Efficacy of tenofovir disoproxil fumarate in antiretroviral therapy-naive and -experienced patients coinfected with HIV-1 and hepatitis B virus

Background. Coinfection with human immunodeficiency virus type 1 (HIV-1) increases the risk of hepatitis B virus (HBV)-associated progressive liver disease. Lamivudine has potent activity against both HIV-1 and HBV; however, lamivudine-resistance mutations in HBV frequently develop. Methods. Substudies of the safety and efficacy of tenofovir disoproxil fumarate (tenofovir DF) for patients coinfected with HIV and HBV were undertaken within 2 phase 3 randomized controlled trials involving antiretroviral therapy - experienced (study 907) and - naive (study 903) HIV-infected populations. Inclusion criteria were detection of hepatitis B surface antigen, an HBV DNA level >10(6) copies/mL at baseline, and HBV DNA specimens 6 10 available at week 24 ( study 907) and week 48 ( study 903). Results. In study 907, the mean decrease in HBV DNA was 4.9 log(10), after 24 weeks, for 10 patients randomized to receive tenofovir DF, compared with a mean increase of 1.2 log(10) for 2 patients randomized to receive placebo (P = .041). The mean decrease in HBV DNA during tenofovir DF treatment was similar for patients with wildtype (5.3 log(10)) and lamivudine-resistant (4.6 log(10)) HBV strains. In study 903, the mean decrease in HBV DNA was 3.0 log(10), after 48 weeks, for 6 patients randomized to receive lamivudine, compared with 4.7 log(10) for 5 patients randomized to receive lamivudine and tenofovir DF (P = .055). Four patients developed tyrosine-methionine-aspartate-aspartate mutations, all in the lamivudine-only treatment arm. Conclusion. Tenofovir DF has potent anti-HBV efficacy in antiretroviral therapy - experienced and - naive individuals coinfected with HIV and HBV.