Clinical performances of two real-time PCR assays and bDNA/TMA to early monitor treatment outcome in patients with chronic hepatitis C

Differences between quantification of genotype 3 hepatitis C virus RNA by Versions 1.0 and 2.0 of the COBAS AmpliPrep/COBAS TaqMan HCV Test

Background:

Differences between the designs of hepatitis C virus (HCV) viral load assays can result in genotype-related variability in RNA quantification. We tested paired aliquots of plasma specimens from HCV-infected individuals using two versions (v1.0 and v2.0) of the Roche COBAS AmpliPrep/COBAS TaqMan HCV Test (CAP/CTM HCV) and noted variability between results for a subset of specimens; we then sought to determine whether discrepant results were more prevalent among specific HCV genotypes.

Methods:

Archived and prospectively-collected plasma samples from 114 unique patients were tested using CAP/CTM HCV v1.0 and v2.0. The HCV genotype result for each patient was determined by retrospectively reviewing laboratory records.

Results:

All (46/46) specimens with quantifiable viral loads from patients with genotype 1 or 2 infection had CAP/CTM HCV v1.0 and v2.0 results that were within 0.5 log

Conclusions:

In patients infected with HCV genotype 3, sequential CAP/CTM HCV viral load results should be compared with caution and interpreted in the context of the specific assay version used.

Rapid virological response assessment by Abbott RealTime hepatitis C virus assay for predicting sustained virological responses in patients with hepatitis C virus genotype 1 treated with pegylated-interferon and ribavirin

The lower limits of virus detection of hepatitis C virus (HCV) RNA detection assays are continuously improving. We aimed to assess the utility of more precise definition of 4(th) week viral load [rapid virological response (RVR)] in predicting sustained virological response (SVR) in HCV genotype 1 patients treated with pegylated-interferon (PEG-IFN) and ribavirin. Clinical data of treatment-naïve HCV genotype 1 patients were retrospectively collected from 2009 to 2014. Patients were grouped according to 4(th) week viral load as follows: undetectable (n = 90) and detectable but not quantifiable (< 12 IU/mL, n = 27). All patients received PEG-IFNα-2a or -2b and ribavirin for 24 weeks. Serum HCV RNA levels were measured by Abbott RealTime (ART; Abbott Molecular, Abbott Park, IL, USA) HCV assay. SVR was 95.5% and 63% in the undetectable group and < 12 IU/mL group of 4(th) week viral load, respectively. The between-group difference in SVR was significant (p < 0.001). We determined 4(th) week viral load was independently associated with SVR (odds ratio = 19.28; p = 0.002) and a good predictor of SVR [area under the curve (AUC) = 0.775; p = 0.001]. ART HCV assays had a stronger SVR predictive value in HCV genotype 1 patients, indicating that only the undetectable group of 4(th) week viral load patients measured by ART HCV assay should be considered for shorter treatment time (24 weeks) with PEG-IFN and ribavirin.

The Usefulness of Defining Rapid Virological Response by a Very Sensitive Assay (TMA) during Treatment of HCV Genotype 2/3 Infection

The aim of this study was to determine in patients with HCV genotype 2 or 3 the performance at week 4 of two assays with different sensitivities for HCV RNA detection, for the prediction of SVR and stratification for treatment duration (14 and 24 weeks). Recruitment was from two trials comparing 14 and 24 weeks treatment to patients with rapid virological response (RVR) (n = 550). RVR was originally defined as HCV RNA <50 IU/ml at week 4. Patients with an available frozen plasma sample drawn at week 4 and with follow-up data week 24 post-treatment were included (n = 429). HCV-RNA was prospectively measured with COBAS Amplicor V2, Roche (CA) (lower detection limit 50 IU/ml) and retrospectively assessed with VERSANT HCV-RNA Qualitative Assay, Siemens (TMA) (lower limit detection 10 IU/ml). Genotype 3 was present in 80% and genotype 2 in 20%. A SVR was achieved in 82%. At week 4 HCV-RNA was undetectable in 74.8% and 63% of serum samples tested with CA and TMA, respectively. CA undetectable/TMA positive was observed in 61/341 (18%) of the samples. In genotype 3 patients a relapse was seen in 9% of the patients with both CA and TMA undetectable and in 25% of the patients who were CA undetectable/TMA positive (p = 0.006). In patients allocated to 14 weeks treatment a relapse was observed in 11% of TMA undetectable patients and 26% of TMA positive (p = 0.031). In genotype 2 patients treated for 14 weeks relapse was observed in 6% of the patients with both CA and TMA undetectable week 4. Assays with high sensitivity for HCV RNA identifies patients at week 4 with high risk of virological relapse. We recommend that patients with genotype 3 and detectable HCV RNA at levels below 50 IU/ml do not receive truncated therapy with pegIFN and ribavirin.

Real-Time PCR Assays for the Quantification of HCV RNA: Concordance, Discrepancies and Implications for Response Guided Therapy

BACKGROUND AND AIMS

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 (

CONCLUSION

An abbreviated course of treatment can safely be applied in patients with residual viremia ( Collapse

Key Words Collapse

MESH Headings

• Female
• Hepatitis C, Chronic/blood
• Hepatitis C, Chronic/drug therapy
• Humans
• Male
• Monitoring, Physiologic/instrumentation
• Monitoring, Physiologic/methods
• RNA, Viral/blood
• Real-Time Polymerase Chain Reaction/instrumentation
• Real-Time Polymerase Chain Reaction/methods

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Grants Collapse

Affiliation(s)

Robert Strassl Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria
Karoline Rutter Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Albert Friedrich Stättermayer Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Sandra Beinhardt Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Michael Kammer Center for Medical Statistics, Informatics, and Intelligent Systems (CeMSIIS), Medical University of Vienna, Vienna, Austria
Harald Hofer Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Peter Ferenci Department of Internal Medicine III, Division of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Vienna, Austria
Theresia Popow-Kraupp Department of Laboratory Medicine, Division of Clinical Virology, Medical University of Vienna, Vienna, Austria

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Tools for the diagnosis of hepatitis C virus infection and hepatic fibrosis staging

Hepatitis C virus (HCV) infection represents a major public health issue. Hepatitis C can be cured by therapy, but many infected individuals are unaware of their status. Effective HCV screening, fast diagnosis and characterization, and hepatic fibrosis staging are highly relevant for controlling transmission, treating infected patients and, consequently, avoiding end-stage liver disease. Exposure to HCV can be determined with high sensitivity and specificity with currently available third generation serology assays. Additionally, the use of point-of-care tests can increase HCV screening opportunities. However, active HCV infection must be confirmed by direct diagnosis methods. Additionally, HCV genotyping is required prior to starting any treatment. Increasingly, high-volume clinical laboratories use different types of automated platforms, which have simplified sample processing, reduced hands-on-time, minimized contamination risks and human error and ensured full traceability of results. Significant advances have also been made in the field of fibrosis stage assessment with the development of non-invasive methods, such as imaging techniques and serum-based tests. However, no single test is currently available that is able to completely replace liver biopsy. This review focuses on approved commercial tools used to diagnose HCV infection and the recommended hepatic fibrosis staging tests.

Closing in on the target: sustained virologic response in hepatitis C virus genotype 1 infection response-guided therapy

Retrospective analyses of the boceprevir and telaprevir phase 3 trial data demonstrate the clinical relevance of detected but not quantifiable hepatitis C virus (HCV) genotype 1 RNA during treatment. These analyses illustrate the importance of using precise and standard terminology in reporting low-level HCV RNA results for consistent data collection across clinical trials, and to ensure optimal virologic response-guided treatment decision making in clinical practice. In the context of currently available quantitative HCV RNA assays, we clarify that unquantifiable HCV RNA should be classified as target detected or target not detected, as both have been shown to reflect clinically different qualitative HCV RNA levels during treatment. Additionally, use of terms such as "undetectable" or "below limit of detection" should be avoided as such terms are imprecise, not consistently defined, and often misinterpreted.

Patterns of HCV-RNA and HCV core antigen in the early monitoring of standard treatment for chronic hepatitis C

BACKGROUND

An early drop of HCV-RNA levels is useful in assessing response to antiviral treatment in chronic hepatitis C; the first recommended time point is 4 weeks after the start of therapy.

OBJECTIVES

We evaluated retrospectively HCV-RNA and HCVAg levels at different time points to assess the clinical value of an early monitoring.

STUDY DESIGN

Thirty-five patients with chronic hepatitis C infected by genotype 1b and consecutively enrolled in an open-label study on PegIFN plus Ribavirin and/or ketoprofene were tested for HCV-RNA (real-time PCR) and HCVAg (ARCHITECT) at baseline and after 1 and 2 days and 1, 2, 4 and 12 weeks after the start of treatment. Treatment response was assessed according to the EASL consensus criteria.

RESULTS

In the 17 sustained responders (SR) the median log decrease of HCV-RNA and HCVAg at the different time points was 0.40 and 0.37; 1.36 and 0.84; 1.47 and 0.97; 2.34 and 1.86; 2.51 and 2.32; 3.28 and 2.61, respectively. The best time point to predict SR was 2 weeks after the start of therapy, with a sensitivity, specificity and overall accuracy of 76.9%, 86.7% and 82.1% for HCV-RNA and 81.8%, 75.0% and 76.8% for HCVAg, respectively.

DISCUSSION

An early monitoring is at least equally effective than standard monitoring in predicting response to hepatitis C therapy. The similarity of HCV-RNA and HCVAg kinetics suggests that HCVAg may be useful in the early phases as a trigger to evaluate HCV-RNA levels at earlier time points for a personalized approach to therapy monitoring.

Occult infection with hepatitis C virus: friend or foe?

Hepatitis C virus (HCV) infection is a global pandemic associated with a growing disease burden due to cirrhosis and the consequent morbidity and mortality. Transmission is largely via blood-to-blood contact. Following primary infection, a minority of individuals clear the infection predominantly via cellular immune mechanisms, whereas the majority become chronically infected. Recent data suggest that a third outcome may also be possible, termed 'occult' infection in which subjects who are known, or suspected to have previously been infected with HCV, no longer have viral RNA in their serum at levels detectable by sensitive commercial assays, but do have virus detected by ultra-sensitive techniques. Occult infection has also been detected in peripheral blood mononuclear cells, which may indicate an extra-hepatic reservoir of the virus. Although the clinical significance of occult infection remains unknown, most authors have raised concerns of recrudescent infection. Here we critically review the published literature, suggest further avenues of investigation and propose that occult infection may be beneficial to the host by maintaining immunological memory to protect against reinfection.

The COBAS ® TaqMan ® hepatitis C virus assays: automated systems for accurate and sensitive viral load quantification

In recent years, the real time-based TaqMan(®) technology has allowed the development of highly sensitive hepatitis viral load tests with broad dynamic ranges. The increasing applications of these tests in clinical diagnostics have shown the utility of viral load as a predictive marker of treatment response and proven its key role in invidualized antiviral therapies. Future refinement in viral load assays, including higher sensitivity, genotype inclusivity, standardization and automation, will further foster the concept of personalized healthcare in the clinical management of chronic hepatitis C.

Discordance between HCV RNA assays for week 24 HCV RNA determination during pegylated interferon-α/ribavirin treatment for chronic hepatitis C

BACKGROUND

The development of more sensitive HCV RNA assays might necessitate re-evaluation of the rules for stopping treatment (for example, HCV RNA negativity at week 24 during treatment with pegylated interferon-α and ribavirin for chronic hepatitis C). The aim of this study was to assess discordance between the week 24 HCV RNA test results of two PCR-based assays (Amplicor and TaqMan) and the transcription-mediated amplification (TMA) HCV RNA qualitative assay.

METHODS

A total of 89 week 24 samples that were negative using PCR-based assays during treatment were retested with the TMA qualitative assay to investigate discordance between tests results. All week 24 samples were HCV RNA negative by Amplicor or by TaqMan.

RESULTS

Of the 89 patients, 46 (52%) achieved sustained virological response (SVR). Viral breakthrough or relapse occurred in 43 patients (48%). All 89 HCV RNA negative week 24 samples were retested with the qualitative TMA assay. Eleven out of 89 samples had detectable HCV RNA (12%). All patients with detectable HCV RNA experienced breakthrough or relapse (negative predictive value 100%). Of the 78 patients with undetectable HCV RNA at week 24 using the TMA assay, 46 achieved SVR. This resulted in a positive predictive value (PPV) of 59% for the TMA assay compared with a PPV of 52% for the PCR-based assays.

CONCLUSIONS

All patients with detectable HCV RNA at week 24 using the TMA assay eventually relapsed. On the basis of these results, the use of this more sensitive HCV RNA assay could lead to the prevention of unnecessary treatment.

Multi-center evaluation of the Abbott RealTime HCV assay for monitoring patients undergoing antiviral therapy for chronic hepatitis C

BACKGROUND

Hepatitis C virus (HCV) RNA monitoring during antiviral therapy is essential for early prediction of treatment success and failure to peginterferon alfa/ribavirin (PEG-IFN/RBV) therapy.

OBJECTIVES

In this multi-center study we assessed the clinical utility of the Abbott RealTime HCV assay for monitoring patients undergoing antiviral therapy for chronic infection with HCV genotypes (GT) 1-3.

STUDY DESIGN

We analyzed serum from 361 patients with chronic hepatitis C who had been treated with PEG-IFN/RBV. The predictive value of rapid virologic response (RVR), partial (≥2log(10) decline) and complete (HCV-RNA undetectable) early virologic response (pEVR/cEVR) based on RealTime HCV for achieving sustained virologic response was evaluated. In addition, the utility of RealTime HCV to tailor treatment duration according to individual virologic responses was studied in a subset of 136 GT 1 patients and compared to the reference tests, Versant HCV Quantitative 3.0 (bDNA) and Qualitative (TMA) assay.

RESULTS

At week 4 of therapy, patients with RVR had a 100% and 93.5% probability to achieve an SVR in GT 1 and GT 2/3 patients, respectively. At week 12, patients who did not achieve a pEVR had a 97.2% and 100% probability of not achieving an SVR. In addition, assignment of GT 1 patients to abbreviated or extended treatment durations based on low baseline HCV-RNA (<800,000IU/mL) and RVR or pEVR was highly concordant between RealTime HCV and bDNA/TMA assays (97.8% and 91.9%, respectively).

CONCLUSIONS

The RealTime HCV assay is suitable for monitoring virologic response to PEG-INF/RBV therapy and tailoring treatment duration accordingly.

Development of a second version of the Cobas AmpliPrep/Cobas TaqMan hepatitis C virus quantitative test with improved genotype inclusivity

Hepatitis C virus (HCV) RNA measurement has been facilitated by the introduction of real-time PCR-based assays with low limits of detection and broad dynamic ranges for quantification. In the present study, the performance of two second-version prototypes of the Cobas AmpliPrep/Cobas TaqMan HCV Quantitative Test (CAP/CTM v2) with decreased sample input volume and improved genotype inclusivity was investigated. A total of 232 serum and plasma samples derived from patients with chronic hepatitis C (genotype 1 [GT1], n = 108; GT2, n = 8; GT3, n = 24; GT4, n = 87; GT5, n = 3; and GT6, n = 2) were processed in parallel with the Cobas AmpliPrep/Cobas TaqMan HCV Test (CAP/CTM), Cobas Amplicor HCV Monitor Test v2.0 (CAM), and two second-version prototype formulations of CAP/CTM, Mastermix 1 (MMx1) and MMx2. In addition, three GT4 transcripts containing rare variant sequences were tested. The mean log(10) HCV RNA differences for the best-performing CAP/CTM v2/MMx2 formulation in comparison to CAM were -0.05, 0.05, -0.12, -0.10, -0.44, and -0.29 for patients with GT1, GT2, GT3, GT4, GT5, and GT6 infections, respectively. GT1, GT2, and GT4 samples including isolates with known variants within the 5' untranslated region (G145A, A165T) that were underquantified with CAP/CTM were correctly quantified with the second-version prototype. In addition, CAP/CTM v2 was able to accurately quantify the three transcripts with rare variant sequences. In conclusion, CAP/CTM v2 accurately quantifies HCV RNA across all HCV genotypes, including specimens with rare polymorphisms previously associated with underquantification.

Hepatitis C virus core antigen: analytical performances, correlation with viremia and potential applications of a quantitative, automated immunoassay

BACKGROUND

Testing for hepatitis C virus core antigen (HCV Ag) may represent a complementary tool to anti-HCV and HCV-RNA in the diagnosis and monitoring of HCV infection.

OBJECTIVE

To evaluate the performance characteristics of the automated Abbott ARCHITECT HCV Ag assay.

STUDY DESIGN

Five sites analyzed over 3000 routine serum samples from populations at different risk, comparing HCV Ag results with anti-HCV screening and supplemental assay results and with HCV-RNA.

RESULTS

The HCV Ag assay showed a specificity of 100%, a good precision (CV<10%) and excellent dilution linearity (r>0.999). The sensitivity (3 fmol/L) corresponds to 700-1100 IU/mL of HCV-RNA. A non-linear correlation with HCV-RNA was found: r=0.713 vs. Siemens bDNA (523 specimens), r=0.736 vs. Roche Cobas TaqMan (356 specimens) and r=0.870 vs. Abbott Real-Time PCR (273 specimens). HCV Ag quantitation was equally effective on different HCV genoypes (239 for genotype 1/1a/1b/1c, 108 for genotype 2/2a/2c, 86 for genotype 3/3a, 50 for genotype 4/4a/4c/4d). Testing of subjects at high risk for HCV and with potential or actual impairment of the immune system identified 2 cases negative for anti-HCV and positive for HCV Ag on 361 hemodialyzed (0.6%) and 7 cases on 97 (7.2%) among transplant recipients. HCV Ag positivity anticipated anti-HCV seroconversion in all three cases of acute hepatitis C.

CONCLUSIONS

HCV Ag may be used as reflex testing on anti-HCV positive individuals to confirm or exclude an active infection, and on subjects with acute hepatitis or belonging to high risk groups.