Second generation amplicor-HCV monitor assay: clinical features and predictors of the response to interferon

The aims of this study were to compare the amplicor-HCV monitor assay versi ons 1.0 and 2.0, and to investigate the clinical usefulness of this assay i n patients with chronic hepatitis C. We retrospectively analyzed 154 patien ts, and 133 of these patients received interferon therapy. Sixty-nine patie nts were complete responders (CR), and 64 were non-responders. Serum HCV RN A levels of version 1.0 and version 2.0 and HCV genotypes were determined i n all patients. There was a good correlation between versions 1.0 and 2.0 i n both genotype Ib and 2a, 2b (r = 0.907 and 0.726, respectively). In genot ype Ib, the mean HCV RNA level obtained by version 1.0 was 384 +/- 547 kcop ies/ml and that obtained by version 2.0 was 488 +/- 825 kI.U./ml. In genoty pe 2a/2b, the mean level obtained by version 1.0 was 170 +/- 369 kcopies/ml and that obtained by version 2.0 was 340+/-402 kI.U./ml. Discriminant anal ysis revealed that the discriminating points of IFN response were 168 kcopi es/ml (genotype Ib, version 1.0), 106 kcopies/ml (genotype 2a and 2b, versi on 1.0), 102 kI.U./ml (genotype Ib, version 2.0), and 277 kI.U./ml (genotyp e 2a and 2b, version 2.0. When the patients were stratified according to th e discriminating points, the CR rate below the discriminating points were 7 3.8 and 86.2% in versions 1.0 and 2.0, respectively, in genotype Ib, and th e rates were 73.2 and 82.3% in genotype 2a/2b. In addition, receiver-operat ing characteristic analysis revealed that version 2.0 had significantly bet ter discriminative ability in patients with genotype 1b. We conclude that t he second version of the amplicor-HCV monitor assay measures HCV RNA levels with the same precision as version 1.0 and is more useful for the predicti on of interferon response than version 1.0. (C) 2000 Elsevier Science Irela nd Ltd. All rights reserved.