Valaciclovir – A Review of its Potential in the Management of Genital Herpes

Abstract

The continued increase in prevalence of herpes simplex virus (HSV) infection indicates a need to develop improved chemotherapeutic strategies so as to enhance options for the management of genital herpes. The clinical and psycho-social impact of genital herpes and the need to encourage patients to participate in controlling their disease create several opportunities for improvement. The higher bioavailability of aciclovir from valaciclovir ensures that plasma aciclovir levels exceed the in vitro IC50 for clinical HSV strains with once- or twice-daily dosing regimens. The satisfactory outcome for valaciclovir in pre-clinical mutagenicity and carcinogenicity bioassays, plus aciclovir's highly specific mode of action, form the basis for the proposal that valaciclovir can match the excellent safety profile established for aciclovir. Controlled clinical trials of valaciclovir for the acute treatment of recurrent genital herpes have demonstrated efficacy in speeding resolution of all signs and symptoms, hastening lesion healing and terminating virus shedding. Further, these results indicate that valaciclovir provides a significant improvement in increasing the numbers of patients in whom lesion development is prevented. These benefits were achieved with twice-daily valaciclovir regimens and without compromise to safety. Studies evaluating valaciclovir in HSV infections in the immunocompromised and for long-term suppressive therapy in otherwise healthy subjects continue. To date, the valaciclovir HSV clinical development programme indicates that efficacy can be achieved with less frequent dosing without compromising safety.