Real-Time PCR Assays for the Quantification of HCV RNA: Concordance, Discrepancies and Implications for Response Guided Therapy.
OBJECTIVE
Monitoring of chronic Hepatitis C (CHC) treatment relies on HCV RNA quantification by means of real-time PCR methods. Assay specific analytical sensitivities may impact therapy management.


METHODS
Comparative analysis between three commercial assays (Roche COBAS AmpliPrep/COBAS TaqMan Version 1 (CAP/CTM Ver. 1), Version 2 (CAP/CTM Ver. 2) and the Abbott RealTime HCV (ART) assay) was performed on 247 available samples taken at key decision time points during antiviral therapy of 105 genotype 1 patients (triple therapy: n = 70; dual therapy: n = 35).


RESULTS
Overall concordance of HCV RNA measurements was high between the two Roche systems (89%; n = 220/247) but lower between the Roche assays and the ART (CAP/CTM Ver. 1 vs ART: 77.3%; n = 191/247 and CAP/CTM v.2 vs ART: 80.1%; n = 198/247). Most discrepancies were noted in week 4/8 samples with residual viremia (<LLOQ) detected by ART (<LLOQ: n = 45, 44.1%) but undetectable HCV RNA by CAP/CTM Ver. 1 (<LLOQ: n = 18, 17.6%) or CAP/CTM Ver. 2 (<LLOQ: n = 26, 25.5%). Based on results by CAP/CTM Ver. 1, 13 eligible patients underwent an abbreviated course of therapy (24 weeks). Only 1 patient experienced virologic breakthrough. If tested by ART, only 6/13 patients (46.2%) would have been eligible for shortened treatment. Consequently, RGT guidelines were adapted and shortening of therapy was allowed if residual viremia was detected by ART at week 4/8.


CONCLUSIONS
An abbreviated course of treatment can safely be applied in patients with residual viremia (<LLOQ) detected by ART in samples collected at week 4/8 of treatment.
Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria.
Robert
R
Strassl
Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria.
Karoline
K
Rutter
Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria.
Albert Friedrich
AF
Stättermayer
Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria.
Sandra
S
Beinhardt
Center for Medical Statistics, Informatics, and Intelligent Systems (CeMSIIS), Medical University of Vienna, Vienna, Austria.
Michael
M
Kammer
Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria.
Harald
H
Hofer
Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria.
Peter
P
Ferenci
Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria.
Theresia
T
Popow-Kraupp
D005260:Female; D019698:Hepatitis C, Chronic / Q000097:blood* / Q000188:drug therapy; D006801:Humans; D008297:Male; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods*; D012367:RNA, Viral / Q000097:blood*; D060888:Real-Time Polymerase Chain Reaction / Q000295:instrumentation* / Q000379:methods*
D012367:RNA, Viral