ASP2151 for the Treatment of Genital Herpes: A Randomized, Double-Blind, Placebo- and Valacyclovir-Controlled, Dose-Finding Study

Background. Current therapies for genital herpes have only partial efficacy. Helicase-primase inhibitors are novel, potent inhibitors of herpes simplex virus replication. Methods. This randomized trial assessed the safety and efficacy of ASP2151 for episodic therapy of recurrent genital herpes. Participants self-initiated with ASP2151 (100, 200, or 400 mg daily for 3 days), ASP2151 (1200 mg as a single dose), placebo for 3 days, or valacyclovir (500 mg twice daily for 3 days). The primary efficacy endpoint, time to lesion healing excluding aborted lesions, was analyzed using a proportional hazards model. Statistical significance was determined by P = .01. Results. Of 695 adults enrolled, 437 experienced a recurrence and received study drug. Median time for lesion healing excluding aborted lesions was 139.8 hours with placebo, 119.6 hours with ASP2151 (100 mg; hazard ratio [HR], 1.40; P = .065), 106.2 with ASP2151 (200 mg; HR, 1.40; P = .081), 115.9 with ASP2151 (400 mg; HR, 1.25; P = .25), 102.1 with ASP2151 (1200 mg; HR, 1.72; P = .007), and 113.9 with valacyclovir (500 mg twice daily; HR, 1.42; P = .077), indicating improvement in all treatment groups except ASP2151 (400 mg). Incidence of treatment-emergent adverse events was similar across groups. Conclusions. Three-day or single-day courses of ASP2151 appear to be effective and safe options for treatment of episodes of recurrent genital herpes. Clinical Trials Registration. NCT00486200.