Standard population-based sequencing of the HCV NS3/4A MK-1775 price protease domain was performed on baseline samples to determine the presence of naturally occurring baseline polymorphisms, including Q80K, and those from selected time points (based on HCV-RNA changes). Standard HCV genotyping assays, the Siemens Versant HCV LiPA v2 assay (Siemens

Healthcare Diagnostics, Tarrytown, NY) or, if that failed, the Trugene 5′NC genotyping assay, were used to determine HCV genotype 1 subtype at screening. In addition, HCV genotype/subtype was determined at baseline using an NS5B sequence-based assay. The results of the NS5B-based assay were used for study analyses. Determination ABT-199 in vitro of the patients’ IL28B genotype (SNP rs12979860) was performed on human genomic DNA by a real-time polymerase chain reaction on the ABI 7900HT platform. AEs were monitored throughout the study. During study visits, patients completed questionnaires

to document changes in fatigue severity (Fatigue Severity Scale),35 as well as productivity and daily activity impairment and work absenteeism (Work Productivity and Activity Impairment questionnaire for Hepatitis C).36 Additional details are provided in the Supplementary Materials and Methods section. This primary analysis was performed when all randomized and treated subjects had completed the week 60 visit or discontinued Silibinin earlier. All analyses were performed on the intent-to-treat population, which comprised all subjects who received at least one dose of simeprevir or placebo. The primary study end point was the proportion of patients achieving SVR (HCV RNA <25 IU/mL undetectable at actual EOT and HCV RNA <25 IU/mL) 12 weeks after planned EOT (SVR12). SVR12 rates in the 2 groups were compared using the Cochran–Mantel–Haenszel test controlling for stratification factors (HCV 1 subtype and IL28B genotype). A Breslow–Day test for homogeneity of odds ratios based on this model also was performed and the 95% confidence

interval (CI) was constructed around each response rate. Phase 3 data for telaprevir and boceprevir show a strong correlation between SVR12 and SVR at 24 weeks after planned EOT (SVR24). Similarly, a good correlation also was observed in phase 2b studies with simeprevir. Sample size calculation based on SVR24 rates therefore was regarded as applicable for SVR12. Based on published data, 37 the SVR24 rate in the placebo group was expected to be approximately 20%. It was calculated that 250 patients in the simeprevir group and 125 patients in the placebo group were needed to provide more than 90% power to detect a significant difference between the 2 treatment groups with a 5% significance level (2-sided).