ABSTRACT
BACKGROUND & AIMS: Hepatitis C virus (HCV)-infected patients with a history of injection drug use have low rates of initiation and completion of interferon-based therapies. This study evaluated efficacy, safety, and pharmacokinetics of a 12-week all-oral regimen of ombitasvir/paritaprevir/ritonavir and dasabuvir+ribavirin in HCV genotype 1-infected patients on stable opioid replacement therapy. METHODS: This was a phase II, multicenter, open-label, single-arm study in treatment-naïve or peginterferon/ribavirin treatment-experienced HCV genotype 1-infected patients on methadone or buprenorphine±naloxone. Patients received 12weeks of co-formulated ombitasvir/paritaprevir/ritonavir (25mg/150mg/100mg once daily) and dasabuvir (250mg twice daily)+weight-based ribavirin. The primary efficacy endpoint was sustained virologic response 12 weeks post-treatment. RESULTS: Thirty-eight non-cirrhotic patients on chronic methadone (n=19) or buprenorphine (n=19) were enrolled. A total of 37 patients (97.4%) had a sustained virologic response 12 weeks post-treatment. No patient had a viral breakthrough or relapse. One patient discontinued due to serious adverse events unrelated to study drug (cerebrovascular accident and sarcoma). The most frequent adverse events were nausea, fatigue, and headache. Eight patients had on-treatment hemoglobin concentrations <10g/dl. Pharmacokinetic analyses indicated no clinically meaningful impact of methadone or buprenorphine on ombitasvir, paritaprevir, ritonavir, dasabuvir, or dasabuvir M1 metabolite exposures. No dose adjustments of methadone or buprenorphine were required. CONCLUSIONS: The interferon-free regimen of ombitasvir/paritaprevir/ritonavir and dasabuvir+ribavirin for 12weeks was well tolerated and achieved sustained virologic response in 97.4% of patients on opioid substitution therapy in this study. This all-oral regimen may provide an effective alternative to interferon-based therapies for HCV-infected patients with a history of injection drug use.
