The purpose of this study is to investigate whether it is possible to augment the response of patients with HBeAg-positive chronic hepatitis B to entecavir by using a temporary peginterferon alpha-2a add-on strategy

Inclusion Criteria:

• Chronic hepatitis B (HBsAg positive > 6 months)
• HBeAg positive, anti-HBe negative at screening
• ALT > 1.3 x ULN within 60 days prior to screening and during screening
• Liver biopsy performed within 2 years prior to screening or during screening
• Age > 18 years
• Written informed consent
• Adequate contraception for males and females during treatment and follow up; negative pregnancy test (for women of childbearing potential)

Exclusion Criteria:

• Antiviral therapy against HBV within the previous 6 months
• Treatment with any investigational drug within 30 days of screening
• Previous treatment with lamivudine or telbivudine for more than six months
• Severe hepatitis activity as documented by ALT>10 x ULN
• History of decompensated cirrhosis (defined as jaundice in the presence of cirrhosis, ascites, bleeding gastric or esophageal varices or encephalopathy)
• Pre-existent neutropenia (neutrophils < 1,500/mm3) or thrombocytopenia (platelets < 90,000/mm3)
• Co-infection with hepatitis C virus or human immunodeficiency virus (HIV)
• Other acquired or inherited causes of liver disease (i.e. alcoholic liver disease, obesity induced liver disease, drug related liver disease, auto-immune hepatitis, hemochromatosis, Wilson's disease or alpha-1 antitrypsin deficiency)
• Alpha fetoprotein > 50 ng/ml
• Hyper- or hypothyroidism (subjects requiring medication to maintain TSH levels in the normal range are eligible if all other inclusion/exclusion criteria are met)
• Immune suppressive treatment within the previous 6 months
• Contra-indications for alpha-interferon therapy like suspected hypersensitivity to interferon or PEG-interferon or any known pre-existing medical condition that could interfere with the patient's participation in and completion of the study.
• Pregnancy, lactation
• Other significant medical illness that might interfere with this study: significant pulmonary dysfunction in the previous 6 months, malignancy other than skin basocellular carcinoma in previous 5 years, immunodeficiency syndromes (e.g. HIV positivity, auto-immune diseases, organ transplants other than cornea and hair transplant)
• Any medical condition requiring, or likely to require chronic systemic administration of steroids, during the course of the study
• Substance abuse, such as alcohol (> 80 g/day), I.V. drugs and inhaled drugs in the past 2 years.
• Any other condition which in the opinion of the principal investigator would make the patient unsuitable for enrollment, or could interfere with the patient participating in and completing the study