1236 MECHANISMS OF ISOLATED UNCONJUGATED HYPERBILIRUBINEMIA INDUCED BY THE HCV NS3/4A PROTEASE INHIBITOR BI201335

POSTERSassay variations in inhibitor susceptibility measurements (IC 50 FC) were defined at <2 and <3-fold, respectively.Using these new assay conditions, the replicons derived from a panel of approximately 50 patient samples all replicated sufficiently to enable phenotypic assessment of polymerase inhibitor susceptibility.Conclusions: A PhenoSense HCV NS5B assay has been developed to support clinical studies of investigational inhibitors that target HCV polymerase.This assay can facilitate phenotypic drug resistance analysis of HCV subtype 1a/b patient virus NS5B populations, clones derived from patient virus populations and SDMs.Optimal assay parameters were identified that significantly increased the proportion of patient samples amenable to phenotypic analysis compared to a prototypic assay.