Common Stock, $0.0001 par value per share

PHATHOM PHARMACEUTICALS, INC.

100 CAMPUS DRIVE,, FLORHAM PARK, NJ, 07932

The entities and persons filing this statement (collectively, the "Reporting Persons") are: Frazier Life Sciences Public Fund, L.P. ("FLSPF") FHMLSP, L.P. FHMLSP, L.L.C. Frazier Life Sciences IX, L.P. ("FLS IX") FHMLS IX, L.P. FHMLS IX, L.L.C. Frazier Life Sciences X, L.P. ("FLS X") FHMLS X, L.P. FHMLS X, L.L.C. Frazier Life Sciences XI, L.P. ("FLS XI") FHMLS XI, L.P. FHMLS XI, L.L.C. Frazier Life Sciences XII, L.P. ("FLS XII") FHMLS XII, L.P. FHMLS XII, L.L.C. James N. Topper ("Topper") Patrick J. Heron ("Heron" and together with Topper, the "Members")

Item 2(c) is hereby amended and restated in its entirety to read as follows: FLSPF is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLSP, L.P. is to serve as general partner of FLSPF. The sole business of FHMLSP, L.L.C. is to serve as general partner of FHMLSP, L.P. FLS IX is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS IX, L.P. is to serve as general partner of FLS IX. The sole business of FHMLS IX, L.L.C. is to serve as general partner of FHMLS IX, L.P. FLS X is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS X, L.P. is to serve as general partner of FLS X. The sole business of FHMLS X, L.L.C. is to serve as general partner of FHMLS X, L.P. FLS XI is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS XI, L.P. is to serve as general partner of FLS XI. The sole business of FHMLS XI, L.L.C. is to serve as general partner of FHMLS XI, L.P. FLS XII is a venture capital fund concentrating in life sciences and related fields. The sole business of FHMLS XII, L.P. is to serve as general partner of FLS XII. The sole business of FHMLS XII, L.L.C. is to serve as general partner of FHMLS XII, L.P. The principal business of the Members is to manage FLSPF, FHMLSP, L.P., FHMLSP, L.L.C., FLS IX, FHMLS IX, L.P., FHMLS IX, L.L.C., FLS X, FHMLS X, L.P., FHMLS X, L.L.C., FLS XI, FHMLS XI, L.P., FHMLS XI, L.L.C., FLS XII, FHMLS XII, L.P., FHMLS XII, L.L.C. and a number of affiliated partnerships with similar businesses.

The information contained in rows 7, 8, 9, 10, 11, and 13 of each Reporting Person's cover page to this Schedule 13D (including the footnotes thereto) is incorporated by reference into this Item 5. FLSPF directly holds 5,323,356 shares of the Issuer's Common Stock (the "FLSPF Shares"). 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. FLS IX directly holds 5,827,415 shares of the Issuer's Common Stock (the "FLS IX Shares"). FHMLS IX, L.P. is the general partner of FLS IX and FHMLS IX, L.L.C. is the general partner of FHMLS IX, L.P. Heron and Topper are the members of FHMLS IX, L.L.C. and therefore share voting and investment power over the FLS IX Shares. FHMLS IX, L.L.C. directly holds 1 share of the Issuer's Common Stock (the "FHMLS IX, L.L.C. Share"). Heron and Topper are the members of FHMLS IX, L.L.C. and therefore share voting and investment power over the FHMLS IX, L.L.C. Share. FLS X directly holds 59,403 shares of the Issuer's Common Stock (the "FLS X Shares"). 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 FLS X Shares. FLS XI directly holds the FLS XI Shares. 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. FLS XII directly holds FLS XI holds 980,286 shares of this Issuer's Common Stock (the "FLS XI Shares"). FHMLS XII, 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. 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 2,596,399 shares of Common Stock and (ii) FLS XII holds Warrants to purchase 12,523 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 Schedule 13D 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 Schedule 13D or a member of a "group" with any other person.

Except as set forth in Item 6 hereof, none of the Reporting Persons has effected any transactions relating to the Common Stock of the Issuer during the past 60 days.

Item 4 is hereby amended to remove references to the "FLSPOF Shares".