Treatment of chronic hepatitis C in patients with drug dependence: time to change the rules?

AIMS: Approximately 170 million people world-wide are chronically infected with the hepatitis C virus (HCV). While the seroprevalence in the general population ranges between 0.2 and 2%, 50-90% of injection drug users are chronically HCV-infected. However, most patients who are drug abusers are still excluded from treatment of chronic HCV infection with interferon (IFN)-alpha. Due to the recent treatment advances resulting in sustained response rates between 50 and 80%, it becomes increasingly important to reflect the still existing contraindications and restrictions for IFN-alpha treatment, especially for patients with intravenous drug use (IDU) with or without psychiatric comorbidity.
METHODS: We reviewed clinical trials that focus on the treatment of chronic hepatitis C in patients with drug addiction published between 1987 and 2003.
FINDINGS: Only seven clinical trials investigating HCV treatment among drug users were found: four open prospective uncontrolled trials and three controlled trials. Thus far, no trials using pegylated IFN-alpha have been conducted. Data about sustained response and adherence in HCV-infected methadone substituted patients were either comparable to control groups or to representative clinically controlled trials using the same treatment regimen (IFN-alpha monotherapy or combined with ribavirin). Patients with former or present drug abuse seem more likely to discontinue treatment early. HCV-infected IDUs tended to be older with higher inflammatory activity and stage of fibrosis when interferon treatment was started. Psychiatric comorbidity did not negatively influence adherence or treatment outcome.
CONCLUSIONS: There is no clinical evidence suggesting that HCV treatment with IFN-alpha should be limited to IDUs or methadone substituted patients. However, more prospective controlled trials on HCV treatment for patients with IDU are needed to establish and apply new rules and guidelines.