Efficacy and Safety of Tenofovir Disoproxil Furmarate for Patients with Lamivudine-Resistant Hepatitis B Virus Infection

Abstract

AIM: Tenofovir disoproxil fumarate (TDF) has potent antiviral efficacy and lack of resistance during long-term use in chronic hepatitis B (CHB) patients. The purpose of this study was to evaluate antiviral efficacy and safety of TDF in lamivudine-resistant CHB patients. METHODS: We performed a retrospective study of consecutive CHB patients who had detectable HBV DNA (>50IU/mL) and documented lamivudine-resistant mutations during antiviral treatment. Patients who had adefovir or entecavir-resistant HBV infection were excluded. They were treated with TDF monotherapy or combination with lamivudine more than 6 months. We analyzed virologic response (HBV DNA <20 IU/mL), biochemical and serologic responses to the TDF treatment and adverse events. RESULTS: A total of 101 CHB patients (HBeAg-positive 86%, mean baseline HBV DNA 3.29 log10IU/ mL) were enrolled. They were treated with TDF (n=74) or combination with lamivudine (n=27) for median duration of 20 months. The proportion of patients achieving virologic response at 6 months and 12 months was 80.2%, and 89.7%, respectively. The mean change from baseline in HBV DNA was –2.05 log10IU/mL, and –2.14 log10IU/mL, respectively. Multivariate Cox regression analysis showed that baseline HBV DNA level was a significant predictive factor of virologic response at 12 months. (HR=0.645; 95% CI 0.504-0.826; p=0.001). Two patients (2.4%) showed HBeAg loss, and no patient lost HBsAg during the treatment period. Serious adverse events or renal impairment was not observed. CONCLUSION: TDF is safe and effective for complete viral suppression in patients with lamivudine-resistant HBV infection.