Update on new antiviral drug development for human herpesviruses

: Development of alternative compounds for treatment of diseases caused by herpesviruses has been required, because (1) all approved anti-herpesvirus drugs target the viral DNA synthesis, (2) strains resistant against these drugs emerge after a long treatment, and (3) some drugs have inevitable side effects. There are three main approaches for the development of novel anti-herpesvirus drugs: (1) modification of the existing drugs to increase their stability and bioavailablity in vivo, (2) increase of the efficacy of the existing drugs by administrating with an additional drug, eg. which is for induction of lytic infections of gamma herpesviruses, and (3) identification of novel drug targets and their clinical development. This review updates the recent efforts for those approaches.