[E-Daily Reporter Hong Ju-yeon ] ST Pharm Co., Ltd.(237690)ST Pharm Co., Ltd.’s human immunodeficiency virus (HIV-1) therapeutic candidate “STP0404” (active ingredient: firmitegravir), currently under development, has demonstrated both antiviral activity and tolerability in a U.S. Phase 2a clinical trial. ST Pharm Co., Ltd. announced the topline results of the trial on the 14th.

STP0404 is an innovative drug candidate with a “first-in-class” mechanism of action that binds to the inactive (allosteric) site of the HIV integrase enzyme, rather than its active site.

According to the announcement, this trial was a randomized, double-blind, placebo-controlled, multicenter clinical trial conducted at 13 institutions in the United States following approval by the U.S. Food and Drug Administration (FDA). From May 2023 to May of this year, ST Pharm Co., Ltd. evaluated the antiviral activity, safety, tolerability, and pharmacokinetics of STP0404 in 36 HIV-1-infected adults aged 18 to 65 who received a single daily oral dose for 10 days.

For the primary endpoint of antiviral activity, the change in plasma HIV-1 RNA (log10 copies) from baseline to day 11 after the 10-day treatment period was -1.50 in the 200 mg group, -1.18 in the 400 mg group, and -1.61 in the 600 mg group. The placebo group recorded a value of 0.10, demonstrating statistical significance in all comparisons between the treatment groups and the placebo group (p<0.0001).

In terms of tolerability, STP0404 also demonstrated generally favorable results throughout the 10-day treatment period. Treatment-emergent adverse events (TEAEs) were reported in 60.0% of subjects, but most were mild; there were no Grade 3 or higher TEAEs, serious adverse events (SAEs), or adverse events leading to treatment discontinuation or death.

Pharmacokinetic analysis revealed no significant accumulation following repeated dosing. Drug exposure generally increased in proportion to the dose. Maximum plasma concentration (Cmax) and total exposure (AUC) also increased with increasing dose.

ST Pharm Co., Ltd. announced that it plans to present the detailed results of this Phase 2a clinical trial at an international academic conference.