Abstract: Objective To investigate the efficacy, safety and drug resistance of entecavir (ETV) in nucleoside analogues (NA)-na ve or NA-experienced chronic hepatitis B (CHB) patients. Methods Eighty-seven CHB outpatients treated with ETV monotherapy in our department was retrospectively analyzed, whose liver function, hepatitis B virus (HBV) DNA, hepatitis B surface antigen (HBsAg) quantitation, hepatitis B e antigen (HBeAg) loss and drug resistance were recorded.Results Among the 87 patients, 32 (37%) were NA-na ve and 55 (63%) were NA-experienced. Following at least 3.5 years of ETV monotherapy, the 7-year cumulative virological response rate (62%) was significantly lower in lamivudine (LAM)-experienced patients than NA-na ve (100%) or adefovir (ADV)-experienced (97%) patients. In contrast, 7-year cumulative drug resistance rate in LAM-experienced (38%) patients was significantly higher than that in NA-na ve (3%) and ADV-experienced patients (3%). Seven-year cumulative HBeAg loss rate was higher in NA-na ve patients (47%) than that in ADV-experienced (45%) and LAM-experienced (20%) patients. Additionally, 2 patients in ADV-experienced group achieved HBsAg loss. In all patients, HBeAg-negative patients had higher virological response rate than HBeAg-positive patients (91% vs. 89%, P=0.012). In NA-na ve patients, HBeAg-negative patients also showed a higher early virological response rate than HBeAg-positive patients (P=0.001), while their cumulative virological response rates were both 100%. The early persistent virological response rate of NA-na ve patients were higher than those of ADV-experienced and LAM-experienced patients (P<0.001).Conclusion ETV monotherapy in NA-na ve and ADV-experienced patients showed satisfactory long-term efficacy, safety and low resistance. However, there was still a high risk of ETV-resistance in LAM-experienced patients.

Key words: Chronic hepatitis B, Entecavir, Lamivudine, Adefovir, Long-term treatment