Efficacy of Sofosbuvir, Velpatasvir, and GS-9857 in Patients With Hepatitis C Virus Genotype 2, 3, 4, or 6 Infections in an Open-Label, Phase 2 Trial

BACKGROUND & AIMS: Studies are needed to determine the optimal regimen for patients with chronic hepatitis C virus (HCV) genotype 2, 3, 4, or 6 infections whose prior course of antiviral therapy has failed, and the feasibility of shortening treatment duration. We performed a phase 2 study to determine the efficacy and safety of the combination of the nucleotide polymerase inhibitor sofosbuvir, the NS5A inhibitor velpatasvir, and the NS3/4A protease inhibitor GS-9857 in these patients. METHODS: We performed a multicenter, open-label trial at 32 sites in the United States and 2 sites in New Zealand from March 3, 2015 to April 27, 2015. Our study included 128 treatment-naive and treatment-experienced patients (1 with HCV genotype 1b; 33 with HCV genotype 2; 74 with HCV genotype 3; 17 with genotype HCV 4; and 3 with HCV genotype 6), with or without compensated cirrhosis. All patients received sofosbuvir-velpatasvir (400 mg/100 mg fixed-dose combination tablet) and GS-9857 (100 mg) once daily for 6-12 weeks. The primary end point was sustained virologic response 12 weeks after treatment (SVR12). RESULTS: After 6 weeks of treatment, SVR12s were achieved by 88% of treatment-naive patients without cirrhosis (29 of 33; 95% confidence interval, 72%-97%). After 8 weeks of treatment, SVR12s were achieved by 93% of treatment-naive patients with cirrhosis (28 of 30; 95% CI, 78%-99%). After 12 weeks of treatment, SVR12s were achieved by all treatment experienced patients without cirrhosis (36 of 36; 95% CI, 90%-100%) and 97% of treatment-experienced patients with cirrhosis (28 of 29; 95% CI, 82%-100%). The most common adverse events were headache, diarrhea, fatigue, and nausea. Three patients (1%) discontinued treatment due to adverse events. CONCLUSIONS: In a phase 2 open-label trial, we found sofosbuvir-velpatasvir plus GS-9857 (8 weeks in treatment-naive patients or 12 weeks in treatment-experienced patients) to be safe and effective for patients with HCV genotype 2, 3, 4, or 6 infections, with or without compensated cirrhosis.