Telbivudine Versus Entecavir in Reducing Serum HBsAg Levels in Patients With HBeAg-positive Chronic Hepatitis B

A single-center randomized active-controlled open-label superiority trial * Patients will be randomly assigned 1:1 to receive telbivudine (600 mg/day) or ongoing entecavir (0.5 mg/day) for 48 weeks. * Eligible patients will be randomized using blocks of permuted treatment assignments after stratification by HBsAg level (1,000 IU/mL-5,000 IU/mL and ≥5,000 IU/mL IU/mL) and by entecavir treatment duration (1 year-2 year, ≥2 year). * Because over 98% of Korean patients with CHB have HBV genotype C,9 HBV genotype will not determined or be regarded as a stratification factor. * There will be no interruption in entecavir therapy before randomization. * Patients' treatment information will be retrospectively collected during entecavir treatment phase as well (DNA change, HBeAg status, HBsAg titre, ALT, and treatment duration. etc) * Patients will be screened within 4 weeks before randomization to determine study eligibility.