Efficacy and Safety of Tenofovir-Based Rescue Therapy for Chronic Hepatitis B Patients with Previous Nucleo(s/t)ide Treatment Failure

BACKGROUND/AIMS: We investigated the efficacy and safety of tenofovir disoproxil fumarate (TDF)-based treatment in chronic hepatitis B (CHB) patients who failed previous antiviral therapies. METHODS: Seventeen patients who failed to achieve virological responses during sequential antiviral treatments were included. The patients were treated with TDF monotherapy (four patients) or a combination of TDF and lamivudine (13 patients) for a median of 42 months. Hepatitis B virus (HBV) DNA and hepatitis B e antigen (HBeAg) were measured, and renal function was also monitored. RESULTS: Prior to TDF therapy, 180 M, 204 I/V/S, 181 T/V, 236 T, and 184 L mutations were detected. After TDF therapy, the median HBV DNA level decreased from 4.6 log(10) IU/mL to 2.0 log(10) IU/mL and to 1.6 log(10) IU/mL at 12 and 24 months, respectively. HBV DNA became undetectable (≤20 IU/mL) in 14.3%, 41.7%, and 100% of patients after 12, 24, and 48 months of treatment, respectively. HBeAg loss was observed in two patients. Viral breakthrough occurred in five patients who had skipped their medication. No significant changes in renal function were observed. CONCLUSIONS: TDF-based rescue treatment is effective in reducing HBV DNA levels and is safe for patients with CHB who failed prior antiviral treatments. Patients' adherence to medication is related to viral rebound.