Business Overview	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Overview	1. Business Overview LB Pharmaceuticals Inc (the “Company” or “LB”) was incorporated under the laws of the State of Delaware in September 2015 and is headquartered in New York, New York. The Company is a late-stage biopharmaceutical company developing novel therapies for the treatment of a wide range of neuropsychiatric disorders including schizophrenia, bipolar depression, adjunctive treatment of major depressive disorder, or MDD, and other diseases. The Company is building a pipeline that leverages the broad therapeutic potential of the Company's lead product candidate, LB-102, which the Company believes has the opportunity to be the first benzamide antipsychotic drug approved for neuropsychiatric disorders in the United States. LB-102 is currently in late-stage clinical development for schizophrenia and bipolar depression. During the three months ended March 31, 2026, the Company initiated a Phase 2 clinical trial (ILLUMINATE-1) of LB-102 in patients with bipolar 1 depression and a Phase 3 clinical trial (NOVA-2) of LB-102 in patients with acute schizophrenia. Concurrently with the Phase 3 trial, the Company is running an outpatient, open label trial (NOVA-3) to accrue the requisite safety population required to support NDA submission as well as other clinical and non-clinical studies typically required by FDA at the time of approval. The Company is also planning to conduct a Phase 2 clinical trial evaluating LB-102 as an adjunctive treatment in MDD that is expected to initiate in early 2027. Since the Company’s inception, it has focused substantially all of its efforts and financial resources on organizing and staffing the Company, raising capital, building its intellectual property portfolio, undertaking preclinical studies and clinical trials and providing general and administrative support for these activities. The Company has not generated any product revenue related to its primary business purpose to date and is subject to a number of risks similar to those of other early stage companies, including dependence on key individuals, regulatory approval of product candidates, uncertainty of market acceptance of products, if approved, competition from substitute products and larger companies, compliance with government regulations, protection of proprietary technology, dependence on third parties, product liability and the need to obtain adequate additional financing to fund the development of its product candidates. Initial Public Offering On September 10, 2025, the Company’s Registration Statement on Form S‑1 (File No. 333‑289812) for its initial public offering (the “IPO”) was declared effective, and on September 12, 2025, the Company closed the IPO and issued 21,850,000 shares of common stock at a price to the public of $15.00 per share, including 2,850,000 shares issued upon the exercise in full of the underwriters’ over-allotment option to purchase additional shares. The Company received gross proceeds of $327.8 million. Net proceeds were $302.3 million, after deducting underwriting commissions and other offering costs totaling $25.4 million. Immediately prior to the IPO closing, all of the outstanding shares of the Company’s redeemable convertible preferred stock automatically converted into an aggregate of 3,191,334 shares of the Company’s common stock, including 391,986 additional shares issuable upon conversion of Series C preferred stock due to certain anti‑dilution adjustments. Reverse Stock Split On September 8, 2025, the Company effected a 1‑for‑27.8874 Reverse Stock Split of the shares of common stock (the “Reverse Stock Split”). The number of authorized shares and par value per share were not adjusted as a result of the Reverse Stock Split. No fractional shares were issued; stockholders entitled to a fractional share received a cash payment in lieu thereof. All references to shares, equity awards and options (including exercise prices), share data, per share data, and related information contained in the financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented. Private Placement On February 4, 2026, the Company entered into a Securities Purchase Agreement with certain investors in connection with a private placement. Pursuant to the Securities Purchase Agreement, the Company agreed to issue (i) 3,306,571 shares of its common stock, par value $0.0001 per share, at a purchase price of $21.17 per share and (ii) pre-funded warrants to purchase an aggregate of 1,417,107 shares of common stock at a purchase price of $21.1699 per pre-funded warrant, which represents the $21.17 share price less the $0.0001 per share exercise price. The transaction closed on February 6, 2026 and resulted in aggregate gross proceeds of approximately $100.0 million, consisting of approximately $70.0 million from the sale of common stock and approximately $30.0 million from the sale of pre-funded warrants. Liquidity and Capital Resources As of March 31, 2026, the Company had approximately $365.6 million of cash, cash equivalents and marketable securities and working capital of approximately $378.5 million. As of March 31, 2026, the Company had an accumulated deficit of $148.6 million. During the three months ended March 31, 2026, the Company incurred a net loss of $19.1 million, and negative cash flows from operations of $23.3 million. The Company has incurred net losses and negative cash flows from operations since its inception and anticipates it will continue to incur net losses for the foreseeable future. Historically, the Company funded its operations primarily through proceeds from issuances of redeemable convertible preferred stock, common stock and convertible notes. In September 2025, the Company completed its IPO as detailed above. In February 2026, the Company completed a private placement financing resulting in total gross proceeds of $100.0 million. Net proceeds were approximately $93.8 million, after deducting financial advisory fees and other financing costs. The Company believes that its current capital resources, which consist of cash, cash equivalents and marketable securities, will be sufficient to fund operations through at least the next twelve months from the date the accompanying financial statements are issued based on its expected cash needs. As the Company continues to pursue its business plan, it expects to finance its operations through equity offerings, debt financings, or other capital sources, including current or potential future collaborations, licenses, and other similar arrangements. However, there can be no assurance that any additional financing or strategic arrangements will be available to the Company on acceptable terms, if at all.

Business Overview

3 Months Ended

Mar. 31, 2026

Organization, Consolidation and Presentation of Financial Statements [Abstract]

1. Business Overview

LB Pharmaceuticals Inc (the “Company” or “LB”) was incorporated under the laws of the State of Delaware in September 2015 and is headquartered in New York, New York.

The Company is a late-stage biopharmaceutical company developing novel therapies for the treatment of a wide range of neuropsychiatric disorders including schizophrenia, bipolar depression, adjunctive treatment of major depressive disorder, or MDD, and other diseases. The Company is building a pipeline that leverages the broad therapeutic potential of the Company's lead product candidate, LB-102, which the Company believes has the opportunity to be the first benzamide antipsychotic drug approved for neuropsychiatric disorders in the United States. LB-102 is currently in late-stage clinical development for schizophrenia and bipolar depression. During the three months ended March 31, 2026, the Company initiated a Phase 2 clinical trial (ILLUMINATE-1) of LB-102 in patients with bipolar 1 depression and a Phase 3 clinical trial (NOVA-2) of LB-102 in patients with acute schizophrenia. Concurrently with the Phase 3 trial, the Company is running an outpatient, open label trial (NOVA-3) to accrue the requisite safety population required to support NDA submission as well as other clinical and non-clinical studies typically required by FDA at the time of approval. The Company is also planning to conduct a Phase 2 clinical trial evaluating LB-102 as an adjunctive treatment in MDD that is expected to initiate in early 2027.

Since the Company’s inception, it has focused substantially all of its efforts and financial resources on organizing and staffing the Company, raising capital, building its intellectual property portfolio, undertaking preclinical studies and clinical trials and providing general and administrative support for these activities. The Company has not generated any product revenue related to its primary business purpose to date and is subject to a number of risks similar to those of other early stage companies, including dependence on key individuals, regulatory approval of product candidates, uncertainty of market acceptance of products, if approved, competition from substitute products and larger companies, compliance with government regulations, protection of proprietary technology, dependence on third parties, product liability and the need to obtain adequate additional financing to fund the development of its product candidates.

Initial Public Offering

On September 10, 2025, the Company’s Registration Statement on Form S‑1 (File No. 333‑289812) for its initial public offering (the “IPO”) was declared effective, and on September 12, 2025, the Company closed the IPO and issued 21,850,000 shares of common stock at a price to the public of $15.00 per share, including 2,850,000 shares issued upon the exercise in full of the underwriters’ over-allotment option to purchase additional shares. The Company received gross proceeds of $327.8 million. Net proceeds were $302.3 million, after deducting underwriting commissions and other offering costs totaling $25.4 million. Immediately prior to the IPO closing, all of the outstanding shares of the Company’s redeemable convertible preferred stock automatically converted into an aggregate of 3,191,334 shares of the Company’s common stock, including 391,986 additional shares issuable upon conversion of Series C preferred stock due to certain anti‑dilution adjustments.

Reverse Stock Split

On September 8, 2025, the Company effected a 1‑for‑27.8874 Reverse Stock Split of the shares of common stock (the “Reverse Stock Split”). The number of authorized shares and par value per share were not adjusted as a result of the Reverse Stock Split. No fractional shares were issued; stockholders entitled to a fractional share received a cash payment in lieu thereof. All references to shares, equity awards and options (including exercise prices), share data, per share data, and related information contained in the financial statements have been retrospectively adjusted to reflect the effect of the Reverse Stock Split for all periods presented.

Private Placement

On February 4, 2026, the Company entered into a Securities Purchase Agreement with certain investors in connection with a private placement. Pursuant to the Securities Purchase Agreement, the Company agreed to issue (i) 3,306,571 shares of its common stock, par value $0.0001 per share, at a purchase price of $21.17 per share and (ii) pre-funded warrants to purchase an aggregate of 1,417,107 shares of common stock at a purchase price of $21.1699 per pre-funded warrant, which represents the $21.17 share price less the $0.0001 per share exercise price. The transaction closed on February 6, 2026 and resulted in aggregate gross proceeds of approximately $100.0 million, consisting of approximately $70.0 million from the sale of common stock and approximately $30.0 million from the sale of pre-funded warrants.

Liquidity and Capital Resources

As of March 31, 2026, the Company had approximately $365.6 million of cash, cash equivalents and marketable securities and working capital of approximately $378.5 million. As of March 31, 2026, the Company had an accumulated deficit of $148.6 million. During the three months ended March 31, 2026, the Company incurred a net loss of $19.1 million, and negative cash flows from operations of $23.3 million. The Company has incurred net losses and negative cash flows from operations since its inception and anticipates it will continue to incur net losses for the foreseeable future.

Historically, the Company funded its operations primarily through proceeds from issuances of redeemable convertible preferred stock, common stock and convertible notes. In September 2025, the Company completed its IPO as detailed above. In February 2026, the Company completed a private placement financing resulting in total gross proceeds of $100.0 million. Net proceeds were approximately $93.8 million, after deducting financial advisory fees and other financing costs. The Company believes that its current capital resources, which consist of cash, cash equivalents and marketable securities, will be sufficient to fund operations through at least the next twelve months from the date the accompanying financial statements are issued based on its expected cash needs. As the Company continues to pursue its business plan, it expects to finance its operations through equity offerings, debt financings, or other capital sources, including current or potential future collaborations, licenses, and other similar arrangements. However, there can be no assurance that any additional financing or strategic arrangements will be available to the Company on acceptable terms, if at all.