Patterns and causes of suboptimal response to tenofovir-based therapy in individuals coinfected with HIV and hepatitis B virus

Background. Tenofovir (TDF) is effective for treatment of hepatitis B virus (HBV) in human immunodeficiency virus (HIV) infection; however, some individuals have ongoing HBV viremia, the reasons for which are unclear. We determined the patterns and factors associated with detectable HBV DNA in HIV-HBV-coinfected subjects on highly active antiretroviral therapy (HAART).Methods. One hundred sixty-five HIV-HBV-coinfected individuals from the United States, Australia, and Thailand, the majority of whom were on HAART at study entry, were prospectively followed semiannually for a median of 2.8 years. Logistic regression was used to determine factors associated with detectable HBV DNA.Results. Anti-HBV regimens were TDF/emtricitabine (57%), lamivudine or emtricitabine (19%), or TDF monotherapy (13%). During follow-up, HBV DNA was detected at 21% of study visits and was independently associated with hepatitis B e antigen (HBeAg), HAART <2 years, CD4 <200 cells/mm³, detectable HIV RNA, reporting <95% adherence, and anti-HBV regimen. TDF/emtricitabine was less likely to be associated with detectable HBV than other regimens, including TDF monotherapy (odds ratio, 2.79; P =. 02). In subjects on optimal anti-HBV therapy (TDF/emtricitabine) and with undetectable HIV RNA, HBeAg, CD4 <200 mm³, and reporting <95% adherence remained associated with detectable HBV DNA. Three main patterns of HBV viremia were observed: persistent HBV viremia, viral rebound (>1 log from nadir), and viral blips. No TDF resistance was identified.Conclusions. Tenofovir/ emtricitabine was superior to other anti-HBV regimens in long-term HBV suppression. HBV viremia on therapy was identified in 1 of 3 main patterns. Suboptimal adherence was associated with detectable HBV DNA during therapy, even when HIV was undetectable.