A Study of Peginterferon Alfa-2a in Participants With Chronic Hepatitis B Virus (HBV) in an Expanded Access Program

Inclusion Criteria: * Non-cirrhotic participants * Hepatitis B surface antigen (HBsAg) positive for at least 6 months * Hepatitis B surface antibody (anti-HBs) negative * Elevated serum alanine aminotransferase (ALT) greater than (\>) upper limit of normal (ULN) but less than or equal to (\</=) 10 times of ULN * HBeAg positive participants: HBV DNA \> 500,000 copies/mL, HBeAg negative participants: HBV DNA \>100,000 copies/mL by polymerase chain reaction (PCR) * Participants with chronic hepatitis B (CHB) who are treatment-naive * No previous antiviral treatment with interferon (IFN: standard or pegylated) or with a nucleoside analogue * For women of childbearing potential: negative urine or serum pregnancy test documented within the 24-hour period prior to the first dose of test drug. Willingness to use reliable contraception during the study and for 3 months after treatment completion Exclusion Criteria: * Previous antiviral or IFN-based therapy for CHB before enrolment * Pregnant or breast feeding women participants * Evidence of decompensated liver disease * Co-infection with active hepatitis A, hepatitis C, hepatitis D and/or human immunodeficiency virus (HIV) * History or other evidence of a medical condition associated with chronic liver disease other than viral hepatitis * Previous or current hepatocellular carcinoma * History of or other evidence of bleeding from esophageal varices or other conditions consistent with decompensated liver disease * Alpha-fetoprotein levels of \>100 nanograms (ng)/mL * Severe psychiatric disease * History of a severe seizure disorder or current anticonvulsant use * History of immunologically mediated disease, chronic pulmonary disease associated with functional limitation, severe cardiac disease, major organ transplantation or other evidence of severe illness, malignancy, or any other conditions which would make the participant, in the opinion of the investigator, unsuitable for the study * Thyroid disease uncontrolled by prescribed medications * Evidence of severe retinopathy * Alcohol intake more than 3 standard drinks per day for men and 2 standard drinks per day for women