This 3 arm study will assess the efficacy and safety of PEGASYS + entecavir combination therapy in treatment-naive patients with HBeAg positive chronic hepatitis B. Patients will be randomized to receive 1)PEGASYS 180 micrograms s.c./week for 48 weeks, 2)PEGASYS 180 micrograms s.c./week for 48 weeks + entecavir 0.5mg p.o. once daily from week 13 to week 36 or 3) entecavir 0.5mg p.o. once daily for 24 weeks + PEGASYS 180 micrograms s.c./week from week 21 to 68. Treatment will be followed by 24 weeks treatment-free follow up. The anticipated time on study treatment is 3-12 months for groups 1 and 2, and 1-2 years for group 3, and the target sample size is 100-500 individuals.

Inclusion Criteria:

• adult patients, 18-65 years of age;
• HBsAg positive, HBeAg positive and anti-HBe negative for at least 6 months, anti-HBs negative;
• absence of cirrhosis confirmed by liver biopsy in previous 12 months.

Exclusion Criteria:

• previous treatment for chronic hepatitis B within previous 6 months;
• antiviral, anti-neoplastic or immunomodulatory treatment in previous 6 months;
• co-infection with active hepatitis A, hepatitis C, hepatitis D or HIV;
• history or other evidence of a medical condition associated with chronic liver disease other than viral hepatitis.