SAN FRANCISCO, CAThe 3 direct-acting antiviral (3D) regimen of ombitasvir, paritaprevir (boosted with ritonavir), and dasabuvir, with or without ribavirin, demonstrated long-term efficacy in a broad population of patients with hepatitis C virus (HCV) infected with genotype (GT) 1, results from six Phase 3 studies reported at The Liver Meeting® 2015.

“Relapse beyond SVR12 may occur in <0.5% of patients,” stated Stefan Zeuzem, MD, J.W. Goethe University Hospital, Frankfurt, Germany.

In the studies, patients received ombitasvir 25mg and paritaprevir 150mg (boosted with ritonavir 100mg) once daily and dasabuvir 250mg twice daily with and without weight-based ribavirin for 12 or 24 weeks. Patients with GT1b-infection without cirrhosis did not receive ribavirin.

Following 12 or 24 weeks of treatment with the 3D regimen, 97% of 1,085 treatment-naïve and treatment-experienced patients—66% of whom had HCV GT1a and 17%, cirrhosis—achieved sustained virologic response at 12 weeks (SVR12). Specifically, SVR12 rates were 96% for GT1a without cirrhosis, 95% for GT1a with cirrhosis, 100% for GT1b without cirrhosis, and 99% for GT1b with cirrhosis.

Of the 97% of patients (n=1,054) who achieved SVR12, 1,023 were followed through at least post-treatment Week 48, with the current analysis examining efficacy of the 3D regimen in HCV GT1-infected patients with or without cirrhosis, Dr. Zeuzem noted.

These results showed that “between post-treatment Weeks 12 and 48, phylogenetic analyses confirmed that 4 (0.4%) patients experienced relapse after SVR12 and 1 patient had reinfection; all 5 patients were GT1a-infected,” he stated. Four patients were GT1a without cirrhosis and 1 was GT1a with cirrhosis.

Study authors noted that additional research is needed to identify predictors of late relapse.