Active Drug Comparative Trial to Evaluate the Antiviral Activity and Safety in Chronic Hepatitis B Patients

Inclusion Criteria: 1. Over the age of 20 years old 2. Patients with Chronic Hepatitis B diagnosed 3. Patients who show positive HBsAg 4. Patients who show positive HBeAg or negative HBeAg 5. Patients who showed HBV DNA undetected(less than 300 copies/mL) 6. Patients who have administered Baraclude Tab. 0.5mg for 1\~4 years 7. Patients who showed ALT less than 5 times of the upper limit in the normal range 8. Patient who decided to participate and signed on an informed consent form willingly Exclusion Criteria: 1. Patients who have hepatitis C (HCV), hepatitis D (HDV), or human immunodeficiency virus (HIV) 2. Patients with a uncompensated liver disease who have at least one of the following values or signs * Total bilirubin \> 2.5mg/dl * Prothrombin time delayed more than three seconds of upper limit in the normal range * Serum Albumin \< 3 g/dL * A medical history of ascites, jaundice, hemorrhage by varix, hepatic encephalopathy, or other signs of liver function loss 3. Patients who are estimated to have hepatocellular carcinoma (HCC) through imaging examination or showed alpha-fetoprotein(AFP) more than 100 ng/mL 4. Patients who showed Creatinine Clearance \< 50 mL/min by calculating Cockcroft-Gault equation 5. Patients who were not administered any anti-viral agents except Baraclude Tab.(Entecavir) 6. Administration of other Investigational Product within 30 days 7. History of malignant tumor within 5 years (including leukemia and lymphoma) 8. Patients who have a severe disease, such as heart failure, renal failure, and pancreatitis, decided by an investigator to have an effect on this clinical trial 9. Patients who have other hepatic diseases except hepatitis B 10. Administration immunosuppressants or corticosteroids over 2 weeks within 24 weeks 11. Patients who have to administer immunosuppressants or Nephrotoxic drugs, Hepatotoxic drugs for period of Clinical Trial 12. Pregnant, breast-feeding and childbearing age who don't use adequate contraception 13. Patients who are possible to decline daily function due to a mental disease or patients who are not able to understand the purpose and methods of this clinical trial 14. Patients who received an organ transplant or are going to received an organ transplant 15. Severe hypersensitivity to Entecavir 16. Another clinical condition in investigator's judgement