Interferon alfacon-1: a novel interferon for the treatment of chronic hepatitis C

Interferon alfacon-1 (consensus interferon; CIFN) is a novel, recombinant interferon which has been shown to have greater biological activity in vitro than other interferons. CIFN was tested in a large, phase 3, multicentre, North American study in patients with chronic hepatitis C. Patients were treated with 9microg CIFN or 3MU interferon (IFN)-alpha-2b 3 times weekly for 6 months. Efficacy was assessed by changes in ALT, decrease in hepatitis C virus (HCV) RNA and improvement in histology. CIFN produced similar overall response rates to those seen with IFNalpha-2b. However, the response rate and decrease in HCV RNA were greater among genotype 1 patients treated with CIFN than among those treated with IFNalpha-2b. Patients with sustained response generally responded early in treatment, with 96% responding by week 12. There was also a better response to CIFN than to IFNalpha-2b in patients with a high baseline viral concentration. Although the majority of CIFN-treated patients had histological improvement in the liver, it is notable that even patients who relapsed or did not respond had histological improvement and thus benefited from CIFN treatment. Viral and histological benefits were similar in patients with and without cirrhosis although ALT levels were not as improved in those with cirrhosis. Patients who relapsed or did not respond to initial treatment with either CIFN or IFNalpha-2b were re-treated with a higher dose of CIFN (15microg). Patients who relapsed had a 58% sustained viral response rate with 12 months of re-treatment. The response to re-treatment with this regimen of CIFN monotherapy is similar to that reported with the standard combination regimen of IFNalpha-2b plus ribavirin and far superior to that observed with 3MU IFNalpha-2b alone. Although prior nonresponders had a lower response rate than relapsers (sustained viral response rate of 13%), it is nonetheless clinically meaningful and clearly superior to the negligible responses among nonresponders reported in previous studies using re-treatment with other interferons. The adverse effects noted with CIFN are similar to those reported for IFNalpha-2b and are recognised adverse effects for all interferons. Thus, CIFN is a unique interferon with enhanced antiviral activity. Providing greater benefit for the difficult-to-treat patients makes CIFN a beneficial alternative in the initial treatment and re-treatment of patients with chronic hepatitis C.