IRON

SEC source: 0000950170-24-073669 · ownership.xml · derivative · entry 1

Nicholson Donald William · CIK 0001814617 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2034-06-11

F1 · derivative.exercise_date: The shares underlying this option vest upon the first to occur of (i) the date of the Company's 2025 annual meeting of its stockholders, or (ii) the one-year anniversary of the grant date, subject to the Reporting Person's continued service on such vesting date.

SEC source: 0000950170-24-073668 · ownership.xml · derivative · entry 1

Ashiya Mona · CIK 0001794070 · Director

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 10,000

Underlying: Common Stock · 10,000 shares

Expires 2034-06-11

F1 · derivative.exercise_date: The shares underlying this option vest upon the first to occur of (i) the date of the Company's 2025 annual meeting of its stockholders, or (ii) the one-year anniversary of the grant date, subject to the Reporting Person's continued service on such vesting date.

F2 · ownership.direct: Pursuant to an agreement with OrbiMed Advisors LLC, OrbiMed Capital GP VI LLC, and OrbiMed Capital GP VIII LLC, the Reporting Person is obligated to transfer any securities issued under any such stock options or other awards, or the economic benefit thereof, to OrbiMed Advisors LLC, OrbiMed Capital GP VI LLC, and OrbiMed Capital GP VIII LLC, which will in turn ensure that such securities or economic benefits are provided to OrbiMed Private Investments VI, LP and OrbiMed Private Investments VIII, LP.

SEC source: 0000950170-24-069281 · ownership.xml · derivative · entry 7

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 3,010

Underlying: Common Stock · 201 shares

Expires 2031-09-13

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F6 · derivative.exercise_date: The shares underlying this option vest in 48 equal monthly installments following September 1, 2021, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-069281 · ownership.xml · derivative · entry 6

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 3,512

Underlying: Common Stock · 1,756 shares

Expires 2030-11-26

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F5 · derivative.exercise_date: The shares underlying this option vest in 16 equal quarterly installments following November 27, 2020, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-069281 · ownership.xml · nonDerivative · entry 5

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F4 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $36.655 to $36.77, inclusive.

SEC source: 0000950170-24-069281 · ownership.xml · nonDerivative · entry 4

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 95

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $35.575 to $35.565, inclusive.

SEC source: 0000950170-24-069281 · ownership.xml · nonDerivative · entry 3

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 1,850

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $34.54 to $35.53, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (3) and (4) to this Form 4.

SEC source: 0000950170-24-069281 · ownership.xml · nonDerivative · entry 2

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 1,957

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

SEC source: 0000950170-24-069281 · ownership.xml · nonDerivative · entry 1

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 1,756

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

SEC source: 0000950170-24-052876 · ownership.xml · derivative · entry 4

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 3,211

Underlying: Common Stock · 201 shares

Expires 2031-09-13

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F4 · derivative.exercise_date: The shares underlying this option vest in 48 equal monthly installments following September 1, 2021, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-052876 · ownership.xml · nonDerivative · entry 3

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $28.79 to $29.682, inclusive.

SEC source: 0000950170-24-052876 · ownership.xml · nonDerivative · entry 2

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 39

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $27.79 to $28.78, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (3) to this Form 4.

SEC source: 0000950170-24-052876 · ownership.xml · nonDerivative · entry 1

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 201

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

SEC source: 0000950170-24-044538 · ownership.xml · derivative · entry 6

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 3,412

Underlying: Common Stock · 804 shares

Expires 2031-09-13

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F5 · derivative.exercise_date: The shares underlying this option vest in 48 equal monthly installments following September 1, 2021, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-044538 · ownership.xml · derivative · entry 5

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 5,268

Underlying: Common Stock · 1,756 shares

Expires 2030-11-26

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F4 · derivative.exercise_date: The shares underlying this option vest in 16 equal quarterly installments following November 27, 2020, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-044538 · ownership.xml · nonDerivative · entry 4

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 0

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F3 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $32.1247 to $32.3048, inclusive.

SEC source: 0000950170-24-044538 · ownership.xml · nonDerivative · entry 3

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 78

F1 · kind: The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

F2 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $31.1178 to $32.1005, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) and (3) to this Form 4.

SEC source: 0000950170-24-044538 · ownership.xml · nonDerivative · entry 2

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 2,560

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

SEC source: 0000950170-24-044538 · ownership.xml · nonDerivative · entry 1

White William Richard · CIK 0001778739 · Director

10b5-1 filing: Plan reported

Ownership: Direct

Disclosed balance after: 1,756

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 transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on December 13, 2023.

SEC source: 0000950170-24-043769 · ownership.xml · derivative · entry 3

Savage William Jacob · CIK 0001951852 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,498

Underlying: Common Stock · 8,777 shares

Expires 2030-10-22

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_date: 2,140 shares underlying this option vested on August 3, 2021, with the remaining shares vesting in 38 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-043769 · ownership.xml · derivative · entry 2

Savage William Jacob · CIK 0001951852 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 4,233

Underlying: Common Stock · 13,093 shares

Expires 2030-08-10

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_date: 25% of the shares underlying this option vested on August 3, 2021, with the remaining shares vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-043769 · ownership.xml · nonDerivative · entry 1

Savage William Jacob · CIK 0001951852 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 43,405

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

SEC source: 0001415889-24-007190 · form4-03072024_090324.xml · nonDerivative · entry 1

Bitterman Kevin · CIK 0001591747 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 677,503

F1 · price: The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $73.00 to $73.80 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

F2 · ownership.nature: These shares are held by Atlas Venture Opportunity Fund I, LP ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, LP ("Associates I"). Atlas Venture Associates Opportunity I, LLC ("Associates I LLC") is the general partner of Associates I. The Reporting Person is a member of Associates I LLC and disclaims beneficial ownership of such securities held by Opportunity I, except to the extent of his pecuniary interest therein, if any.

SEC source: 0000950170-24-021448 · ownership.xml · derivative · entry 2

Stephenson Pamela · CIK 0001767650 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,000

Underlying: Common Stock · 55,000 shares

Expires 2034-02-25

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on February 26, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-021448 · ownership.xml · nonDerivative · entry 1

Stephenson Pamela · CIK 0001767650 · Chief Commercial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 36,666

SEC source: 0000950170-24-016133 · ownership.xml · derivative · entry 2

Franchi Jean M. · CIK 0001653053 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 55,000

Underlying: Common Stock · 55,000 shares

Expires 2034-02-06

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on February 7, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-016133 · ownership.xml · nonDerivative · entry 1

Franchi Jean M. · CIK 0001653053 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 36,666

SEC source: 0001209191-24-002231 · doc4.xml · nonDerivative · entry 3

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

Atlas Venture Opportunity Fund II, L.P. · CIK 0001885327 · 10% owner

Atlas Venture Associates Opportunity II, LP · CIK 0001935814 · 10% owner

Atlas Venture Associates Opportunity II, LLC · CIK 0001935810 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 198,326

F3 · ownership.nature: These shares are held directly by Atlas Venture Opportunity Fund II, L.P. ("Atlas Opportunity II"). Atlas Venture Associates Opportunity II, L.P. ("Associates II") is the general partner of Atlas Opportunity II. Atlas Venture Associates Opportunity II, LLC ("Associates II LLC") is the general partner of Associates II. Each of Associates II and Associates II LLC disclaims Section 16 beneficial ownership of the securities held by Atlas Opportunity II, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001209191-24-002231 · doc4.xml · nonDerivative · entry 2

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

Atlas Venture Opportunity Fund II, L.P. · CIK 0001885327 · 10% owner

Atlas Venture Associates Opportunity II, LP · CIK 0001935814 · 10% owner

Atlas Venture Associates Opportunity II, LLC · CIK 0001935810 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 703,660

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

SEC source: 0001209191-24-002231 · doc4.xml · nonDerivative · entry 1

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

Atlas Venture Opportunity Fund II, L.P. · CIK 0001885327 · 10% owner

Atlas Venture Associates Opportunity II, LP · CIK 0001935814 · 10% owner

Atlas Venture Associates Opportunity II, LLC · CIK 0001935810 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,402,186

F1 · ownership.direct: These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas X"). Atlas Venture Associates X, L.P. ("Associates X") is the general partner of Atlas X. Atlas Venture Associates X, LLC ("Associates X LLC") is the general partner of Associates X. Each of Associates X and Associates X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas X, except to the extent of its pecuniary interest therein, if any.

SEC source: 0001209191-24-002233 · doc4.xml · nonDerivative · entry 2

Bitterman Kevin · CIK 0001591747 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 198,326

F2 · ownership.nature: These shares are held by Atlas Venture Opportunity Fund II, LP ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, LP ("Associates II"). Atlas Venture Associates Opportunity II, LLC ("Associates II LLC") is the general partner of Associates II. The Reporting Person is a member of Associates II LLC and disclaims beneficial ownership of such securities held by Opportunity II, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-24-002233 · doc4.xml · nonDerivative · entry 1

Bitterman Kevin · CIK 0001591747 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 703,660

F1 · ownership.nature: These shares are held by Atlas Venture Opportunity Fund I, LP ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, LP ("Associates I"). Atlas Venture Associates Opportunity I, LLC ("Associates I LLC") is the general partner of Associates I. The Reporting Person is a member of Associates I LLC and disclaims beneficial ownership of such securities held by Opportunity I, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-24-001543 · doc4.xml · nonDerivative · entry 1

Bitterman Kevin · CIK 0001591747 · Director

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 786,160

F1 · ownership.nature: These shares are held by Atlas Venture Opportunity I, LP ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, LP ("Associates I"). Atlas Venture Associates Opportunity I, LLC ("Associates I LLC") is the general partner of Associates I. The Reporting Person is a member of Associates I LLC and disclaims beneficial ownership of such securities held by Opportunity I, except to the extent of his pecuniary interest therein, if any.

SEC source: 0001209191-24-001540 · doc4.xml · nonDerivative · entry 2

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Indirect · See footnote

Disclosed balance after: 786,160

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

SEC source: 0001209191-24-001540 · doc4.xml · nonDerivative · entry 1

Atlas Venture Fund X, L.P. · CIK 0001628098 · 10% owner

ATLAS VENTURE ASSOCIATES X, L.P. · CIK 0001742766 · 10% owner

Atlas Venture Associates X, LLC · CIK 0001742765 · 10% owner

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

Atlas Venture Associates Opportunity I, L.P. · CIK 0001780065 · 10% owner

Atlas Venture Associates Opportunity I, LLC · CIK 0001780066 · 10% owner

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 1,449,686

F1 · ownership.direct: These shares are held directly by Atlas Venture Fund X, L.P. ("Atlas X"). Atlas Venture Associates X, L.P. ("Associates X") is the general partner of Atlas X. Atlas Venture Associates X, LLC ("Associates X LLC") is the general partner of Associates X. Each of Associates X and Associates X LLC disclaims Section 16 beneficial ownership of the securities held by Atlas X, except to the extent of its pecuniary interest therein, if any.

SEC source: 0000950170-24-024210 · ownership.xml · derivative · entry 2

Bryce Joanne · CIK 0001951845 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,250

Underlying: Common Stock · 27,250 shares

Expires 2034-01-09

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on January 10, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-024210 · ownership.xml · nonDerivative · entry 1

Bryce Joanne · CIK 0001951845 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 23,665

SEC source: 0000950170-24-024199 · ownership.xml · derivative · entry 2

Quisel John D · CIK 0001586788 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 99,550

Underlying: Common Stock · 99,550 shares

Expires 2034-01-09

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on January 10, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-024199 · ownership.xml · nonDerivative · entry 1

Quisel John D · CIK 0001586788 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 69,065

SEC source: 0000950170-24-024193 · ownership.xml · derivative · entry 2

Khara Rahul · CIK 0001951850 · General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,050

Underlying: Common Stock · 21,050 shares

Expires 2034-01-09

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on January 10, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-024193 · ownership.xml · nonDerivative · entry 1

Khara Rahul · CIK 0001951850 · General Counsel

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 14,035

SEC source: 0000950170-24-024190 · ownership.xml · derivative · entry 2

Yu Jonathan Yen-Wen · CIK 0001951849 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,250

Underlying: Common Stock · 27,250 shares

Expires 2034-01-09

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on January 10, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-024190 · ownership.xml · nonDerivative · entry 1

Yu Jonathan Yen-Wen · CIK 0001951849 · Chief Business Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 18,165

SEC source: 0000950170-24-024187 · ownership.xml · derivative · entry 2

Savage William Jacob · CIK 0001951852 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 27,800

Underlying: Common Stock · 27,800 shares

Expires 2034-01-09

F1 · derivative.exercise_date: 25% of the shares underlying this option shall vest and become exercisable on January 10, 2025, with the remainder vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-024187 · ownership.xml · nonDerivative · entry 1

Savage William Jacob · CIK 0001951852 · Chief Medical Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 21,535

SEC source: 0000950170-24-000880 · ownership.xml · derivative · entry 2

Quisel John D · CIK 0001586788 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 241,211

Underlying: Common Stock · 2,700 shares

Expires 2030-03-10

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_date: 25% of the shares underlying this option vested on February 25, 2021, with the remaining shares vesting in 36 equal monthly installments thereafter, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-24-000880 · ownership.xml · nonDerivative · entry 1

Quisel John D · CIK 0001586788 · Director · Chief Executive Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 2,700

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

SEC source: 0000950170-23-073844 · ownership.xml · derivative · entry 2

Bryce Joanne · CIK 0001951845 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 73,745

Underlying: Common Stock · 3,000 shares

Expires 2031-09-13

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_date: The shares underlying this option vest in 48 equal monthly installments following September 1, 2021, subject to the Reporting Person's continued service on each such vesting date.

SEC source: 0000950170-23-073844 · ownership.xml · nonDerivative · entry 1

Bryce Joanne · CIK 0001951845 · Chief Financial Officer

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 5,500

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

SEC source: 0000947871-23-001168 · ownership.xml · derivative · entry 6

ORBIMED ADVISORS LLC · CIK 0001055951 · Director

OrbiMed Capital GP VI LLC · CIK 0001682115 · Director

OrbiMed Capital GP VIII LLC · CIK 0001845804 · Director

OrbiMed Genesis GP LLC · CIK 0001808744 · Director

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

10b5-1 filing: No plan indicated

Ownership: Direct

Disclosed balance after: 0

Underlying: Common Stock · 1,724 shares

Expires 2031-10-03

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: Represents the exercise of stock options granted to Carl L. Gordon ("Gordon") on October 4, 2021 by Gemini Therapeutics, Inc. ("Gemini"). On December 29, 2022, Gemstone Merger Sub, Inc., a wholly owned subsidiary of Gemini, merged with and into Disc Medicine Opco, Inc. ("Disc"), with Disc continuing as a wholly owned subsidiary of Gemini and the surviving corporation of the merger. In connection with the merger, Disc changed its name to Disc Medicine, Inc. Gordon is a member of OrbiMed Advisors LLC ("OrbiMed Advisors") and was a member of Gemini's board of directors. Pursuant to an agreement with OrbiMed Advisors, Gordon assigned these stock options to OrbiMed Advisors.

F6 · derivative.exercise_date: These stock options vested on October 4, 2022.