A Multicenter, Randomized, Controlled Study Comparing the Efficacy and Safety of 48 weeks of 40 kD Branched Pegylated Interferon Alfa-2a (PEG-IFN, RO 25-8310) Versus 96 Weeks of PEG-IFN, Alone or in Combination with 100 mg Lamivudine for 48 Weeks in Patients with HBeAg-Negative Chronic Hepatitis B. The gene discussed is IFNA1; the disease is chronic hepatitis B virus infection.