An Open Study to Evaluate the Efficacy, Safety of Clevudine Monotherapy or Adefovir and Clevudine Combination in Patients With Chronic Hepatitis B

Inclusion Criteria: * Patient is 18 years and older. * Patient is documented to be HBsAg positive for \> 6 months. * Patient is HBV DNA positive with DNA levels ≥ 1×10\^5 copies/mL within 30days of baseline. * Patient has ALT levels ≥ 1×ULN * Patient who is able to give written informed consent prior to study start and to comply with the study requirements. Exclusion Criteria: * Patient is currently receiving antiviral, immunomodulatory, cytotoxic or corticosteroid therapy. * Patients previously treated with interferon, peg-interferon or other immunomodulatory within the previous 6 months. * Patients previously treated with clevudine, lamivudine, adefovir, entecavir, telbivudine, Tenofovir or any other investigational nucleoside for HBV infection. * Patient with clinical evidence of decompensated liver disease (Total bilirubin \< 2.0mg/dL, Prothrombin time \< 1.7(INR), Serum albumin≥3.5g/dL) * Patient is coinfected with HCV, HDV or HIV. * Patient has a history of ascites, variceal hemorrhage or hepatic encephalopathy. * Patient with clinical evidence of hepatocellular carcinoma * Patient with previous liver transplantation * Patient is pregnant or breast-feeding. * Patient has a clinically relevant history of abuse of alcohol or drugs. * Patient has a significant immunocompromised, gastrointestinal, renal, * hematological, psychiatric, bronchopulmonary, biliary diseases excluding asymptomatic GB stone, neurological, cardiac, oncologic(except HCC)or allergic disease or medical illness that in the investigator's opinion might interfere with therapy. * Patient has creatinine clearance less than 60mL/min as estimated by the following formula: (140-age in years) (body weight \[kg\])/(72) (serum creatinine \[mg/dL\]) \[Note: multiply estimates by 0.85 for women\]