X0202 SCHEDULE 13G 0001727492 XXXXXXXX LIVE Common Stock, $0.0001 par value per share 03/31/2026 0001691082 LB PHARMACEUTICALS INC 50180M108 575 MADISON AVENUE NEW YORK NY 10022 Rule 13d-1(b) Caligan Partners LP DE 0.00 1438070.00 0.00 1438070.00 1438070.00 5.0 IA PN JOHNSON DAVID EDWARD X1 0.00 1438070.00 0.00 1438070.00 1438070.00 5.0 HC IN LB PHARMACEUTICALS INC 575 MADISON AVENUE, NEW YORK, NEW YORK, 10022. This statement is filed by: (i) Caligan Partners LP, a Delaware limited partnership ("Caligan"), which serves indirectly as the investment manager to certain funds and accounts (the "Caligan Funds and Accounts"), with respect to the shares of common stock, $0.0001 par value per share ("Common Stock") of LB Pharmaceuticals Inc, a Delaware corporation (the "Company"), held by the Caligan Funds and Accounts; and (ii) David Johnson, the Managing Partner of Caligan and Managing Member of Caligan Partners GP LLC, the general partner of Caligan ("Mr. Johnson"), with respect to the shares of Common Stock held by the Caligan Funds and Accounts. Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons." The principal business address of each of the Reporting Persons is 780 Third Avenue, 30th Floor, New York, NY 10017. Caligan is a Delaware limited partnership. Mr. Johnson is a United States citizen. N IA HC The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The percentages set forth in this Schedule 13G are calculated based upon an aggregate of 28,674,827 shares of Common Stock outstanding as of March 23, 2026, as reported in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the Securities and Exchange Commission on March 26, 2026. 5.0% The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference. The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference. Y N N See Item 2(a). Y Y Y N By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and 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. Caligan Partners LP /s/ David Johnson 05/15/2026 JOHNSON DAVID EDWARD /s/ David Johnson 05/15/2026