Antiviral activity of the polybasic anion, suramin and acyclovir in Hepadna virus infection

Acyclovir and suramin were examined for their efficacy alone and in combination against duck hepatitis B virus (DHBV) in persistently infected Pekin ducks. In ducks the peak plasma concentration of acyclovir was reached thirty minutes after oral administration. Oral acyclovir and suramin administered intravenously suppressed the replication and production of infectious virions as measured by marked reduction of DNA polymerase activity during treatment. However, rebound of enzyme activity was observed soon after cessation of drug therapy. In contrast, sustained reduction of polymerase activity was attained by combined therapy of acyclovir followed by suramin, demonstrating a significant enhancement of anti-DHBV activity which requires confirmation in a larger experimental study. This report establishes that the duck model is ideal for screening antiviral compounds in treatment of infection with Hepadna viruses.