The investigational compound GS 9190 is being evaluated in a two-part Phase I study of treatment-naive patients infected with HCV genotype 1. In the first part of the study (Part A), a single dose of GS 9190 demonstrated encouraging pharmacokinetics and antiviral activity. The second, multiple dose part of the study (Part B) is designed to enroll 60 HCV infected patients in total, and assess the safety, tolerability, pharmacokinetics and antiviral activity of ascending doses of GS 9190, once or twice daily, for eight days.
Part A of the study (n=31) evaluated escalating single doses of GS 9190 compared to placebo in five successive cohorts: 40mg, 120mg, 240mg, 240mg (dosed with food) and 480mg. At baseline, participants in Part A had a mean age of 44 years, were predominantly white males, and had a median HCV RNA of 6.56 log10 IU/mL.
All single doses of GS 9190 demonstrated antiviral activity. The compound showed greatest effect 24 hours after administration, at which time the change in HCV RNA log10 copies/mL compared to baseline ranged from approximately -0.7 to -1.2 versus essentially no change for the placebo arm. Across cohorts, the median half-life of GS 9190 was 10-15 hours, supporting potential once or twice daily administration of the compound in future studies. GS 9190 pharmacokinetics were dose proportional following single-dose administration over the range of 40mg to 240mg.