A Study Evaluating IL28B Polymorphism in Patients With HBeAg-Negative Chronic Hepatitis B Treated With Pegasys (Peginterferon Alfa-2a) in Study ML18253

Cross-sectional Multicenter Study Evaluating the IL28B Polymorphism in Patients With HBeAg-negative Chronic Hepatitis B Treated With Pegylated Interferon Alfa-2a in the Course of Peg.Be.Liver Study

This cross-sectional multicenter study will evaluate the IL28B polymorphism in patients with HBeAg-negative chronic hepatitis B treated with Pegasys (peginterferon alfa-2a) in the predecessor ML18253 study. The study consists of a single visit where eligible patients will undergo a blood test for IL28B genotyping, with a phone follow-up 7 days after the visit.

Inclusion Criteria:

• Adult patients, >/= 18 years of age
• Chronic hepatitis B
• Previous participation in study ML18253
• Administration of at least one dose of the study drug during ML18253 study

Exclusion Criteria:

• Patients not satisfying the above inclusion criteria will not be enrolled in the study