X0202 SCHEDULE 13G/A 0001969280 XXXXXXXX LIVE 1 Common Stock, par value $0.0001 per share 03/31/2026 0001691082 LB Pharmaceuticals Inc. 50180M108 One Pensylvania Plaza, Suite 1025 New York NY 10119 Rule 13d-1(c) TCG Crossover GP II, LLC b DE 0 1839489 0 1839489 1839489 N 6.4 OO These securities are held of record by TCG Crossover II (as defined in Item 2(a) below). TCG Crossover GP II (as defined in Item 2(a) below) is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP II and may be deemed to share voting, investment and dispositive power with respect to these securities. Based on 28,674,827 shares of Common Stock outstanding as of March 23, 2026, as reported by the Issuer (as defined in Item 1(a) below) in its annual report on Form 10-K filed with the Securities and Exchange Commission (the "Commission") on March 26, 2026 (the "Form 10-K"). TCG Crossover Fund II, L.P. b DE 0 1839489 0 1839489 1839489 N 6.4 PN These securities are held of record by TCG Crossover II. TCG Crossover GP II is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP II and may be deemed to share voting, investment and dispositive power with respect to these securities. Based on 28,674,827 shares of Common Stock outstanding as of March 23, 2026, as reported by the Issuer in the Form 10-K. Chen Yu b X1 0 1839489 0 1839489 1839489 N 6.4 IN These securities are held of record by TCG Crossover II. TCG Crossover GP II is the general partner of TCG Crossover II and may be deemed to have voting, investment, and dispositive power with respect to these securities. Chen Yu is the sole managing member of TCG Crossover GP II and may be deemed to share voting, investment and dispositive power with respect to these securities. Based on 28,674,827 shares of Common Stock outstanding as of March 23, 2026, as reported by the Issuer in the Form 10-K. LB Pharmaceuticals Inc. One Pennsylvania Plaza, Suite 1025, New York, NY 10119 This Amendment No. 1 (Amendment No. 1) amends and supplements the Schedule 13G initially filed with the Commission on September 18, 2025 (the Original Schedule 13G) and is being filed by TCG Crossover Fund II, L.P. (TCG Crossover II), TCG Crossover GP II, LLC (TCG Crossover GP II, and together with TCG Crossover II, the Reporting Entities) and Chen Yu (the Reporting Individual). The Reporting Entities and the Reporting Individual are collectively referred to as the Reporting Persons. The Reporting Persons expressly disclaim status as a group for purposes of this Schedule 13G. The agreement among the Reporting Persons to file jointly in accordance with the provisions of Rule 13d-1(k)(1) under the Act is attached as Exhibit 1 to the Original Schedule 13G. Other than those securities reported herein as being held directly by such Reporting Person, each Reporting Person disclaims beneficial ownership of all securities reported in this Statement except to the extent of such Reporting Person's pecuniary interest therein. Capitalized terms not defined in this Amendment No. 1 have the meanings ascribed to them in the Original Schedule 13G. The address of the principal business office of each Reporting Person is 245 Lytton Ave., Suite 350, Palo Alto, CA 94301. TCG Crossover GP II is a limited liability company organized under the laws of the State of Delaware. TCG Crossover II is a limited partnership organized under the laws of the State of Delaware. The Reporting Individual is a citizen of the United States of America. Y See Row 9 of the cover page for each Reporting Person and the corresponding comments. See Row 11 of the cover page for each Reporting Person and the corresponding comments. See Row 5 of the cover page for each Reporting Person and the corresponding comments. See Row 6 of the cover page for each Reporting Person and the corresponding comments. See Row 7 of the cover page for each Reporting Person and the corresponding comments. See Row 8 of the cover page for each Reporting Person and the corresponding comments. Y N Under certain circumstances set forth in the limited partnership agreements of TCG Crossover II and the limited liability company agreement of TCG Crossover GP II, the general and limited partners or members, as the case may be, of each of such entities may be deemed to have the right to receive dividends from, or the proceeds from, the sale of securities of the Issuer owned by each such entity of which they are a partner or member, as the case may be. 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. TCG Crossover GP II, LLC /s/ Craig Skaling 05/15/2026 TCG Crossover Fund II, L.P. /s/ Craig Skaling 05/15/2026 Chen Yu /s/ Craig Skaling 05/15/2026