Antiviral Treatment of Cytomegalovirus Infection

Cytomegalovirus (CMV) is an opportunistic pathogen associated with significant morbidity and mortality in immunocompromised hosts. Antiviral agents specifically targeting CMV were initially developed during the human immunodeficiency virus (HIV) epidemic to treat end-organ disease in patients with acquired immunodeficiency syndrome (AIDS). There are currently four antiviral drugs licensed for the treatment of CMV infections: ganciclovir (GCV), valganciclovir (VGCV), foscarnet (FOS), and cidofovir (CDV). The role of these agents has evolved from the treatment of disease to include prevention of CMV infection and disease, primarily in solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients. The potential use of these drugs is being explored for the treatment of congenital CMV infection, another CMV-associated disease with significant morbidity. The availability of antiviral therapy has provided major advances in the treatment and prevention of CMV infection and has resulted in dramatically improved outcomes for immunocompromised hosts. At the same time, the clinical utility of most of these agents is limited by poor oral bioavailability, associated toxicities, and the potential for development of resistance with extended use. Novel therapeutic agents are needed to address these limitations. In this article, currently available anti-CMV agents will be described. An overview of the clinical syndromes caused by CMV will be provided, with specific reference to the role of antiviral agents in treating and preventing these infections. Antiviral resistance in CMV will be reviewed and novel therapeutic agents that may address resistance will be briefly discussed.