Antiviral activities of penciclovir and famciclovir on duck hepatitis B virus in vitro and in vivo.

Chronic hepatitis B virus (HBV) infection is a major health problem worldwide. Antiviral strategies available at present, including interferon-alpha, have only limited efficacy, leading us to analyse the antiviral effects of penciclovir and famciclovir in the duck hepatitis B virus (DHBV) model of HBV infection in vitro and in vivo. In DHBV-infected duck hepatocytes, penciclovir effectively inhibited viral replication, with a concentration giving half-maximal inhibition of 0.25 microM. Furthermore, in vivo, penciclovir and its orally administered prodrug famciclovir strongly inhibited DHBV replication. These data demonstrate that penciclovir and famciclovir both have strong antiviral activities, and suggest that these agents might be useful for treating HBV infection in humans.