Single-day famciclovir for the treatment of genital herpes: follow-up results of time to next recurrence and assessment of antiviral resistance

Abstract

Background: Episodic therapy of genital herpes is usually recommended for patients with infrequent symptomatic recurrences and where transmission is not a concern. While shorter courses are as effective as standard 5-day regimens, it is unknown whether abbreviated therapy has detrimental effects on natural history and the development of antiviral resistance. Objectives: To assess time to next recurrence and development of antiviral resistance in patients with recurrent genital herpes treated with either single-day famciclovir (1 g twice-daily) or 3-day valacyclovir (500 mg twice-daily). Methods: Longer-term, follow-up data on the time to next recurrence and antiviral sensitivity were collected from a previously reported multicenter, multinational, double-blind, parallel group study in which 1179 immunocompetent adults were randomized 1 : 1 to receive either single-day famciclovir or 3-day valacyclovir. Treatment was self-initiated within 6 hours of a recurrence. Swabs for viral culture and sensitivity testing were collected for two sequential recurrences. Results: The median time to next recurrence from treatment initiation was 33.5 days for famciclovir and 38.0 days for valacyclovir. No drug resistance to penciclovir, the active metabolite of famciclovir, was observed at baseline nor did any develop by the time of the next recurrence. Limitations: The study had no placebo arm, typing of viral isolates was not performed and viral resistance testing was restricted to penciclovir only. Conclusion: Treatment with single-day famciclovir for recurrent genital herpes did not shorten the time to the next recurrence. Drug resistance to penciclovir continues to be a rare event in immunocompetent patients.