Combination antiviral therapy for cytomegalovirus disease in patients with AIDS

Currently, combination therapy with ganciclovir and foscarnet should be reserved for patients with disease progression while receiving monotherapy or for those who are unresponsive to either agent alone. Although cidofovir and ganciclovir were shown to have synergistic activity against human CMV in vitro, there have been no in vivo studies to confirm this activity. Therefore, if a combination regimen is necessary to control CMV in a patient, foscarnet and ganciclovir should be used first. There are several advantages of the combination therapy regimen. For instance, lower doses of the individual agents can be used with superior efficacy to monotherapy and similar toxicities. Also, for neurologic CMV involvement, the combination therapy may be superior to monotherapy because of the variable CSF penetration of either drug alone. In addition, combined therapy may be beneficial in treating and/or preventing drug-resistant strains of CMV. Even though combination therapy has evidence of superior efficacy compared with monotherapy in the treatment of CMV, several issues must be considered. First, combination therapy has longer administration times because of the infusion of multiple drugs, which may be an inconvenience. Also, even though the toxic effects are similar with both combined therapy and monotherapy, the adverse effects associated with combination therapy may be less well tolerated and may negatively affect the patient's quality of life. Finally, combination therapy is more expensive than monotherapy with ganciclovir or foscarnet alone. Patients should be evaluated with these issues in mind before combination therapy is initiated.