Schedule 13G: TCG Crossover Reports 1.75M Shares (7.8%) of LBRX

Rhea-AI Filing Summary

TCG Crossover II and affiliated parties report a passive >5% stake in LB Pharmaceuticals Inc. This Schedule 13G shows that TCG Crossover Fund II, L.P., TCG Crossover GP II, LLC and individual Chen Yu collectively beneficially own 1,745,015 shares, representing 7.8% of LB Pharmaceuticals' common stock based on 22,442,989 shares outstanding as stated in the issuer's prospectus.

The filing identifies shared voting and dispositive power for the reported shares and expressly disclaims an intent to influence control of the issuer. The reporting parties certify the holdings are not intended to change or affect control and provide the reporting entities' and representative's addresses and organizational details.

Positive

• Disclosed a material passive holding: 1,745,015 shares representing 7.8% of outstanding stock
• Clear chain of ownership and authority: record owner TCG Crossover II, GP identified, and managing member named
• Affirmation of passive intent: filing on Schedule 13G and certification that holdings are not intended to change control

Negative

• None.

Insights

Financial Analyst

TL;DR: A material passive stake of 7.8% has been disclosed; no control intent declared.

The filing documents a significant passive position—1,745,015 shares or 7.8% of outstanding stock—owned of record by TCG Crossover II with shared voting and dispositive power attributed to its GP and managing member. Because the statement is filed on Schedule 13G and includes a certification that the stake is not held to influence control, the market implication is largely informational: it notifies investors of a concentrated ownership position without indicating activist intentions or board-change plans. This size of holding is material enough to be monitored for potential future changes in intent or additional filings that would signal activism or control attempts.

Corporate Governance Expert

TL;DR: Ownership structure shows shared control through GP relationships but no asserted governance change objective.

The disclosure clarifies the ownership chain: securities are held of record by TCG Crossover II, whose general partner is TCG Crossover GP II, with Chen Yu as the sole managing member. The report appropriately attributes shared voting and dispositive power to the GP and the individual. The explicit disclaimer of group status and the Schedule 13G filing indicate a passive investor posture rather than a coordinated governance effort. For governance watchers, the key takeaway is transparency of a material holder without present indications of activism; future amendments or a Schedule 13D would signal a change.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

LB Pharmaceuticals Inc.

(Name of Issuer)

Common Stock, par value $0.0001 per share

(Title of Class of Securities)

50180M108

(CUSIP Number)

09/12/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 50180M108

1

Names of Reporting Persons

TCG Crossover GP II, LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,745,015.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,745,015.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,745,015.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.8 %

12

Type of Reporting Person (See Instructions)

OO

Comment for Type of Reporting Person: 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 22,442,989 shares of Common Stock outstanding as of September 12, 2025, as reported by the Issuer (as defined in Item 1(a) below) in its final prospectus filed pursuant to Rule 424(b)(4) dated September 10, 2025, and filed with the Securities and Exchange Commission (the "Commission") on September 12, 2025 (the "Prospectus").

SCHEDULE 13G

CUSIP No. 50180M108

1

Names of Reporting Persons

TCG Crossover Fund II, L.P.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,745,015.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,745,015.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,745,015.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.8 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: 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 22,442,989 shares of Common Stock outstanding as of September 12, 2025, as reported by the Issuer in its Prospectus.

SCHEDULE 13G

CUSIP No. 50180M108

1

Names of Reporting Persons

Chen Yu

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,745,015.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,745,015.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,745,015.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

7.8 %

12

Type of Reporting Person (See Instructions)

IN

Comment for Type of Reporting Person: 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 22,442,989 shares of Common Stock outstanding as of September 12, 2025, as reported by the Issuer in its Prospectus.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: LB Pharmaceuticals Inc.
(b)	Address of issuer's principal executive offices: One Pennsylvania Plaza, Suite 1025, New York, NY 10119
Item 2.
(a)	Name of person filing: This joint statement on Schedule 13G 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 to this Statement as Exhibit 1. 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.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each Reporting Person is 245 Lytton Ave., Suite 350, Palo Alto, CA 94301.
(c)	Citizenship: 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.
(d)	Title of class of securities: Common Stock, par value $0.0001 per share
(e)	CUSIP No.: 50180M108
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: See Row 9 of the cover page for each Reporting Person and the corresponding comments.
(b)	Percent of class: See Row 11 of the cover page for each Reporting Person and the corresponding comments.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Row 5 of the cover page for each Reporting Person and the corresponding comments.
	(ii) Shared power to vote or to direct the vote: See Row 6 of the cover page for each Reporting Person and the corresponding comments.
	(iii) Sole power to dispose or to direct the disposition of: See Row 7 of the cover page for each Reporting Person and the corresponding comments.
	(iv) Shared power to dispose or to direct the disposition of: See Row 8 of the cover page for each Reporting Person and the corresponding comments.
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. 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.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

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.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

TCG Crossover GP II, LLC

Signature:	/s/ Craig Skaling
Name/Title:	Craig Skaling, Authorized Signatory
Date:	09/18/2025

TCG Crossover Fund II, L.P.

Signature:	/s/ Craig Skaling
Name/Title:	Craig Skaling, Authorized Signatory
Date:	09/18/2025

Chen Yu

Signature:	/s/ Craig Skaling
Name/Title:	Craig Skaling, as Attorney-in-Fact for Chen Yu
Date:	09/18/2025

FAQ

How many LB Pharmaceuticals (LBRX) shares were disclosed in this Schedule 13G?

The filing reports 1,745,015 shares beneficially owned.

What percentage of LBRX does the reported stake represent?

The reported position represents 7.8% of the common stock based on 22,442,989 shares outstanding.

Who are the reporting persons in this filing for LBRX?

The reporting persons are TCG Crossover Fund II, L.P., TCG Crossover GP II, LLC, and individual Chen Yu.

Is the reported stake intended to influence control of LB Pharmaceuticals?

No. The filing includes a certification that the securities were not acquired and are not held for the purpose of changing or influencing control.

Where can the record ownership be traced?

The securities are held of record by TCG Crossover II, with TCG Crossover GP II as its general partner and Chen Yu as the sole managing member.