Recent developments in herpesvirus therapy.

The antiherpes drugs, aciclovir and ganciclovir, are considered the standard treatments and prophylactic agents for infections caused by herpes simplex virus (HSV), varicella zoster virus (VZV) and cytomegalovirus (CMV). Until a decade ago, the impact of aciclovir on the control of severe and life-threatening herpesvirus infections was unprecedented. During the past few years, we have witnessed approval of new therapeutic drugs for infections caused by HSV and VZV (i.e. penciclovir and the oral prodrugs, valaciclovir and famciclovir), CMV (i.e. ganciclovir, cidofovir and fomivirsen) or HSV, VZV and CMV (i.e. foscarnet). A few agents, such as brivudin and benzimidavir, are in ongoing clinical development; others have been suspended because of safety concerns. New antiherpes agents are needed to face clinical issues such as drug resistance, increased use of antiherpes prophylaxis in transplantation and safety concerns in small children or pregnant women.