Company: SMNR
Filing Date: 2025-04-21
Form Type: S-4/A
Source: 0001193125-25-087342
Chunk: 490

Company: Semnur Pharmaceuticals, Inc.
Filing Date: 2025-04-21
Form: S-4/A
Chunk 490
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, all of whom received SP-102followed by the intravenous dexamethasone sodium phosphate injection (RLD) administered one month later. A RLD is an approved drug product to which new 299

versions are compared to show that they are bioequivalent. The purpose of this study was to establish the pharmaceutical bridge between SP-102 and the RLD. The time to maximum serum concentration (“Tmax”) observed with the administration of SP-102 was four hours, compared to 15 minutes observed with intravenous dexamethasone. The PD parameters and tolerability profiles of both products were similar, and SP-102 did not prolong cortisol suppression time. SP-102 also maintained analgesic effects throughout a one-month observation period.

The overall systemic exposure of dexamethasone was similar, whether administered as SP-102 or injected intravenously, with a mean AUCinf of 0.916 µg*h/mL (observed with SP-102) compared to 0.943 µg*h/mL (observed with intravenously administered dexamethasone). Notably, there was a 16-fold increase in the Tmax following epidural injection of SP-102. The median Tmax was 4.00 hours for SP-102 compared to 0.25 hours for the comparison group. All 12 subjects with sciatica showed continuous reduction in back and leg pain during the one-month observation period following a single epidural injection of SP-102.

This study demonstrated that at an equivalent initial dose of dexamethasone, the systemic exposure to dexamethasone following epidural injection of SP-102 did not exceed the exposure following intravenous injection of the RLD. The PD effects, measured as white blood cell count, cortisol levels and glucose levels, as well as the tolerability profile, were similar between the two treatments. SP-102 injections were generally well tolerated and did not result in new unexpected side effects. We believe this trial supports a 505(b)(2) NDA, utilizing the known systemic safety of the FDA-approved RLD dose.

Toxicology Studies — Study Nos. 1014-1512 and 1014-2847

We conducted PK and toxicology studies in two non-rodent animal species to assess SP-102 administered via epidural and intrathecal routes with single and multiple dose regimens. Pharmacokinetically, a prolonged increase in the active dexamethasone metabolite was consistent with the extended