Clinical significance of antiviral therapy for episodic treatment of herpes labialis: exploratory analyses of the combined data from two valaciclovir trials

Valaciclovir (Valtrex) 2 g twice daily for 1 day was recently approved in the United States for treatment of cold sores. In order to apply more clinically relevant assumptions to the analysis, we examined the effect of different missing data and endpoint assumptions on apparent valaciclovir efficacy. Results of each analysis demonstrate statistically significant increases in the proportion of subjects whose cold sores were aborted with valaciclovir compared with placebo, and significant decreases in healing times for subjects with cold sore lesions who were treated with valaciclovir compared with placebo. These exploratory analyses provide evidence of the robustness of the results to differing missing data assumptions and show that use of more clinically relevant endpoint assumptions increases the magnitude of some therapeutic responses. We also introduce a new measure that combines the two observed drug effects (reduced lesion duration, increased aborted lesions) into a single endpoint that captures the global benefit of the drug to the patient.