Abbott RealTime Hepatitis C Virus (HCV) and Roche Cobas AmpliPrep/Cobas TaqMan HCV Assays for Prediction of Sustained Virological Response to Pegylated Interferon and Ribavirin in Chronic Hepatitis C Patients

Abstract

Two commercial real-time PCR assays are currently available for sensitive hepatitis C virus (HCV) RNA quantification: the Abbott RealTime HCV assay (ART) and Roche Cobas AmpliPrep/Cobas TaqMan HCV assay (CAP/CTM). We assessed whether the two real-time PCR assays were more effective than Roche Cobas Amplicor HCV Monitor test, v.2.0 (CAM) for prediction of the sustained virological response (SVR) to pegylated interferon (PEG-IFN) plus ribavirin (RBV) in chronic hepatitis C. Sixty patients chronically infected with HCV genotype 1b (37 males and 23 females, 53 ؎ 12 years of age) were treated with PEG-IFN␣2b plus RBV for 48 weeks. Stored specimens at nine time points for each patient (at baseline, on treatment, and 24 weeks after treatment) were tested by the two real-time PCR assays and CAM. Twenty-six (43.3%) patients reached SVR. The positive predictive values (PPVs) for SVR of undetectable HCV RNA at week 12 by CAM, ART, and CAP/CTM were 74.3%, 88.0%, and 95.2%, respectively. An undetectable HCV RNA level by CAM, ART, and CAP/CTM correctly predicted SVR at week 4 in 100%, 100%, and 100% of patients, at weeks 5 to 8 in 91.7%, 100%, and 100% of patients, at weeks 9 to 12 in 55.6%, 75%, and 87.5% of patients, and at weeks 13 to 24 in 0%, 26.7%, and 40% of patients, respectively. Of 16 patients who relapsed after treatment, HCV RNA was detectable in 2 patients at the end of treatment by CAP/CTM but undetectable by ART and CAM. HCV RNA tests using ART and CAP/CTM are considered to be more effective at predicting SVR than CAM, and the PPV for SVR was slightly higher in CAP/CTM than in ART.The quantification of hepatitis C virus (HCV) RNA is essential for the management of chronic hepatitis C therapy based on the combination of pegylated interferon (PEG-IFN) and ribavirin (RBV). Based on pivotal trials in large multicenter studies, positive and negative predictions of sustained virological response (SVR) using viral load kinetics have been established and are now used for recommendations on antiviral therapy management by the American and European international consensus conferences (6, 9, 17). Initially, the effectiveness of antiviral therapy had been controlled by HCV RNA tests using end-point PCR assays sensitive to a level of 50 to 100 IU/ml, according to the Roche Cobas Amplicor HCV Monitor test, v.2.0 (CAM; Roche Molecular Systems, Inc., Pleasanton, CA). Recently, two novel commercial real-time PCR assays became available for highly sensitive HCV RNA quantification: the Abbott RealTime HCV assay (ART; Abbott Molecular, Inc., Des Plaines, IL) and the Roche Cobas AmpliPrep/Cobas TaqMan HCV assay (CAP/CTM; Roche Molecular Systems, Inc., Pleasanton, CA). The reported sensitivity of these real-time PCR assays is higher than that of CAM, they are reportedly not prone to carryover contamination, and they have a consistently wider dynamic range of quantification, which makes them particularly useful for quantifying the full range of viral genome levels observed in treated and untreated patients. Real-time PCR is rapidly r...

Strong Correlation between Liver and Serum Levels of Hepatitis C Virus Core Antigen and RNA in Chronically Infected Patients

“…Therefore, assays of the HCV RNA load in serum or plasma have become essential for confirming active infections and guiding the initiation and continuation of treatment with pegylated interferon and ribavirin or other antivirals. At present, real-time PCR is the benchmark technique for detecting and quantitating HCV RNA in clinical practice, with limits of detection of 10 to 15 IU/ml (4,7,15). However, these assays require high levels of technical skill and are labor-intensive in routine use.…”

Abbott RealTime PCR assay is useful for evaluating virological response to antiviral treatment for chronic hepatitis C

“…These results indicate that ART is more useful than CAM for the prediction of SVR when patients have rapid declines of HCV RNA levels during the early phase of treatment. The reasons for this are that ART is an advanced quantitative assay based on the real-time PCR method, it is more sensitive, and has a broader range of determination than conventional methods [20,[27][28][29]. The lower limit of detection of ART is 12 IU/ml and the range of measurement is from 1.08 to 8.0 log IU/ml, but the detection limit of CAM is 500 IU/ml and the range of CAM is 2.7 to 6.7 log IU/ml.…”

Hepatitis C Assays: The Pitfalls of Polymerase Chain Reaction and Genotyping

“…One study examining the potential benefits of real-time versus traditional PCR found higher positive predictive values (PPVs) for subsequent sustained viral response when assessing for undetectable virus at weeks 4 and 12. The combined PPV for sustained viral response for the two real-time PCR assays with undetectable virus at week 12 was 94%, versus only 74% for those with undetectable virus by traditional PCR [24]. An additional assay called transcription-mediated amplification (TMA) is a qualitative test that reports a LLOD as low at 5 IU/mL.…”