Company: LBRX
Filing Date: 2025-09-08
Form Type: S-1/A
Source: 0001193125-25-197877
Chunk: 337

Company: LB PHARMACEUTICALS INC
Filing Date: 2025-09-08
Form: S-1/A
Chunk 337
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 Securities Act. These restricted securities are eligible for public sale only if they are registered under the Securities Act or if they qualify for an exemption from registration, including the exemptions provided by under Rules 144 or 701 under the Securities Act, which rules are summarized below. As a result of the lock-upagreements described below and subject to the provisions of Rules 144 or 701, these restricted securities will be available for sale in the public market as follows:

| Approximate Number of Shares |     | First Date Available for Sale into the Public                                                                                                                                              
 Market                                                                                                                                                                                     |
| 3,433,470 Shares             |     | 181 days after the date of this prospectus, upon expiration of the lock-up agreements referred to below, subject in some cases to applicable volume, manner of sale, and other limitations 
 under Rule 144 and Rule 701.                                                                                                                                                               |

Rule 144 In general, non-affiliatepersons who have beneficially owned restricted shares of our common stock for at least six months, and any affiliate of the company who owns either restricted or unrestricted shares of our common stock, are entitled to sell their securities without registration with the SEC under an exemption from registration provided by Rule 144 under the Securities Act. Non-Affiliates Any person who is not deemed to have been one of our affiliates at the time of, or at any time during the three months preceding, a sale may sell an unlimited number of restricted securities under Rule 144 if:

| • |     | the restricted securities have been held for at least six months, including the holding period of any prior owner 
 other than one of our affiliates (subject to certain exceptions);                                                 |

| • |     | we have been subject to the Exchange Act periodic reporting requirements for at least 90 days before the sale; 
 and                                                                                                            |

| • |     | we are current in our Exchange Act reporting at the time of sale. |

Any person who is not deemed to have been an affiliate of ours at the time of, or at any time during the three months preceding, a sale and has held the restricted securities for at least one year, including the holding period of any prior owner other than one of our affiliates, will be entitled to sell an unlimited number of restricted securities without regard to the length of time we have been subject to Exchange Act periodic reporting or whether we are current in our Exchange Act reporting. Non-affiliateresales are not subject to the manner of sale, volume limitation, or notice filing provisions of Rule 144. 225