Hepatitis C RNA assay differences in results: Potential implications for shortened therapy and determination of Sustained Virologic Response.

Cloherty, Gavin; Chevaliez, Stephane; Sarrazin, Christoph; Herman, Christine; Holzmayer, Vera; Dawson, George; Maasoumy, Benjamin; Vermehren, Johannes; Wedemeyer, Heiner; Feld, Jordan J; Pawlotsky, Jean-Michel

Approval of Ledipasvir/Sofosbuvir for the treatment of chronic hepatitis C (HCV) includes the truncation of therapy from 12 to 8 weeks in treatment naïve, non-cirrhotic patients with baseline HCV RNA levels <6 million IU/mL (6.8 log10 IU/mL). The aim of this study was to evaluate this clinical cutoff with a different widely used commercially available HCV RNA test. Results from samples tested prospectively with Roche High Pure TaqMan HCV 2.0 test (HPS) were compared to those tested retrospectively with the Abbott RealTime HCV RNA test (ART). Using 6 million IU/mL as the cut-off, pre-treatment results were concordant in 70.4% of cases. When results with the same test measured at screening and baseline, clinical decisions could be impacted in 14.4% and 6.2% of cases for HPS and ART respectively. Using only HCV RNA cutoff of 6 million IU/mL, 29.55% of subjects would receive a different and potentially incorrect treatment duration based solely on HCV RNA test method used. A further 6-14% of subjects would have treatment decision change based on the day the sample was taken.