High-dose, short-duration, early valacyclovir therapy for episodic treatment of cold sores: results of two randomized, placebo-controlled, multicenter studies.

Abstract

Oral valacyclovir is better absorbed than oral acyclovir, increasing acyclovir bioavailability three- to fivefold. This provides the opportunity to explore whether high systemic acyclovir concentrations are effective in the treatment of cold sores (herpes labialis). Two randomized, double-blind, placebo-controlled studies were conducted. Subjects were provided with 2 g of valacyclovir twice daily for 1 day (1-day treatment), 2 g of valacyclovir twice daily for 1 day and then 1 g of valacyclovir twice daily for 1 day (2-day treatment), or a matching placebo and instructed to initiate treatment upon the first symptoms of a cold sore. In study 1, the median duration of the episode (primary endpoint) was reduced by 1.0 day (P = 0.001) with 1-day treatment and 0.5 days (P = 0.009) with 2-day treatment compared to placebo. Similarly, the mean duration of the episode was statistically significantly reduced by 1.1 days with 1-day treatment and 0.7 days with 2-day treatment compared to placebo. The proportion of subjects in whom cold sore lesion development was prevented and/or blocked was increased by 6.4% (P = 0.096) with 1-day treatment and 8.5% (P = 0.061) with 2-day treatment compared to placebo. The time to lesion healing and time to cessation of pain and/or discomfort were statistically significantly reduced with valacyclovir compared to placebo. In study 2, results similar to those in study 1 were obtained. AEs were similar across treatment groups. These studies provide evidence supporting a simple, 1-day valacyclovir treatment regimen for cold sores that is safe and effective. The 1-day valacyclovir regimen offers patients a unique and convenient dosing alternative compared to available topical therapies.