Peginterferon alfa-2b/Ribavirin(Merck & Co., Inc.)

Hepatitis C is the leading cause of chronic liver disease in industrialized countries, and is the most common indication for liver transplantation. In the Western world, the absolute majority of cases of Hepatitis C Virus (HCV) infection are related to the use of injectable narcotic drugs. Most injecting drug users contract HCV infection within the first years after starting injecting drug use. The aim of this study is to study hepatitis C in a cohort of patients registered in clinics providing maintenance therapy for opiate dependence in three metropolitan areas of Sweden. The cohort is defined as all patients registered in these three clinics at the date of study initiation. The study contains four parts:
Part I: the first part of the study aims to evaluate the prevalence of HCV exposure in the cohort and the proportion of anti-HCV positive participants with chronic infection.
Part II: Patients with chronic HCV infection will be offered further investigation of chronic liver disease, including liver biopsy, for selection of candidates for antiviral therapy and identification of risk factors for development of severe liver disease.
Part III: Based on the results of these investigations, patients will be considered for antiviral therapy. Indications for such therapy will mainly be clinical and/or histological signs of chronic liver disease with fibrosis. All patients will receive weight-based doses of pegylated interferon-alfa-2b and ribavirin.
Part IV: Study of pharmacokinetic interactions between ribavirin and opiate substitution molecule (methadone or buprenorphine) in patients receiving antiviral therapy according to part III.

This is a Phase 3b/4, prospective, open-label, randomized, multicenter study of peginterferon alfa-2b plus ribavirin in participants with chronic hepatitis C, genotype 1. The study consists of two parts: (1) a noninterventional arm (HOMA IR <= 2) and (2) an interventional arm (HOMA IR > 2), where HOMA IR is the insulin resistance index for the participants calculated by fasting insulin (uU/mL) x [fasting glucose (mmol/L)/22.5]. Participants in the noninterventional arm are treated according to the European labeling and response rates are evaluated at Month 1 (optional), 3, 6, 12, and follow up. Participants in the interventional arm are treated with PEG-Intron 1.5 ug/kg (subcutaneous) once weekly plus weight-based REBETOL 800-1400 mg (oral capsules) daily for a variable period depending on their response at Week 12: (1) HCV-RNA positive with < 2-log drop in viral load, treatment will be discontinued; (2) HCV-RNA positive with >= 2-log drop in viral load; participants will be randomized (1:1) to Group A (stop treatment at Week 48) or Group B (stop treatment at Week 72); and (3) HCV-RNA negative, treatment will be changed to be according to the European labeling and response rates will be evaluated at Month 6, 12, and follow up. All participants will go on with their treatment after Week 12 until the results of the HCV polymerase chain reaction (PCR) are available (maximum of 4 weeks).