ST Pharm announced that it has received the Clinical Study Report (CSR) for the Phase 2a clinical trial of STP0404, a candidate treatment for HIV-1. The trial results confirmed significant antiviral activity across all dose groups.

■ Trial Overview The clinical trial was approved by the U.S. Food and Drug Administration (FDA) and conducted at 13 institutions in the United States. It aimed to evaluate the antiviral activity, safety, tolerability, and pharmacokinetics of STP0404 in adults aged 18 to 65 infected with HIV-1. The study was designed as a randomized, double-blind, placebo-controlled trial, with participants receiving STP0404 once daily for 10 days. The trial period ran from May 23, 2023 to May 6, 2026, with a target enrollment of approximately 36 subjects.

■ Antiviral Activity… -1.61 log10 copies in the 600mg Group For the key endpoint of antiviral activity, the change in plasma HIV-1 RNA from baseline to Day 11 of dosing was -1.50 log10 copies in the 200mg group, -1.18 log10 copies in the 400mg group, and -1.61 log10 copies in the 600mg group. The placebo group showed only a 0.11 log10 copies change. According to the regulatory filing, all comparisons between treatment groups were statistically significant.

■ Safety and Pharmacokinetics Results In the safety and tolerability evaluation, 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. In the pharmacokinetic evaluation, no significant accumulation was observed after repeated dosing, and drug exposure generally increased in a dose-proportional manner. The geometric mean maximum concentration (Cmax) for the 200mg, 400mg, and 600mg groups was 3,130 ng/mL, 5,390 ng/mL, and 8,570 ng/mL, respectively. Total exposure (AUC0-24h) was tallied at 41,100 h·ng/mL, 60,200 h·ng/mL, and 118,000 h·ng/mL, respectively.

■ Future Plans and Investment Cautions ST Pharm plans to present the detailed results of this Phase 2a trial at an international academic conference. It also intends to establish a follow-up clinical trial strategy based on these evaluation results to provide a new option alongside existing standard HIV-1 treatments. The company noted that the CSR values differ from the topline results disclosed on July 14. Meanwhile, ST Pharm stated in its investment cautionary notice that the statistical probability of a clinical trial drug receiving final approval as a pharmaceutical product is known to be approximately 10%. It added that if the clinical trial and product approval process yields results that fall short of expectations, the company may change or abandon its commercialization plans.