Dose adjustment: In the event that a patient did not achieve an RVR at week 4, and provided they were not experiencing adverse events, the daily dosage of ribavirin was increased by 200 mg or 300 mg, and in the case of those who started treatment on the lower dosage of peginterferon alfa-2a (40KD) or conventional interferon alfa, the dosage of peginterferon alfa-2a (40KD) was increased from 135 µg/week to 180 µg/week. In the event of adverse events that could not be ameliorated with symptomatic treatment, the dose of peginterferon alfa-2a (40KD) was reduced from 180 µg/week to 135 µg/week and of ribavirin by 200 mg/day or 300 mg/day.