Randomized Trial of Interferon- and Ribavirin-Free Ombitasvir/Paritaprevir/Ritonavir in Treatment-Experienced Hepatitis C Virus-Infected Patients

Approximately 2 million Japanese individuals are infected with hepatitis C virus and are at risk for cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Patients in whom interferon (IFN)/ribavirin (RBV) therapy has failed remain at risk as effective therapeutic options are limited. This phase 2, randomized, open-label study evaluated an IFN- and RBV-free regimen of once-daily ombitasvir (ABT-267), an NS5A inhibitor, plus paritaprevir (ABT-450), an NS3/4A protease inhibitor dosed with ritonavir (paritaprevir/ritonavir), in pegylated IFN/RBV treatment-experienced Japanese patients with hepatitis C virus subtype 1b or genotype 2 infection. Patients without cirrhosis (aged 18-75 years) with subtype 1b infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 or 24 weeks; patients with genotype 2 infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 weeks. Sustained virologic response (SVR) at posttreatment week 24 (SVR24) was the primary endpoint. Adverse events were collected throughout the study. One hundred ten patients received 1 dose of study medication. In the subtype 1b cohort, SVR24 rates were high (88.9%-100%) regardless of paritaprevir dose or treatment duration. In the genotype 2 cohort, SVR24 rates were 57.9% and 72.2% with 100 mg and 150 mg of paritaprevir, respectively. The SVR24 rate was higher in patients with subtype 2a (90%) than 2b (27%). Concordance between SVR12 and SVR24 was 100%. The most common adverse events overall were nasopharyngitis (29%) and headache (14%). Conclusion: In this difficult-to-treat population of patients in whom prior pegylated IFN/RBV had failed, ombitasvir/paritaprevir/ritonavir demonstrated potent antiviral activity with a favorable safety profile among Japanese patients with hepatitis C virus genotype 1b or 2a infection. (Hepatology 2015;61:1523-1532)