# EDGAR Filing Document

**Accession Number:** 0001691082
**File Stem:** 0001415889-25-024200
**Filing Date:** 2025-9
**Character Count:** 17040
**Document Hash:** cf6b0544fb1bb79c2f3a553de0591c34
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001415889-25-024200.hdr.sgml**: 20250910

**ACCESSION NUMBER**: 0001415889-25-024200

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 2

**CONFORMED PERIOD OF REPORT**: 20250910

**FILED AS OF DATE**: 20250910

**DATE AS OF CHANGE**: 20250910

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Belldegrun Arie
- **CENTRAL INDEX KEY:** 0001296549

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42831
- **FILM NUMBER:** 251307004

**MAIL ADDRESS:**
- **STREET 1:** UCLA SCHOOL OF MEDICINE
- **STREET 2:** 10833 LE CONTE 66-118 CHS BOX 951738
- **CITY:** LOS ANGELES
- **STATE:** CA
- **ZIP:** 9095-1738
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Vida Ventures GP III, L.L.C.
- **CENTRAL INDEX KEY:** 0001855502

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42831
- **FILM NUMBER:** 251307007

**BUSINESS ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
- **BUSINESS PHONE:** (424) 313-1550

**MAIL ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Vida Ventures III, L.P.
- **CENTRAL INDEX KEY:** 0001855504

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42831
- **FILM NUMBER:** 251307006

**BUSINESS ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
- **BUSINESS PHONE:** (424) 313-1550

**MAIL ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Vida Ventures III-A, L.P.
- **CENTRAL INDEX KEY:** 0001855503

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-42831
- **FILM NUMBER:** 251307005

**BUSINESS ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
- **BUSINESS PHONE:** (424) 313-1550

**MAIL ADDRESS:**
- **STREET 1:** 455 MARKET STREET, SUITE 1420
- **CITY:** SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94105
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** LB PHARMACEUTICALS INC
- **CENTRAL INDEX KEY:** 0001691082
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 575 MADISON AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022
- **BUSINESS PHONE:** 917-450-6581

**MAIL ADDRESS:**
- **STREET 1:** 575 MADISON AVENUE
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10022

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** LB PHARMACEUTICALS INC.
- **DATE OF NAME CHANGE:** 20161129

## Ex-24

<u>POWER OF ATTORNEY</u>

The undersigned (the "***Reporting Person***") hereby constitutes and appoints Jean-Philippe Kouakou-Zebouah, signing singly, with full power of substitution, as the Reporting Person's true and lawful attorney in fact to:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1) prepare, execute in the Reporting Person's name and on the Reporting Person's behalf, and submit to the U.S. Securities and Exchange Commission (the "SEC") a Form ID, including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the Reporting Person to make electronic filings with the SEC of Reports required by Section 16(a) of the Securities Exchange Act of 1934 or any rule or regulation of the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2) prepare and file on behalf of such Reporting Person any and all reports, notices, communications and other documents (including, but not limited to, reports on Schedule 13D, Schedule 13G, Form 13F, Form 3, Form 4 and Form 5) that such Reporting Person may be required to file with the SEC pursuant to the Securities Act of 1933, as amended (together with the implementing regulations thereto, the "Act") and the Securities Exchange Act of 1934, as amended (together with the implementing regulations thereto, the "Exchange Act") (collectively, the "Reports") with respect to the Reporting Person's (a) status as an officer or director of, or (b) ownership of, or transactions in, the securities of, any entity whose securities are beneficially owned (directly or indirectly) by the Reporting Person ("Portfolio Companies");

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3) do and perform any and all acts for and on behalf of the Reporting Person which may be necessary or desirable to complete and execute any such Reports, complete and execute any amendment or amendments thereto, and timely file such form with the SEC and any stock exchange or similar authority; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4) take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney in fact, may be of benefit to, in the best interest of, or legally required by, the Reporting Person, it being understood that the documents executed by such attorney in fact on behalf of the Reporting Person pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney in fact may approve in such attorney in fact's discretion.

The Reporting Person hereby grants to such attorney in fact full power and authority to do and perform any and every act and thing whatsoever requisite, necessary, or proper to be done in the exercise of any of the rights and powers herein granted, as fully to all intents and purposes as the Reporting Person might or could do if personally present, with full power of substitution or revocation, hereby ratifying and confirming all that such attorney in fact, or such attorney in fact's substitute or substitutes, shall lawfully do or cause to be done by virtue of this power of attorney and the rights and powers herein granted. The Reporting Person acknowledges that the foregoing attorney in fact, in serving in such capacity at the request of the Reporting Person, is not assuming any of the Reporting Person's responsibilities to comply with Section 16 of the Exchange Act.

A copy of this Power of Attorney shall be filed with the SEC. This Power of Attorney with respect to the Reporting Person shall remain in full force and effect until such Reporting Person is no longer required to file any Reports with respect to the Reporting Person's ownership of, or transactions in, the securities of Portfolio Companies, unless earlier revoked in a signed writing delivered to the foregoing attorney in fact. This Power of Attorney shall automatically terminate upon the attorney-in-fact's separation of employment from, or termination of any other service relationship with respect to, Vida Ventures.

------

IN WITNESS WHEREOF, the undersigned have caused this Power of Attorney to be executed as of this 10th day of September, 2025.

Arie Belldegrun

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Vida Ventures GP III, L.L.C.<br><sub>(Last) (First) (Middle)</sub><br>10100 SANTA MONICA BOULEVARD<br>SUITE 1500<br><sub>(Street)</sub><br>LOS ANGELES, CA 90067<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>LB PHARMACEUTICALS INC [ LBRX ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2025-09-10 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [X] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Vida Ventures III, L.P.<br><sub>(Last) (First) (Middle)</sub><br>10100 SANTA MONICA BOULEVARD<br>SUITE 1500<br><sub>(Street)</sub><br>LOS ANGELES, CA 90067<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>LB PHARMACEUTICALS INC [ LBRX ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2025-09-10 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [X] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Vida Ventures III-A, L.P.<br><sub>(Last) (First) (Middle)</sub><br>10100 SANTA MONICA BOULEVARD<br>SUITE 1500<br><sub>(Street)</sub><br>LOS ANGELES, CA 90067<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>LB PHARMACEUTICALS INC [ LBRX ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2025-09-10 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [X] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Belldegrun Arie<br><sub>(Last) (First) (Middle)</sub><br>10100 SANTA MONICA BOULEVARD<br>SUITE 1500<br><sub>(Street)</sub><br>LOS ANGELES, CA 90067<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>LB PHARMACEUTICALS INC [ LBRX ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2025-09-10 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [X] 10% Owner<br>[ ] Officer (give title below)   [ ] Other (specify below)<br>_ _ | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 1434 | I | By Vida Ventures Management Co. LLC<sup>(1)</sup> |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| Series C Preferred Stock | <sup>(2)</sup> | <sup>(2)</sup> | Common Stock | 547648 | <sup>(2)</sup> | I | By Vida Ventures III, L.P.<sup>(3)(4)</sup> |
| Series C Preferred Stock | <sup>(2)</sup> | <sup>(2)</sup> | Common Stock | 1262 | <sup>(2)</sup> | I | By Vida Ventures III-A, L.P.<sup>(5)</sup> |

---

### Footnotes:

(1) 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.

(2) Each share of Series C Preferred Stock is convertible at anytime at the option of the holder, without payment of additional consideration, into Common Stock and has no expiration date. Immediately prior to the closing of the Issuer's initial public offering, the Series C Preferred Stock will convert automatically at a conversion ratio that is dependent upon the initial price per share to the public in the Issuer's initial public offering.

(3) 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, a member of the Issuer's board of directors, are the members of the investment committee of Vida III GP (each, an "Investment Committee Member" and such committee, the "Investment Committee").

(4) (Continued from Footnote 3) 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.

(5) 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.

**Signature:** VIDA VENTURES GP III, L.L.C., By: /s/ Jean-Philippe Kouakou-Zebouah, its Managing Member  
**Date:** 2025-09-10

**Signature:** VIDA VENTURES III, L.P., By: Vida Ventures GP III, L.L.C., its general partner, By: /s/ Jean-Philippe Kouakou-Zebouah, its Managing Member  
**Date:** 2025-09-10

**Signature:** VIDA VENTURES III-A, L.P., By: Vida Ventures GP III, L.L.C., its general partner, By: /s/ Jean-Philippe Kouakou-Zebouah, its Managing Member  
**Date:** 2025-09-10

**Signature:** ARIE BELLDEGRUN By: /s/ Jean-Philippe Kouakou-Zebouah, his attorney-in-fact  
**Date:** 2025-09-10

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**