STP0404, an HIV drug candidate being developed by ST Pharm, showed a significant antiviral effect in the final analysis of a Phase 2a trial in the U.S. After 10 days of dosing, blood viral loads fell about 93% to 98% from pre-treatment levels, with no serious adverse events reported.
ST Pharm said in a regulatory filing on the 6th that it had received the clinical study report for the Phase 2a trial of STP0404. The trial was conducted at 13 sites in the U.S. in adults infected with human immunodeficiency virus (HIV)-1. Patients were divided into groups receiving 200 mg, 400 mg or 600 mg of STP0404 and a placebo group, and took the drug for 10 days before blood viral levels and safety were compared.
After dosing, HIV-1 viral loads in the blood fell about 97% in the 200 mg group, about 93% in the 400 mg group and about 98% in the 600 mg group, demonstrating statistical significance. By contrast, viral concentrations in the placebo group rose about 29% over the same period.
The trial also confirmed the drug's safety profile. Treatment-emergent adverse events were reported in 60% of all patients, but most were mild. There were no Grade 3 or higher adverse events, no serious adverse events, and no cases of treatment discontinuation or death due to side effects. No clear drug accumulation was observed with repeated dosing, and overall drug exposure in the body generally increased as doses rose.
ST Pharm plans to present detailed results from the Phase 2a trial at an international academic conference later this year and to use them to set its strategy for follow-up trials of STP0404.
