24 Background : Despite recent advances in hepatitis C virus (HCV) therapeutics, the combination 25 of pegylated interferon (PEGIFN) and ribavirin (RBV) remains the cornerstone of treatment. 26 Optimization and individualization of PEGIFN dosing could improve outcomes. 27 Methods: Week one PEGIFN serum concentrations in 42 HCV genotype 1 infected patients 28 treated with conventional PEGIFN/RBV...