This multicenter, randomized, controlled, double-blind, phase III study in 704 patients with chronic hepatitis C infection compared treatment with consensus interferon (CIFN), a non-natural recombinant type-1 interferon, with a standard regimen of recombinant interferon alfa-2b (IFN-α2b). Patients were randomized to receive CIFN at doses of 3 μg or 9 μg, or 15 μg IFN-α2b (3 million units), subcutaneously three times weekly for 24 weeks, followed by 24 weeks of observation. Efficacy was assessed by normalization of serum alanine transaminase (ALT) concentration and decrease in serum hepatitis C virus (HCV) RNA concentration below the limit of detection by reverse-transcription polymerase chain reaction (RT-PCR) (100 copies/mL). The beneficial effect of CIFN was greater with the 9-μg dose than the 3-μg dose. The sustained ALT and HCV RNA response rates were 20.3% and 12.1%, respectively, in the 9-μg CIFN cohort and 19.6% and 11.3%, respectively, in the 15-μg IFN-α2b cohort. However, patients receiving 9 μg of CIFN had a greater reduction in serum HCV RNA concentrations compared with patients receiving 15 μg IFN-α2b over the course of treatment (P <.01). Similarly, analysis of patients infected with FICV genotype 1 showed a greater reduction in serum HCV RNA concentration over the course of treatment for the 9-μg CIFN group when compared with the 15-μg IFN-α2b group (P < .01). In addition, a greater percentage of patients infected with HCV genotype 1 treated with 9 μg CIFN had undetectable HCV RNA concentrations when compared with patients in the 15-μg IFN-α2b cohort at the end of treatment (24% vs. 15%; P = .04). Improvements in liver histology were noted in all three treatment groups; 52% to 55% of the patients in the three cohorts had at least a 2-unit improvement in the Knodell score at the end of the posttreatment period. The adverse-events profiles were characteristic of treatment with type-1 interferon, and the incidences of anti-interferon antibody formation did not significantly differ among the three treatment groups. These results show that administration of 9 μg CIFN three times weekly for 6 months is safe and is effective in reducing serum HCV RNA concentration.
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