A Study of Switch From Nucleotide to Peginterferon Alfa-2a in CHB Patients Achieving HBeAg Loss and HBV DNA <200IU/ml

A Randomized, open-label, multicenter study. The patients after 1-3 years NAs treatment and having achieved HBeAg loss and HBV DNA \<200IU/ml will be switched to Pegasys for 48 or 96 weeks (with a 12 weeks period of overlap with the NA for safety reasons). The subjects will be randomized into 2 groups: Group 1 : 48-week standard treatment by Peginterferon alfa 2a 180µg/week Group 2 : 96-week prolonged treatment by Peginterferon alfa 2a 180µg/week. All the patients will be followed up for 48 weeks after discontinuation of the study medication. Note: NAs will be stratified LAM, ETV and ADV, with the ratio 1:1:1.