Efficacy and safety of tenofovir in nucleos(t)ide-na⟨ve patients with genotype C chronic hepatitis B in real-life practice

Background Tenofovir disoproxil fumarate (TDF) has demonstrated potent antiviral activity against hepatitis B virus (HBV) in clinical trials. Although its efficacy has been demonstrated in Caucasian populations, TDF has not previously been studied in Korean patients who present the predominance of HBV genotype C and of vertical or perinatal transmission. Objective The aim of this study was to evaluate the efficacy of TDF in Korean chronic hepatitis B (CHB) patients in real-life practice, and to determine the clinical variables that contribute to virologic response.Setting Large academic medical center in Korea. Method We retrospectively investigated the efficacy of TDF treatment for more than 6 months in 151 nucleos(t)ide-na < ve CHB patients. Main outcome measure The primary endpoint was a virologic response (VR), defined as an HBV DNA level of < 12 IU/mL. Secondary endpoints were rates of alanine aminotransaminase (ALT) normalization, hepatitis B e antigen (HBeAg) seroconversion, virologic breakthrough, and safety. Results All patients were the genotype C2. The median duration of TDF treatment was 13 months (range 7-18 months). Ninety-two (61.0 %) patients were HBeAg positive. The mean pre-treatment HBV DNA level was 6.34 +/- A 1.42 log(10) IU/mL. Among the 131 patients with elevated ALT levels at baseline, 128 (97.7 %) patients achieved ALT normalization during TDF treatment. VR was achieved in 97 (64.2 %) patients. The cumulative rates of VR at 6, 9, 12, and 18 months were 47.0, 59.4, 67.9, and 69.3 %, respectively. Among the 92 HBeAg-positive patients, 14 (15.2 %) patients achieved HBeAg seroconversion. In multivariate analysis, absolute HBV DNA levels at baseline (P < 0.001; OR 0.529; 95 % CI 0.560-0.744) and HBeAg positivity (P = 0.015; OR 0.731; 95 % CI 0.615-0.869) were significantly associated with VR. Virologic breakthrough was observed in four patients. These four patients had poor adherence to TDF. Most of the adverse events were mild in severity. No significant changes were observed in serum creatinine and phosphorus levels. Conclusions TDF was effective and well tolerated in Korean genotype C CHB patients in real life practice, consistent with larger registration trials. The absolute HBV DNA levels at baseline and HBeAg positivity were significantly associated with VR.