The safety and tolerability of daily infergen plus ribavirin in the treatment of naíïve chronic hepatitis C patients.

The treatment of chronic hepatitis C patients was enhanced when the combination of interferon alfa-2b and ribavirin was shown to be safe and more effective than interferon monotherapy. To date, no published reports have addressed the use of consensus interferon (CIFN) when combined with ribavirin. We conducted a pilot study to compare the safety and tolerability of daily CIFN plus ribavirin to CIFN monotherapy for the initial treatment of chronic hepatitis C patients. Forty subjects were randomized to two treatment groups; CIFN 9 microg daily, or CIFN 9 microg daily plus ribavirin 1000 or 1200 mg daily. All subjects received 48 weeks of therapy except for nongenotype 1 subjects in the combination treatment group who received only 24 weeks of therapy. The results show that at baseline, age, gender, risk factors, race, RNA titres, and liver histology were not different between the two groups. The proportion of subjects with genotype 1 infection was 50% (10/20) and 55% (11/20) for the monotherapy and combination therapy groups, respectively. Fifty (10/20) and sixty-five (13/20) per cent of subjects in the monotherapy and combination therapy groups exhibited a 2-log or greater decrease in viral titre at week 12 (P = NS). Using intent-to-treat analysis, 20% and 40% of enrolled subjects exhibited a sustained viral response in the monotherapy and combination therapy groups, respectively (P = NS). The proportion of subjects requiring dose reduction was 55% (11/20) and 65% (13/20), respectively. Study discontinuations for any reason were 25% (5/20) and 35% (7/20) for the monotherapy and combination groups, respectively. Discontinuations due to adverse events related to study drug were 20% (4/20) and 25% (5/20), respectively. A total of four serious adverse events occurred, two in each treatment group, only one of which was determined to be study-drug related. It is concluded that the safety and tolerability profiles of the two treatments were similar suggesting that daily dosing of CIFN may be difficult to tolerate resulting in discontinuation of therapy in a significant proportion of patients. The combination regimen resulted in a trend towards a higher viral response rate than monotherapy treatment. These data suggest that CIFN may be safely combined with ribavirin and may enhance the sustained response rate but is not well tolerated in US patients when given in a daily dosing regimen.