Alexandria Venture Investments, LLC · CIK 0001722024 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Direct

Disclosed balance after: 166,423

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

F1 · price: Each share of preferred stock automatically converted into the Issuer's common stock at a ratio of 9.5 shares of preferred stock to 1 share of common stock upon closing of the Issuer's initial public offering on October 22, 2021, for no additional consideration. The shares had no expiration date.

SEC source: 0000899243-21-041580 · doc4.xml · derivative · entry 5

RiverVest Venture Fund IV, L.P. · CIK 0001725443 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 359,324 shares

Expires not disclosed

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

F1 · derivative.exercise_price: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F1 · derivative.exercise_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F1 · derivative.expiration_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F2 · ownership.nature: The shares held by RiverVest Venture Fund IV, L.P. ("RiverVest IV") are indirectly held by RiverVest Venture Partners IV, L.P. ("RiverVest Partners IV"), which is the general partner of RiverVest IV. RiverVest Venture Partners IV, LLC is the general partner of RiverVest Partners IV.

F3 · ownership.nature: The individual managers of RiverVest Ventures Partners IV, LLC are Jay Schmelter, John P. McKearn, Ph.D. and Niall O'Donnell. RiverVest Partners IV, RiverVest Venture Partners IV, LLC and each of the individual managers share voting and dispositive power with regard to the securities directly held by RiverVest Venture Fund IV, L.P.

SEC source: 0000899243-21-041580 · doc4.xml · derivative · entry 4

RiverVest Venture Fund IV, L.P. · CIK 0001725443 · 10% owner

10b5-1 filing: Not disclosed

Ownership: Indirect · See Footnotes

Disclosed balance after: 0

Underlying: Common Stock · 832,120 shares

Expires not disclosed

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

F1 · derivative.exercise_price: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F1 · derivative.exercise_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F1 · derivative.expiration_date: Each share of Series B Preferred Stock and Series C Preferred Stock automatically converted into 1 share of the Issuer's common stock upon the closing of the Issuer's initial public offering on October 26, 2021. The shares have no expiration date.

F2 · ownership.nature: The shares held by RiverVest Venture Fund IV, L.P. ("RiverVest IV") are indirectly held by RiverVest Venture Partners IV, L.P. ("RiverVest Partners IV"), which is the general partner of RiverVest IV. RiverVest Venture Partners IV, LLC is the general partner of RiverVest Partners IV.

F3 · ownership.nature: The individual managers of RiverVest Ventures Partners IV, LLC are Jay Schmelter, John P. McKearn, Ph.D. and Niall O'Donnell. RiverVest Partners IV, RiverVest Venture Partners IV, LLC and each of the individual managers share voting and dispositive power with regard to the securities directly held by RiverVest Venture Fund IV, L.P.