X0202 SCHEDULE 13G/A 0001843384 XXXXXXXX LIVE 2 Common Stock, par value $0.001 per share 03/31/2026 0001746466 EQUILLIUM, INC. 29446K106 2223 AVENIDA DE LA PLAYA SUITE 105 LA JOLLA CA 92037 Rule 13d-1(c) Decheng Capital Management IV (Cayman), LLC b E9 0.00 4271423.00 0.00 4271423.00 4271423.00 6.7 OO Decheng Capital Global Life Sciences Fund IV, L.P. b E9 0.00 4271423.00 0.00 4271423.00 4271423.00 6.7 PN Decheng Capital Global Healthcare Fund (Master), LP b E9 0.00 1461598.00 0.00 1461598.00 1461598.00 2.3 PN Decheng Capital Global Healthcare GP, LLC b E9 0.00 1461598.00 0.00 1461598.00 1461598.00 2.3 OO Xiangmin Cui b X1 0.00 5733021.00 0.00 5733021.00 5733021.00 8.9 IN EQUILLIUM, INC. 2223 AVENIDA DE LA PLAYA, SUITE 105, LA JOLLA, CA, 92037. The names of the persons filing this report (collectively, the "Reporting Persons") are: Decheng Capital Global Life Sciences Fund IV, L.P. ("Fund IV") Decheng Capital Management IV (Cayman), LLC ("GP IV") Decheng Capital Global Healthcare Fund (Master), LP ("Healthcare") Decheng Capital Global Healthcare GP, LLC ("Healthcare GP") Xiangmin Cui ("Dr. Cui") The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G. 3000 Sand Hill Road, Building 2, Suite 110 Menlo Park, CA 94025 Fund IV Cayman Islands GP IV Cayman Islands Healthcare Cayman Islands Healthcare GP Cayman Islands Dr. Cui United States Y Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference. The Reporting Persons' ownership of the Issuer's securities consists of (i) 3,285,710 shares of common stock and warrants ("Warrants") exercisable for up to 985,713 shares of common stock directly held by Fund IV and (ii) 1,161,598 shares of common stock and Warrants exercisable for up to 300,000 shares of common stock directly held by Healthcare. GP IV is the general partner of Fund IV and shares voting and investment authority over the shares held by Fund IV. Healthcare GP is the general partner of Healthcare and shares voting and investment authority over the shares held by Healthcare. Dr. Cui is the manager of GP IV and the indirect managing member and ultimate beneficial owner of Healthcare GP. Dr. Cui shares voting and investment authority over the shares held by each of Fund IV and Healthcare. Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of the securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference. The percentage set forth in each row 11 is based upon 63,226,556 shares of the Issuer's common stock outstanding as of March 20, 2026, as reported in the Issuer's Annual Report on Form 10-K filed with the Securities and Exchange Commission (the "SEC") on March 25, 2026, and assume the exercise of Warrants held by each Reporting Person. Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference. Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference. Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and is incorporated by reference. Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of March 31, 2026 and 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 (incorporated by reference to Exhibit A to the Reporting Persons' Schedule 13G filed with the SEC on November 14, 2024). Decheng Capital Management IV (Cayman), LLC /s/ Xiangmin Cui 05/15/2026 Decheng Capital Global Life Sciences Fund IV, L.P. /s/ Xiangmin Cui 05/15/2026 Decheng Capital Global Healthcare Fund (Master), LP /s/ Xiangmin Cui 05/15/2026 Decheng Capital Global Healthcare GP, LLC /s/ Xiangmin Cui 05/15/2026 Xiangmin Cui /s/ Xiangmin Cui 05/15/2026