IRON · Disc Medicine, Inc. · Insider Trading

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.70 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.70 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.70 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.00 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.00 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.00 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.2476 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.2476 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.2476 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

The shares underlying this option are fully vested and exercisable as of the date hereof.

Fully vested and exercisable.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $70.10 to $70.37 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.

Fully vested and exercisable.

Fully vested and exercisable.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $79.98 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $79.98 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $79.98 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.28 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.28 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.28 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.9677 to $81.0079 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.9421 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.9421 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.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.9677 to $81.0079 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.95 to $80.9421 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.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $80.9677 to $81.0079 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.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

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

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

These shares are held by Atlas Venture Opportunity Fund I, L.P. ("Opportunity I"). The general partner of Opportunity I is Atlas Venture Associates Opportunity I, L.P. ("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.

Shares were sold pursuant to a Rule 10b5-1 trading plan adopted on July 30, 2026.

These shares are held by Atlas Venture Opportunity Fund II, L.P. ("Opportunity II"). The general partner of Opportunity II is Atlas Venture Associates Opportunity II, L.P. ("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.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.57 to $83.47, inclusive.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.50 to $82.60, 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 footnotes (2) and (3) to this Form 4.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $77.50 to $78.49, 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.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2026.

The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $79.53 to $80.02, inclusive.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $78.53 to $79.52, inclusive.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2026.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The shares underlying this option vest in 48 equal monthly installments following December 29, 2022, subject to the Reporting Person's continued service on each such vesting date.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $82.54 to $82.83, 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 (2) to this Form 4.

These transactions were effected by the Reporting Person pursuant to a Rule 10b5-1 trading plan adopted on March 17, 2026.

The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on March 19, 2026.

The shares underlying this option are fully vested and exercisable as of the date hereof.

The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on March 19, 2026.

Includes 151 shares purchased pursuant to the Disc Medicine, Inc. Amended and Restated 2021 Employee Stock Purchase Plan on July 31, 2026.

The transactions reported by the Reporting Person were effected pursuant to a Rule 10b5-1 trading plan adopted on March 19, 2026.

Includes 151 shares purchased pursuant to the Disc Medicine, Inc. Amended and Restated 2021 Employee Stock Purchase Plan on July 31, 2026.