Amendment: SEC Form SCHEDULE 13G/A filed by Lexeo Therapeutics Inc.

The address of the principal place of business for each of the Reporting Persons is: c/o Frazier Life Sciences Management, L.P. 1001 Page Mill Rd, Building 4, Suite B Palo Alto, CA 94304

The information contained in row 4 of each Reporting Person's cover page to this Statement is incorporated by reference.

The information contained in row 9 of each Reporting Person's cover page to this Statement (including the footnotes thereto) is incorporated by reference. FLSPF directly holds 3,073,467 shares of Common Stock. FHMLSP, L.P. is the general partner of FLSPF and the general partner of FHMLSP, L.P. is FHMLSP, L.L.C., which is managed by an investment committee of four that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLSPF, and this Statement corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. FLSPOF directly holds 624,804 shares of Common Stock. FHMLSP Overage, L.P. is the general partner of FLSPOF and the general partner of FHMLSP Overage, L.P. is FHMLSP Overage, L.L.C., which is managed by an investment committee of four that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLSPOF, and this Statement corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. FLS X directly holds 87,424 shares of Common Stock. FHMLS X, L.P. is the general partner of FLS X and FHMLS X, L.L.C. is the general partner of FHMLS X, L.P. Heron and Topper are the members of FHMLS X, L.L.C. and therefore share voting and investment power over the shares of Common Stock held by FLS X. FLS XI directly holds 232,784 shares of Common Stock. FHMLS XI, L.P. is the general partner of FLS XI and the general partner of FHMLS XI, L.P. is FHMLS XI, L.L.C., which is managed by an investment committee of three that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLS XI, and this Statement corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. FLS XII directly holds 406,246 shares of Common Stock. FHMLS XI, L.P. is the general partner of FLS XII and the general partner of FHMLS XII, L.P. is FHMLS XII, L.L.C., which is managed by an investment committee of three that acts by majority vote. Accordingly, no members of such committee are attributed beneficial ownership of the securities directly held by FLS XII, and this Statement corrects any previous attribution to, and overstatement of beneficial ownership by, such members as reflected in any prior Statements. The above referenced beneficial ownership and amounts reflected on the cover pages hereto do not include certain warrants and prefunded warrants to acquire shares of Common Stock (the "Warrants"), the exercise of which is subject to certain beneficial ownership limitations. In this regard, (i) FLSPF holds Warrants to purchase 2,647,440 shares of Common Stock, (ii) FLSPOF holds Warrants to purchase 781,005 shares of Common Stock, (iii) FLS X holds Warrants to purchase 109,280 shares of Common Stock, (iv) FLS XI holds Warrants to purchase 290,980 shares of Common Stock and (v) FLS XII holds Warrants to purchase 507,809 shares of Common Stock, each of which cannot be exercised, if, upon giving effect to such exercise, the aggregate number of shares of Common Stock beneficially owned by the holder of such Warrant (together with its affiliates or any other persons acting as a group together with such holder) would exceed 9.99% of the number of shares of Common Stock outstanding immediately after giving effect to such exercise. Except as specifically stated herein, the filing of this Statement shall not be construed as an admission that any Reporting Person or any of the foregoing is, for the purposes of Section 13(d) and/or Section 13(g) of the Act or otherwise, the beneficial owner of any securities covered by this Statement or a member of a "group" with any other person.

The information contained in row 11 of each Reporting Person's cover page to this Schedule 13G (including the footnotes thereto) is incorporated by reference.

The information contained in row 5 of each Reporting Person's cover page to this Schedule 13G (including the footnotes thereto) is incorporated by reference.

The information contained in row 6 of each Reporting Person's cover page to this Schedule 13G (including the footnotes thereto) is incorporated by reference.

The information contained in row 7 of each Reporting Person's cover page to this Schedule 13G (including the footnotes thereto) is incorporated by reference.

The information contained in row 8 of each Reporting Person's cover page to this Schedule 13G (including the footnotes thereto) is incorporated by reference.