Multicenter randomized study comparing initial daily induction with high dose lymphoblastoid interferon vs. standard interferon treatment for chronic hepatitis C

Efficacy of short-term interferon therapy for patients infected with hepatitis C virus genotype 2a

BACKGROUND AND AIMS

The efficacy of interferon (IFN)-based antiviral therapy for chronic hepatitis C (CHC) varies depending on predictive factors such as hepatitis C virus (HCV) genotype and viral load. For patients with good predictive factors, a low dose and short course of IFN-based therapy may be adequate. However, there is no evidence about the optimal duration of IFN-based therapy for these patients. The aim of this study was to clarify whether the duration of IFN therapy could be shortened to less than the conventional treatment period for patients with good predictive factors.

METHODS

A total of 25 treatment-naive CHC patients with genotype 2a were randomized to receive either IFN monotherapy for 24 wks (group A: long-term IFN therapy, n = 13) or for 6 wks (group B: short-term IFN therapy, n = 12). Patients were monitored for HCV RNA and routine liver function tests during and following treatment, and data were examined according to intention-to-treat analysis.

RESULTS

Eleven of 13 patients in group A and all patients in group B completed IFN therapy according to the original planned schedule. At the end of the treatment, viral clearance occurred in all patients. However, 4 patients in group A and 5 in group B relapsed within 6 months of follow-up. There was no significant difference of sustained response rate between group A (53.8%) and group B (58.3%). Among patients who had HCV viral load of <100 kIU/ml, the sustained response rate was 83.3% (5/6) in group A and 100% (5/5) in group B.

CONCLUSIONS

In this study, our results suggest that the duration of IFN therapy can be shortened to less than 24 wks in patients with good predictive factors. Further studies, however, should examine the optimal regimen of IFN therapy based on the backgrounds of patients.

Antiviral action of ribavirin in chronic hepatitis C

BACKGROUND & AIMS

In the patients with chronic hepatitis C, the addition of ribavirin to interferon (IFN)-alpha significantly increases the virologic responses. Our aim was to assess the antiviral action of ribavirin on hepatitis C virus (HCV) as a function of ribavirin pharmacokinetics and to evaluate the influence of this antiviral effect on IFN-alpha efficacy.

METHODS

Forty-five patients with chronic hepatitis C (genotype 1b) received various schedules of IFN-alpha and/or ribavirin administration. Frequent blood sampling was performed for HCV RNA kinetics and ribavirin pharmacokinetics assessment.

RESULTS

Ribavirin monotherapy induced a significant, moderate, early, and transient viral load decrease in approximately half of the patients. The occurrence of this effect was associated with longer ribavirin clearance half-lives and higher serum ribavirin concentrations. Ribavirin antiviral effect partly reduced the rebound preceding the second IFN-alpha injection in patients receiving standard IFN-alpha 3 times per week plus ribavirin. The magnitude of the rebound was inversely related to ribavirin concentrations. These patients subsequently experienced a slow, but significant, second slope of viral decrease and cleared HCV RNA. The addition of ribavirin to daily IFN-alpha monotherapy did not have any impact on the second phase of viral decline.

CONCLUSIONS

Ribavirin exerts a significant, moderate, and transient antiviral effect in a significant proportion of patients with chronic hepatitis C. The antiviral effect of ribavirin correlates with ribavirin pharmacokinetics and is partly responsible for the improved efficacy of the combination of standard IFN-alpha and ribavirin compared with IFN-alpha monotherapy by increasing the incidence of the initial response.

Interferon-alpha2b induction treatment with or without ribavirin in chronic hepatitis C: a multicenter, randomized, controlled trial

We aimed to compare the efficacy of interferon-alpha2b (IFN) induction treatment in combination with ribavirin to IFN induction alone in chronic hepatitis C. In total, 125 patients (66 male, 59 female, mean age: 48 +/- 9, range: 21-70) were enrolled and randomized into two arms: In the first, patients received 5 MU/day of IFN for 4 weeks followed by 3 MU/day for the next 4 weeks. Treatment was continued with 3 MU three times a week IFN for an additional 40 weeks. Ribavirin was administered 1000-1200 mg/day according to the body weight for the entire 48-week period. In the second arm, patients received placebo in addition to IFN. Fifty-nine patients were placed in the ribavirin arm and 66 in placebo arm. All patients were genotype 1. At week 48, 24/66 (36%) from the placebo and 31/59 (52%) from the ribavirin group responded (P > 0.05). However, during the 24-week untreated follow-up period, 13/24 (54%) from the placebo, and 8/31 (26%) from the ribavirin group relapsed (P = 0.002.), resulting in a sustained virologic response (SVR) rate of 17% in the placebo and 39% in the ribavirin group (P = 0.005.) In conclusion, IFN induction treatment in combination with ribavirin is superior to IFN induction treatment alone in genotype 1 patients, and the SVR rate of 39% is encouraging.

Hepatitis C viral dynamics: basic concept and clinical significance

Viral dynamics is a concept analyzing the time course of treatment-induced changes in blood virion concentration (kinetics) to derive conclusions of where, when and how in the living organism virions are produced or eliminated. Originally applied to human immunodeficiency virus type 1 and hepatitis B virus, it has elucidated mechanisms of antiviral therapy in hepatitis C virus infection as well. This review summarizes key aspects of mathematical modeling as well as important clinical applications, namely induction therapy and prediction of virologic response to treatment. Furthermore, limitations of currently available quantitative assays will be discussed.