The era of highly active antiretroviral therapy (ART) has led to declining rates of opportunistic infections and a new focus on other leading causes of morbidity, such as end-stage liver disease (ESLD) secondary to hepatitis B virus (HBV) infection . The treatment and prevention of hepatitis B has taken on great significance in light of the negative impact HIV has on the natural history of chronic hepatitis B infection.
However, the use of antiviral medications for hepatitis B is complicated by the fact that some of these agents have dual activity against HIV infection. Also the available agents vary widely in efficacy and safety.
This topic will address the clinical data available on the various antiviral agents. Information on the evaluation of the treatment candidate, treatment approach, and patient monitoring, are discussed elsewhere. (See "Epidemiology, clinical manifestations, and diagnosis of hepatitis B in the HIV-infected patient" and "Treatment of hepatitis B in the HIV-infected patient" and "Evaluation of chronic hepatitis B virus infection in the HIV-infected patient" and "Monitoring the HIV-infected patient with chronic hepatitis B virus infection" and "Immunizations in HIV-infected patients", section on 'Hepatitis B vaccine'.)
Tenofovir has activity against both HIV and HBV. Like adefovir, tenofovir is a nucleotide reverse transcriptase inhibitor with activity against lamivudine-resistant virus [2-4]. The efficacy and safety of tenofovir has been evaluated in small substudies within two phase III clinical trials of tenofovir for the treatment of HIV in antiretroviral-naive and experienced patients. HIV/HBV coinfected patients treated with tenofovir experienced significant HBV viral load declines compared to placebo . Tenofovir was also effective against lamivudine resistant virus [4-6]. Development of resistance to tenofovir has not been demonstrated in HIV/HBV coinfection, but the duration of treatment in these small trials was only 24 weeks.
These data prompted a randomized, double-blind placebo-controlled trial of adefovir compared to tenofovir in 52 HIV/HBV co-infected patients on stable HAART . At baseline, median serum HBV DNA levels were 8.7 log(10) copies/microL and 9.3 log(10) copies/microL in the adefovir and tenofovir arms, respectively. After a median duration of follow-up of 75 weeks, mean log HBV DNA declines were -4.4 logs and -3.2 logs on tenofovir and adefovir, respectively.