HBsAg Decline After Pegylated-interferon-α in e Antigen Positive Chronic Hepatitis B With Nucleoside Maintenance

Inclusion Criteria:

• Informed consent

• Age over 20 years

• HBeAg-positive CHB patients

• Patients treated with all available nucleoside analogue monotherapy or combination inKorea except telbivudine ( e.g.entecavir monotherapy or lamivudine/adefovircombination , lamivudine, adefovir monotherapy) for ≥ 18months and patients who haveundetectable HBV viral load at least one year HBV DNA undetectable (≤ 400 copies/ml )Serum alanine transferase: ≤ 10 X upper limit of normal (ULN) Baseline HBsAg: ≥ 102IU/ml

• Negative urine or serum pregnancy test (for women of childbearing potential)documented within the 24-hour period prior to the first dose of test drug.Additionally, all fertile males with partners of childbearing age and females must beusing reliable contraception during the study and for 3 months after treatmentcompletion.

• Obtaining written informed consent form

Exclusion Criteria:

• Decompensated cirrhosis or other contraindications to interferon alfa 2a therapyfollowing local label.

• Concomitant or prior use of telbivudine.

• Positive test at screening for hepatitis A virus immunoglobulin M Ab, Hepatitis Cvirus-RNA or hepatitis C virus Ab, hepatitis delta virus Ab or HIV Ab.

• Diagnosed hepatic cellular carcinoma

• Any evidence of decompensated liver disease (Childs B-C)

• History or other evidence of a medical condition associated with chronic liver disease (e.g., hemochromatosis, autoimmune hepatitis, alcoholic liver disease, toxinexposures, thalassemia).

• Women with ongoing pregnancy or who are breast feeding.

• Evidence of alcohol and/or drug abuse within one year of entry.

• History of major organ transplantation with an existing functional graft.

• Inability or unwillingness to provide informed consent or abide by the requirements ofthe study.

• History or other evidence of severe illness or any other conditions which would makethe patient, in the opinion of the investigator, unsuitable for the study.

• Patients with a value of alpha-fetoprotein >100 ng/mL are excluded, unless stability (less than 10% increase) has been documented over at least the previous 3 months.

• patients having hypersensitivities for peginterferon alfa-2a or NAs