Single-Dose, Patient-Initiated Amenamevir Therapy for Recurrent Genital Herpes: A Phase 3, Randomized, Double-Blind, Placebo-Controlled Study

Abstract

Background Amenamevir is a helicase-primase inhibitor with novel mechanisms of anti-herpetic action. A patient-initiated single-dose regimen showed clinical efficacy for genital herpes in a phase 2 study. Methods In this phase 3 study, adult immunocompetent patients with recurrent genital herpes and able to accurately recognize prodromal symptoms were randomly assigned to administer amenamevir 1200 mg or placebo as a patient-initiated therapy within 6 hours after onset of prodromal symptoms. The primary efficacy endpoint was time to healing of all genital herpes lesions. Results In the modified intention-to-treat population, which excluded patients with aborted lesions (amenamevir, n = 89; placebo, n = 97), the median time to all lesion healing was 4.0 days for amenamevir versus 5.1 days for placebo (hazard ratio 1.60; 95% confidence intervals, 1.19–2.15; P = .0018), indicating superiority of amenamevir. All treatment-emergent adverse events in both groups were mild in severity. Conclusions Patient-initiated single-dose amenamevir reduced the time to all lesion healing of recurrent genital herpes versus placebo, with no safety concerns, suggesting it could be an effective treatment option for patients with recurrent genital herpes. Clinical Trial Registration JapicCTI-194955 (https://www.clinicaltrials.jp/cti-user/trial/ShowDirect.jsp?clinicalTrialId=33260)

Recent advance in management of herpes simplex in Japan

“…Amenamevir also suppresses the acyclovir‐resistant strain of HSV and VZV 53 . Amenamevir is currently available and labeled only for herpes zoster in Japan but is now being developed for the treatment of herpes simplex 54,55 . The efficacy and safety of amenamevir against HSV have already been confirmed in two independent clinical trials for oral 54 and genital 55 herpes, respectively, with patient‐initiated therapy format.…”

“…Amenamevir is currently available and labeled only for herpes zoster in Japan but is now being developed for the treatment of herpes simplex 54,55 . The efficacy and safety of amenamevir against HSV have already been confirmed in two independent clinical trials for oral 54 and genital 55 herpes, respectively, with patient‐initiated therapy format. The dosage and administration of amenamevir is 1200 mg only once, which should contribute to improved compliance.…”