ABSTRACT
This first-time-in-human, randomized, double-blind, placebo-controlled, dose-escalation study assessed the safety, tolerability, pharmacokinetics, and antiviral activity of GSK2485852, a hepatitis C virus (HCV) NS5B inhibitor, in 27 chronically infected HCV genotype-1 subjects. Subjects received GSK2485852 70, 420, and 70 mg with a moderate fat/caloric meal. Safety, pharmacokinetics, antiviral activity, HCV genotype/phenotype, and interleukin 28B genotype were evaluated. A statistically significant reduction in HCV ribonucleic acid (RNA) was observed after a single dose of 420 mg GSK2485852 (-1.33 log10 IU/mL) compared with placebo (-0.09 log10 IU/mL) at 24 hours post-dose. Subjects receiving 70 mg GSK2485852 were exposed to concentrations above the protein-adjusted 90% effective concentration for a short time; none experienced a significant decline in HCV RNA (-0.47 log10 copies/mL). GSK2485852 was readily absorbed; however, the observed geometric mean maximum plasma concentration (Cmax ) and area under the curve (AUC) values were significantly lower than expected due to a higher-than-predicted-oral clearance. Co-administration with food reduced the AUC and Cmax of GSK2485852 by 40% and 70%, respectively. Two metabolites were detected in human blood with one having approximately 50% higher concentrations than those of the parent. GSK2485852 was well-tolerated and exhibited antiviral activity after a single 420 mg dose in HCV subjects.
