SCHEDULE 13G/A 0001415889-25-016985 0001863769 XXXXXXXX LIVE 2 Common Stock, par value $0.0001 per share 12/31/2025 0001840233 Xilio Therapeutics, Inc. 98422T100 828 Winter Street, Suite 300 Waltham MA 02451 Rule 13d-1(c) Frazier Life Sciences Public Fund, L.P. b DE 0.00 4676472.00 0.00 4676472.00 4676472.00 6.7 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLSP, L.P. b DE 0.00 4676472.00 0.00 4676472.00 4676472.00 6.7 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLSP, L.L.C. b DE 0.00 4676472.00 0.00 4676472.00 4676472.00 6.7 OO The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. Frazier Life Sciences X, L.P. b DE 0.00 149060.00 0.00 149060.00 149060.00 0.2 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS X, L.P. b DE 0.00 149060.00 0.00 149060.00 149060.00 0.2 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS X, L.L.C. b DE 0.00 149060.00 0.00 149060.00 149060.00 0.2 OO The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. Frazier Life Sciences XI, L.P. b DE 0.00 396902.00 0.00 396902.00 396902.00 0.6 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS XI, L.P. b DE 0.00 396902.00 0.00 396902.00 396902.00 0.6 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS XI, L.L.C. b DE 0.00 396902.00 0.00 396902.00 396902.00 0.6 OO The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. Frazier Life Sciences XII, L.P. b DE 0.00 692657.00 0.00 692657.00 692657.00 1.0 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS XII, L.P. b DE 0.00 692657.00 0.00 692657.00 692657.00 1.0 PN The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. FHMLS XII, L.L.C. b DE 0.00 692657.00 0.00 692657.00 692657.00 1.0 OO The amounts reported in rows 6, 8 and 9 represent shares held by the Reporting Person and do not include any warrants held by the Reporting Person. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. James N. Topper b X1 0.00 149060.00 0.00 149060.00 149060.00 0.2 IN The amounts reported in rows 6, 8 and 9 represent shares held directly by Frazier Life Sciences X, L.P. and do not include any warrants held directly by Frazier Life Sciences X, L.P. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. Patrick J. Heron b X1 0.00 149060.00 0.00 149060.00 149060.00 0.2 IN The amounts reported in rows 6, 8 and 9 represent shares held directly by Frazier Life Sciences X, L.P. and do not include any warrants held directly by Frazier Life Sciences X, L.P. See item 4(a) to this Statement. The percentage listed in row 11 is calculated based on the sum of (i) 63,429,555 shares of the Issuer's Common Stock outstanding on December 19, 2025, as reported to the Reporting Persons by the Issuer and (ii) 5,915,091 shares of Common Stock that were subsequently purchased by the Reporting persons pursuant to the exercise of warrants to purchase shares of the Issuer's Common Stock. Xilio Therapeutics, Inc. 828 Winter Street, Suite 300, Waltham, MA, 02451. 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 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") 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 Schedule 13G is incorporated by reference. Y 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 4,676,472 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. FLS X directly holds 149,060 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 396,902 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. FLS XII directly holds 692,657 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. 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 37,494,128 shares of Common Stock, (ii) FLS X holds Warrants to purchase 1,195,108 shares of Common Stock, (iii) FLS XI holds Warrants to purchase 3,182,214 shares of Common Stock and (iv) FLS XII holds Warrants to purchase 5,553,459 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. Y Y Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11. Exhibit 99.1 Joint Filing Agreement Frazier Life Sciences Public Fund, L.P. /s/ Jennifer Martin 02/13/2026 FHMLSP, L.P. /s/ Jennifer Martin 02/13/2026 FHMLSP, L.L.C. /s/ Jennifer Martin 02/13/2026 Frazier Life Sciences X, L.P. /s/ Jennifer Martin 02/13/2026 FHMLS X, L.P. /s/ Jennifer Martin 02/13/2026 FHMLS X, L.L.C. /s/ Jennifer Martin 02/13/2026 Frazier Life Sciences XI, L.P. Jennifer Martin 02/13/2026 FHMLS XI, L.P. /s/ Jennifer Martin 02/13/2026 FHMLS XI, L.L.C. /s/ Jennifer Martin 02/13/2026 Frazier Life Sciences XII, L.P. /s/ Jennifer Martin 02/13/2026 FHMLS XII, L.P. /s/ Jennifer Martin 02/13/2026 FHMLS XII, L.L.C. /s/ Jennifer Martin 02/13/2026 James N. Topper /s/ Jennifer Martin 02/13/2026 Patrick J. Heron /s/ Jennifer Martin 02/13/2026