Efficacy of HBV Vaccine in Consolidation of Nucleos(t)Ide Analogues Therapy

Background and aims: Nucleos(t)ide analogues may suppress HBV DNA to undetectable level, but only about 30-40% remain sustained response 1-3 years after discontinued therapy. The investigators will try to improve the sustained response rate by given a course of HBV vaccination during the last 6 months on patients receiving a 3-year entecavir or tenofovir therapy. Rational: The host may response to HBV vaccine when HBV DNA and immune tolerance are suppressed during entecavir or tenofovir therapy. Patients: Patients who have been receiving entecavir or tenofovir therapy for at least 30 months will be invited to this study. The case group will receive 5 Engerix-B injections during the last 6 months of entecavir or tenofovir therapy. Arm A-entecavir pretreated group: 75 cases will be enrolled to receive Engerix-B injection and compared with histological non-vaccine treated controls; Arm B-tenofovir pretreated group: 50 patients will be randomized into case (vaccine) and control group according to age, gender, pretreatment HBV DNA level. Therapy: Both case and control groups will receive a 3 year or longer entecavir or tenofovir therapy. Patients will be screen at 24-30 months and enrolled at 30 months after entecavir or tenofovir therapy. They will receive 5 Engerix-B injections at 0,1st ,2nd,3rd and 6th month \[30-36 +/-1 month post nucleos(t)ide therapy\] post enrollment. Both drugs will be discontinued after completed therapy. Follow-up: Both groups will be monitoring by biochemistry, alpha-fetoprotein, quantitative HBsAg, HBV DNA levels and immunological parameter periodically for 2 years after therapy. Efficacy: Those patients with persistent normal ALT and HBV DNA lower than 1\*100000 cps/mL after discontinued nucleos(t)ide analogues therapy will be considered to have sustained response. Patients with transient elevation of HBV DNA and ALT, but normalized spontaneously without further therapy will be defined as delayed response. Patients with persistent HBV D