Company: LBRX
Filing Date: 2025-08-22
Form Type: S-1
Source: 0001193125-25-186467
Chunk: 13

Company: LB PHARMACEUTICALS INC
Filing Date: 2025-08-22
Form: S-1
Chunk 13
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 fiscal quarter, or our annual revenue is less than $100.0 million during the most recently completed fiscal year, and the market value of our voting and non-voting common stock
held by non-affiliates is less than $700.0 million measured on the last business day of our second fiscal quarter.

7

THE OFFERING

| Common stock offered by us | shares. |

| Option to purchase additional shares of common stock | The underwriters have a 30-day option to purchase up to     additional shares of our common stock at the initial public offering price less the underwriting discounts and 
 commissions.                                                                                                                                                               |

| Total common stock to be outstanding immediately after this offering | shares, or    shares if the underwriters exercise their option to purchase additional shares of our common stock in full. |

| Use of proceeds | We estimate that our net proceeds from this offering will be approximately $  (or approximately $  if the underwriters exercise in full their option to purchase additional shares of our common stock), based on the assumed                 
 initial public offering price of $  per share, which is the midpoint of the price range set forth on the cover page of this prospectus, after deducting the underwriting discounts and commissions and estimated offering expenses payable by 
 us.                                                                                                                                                                                                                                           |

| We intend to use the net proceeds of this offering, together with our existing cash and cash equivalents, to advance the clinical development of LB-102 to treat acute 
 schizophrenia and bipolar depression and utilize the remainder for general corporate purposes.                                                                         |

| See the section titled “Use of Proceeds” for additional information. |

| Risk factors | You should carefully read and consider the information set forth in the section titled “Risk Factors,” together with all of the other information set forth in this prospectus, before deciding whether to invest in our common stock. |

| Proposed Nasdaq trading symbol | “LBRX.” |

The number of shares of our common stock to be outstanding after this offering is based on 85,094,050 shares of common stock outstanding as of June 30, 2025, after giving effect to the conversion of all outstanding shares of our convertible preferred stock into 78,072,306 shares of common stock upon the closing of this offering and excludes:

| • |     | 11,923,082 shares of common stock issuable upon the exercise of outstanding stock options under our 2023