Efficiency of oxetanocin-G, a novel nucleoside against the woodchuck hepatitis virus.

Oxetanocin-G (OXT-G), a potent antiviral agent, is a novel nucleoside isolated from the culture filtrate of Bacillus megaterium. We investigated the antiviral effect of oral administration of OXT-G for five days on woodchuck hepatitis virus (WHV), in vivo, using 12 woodchucks. Woodchucks were randomized into each of four treatment groups according to the dose of OXT-G. Two out of six woodchucks treated with 1.0 or 2.0 mg/kg/day of OXT-G died. After treatment with OXT-G, serum levels of WHV-DNA significantly decreased in all woodchucks. However, the antiviral effect was only partial and levels of serum WHV-DNA returned after the cessation of treatment. The amount of viral replicative intermediates was decreased in livers of woodchucks treated with OXT-G. Although further study of the toxicity of this compound would be essential before studies in man can be carried out, OXT-G has potent antiviral activity against WHV and may deserve evaluation as an antiviral agent in the treatment of chronic hepatitis B infections in humans.