Activity of tenofovir on hepatitis B virus replication in HIV-co-infected patients failing or partially responding to lamivudine.

Treatment of hepatitis B virus (HBV) with lamivudine may not completely suppress viral replication and often fails as a result of lamivudine resistance. Tenofovir is a new HIV inhibitor with further activity against HBV, which was explored in 12 HBV/HIV-co-infected patients with detectable levels of serum HBV-DNA, despite receiving a lamivudine-containing antiretroviral regimen. Lamivudine-resistance mutations were found in HBV from seven patients. HBV-DNA levels dropped a median of 3.78 logs from baseline to 24 weeks. Tenofovir was very effective at reducing HBV-DNA levels in HIV/HBV-co-infected patients carrying either wild-type or lamivudine-resistant viruses.