Fogle JE, Tompkins WA, Campbell B et al: Fozivudine tidoxil as single-agent therapy decreases plasma and cell-associated viremia during acute feline immunodeficiency virus infection, J Vet Intern Med 25:413, 2011.
Feline immunodeficiency virus (FIV) is a natural lentivirus infection of domestic and wild cats. The course of the disease is similar to that of human immunodeficiency virus. One of two drugs, zidovudine (ZDV, also known as AZT), has demonstrated some benefit in controlled trials in naturally infected cats. ZDV has been shown to lower viral burden in both acute and chronic infection, to transiently improve CD4:CD8 ratios, and to improve clinical signs in chronically infected cats. Anemia is the most common and significant adverse side effect associated with ZDV that resolves on lowering the dosage or cessation of administration. Because there is a need for more effective drugs with fewer side effects for FIV treatment, the authors evaluated a compound related to ZDV, fozivudine (FZD), in a controlled experimental trial. Data from the study showed that FZD is effective at lowering viral load the first 2 weeks of FIV infection and may decrease early FIV- associated lympholysis. The adverse effects associated with ZDV administration, including anemia, were not evident in any of the cats treated with FZD at the dosage used during the study. Further investigation is needed to assess pharmacokinetics and optimal dosages for antiviral activity of the drug. [VT]