Open-label phase 2 study of faldaprevir, deleobuvir and ribavirin in Japanese treatment-naive patients with chronic hepatitis C virus genotype 1 infection.

Aim: The safety and efficacy of the NS3/4A protease inhibitor faldaprevir in combination with the non-nucleoside NS5B polymerase inhibitor deleobuvir and ribavirin in Japanese treatment-naive patients with chronic genotype 1 hepatitis C virus (HCV) infection was evaluated.

Methods: In this multicenter, open-label phase 2 study, patients were assigned to 8 weeks of treatment with 80 mg (group 1) or 120 mg (group 2) faldaprevir once daily (q.d.) in combination with deleobuvir 600 mg twice daily and weight-based ribavirin. This was followed by a 24-week treatment with faldaprevir 120 mg q.d. in combination with peginterferon-α-2a and ribavirin. The primary objective was safety; virological response at weeks 4 and 8 was a secondary endpoint.

Results: Twelve and 13 patients were treated in group 1 and 2, respectively; all were infected with HCV genotype 1b. All patients experienced a drug-related adverse event (AE). The frequency of individual events was generally numerically greater in group 2 than 1. The most common AEs were nausea (66.7%, group 1; 76.9%, group 2) and vomiting (33.3%, group 1; 61.5%, group 2). Virological response at weeks 4 and 8 was achieved by 11 (91.7%) patients in group 1; in group 2, 12 (92.3%) patients achieved virological response at week 4 and all at week 8. All patients who achieved the week 8 endpoint achieved sustained virological response at week 12.

Conclusion: Faldaprevir 80 or 120 mg q.d. in combination with deleobuvir and ribavirin was tolerable and had similar efficacy in Japanese patients with HCV genotype 1 infection. ClinicalTrials.gov: NCT01528735.