LB PHARMACEUTICALS INC — Director's Dealing 2025

Sep 16, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: LB PHARMACEUTICALS INC (LBRX)
CIK: 0001691082
Period of Report: 2025-09-12

Reporting Person: Vida Ventures GP III, L.L.C. (N/A)
Reporting Person: Vida Ventures III, L.P. (N/A)
Reporting Person: Vida Ventures III-A, L.P. (N/A)
Reporting Person: Belldegrun Arie (N/A)
Reporting Person: Vida Ventures Management Co. LLC (N/A)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-09-12	Common Stock	C	547648	—	Acquired	547648	Indirect
2025-09-12	Common Stock	C	1262	—	Acquired	1262	Indirect
2025-09-12	Common Stock	P	332566	$15.00	Acquired	880214	Indirect
2025-09-12	Common Stock	P	767	$15.00	Acquired	2029	Indirect

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-09-12	Series C Preferred Stock	$	C	13302666	Disposed		Common Stock (547648)	Indirect
2025-09-12	Series C Preferred Stock	$	C	30667	Disposed		Common Stock (1262)	Indirect

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	1434	Indirect

Footnotes

F1: Each share of Series C Preferred Stock has no expiration date and converted automatically into Common Stock immediately prior to the Issuer's initial public offering at a conversion ratio based upon the initial price per share to the public in the Issuer's initial public offering.

F2: These shares are held directly by Vida Ventures III, L.P. ("Vida III"). Vida Ventures GP III, L.L.C. ("Vida III GP") is the general partner of Vida III and may be deemed to have voting, investment, and dispositive power with respect to these securities. Arie Belldegrun, Helen Kim and Rajul Jain, are the members of the investment committee of Vida III GP (each, an "Investment Committee Member" and such committee, the "Investment Committee").

F3: (Continued from Footnote 2) The Investment Committee and each of the Investment Committee Members may be deemed to share voting, investment and dispositive power with respect to these securities. Vida III GP, the Investment Committee and each of the Investment Committee Members disclaims beneficial ownership of the securities held of record by Vida III, and this report shall not be deemed an admission that they are the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein, if any.

F4: These shares are held directly by Vida Ventures III-A, L.P. ("Vida III-A"). Vida III GP is the general partner of Vida III-A and may be deemed to have voting, investment, and dispositive power with respect to these securities. The Investment Committee and each of the Investment Committee Members may be deemed to share voting, investment and dispositive power with respect to these securities. Vida III GP, the Investment Committee and each of the Investment Committee Members disclaims beneficial ownership of the securities held of record by Vida III-A, and this report shall not be deemed an admission that they are the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein, if any.

F5: These shares are held directly by Vida Ventures Management Co., LLC ("Vida Management"). Each Investment Committee Member (as defined below) disclaims beneficial ownership of the securities held of record by Vida Management, and this report shall not be deemed an admission that they are the beneficial owner of such securities for purposes of Section 16 or for any other purpose, except to the extent of their pecuniary interest therein, if any.