A single-arm, open-label, pilot study evaluating the efficacy and safety of directly observed peginterferon alfa-2a with ribavirin in conjunction with a peer counsellor in patients actively using injecting drugs who have chronic hepatitis C and attend a drug and alcohol centre.

Administration of pegylated interferon alfa-2a plus ribavirin combination therapy (Roche PEGASYS (Registered) RBV (Registered) Combination Therapy) to active injecting drug users with chronic Hepatitis C infection (HCV) for a period of 24 to 48 weeks who will be subjected to the following interventions: 1. Directly observed administration of pegylated interferon alfa-2a (to ensure therapy compliance), 2. Ribavirin pill counting and adherence questioning (to monitor therapy compliance), and 3. Peer counsellor assistance (to encourage therapy compliance). Participant visits to the investigator site will be comprised of: one screening visit for eligibility and safety assessments in the 8 weeks prior to treatment initiation, 24 to 48 therapy/study visits for treatment and safety assessments and three follow-up visits at 4, 12 and 24 weeks post-treatment completion for safety assessments. The overall period of intervention will be 56 or 80 weeks for the 24 or 48 week treatment regimens respectively. Participants infected with HCV genotype 2 or 3 who don't have hepatic cirrhosis or bridging fibrosis will be assigned to the 24 week treatment regimen of peginterferon alfa-2a 180 micrograms/week and ribavirin 800 mg/day (unless contraindicated). Participants infected with HCV genotype 2 or 3 who have hepatic cirrhosis or bridging fibrosis or those infected with HCV genotypes other than 2 or 3 will be assigned to the 48 week treatment regimen of peginterferon alfa-2a 180 micrograms/week and ribavirin 1000 or 1200 mg/day (unless contraindicated). PEGASYS (Registered) comes in pre-filled syringes as a sterile, ready-to-use solution. One PEGASYS (Registered) dose of 180 micrograms will be administered by subcutaneous injection into the stomach or thigh area once weekly under direct observation during a study/therapy visit at the investigator site. The duration of the directly observed therapy (DOT) will be equivalent to the time required to prepare and administer the injection. COPEGUS (or RBV; Registered) is available as 200 mg tablets that are dispensed in bottles of 112, 140 or 168 tablets (equivalent to 4 weeks of treatment). Tablets will be self-administered daily in the home as morning and evening doses taken orally with food ( 1 hour prior to or 2 hours after a meal). Participants assigned to the 24 week treatment regimen will take 2 tablets morning and evening (2 x 400 mg = 800 mg/day). Participants assigned to the 48 week treatment regimen who weigh <75 kg will take 2 and 3 tablets in the morning and evening respectively (400 mg + 600 mg = 1000 mg/day), whereas those who weigh >=75 kg will take 3 tablets morning and evening (2 x 600 mg = 1200 mg/day). Therapy compliance for ribavirin will be evaluated via adherence questioning and pill counting every 4 weeks. The essential role of the peer counsellor will be to facilitate HCV therapy compliance by providing participant advocacy and assistance to participants in the management of physical and psychological issues associated with HCV pharmacotherapy and opioid addiction and pharmacotherapy. The peer counsellor will accompany participants to all study visits including screening, baseline, therapy and follow-up visits where the duration of these visits will depend upon the study procedures being performed (30 minutes - 2 hours). In addition to these scheduled visits, participants will have 24 hours/day, 7 days/week access to peer counsellor support where the method, nature, frequency and duration of contact will be determined by the participant in accordance with their needs. The details of these unscheduled interactions will be recorded in a log maintained by the peer counsellor.