Effect of Phosphonic Acid Analogs of Acyclovir and Ganciclovir on in Vitro Cytomegalovirus Infections

Eight phosphonic acid analogs of acyclovir (ACV) or ganciclovir (DHPG) inhibited human cytomegalovirus in vitro. Therapeutic indices were: phosphonate diacid of DHPG: 500; DHPG: 500; phosphonate monoethylester of DHPG: 258; phosphonate monoethylester of ACV: 94; cyclic phosphonate of DHPG: 64; ACV: 60; phosphonate monobutylester of ACV: 1.5; phosphonate monoethylester of deoxy DHPG: 4.6; 8-bromo ACV phosphonate monoethylester: \u3e2; phosphonate monoethylester heptyl of ACV: 1. Types 1 and 2 herpesvirus (HSV-1, HSV-2) and varicella zoster virus (VZV) were poorly inhibited by these new compounds, suggesting highly specific anti-HCMV activity. None exhibited significant cytotoxic effects as measured by uptake of [3H]thymidine, [3H]uridine and [3H]leucine