Clinical significance of residual viremia detected by two real-time PCR assays for response-guided therapy of HCV genotype 1 infection

Background & Aims The duration of current standard dual and protease inhibitor-based triple therapies for chronic hepatitis C is determined by assessment of early viral kinetics. Little is known about differences between HCV RNA assays for the use in response guided therapy. Methods HCV RNA was assessed by two widely used real-time PCR-based assays, Cobas Ampliprep/Cobas TaqMan (CAP), and Real-Time HCV (ART) in 903 samples of hepatitis C genotype 1 patients treated with dual (n = 169) or telaprevir-based triple therapy (n = 164) in three European countries. Results Overall, CAP and ART were in excellent agreement for the determination of HCV-RNA concentrations (mean difference 0.21 log₁₀ IU/ml). For treatment-naïve patients treated with peginterferon-alfa and ribavirin a lower rate of undetectable HCV-RNA at week 4 (RVR) was observed for ART (9%) vs. CAP (16%). Although 11/27 (41%) of patients with shortened treatment (24 weeks) had detectable HCV-RNA