Clinical trial: pharmacodynamics and pharmacokinetics of re-treatment with fixed-dose induction of peginterferon alpha-2a in hepatitis C virus genotype 1 true non-responder patients.

Background: Patients infected with hepatitis C virus genotype 1 who are true non-responders to previous therapy suffer from a very difficult-to-cure disease. New approaches to treatment are necessary.
Aim: To explore the efficacy, pharmacokinetics and safety of fixed-dose induction with peginterferon alpha-2a and ribavirin in this difficult-to-cure population.
Methods: Seventy-five hepatitis C virus genotype 1 true non-responder patients to a previous interferon-based combination regimen were randomised to receive peginterferon alpha-2a 360, 270 or 180 microg/week for 12 weeks, followed by 180 microg/week for 36 weeks, in combination with ribavirin (1000/1200 mg/day). Peginterferon alpha-2a concentration was measured throughout the study.
Results: Sustained virological response rates were 38%, 30% and 18%, in the 360, 270 and 180 microg/week groups, respectively (relapse rates: 25%, 50% and 64%, respectively). The area under the serum concentration-time curve of peginterferon alpha-2a from 0-12 weeks increased in a dose-dependent manner (P < 0.0001) and was associated with the sustained virological response (odds ratio: 1.35; 95% CI: 0.89, 2.06). The three regimens were equally well tolerated.
Conclusion: Fixed-dose induction of peginterferon alpha-2a resulted in increased drug exposure and improved the likelihood of achieving a cure, without compromising safety in hepatitis C virus genotype 1 true non-responder patients.