Company: SMNR
Filing Date: 2025-08-13
Form Type: 424B3
Source: 0001193125-25-179226
Chunk: 483

Company: Semnur Pharmaceuticals, Inc.
Filing Date: 2025-08-13
Form: 424B3
Chunk 483
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 compared to an intramuscular (i.e., the posterior multifidus muscle) injection of placebo over four weeks. After the primary Week Four
analysis period, and if the subject continued to experience leg pain, a repeat injection of open-label SP-102 was made optional at the investigator’s discretion.

Clinical Development Overview

We have completed a Phase 3 pivotal study of SP-102. The CLEAR study is a randomized, double-blind, placebo-controlled
Phase 3 trial that enrolled 401 patients with sciatica to compare the epidural administration of

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SP-102to placebo. We announced final results from this study in March 2022. The Phase 3 study results have been published in PAIN ®Journal in June 2024 and we also presented the pivotal Phase 3 trial results at the American Society of Interventional Pain Physicians annual meeting in Las Vegas, Nevada in May 2022. Preclinical and Clinical Trial and Highlights SP-102has been evaluated in a number of preclinical studies and clinical trials as a potential treatment for sciatica. Key findings from the preclinical studies and clinical trials include:

| • |     | The introduction of SP-102 into blood vessels did not result in             
 neurological complications in the UPD003-IS21 preclinical toxicology study; |

| • |     | SP-102 showed an extended residence time and tolerability in the 
 1014-1512 and the 1014-2847 preclinical studies;                 |

| • |     | Repeat injections of SP-102 showed continued pain reduction with no                  
 unexpected adverse events based on preliminary results from the SP-102-03 study; and |

| • |     | SP-102 showed an extended local activity with epidural administration in 
 the ES-1504 study.                                                       |

Study Details Phase 3 Pivotal Clinical Trial — CLEAR We have completed a pivotal, randomized, double-blind, placebo-controlled Phase 3 trial, CLEAR, that enrolled 401 patients with sciatica at over 40 sites across the United States. The study included an open-label extension where subjects were followed for up to 24 weeks after treatment to evaluate the tolerability of administering SP-102in a larger patient population. After week four, subjects who met certain pain criteria received open-label SP-102to investigate the tolerability of repeat injections and the duration of pain relief following injection. This well-controlled, double-blind, randomized trial was designed to demonstrate evidence of the analgesic effect and tolerability of SP-102.The