In clinical trial C/ I98-580, 1,530 naïve patients were treated for one year with one of the following combination regimens: • Ribavirin (800 mg/ day) + peginterferon alfa-2b (1.5 micrograms/ kg/ week) (n = 511). • Ribavirin (1,000/ 1,200 mg/ day) + peginterferon alfa-2b (1.5 micrograms/ kg/ week for one month followed by 0.5 microgram/ kg/ week for 11 months) (n = 514). • Ribavirin (1,000/ 1,200 mg/ day) + interferon alfa-2b (3 MIU three times a week) (n = 505).