Real-time PCR assays for hepatitis C virus (HCV) RNA quantitation are adequate for clinical management of patients with chronic HCV infection

Abstract

Because of the use of viral kinetics during polyethylene glycol (PEG)-interferon-ribavirin therapy and the development of specific new anti-hepatitis C virus (anti-HCV) drugs, assessment of the efficacy of anti-HCV drugs needs to be based not on end-point PCR assays but on real-time PCR. The aim of this study was to determine if the two available commercial real-time PCR assays, the Abbott RealTime HCV assay and the Roche Cobas TaqMan HCV assay, can become the standard for HCV RNA quantification. We investigated the prognostic relevance of HCV RNA viral loads at baseline, week 4, and week 12 to a rapid and early virological response to antiviral therapy by using the two assays. Of 59 naïve patients chronically infected by HCV (41 infected with genotype 1) who were treated with ribavirin plus PEG-interferon alfa-2b for 48 weeks, 24 patients (41%) showed a sustained virological response (SVR). With the two assays, viral loads were highly correlated, irrespective of genotype (R2=0.94 for all cases). No difference in diagnostic value was found between the Abbott and Roche assays at week 4, with respective negative predictive values (NPVs) of 84% and 78% and positive predictive values (PPVs) of 62% and 56% (not significant), and at week 12, the respective NPVs were 91% and 90% and PPVs were 44% and 46% (not significant). At week 12, 83% (20/24) and 96% (23/24) of patients with SVR tested negative for HCV RNA by the Abbott and Roche assays, respectively (the difference is not significant). In conclusion, the high sensitivities and large dynamic ranges of the Abbott and Roche assays show that a single real-time quantitative PCR assay is fully adequate for clinical and therapeutic management of HCV.

FIG. 1.

Correlation between the results for 59 HCV-infected patients tested by Abbott RealTime HCV and Roche Cobas TaqMan HCV, irrespective of the genotype. Results shows a good correlation between the two assays (R² = 0.94).

FIG. 2.

Correlation between the results for genotype 1 patients tested by the Abbott and Roche assays (R² = 0.94).

FIG. 3.

Correlation between the results for non-genotype 1 patients tested by the Abbott and Roche assays (R² = 0.94).

FIG. 4.

Histograms of median viral loads measured by the Abbott and Roche assays for all genotypes (A), genotype 1 patients (B), and non-genotype 1 patients (C). Bars with dots stand for the Abbott assay, and bars with horizontal lines stand for the Roche assay.

FIG. 5.

Histograms of differences between the Abbott and Roche assays in viral load detection and viral load decline after 4 weeks and 12 weeks of treatment.