Impact of tenofovir-containing antiretroviral therapy on chronic hepatitis B in a cohort co-infected with human immunodeficiency virus

Objectives: We studied the impact of tenofovir disoproxil fumarate, given as an antiretroviral medication, on patients with chronic hepatitis B virus (HBV) co-infection. Methods: The polymerase gene-sequence evolution and quantitative HBV loads (HBVL) were observed for 48 weeks in patients taking tenofovir-containing antiretroviral therapy. The patients were grouped according to baseline strata: high-replicative virus (> 6 log copies/mL), low-replicative virus at detectable virus loads (< 6 log) and HBs-antigen-positive, HBV-DNA-negative individuals. Results: Thirty-one patients were evaluated. The median decline in 20 patients with high-replicative HBV infection was -5.37 log (range: 3.57-7); 11 out of 20 decreased to undetectable levels (lower limit of detection = < 200 copies/mL) and another three were below 400 copies/mL. Out of six patients with detectable HBV-DNA at week 48 (HBVL result: range 3.36-4.32 log(10)), we were able to carry out a re-sequence in four patients. We did not observe relevant emerging resistance mutations, or a relevant virus load re-increase from nadir (>+0.5 log). The patients with low-replicative virus (n = 9) and the baseline DNA-negative patients (n = 2) had an undetectable HBV-DNA at week 48. Two patients became HBeAg-negative; one DNA-negative patient became HBsAg-negative. Conclusions: Tenofovir is effective in treating HBV infection in HIV patients. Patients with high-replicative virus may benefit from this treatment strategy by a reduction in replicative status, a precondition for improved hepatic function. A few patients showed low-level HBV replication. Indicators for clinical HBV-resistance to tenofovir were not observed.