Performance of the Abbott real-time PCR assay using m2000sp and m2000rt for hepatitis C virus RNA quantification. J Clin Microbiol. 2009;47:1726-1732. [PMID: 19369435 DOI: 10.1128/jcm.01300-08]

Drug network identification predicts injecting risk behavior among people who inject drugs on hepatitis C virus treatment in Tayside, Scotland

The risk of Hepatitis C Virus (HCV) acquisition among People Who Inject Drugs (PWID) remains high when injecting risk behavior within networks endures. Several psychosocial factors influence such behavior. Following a drive within Tayside, a geographic region in Scotland, to achieve World Health Organization HCV elimination targets, addressing HCV re-infection risk as a barrier to elimination is critically important. This cross-sectional study seeks to address this barrier to elimination by investigating associations between group identification (one's subjective sense of belonging and connectedness to a social group coupled with a sense of shared goals, beliefs and values with the other members of the group) and injecting risk behavior among PWID on HCV treatment at needle and syringe provision sites in Tayside. Participants completed psychosocial questionnaires between treatment weeks zero and three of treatment. Correlation analyses were undertaken, and significant factors included in multiple linear regression models for injecting risk behavior. Injecting frequency, drug network identification, and family identification, were correlated with injecting risk behavior, and drug network identification had a positive predictive on injecting risk behavior. Identification with a social group, conventionally associated with improved health, may pose health risks in specific contexts. Healthcare providers should consider stratifying individuals with higher group identification with PWID networks for enhanced harm reduction engagement to mitigate transmissible infection risk among PWID. Additionally, psychological interventions to strengthen group identification with networks which impact positively on health behavior should be explored.

Real-world outcomes of rapid regional hepatitis C virus treatment scale-up among people who inject drugs in Tayside, Scotland

BACKGROUND

In 2017, Tayside, a region in the East of Scotland, rapidly scaled-up Hepatitis C Virus (HCV) outreach and treatment among People Who Inject Drugs (PWID) using novel community care pathways.

AIMS

We aimed to determine treatment outcomes for PWID during the scale-up against pre-determined targets; and assess re-infection, mortality, and post-treatment follow up.

METHODS

HCV treatment was delivered in community pharmacies, drug treatment centres, nurse-led outreach clinics, prisons, and needle exchanges, alongside conventional hospital care. We retrospectively analysed clinical outcomes and compared pathways using logistic regression models.

RESULTS

Of 800 estimated HCV-infected PWID, 718 (90%) were diagnosed. 713 treatments commenced among 662 (92%) PWID, delivering 577 (81%) Sustained Virologic Responses (SVR). SVR was 91% among those who attended for testing. Forty-six individuals were treated more than once. Needle exchanges and community pharmacies initiated 49% of all treatments. Regression analyses implied pharmacies had superior follow-up, but there was no difference in likelihood of achieving SVR in community pathways relative to hospital care. Re-infection occurred 39 times over 256.57 person years (PY), yielding a rate of 15.20 per 100 PY (95% CI 10.81-20.78). 54 deaths occurred (29 drug related) over 1,553.04 PY, yielding a mortality rate of 3.48 per 100 PY (95% CI 2.61-4.54). Drug-related mortality was 1.87 per 100 PY (95% CI 1.25-2.68).

CONCLUSIONS

Rapid HCV treatment scale-up to PWID in community settings, whilst maintaining high SVR, is achievable. However, other interventions are required to minimise re-infection; reduce drug-related deaths; and improve post-SVR follow-up testing regionally.

Knowledge of Hepatitis C virus vertical transmission and subsequent pregnancy outcome in virus-positive female blood donors

Introduction

Hepatitis C virus (HCV) can be vertically transmitted from mother to fetus. We evaluated knowledge about HCV vertical transmission in female blood donors who became pregnant following detection of HCV in their donated blood.

Methods

This was a retrospective descriptive study of females seen at a single blood bank in Sao Paulo, Brazil who were diagnosed with HCV infection in their donated blood. HCV-infected donors who subsequently became pregnant were invited to participate through letters or phone calls. Individuals who agreed to participate were interviewed by questionnaire to evaluate their knowledge on HCV vertical transmission.

Results

Among 282 HCV-positive female blood donors, 69 reported becoming pregnant after their HCV diagnosis in donated blood. While 24 of these women were successful treated for their infection prior to becoming pregnant, 45 (65.2%) were at risk for vertical HCV transmission either because they had never been treated for HCV, were pregnant before treatment or became pregnant after unsuccessful treatment. Of the 59 women who responded to the question of whether they were informed about the risk of HCV vertical transmission, 58 (98.3%) reported never receiving this information either after obtaining their blood donation results or during their pregnancy.

Conclusion

The lack of knowledge of HCV-infected women on the possibility for mother-to-child transmission of this virus highlights the critical need to improve communication about pregnancy-related risks between health professionals and HCV-infected women of childbearing age.

Performance assessment of a fully automated deep sequencing platform for HCV resistance testing

BACKGROUND

International liver society guidelines recommended to perform HCV resistance testing at baseline of first-line therapy with certain combination regimens or prior to retreatment in patients previously exposed to a direct-acting antiviral (DAA) containing regimen. Currently, no standardized assays have been developed as purchasable kits for HCV resistance testing. The aim of this study was to evaluate the performance of the Sentosa SQ HCV Genotyping Assay, a novel deep sequencing-based assay, to identify resistance-associated substitutions (RASs) in the NS3 protease, NS5A protein domain I and NS5B polymerase regions for patients infected with HCV genotypes-1a and 1b.

METHODS

Serum samples collected from patients with chronic hepatitis C infection who failed to achieve a sustained virological response after receiving a DAA-containing treatment regimen were extracted and sequenced by two methods including population sequencing of the NS3, NS5A and NS5B coding region reference method and the deep sequencing-based Sentosa SQ HCV Genotyping Assay.

RESULTS

A high concordance rate with Sanger sequencing, the reference method, was found for the NS3, NS5A and NS5 coding regions, regardless of the genotype-1 subtypes. The deep sequencing-based assay was more sensitive than population sequencing to detect minority variants, representing less than 10% of the viral populations, but also some variants representing up to 30% of the viral quasispecies, as expected.

CONCLUSIONS

The Sentosa SQ HCV Genotyping Assay can be confidently used in clinical practice in the indications of HCV resistance testing for these subtypes. Technical improvements are now required to allow for pangenotypic coverage.

Fully automated rapid quantification of Hepatitis C Virus RNA in human plasma and serum by integrated on-chip RT-qPCR and capillary electrophoresis

The quantification of hepatitis C virus (HCV) is essential for the management of chronic hepatitis C therapy. We have developed a fully automated microfluidic RT-qPCR system for rapid quantitative detection of HCV RNA in human EDTA-plasma and serum, and the performance of the method was assessed. The platform for the assay, µTASWako g1 Fully Automated Genetic Analyzer, performs automated sample preparation and RNA extraction, followed by amplification and detection on an integrated RT-qPCR-CE (capillary electrophoresis (CE)) microfluidic chip. The total assay time from sample input to data output is less than 120 minutes. The HCV assay has a linear quantitative range of 15 to 10⁷ IU/mL, with a limit of detection (LOD) of 10.65 IU/mL in EDTA-plasma and 12.43 IU/mL in serum. The assay has a reproducibility of SD ≤ 0.16 log₁₀ IU/mL and an accuracy of ≤ 0.22 log₁₀ IU/mL difference when compared to the assigned values. The main HCV genotypes 1 to 6 are detected with an accuracy of ± 0.3 log₁₀ IU/mL. The assay is specific for HCV RNA and is free of interference from non-HCV pathogens, elevated levels of anti-viral and anti-bacterial drugs, and common endogenous interferents. In the linear quantitative range, the assay is highly correlated with the Roche cobas AmpliPrep/cobas TaqMan HCV Test, version 2.0 (r² = 0.949). As the assay is highly sensitive, accurate and specific, and provides reliable quantification of HCV in plasma and serum, it can potentially be applicable for monitoring the therapy and management of HCV infection.

The new Xpert HCV viral load real-time PCR assay accurately quantifies hepatitis C virus RNA in serum and whole-blood specimens

BACKGROUND

Sensitive and accurate hepatitis C virus (HCV) RNA detection and quantification are essential to diagnose and monitor the virological response to antiviral treatment and the emergence of resistance.

OBJECTIVE AND STUDY DESIGN

The aim of this study was to assess the ability of the new Xpert HCV Viral Load assay to accurately detect and quantify HCV RNA in serum and in whole blood collected on dried blood spot (DBS). Serum and whole blood from a large series of patients chronically infected with different HCV genotypes were tested in parallel for HCV RNA detection and quantification.

RESULTS

A significant relationship between HCV RNA levels measured with the Xpert HCV Viral Load assay and the two commercial real-time PCR comparators (Abbott RealTime HCV test and Cobas AmpliPrep/Cobas Taqman HCV 2.0 test) was found in serum as well as in whole blood specimens.

CONCLUSIONS

The Xpert HCV Viral Load assay accurately quantifies HCV RNA regardless of the HCV genotype and can thus confidently be used to detect active HCV infection in serum and in whole blood specimens.

Evaluation of the Abbott m2000 system for dried blood spot detection of hepatitis C virus RNA

BACKGROUND

Hepatitis C virus RNA testing using dried blood spots (DBS) offers a method for detecting ongoing HCV infection in "hard to reach" populations. Abbott Molecular have developed a quantitative HCV RNA DBS protocol (currently for research use only) for extraction and real-time PCR amplification using them2000sp and m2000rt system.

METHODS

A panel of seventy "mock" DBS were made from patient whole blood; who were known to be either HCV RNA negative or positive. This panel compared the "mock" DBS and the plasma viral load results. A further dilution panel of "mock" DBS made from one HCV positive patient was used to estimate the detection limit of the assay. Abbott was then compared with an in-house real-time Taqman PCR using patient DBS samples.

RESULTS

All "mock" DBS samples with a viral load >1000IU/ml were detected by Abbott, with only 1/8 detected at <1000 IU/ml. The dilution panel suggested the limit of detection to be between 178 to 1779 IU/ml. There were two false positive samples detected at low level <282 IU/ml, both samples were from patients who had been previously positive. The overall sensitivity of the Abbott RUO DBS protocol when compared to plasma was 86% (95 CI 73.76%-74.18%) increasing to 100% (CI 91.59%-100%) when the viral load was >1000IU/ml. Abbott compared well with the in-house assay with sensitivity of 97.5% (95% CI 86.84%-99.94%) and specificity of 100% (95% CI 91.19%-100%).

CONCLUSIONS

The Abbott system is an automated platform which can be used for DBS HCV RNA extraction and amplification. The preliminary data presented here showed a high sensitivity and specificity for DBS with viral loads greater than 1000IU/ml and compared well with a published in-house method.

A novel standardized deep sequencing-based assay for hepatitis C virus genotype determination

Hepatitis C virus (HCV) genotype and subtype (1a/1b) identification is needed to tailor anti-HCV therapy. Currently available methods accurately identify the genotype and differentiate subtypes 1a from 1b. However, these assays have not been designed to identify other HCV subtypes, nor to recognize mixed genotype/subtype infections, emphasizing the need for a high-resolution system based on phylogenetic analysis of reads obtained by deep sequencing of a relevant genome region. The aim of this study was to evaluate the performance of the Sentosa SQ HCV Genotyping Assay, a novel deep sequencing-based assay targeting the HCV nonstructural 5B (NS5B) region, in clinical samples from patients with an indication for anti-HCV therapy. A high concordance rate with Sanger sequencing of the NS5B region, the reference method, was found for genotype 1 to 6 determination, 1a/1b subtype identification, and genotype 4, 5 and 6 subtyping. Discrepancies were seen essentially for HCV genotype 2 subtyping. Overall, the performance of the deep sequencing-based assay in generating the genotypes/subtype information needed to tailor anti-HCV treatment was adequate in this study. Further improvements, such as a longer NS5B fragment analyzed and enriching the database of reference prototype strains used for subtype assignment would make it a method of choice for HCV genotyping and subtyping for future clinical practice and research.

Analytical and clinical performance of the Hologic Aptima HCV Quant Dx Assay for the quantification of HCV RNA in plasma samples

BACKGROUND

Chronic hepatitis C virus (HCV) infection can be effectively treated with directly acting antiviral (DAA) therapy. Measurement of HCV RNA is used to evaluate patient compliance and virological response during and after treatment.

OBJECTIVES

To compare the analytical performance of the Aptima HCV Quant Dx Assay (Aptima) and the COBAS Ampliprep/COBAS TaqMan HCV Test v2.0 (CAPCTMv2) for the quantification of HCV RNA in plasma samples, and compare the clinical utility of the two tests in patients undergoing treatment with DAA therapy.

STUDY DESIGN

Analytical performance was evaluated on two sets of plasma samples: 125 genotyped samples and 172 samples referred for quantification of HCV RNA. Furthermore, performance was evaluated using dilutions series of four samples containing HCV genotype 1a, 2b, 3a, and 4a, respectively. Clinical utility was evaluated on 118 plasma samples obtained from 13 patients undergoing treatment with DAAs.

RESULTS

Deming regression of results from 187 plasma samples with HCV RNA >2 Log IU/mL indicated that the Aptima assay quantified higher than the CAPCTMv2 test for HCV RNA >4.9 Log IU/mL. The linearity of the Aptima assay was excellent across dilution series of four HCV genotypes (slope of the regression line: 1.00-1.02). The Aptima assay detected significantly more replicates below targeted 2 Log IU/mL than the CAPCTMv2 test, and yielded clearly interpretable results when used to analyze samples from patients treated with DAAs.

CONCLUSIONS

The analytical performance of the Aptima assay makes it well suited for monitoring patients with chronic HCV infection undergoing antiviral treatment.

Effectiveness and safety of first-generation protease inhibitors in real-world patients with hepatitis C virus genotype 1 infection in Brazil: a multicenter study

OBJECTIVE:

To evaluate the effectiveness and safety of first-generation protease inhibitors for the treatment of genotype 1 hepatitis C virus-infected patients at Brazilian reference centers.

METHODS:

This multicenter cross-sectional study included hepatitis C virus genotype 1 monoinfected patients treated with Peg-interferon, ribavirin, and either boceprevir (n=158) or telaprevir (n=557) between July 2013 and April 2014 at 15 reference centers in Brazil. Demographic, clinical, virological, and adverse events data were collected during treatment and follow-up.

RESULTS:

Of the 715 patients, 59% had cirrhosis and 67.1% were treatment-experienced. Based on intention-to-treat analysis, the overall sustained viral response was 56.6%, with similar effectiveness in both groups (51.9% for boceprevir and 58% for telaprevir, p=0.190). Serious adverse events occurred in 44.2% of patients, and six deaths (0.8%) were recorded. Cirrhotic patients had lower sustained viral response rates than non-cirrhotic patients (46.9% vs. 70.6%, p<0.001) and a higher incidence of serious adverse events (50.7% vs. 34.8%, p<0.001). Multivariate analysis revealed that sustained viral response was associated with the absence of cirrhosis, viral recurrence after previous treatment, pretreatment platelet count greater than 100,000/mm3, and achievement of a rapid viral response. Female gender, age>65 years, diagnosis of cirrhosis, and abnormal hemoglobin levels/platelet counts prior to treatment were associated with serious adverse events.

CONCLUSION:

Although serious adverse events rates were higher in this infected population, sustained viral response rates were similar to those reported for other patient cohorts.

Clinical performance of the VERIS HCV assay for hepatitis C virus RNA quantification

BACKGROUND

Diagnosis of hepatitis C virus (HCV) infection and treatment monitoring rely on detection/quantification of HCV RNA and real-time polymerase chain reaction (PCR) techniques are expected to equivalently quantify the different HCV genotypes.

OBJECTIVE

The clinical performance of the VERIS HCV assay for HCV RNA quantification was compared to that of the Abbott RealTime HCV assay.

STUDY DESIGN

Qualitative concordance and quantitative comparison were evaluated on a first panel of 286 clinical samples containing HCV genotypes 1-6. Forty additional genotype 4 samples were tested to explore genotype 4 HCV RNA underquantification.

RESULTS

Qualitative discrepancies were observed for low viral loads (<2 log₁₀ IU/mL) in patients under antiviral therapy and would not have had any impact on patients' management with the current guidelines for the monitoring of patients on direct-acting antivirals (DAAs). Quantification results were well correlated (R²=0.89) with an overall minimal quantification bias (mean VERIS - Abbott difference) of -0.09 log₁₀ IU/mL. Quantification agreement for genotypes 1, 2 and 3 samples was excellent, but reached -0.57 log₁₀ IU/mL for 46 genotype 4 samples. A lower quantification bias of -0.24 log₁₀ IU/mL was observed when testing 40 additional genotype 4 samples with a second reagent lot. Underquantification was not associated with 5' untranslated region (UTR) sequence polymorphisms but could be explained by 5' UTR RNA molecular modeling.

CONCLUSION

HCV RNA quantification by the VERIS HCV assay and the Abbott RealTime HCV assay was well correlated for all HCV genotypes, except genotype 4 where 5' UTR RNA folding may impact quantification. Nevertheless, this underestimation of HCV RNA levels had no impact on clinical use.

Real-time PCR assays for hepatitis B virus DNA quantification may require two different targets

Background

Quantification Hepatitis B virus (HBV) DNA plays a critical role in the management of chronic HBV infections. However, HBV is a DNA virus with high levels of genetic variation, and drug-resistant mutations have emerged with the use of antiviral drugs. If a mutation caused a sequence mismatched in the primer or probe of a commercial DNA quantification kit, this would lead to an underestimation of the viral load of the sample. The aim of this study was to determine whether commercial kits, which use only one pair of primers and a single probe, accurately quantify the HBV DNA levels and to develop an improved duplex real-time PCR assay.

Methods

We developed a new duplex real-time PCR assay that used two pairs of primers and two probes based on the conserved S and C regions of the HBV genome. We performed HBV DNA quantitative detection of HBV samples and compared the results of our duplex real-time PCR assays with the COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. The target region of the discordant sample was amplified, sequenced, and validated using plasmid.

Results

The results of the duplex real-time PCR were in good accordance with the commercial COBAS TaqMan HBV Test version 2 and Daan real-time PCR assays. We showed that two samples from Chinese HBV infections underestimated viral loads when quantified by the Roche kit because of a mismatch between the viral sequence and the reverse primer of the Roche kit. The HBV DNA levels of six samples were undervalued by duplex real-time PCR assays of the C region because of mutations in the primer of C region.

Conclusions

We developed a new duplex real-time PCR assay, and the results of this assay were similar to the results of commercial kits. The HBV DNA level could be undervalued when using the COBAS TaqMan HBV Test version 2 for Chinese HBV infections owing to a mismatch with the primer/probe. A duplex real-time PCR assay based on the S and C regions could solve this problem to some extent.

The New Aptima HCV Quant Dx Real-time TMA Assay Accurately Quantifies Hepatitis C Virus Genotype 1-6 RNA

BACKGROUND

Sensitive and accurate hepatitis C virus (HCV) RNA detection and quantification is essential for the management of chronic hepatitis C therapy. Currently available platforms and assays are usually batched and require at least 5hours of work to complete the analyses.

OBJECTIVES AND STUDY DESIGN

The aim of this study was to evaluate the ability of the newly developed Aptima HCV Quant Dx assay that eliminates the need for batch processing and automates all aspects of nucleic acid testing in a single step, to accurately detect and quantify HCV RNA in a large series of patients infected with different HCV genotypes.

RESULTS

The limit of detection was estimated to be 2.3 IU/mL. The specificity of the assay was 98.6% (95% confidence interval: 96.1%-99.5%). Intra-assay and inter-assay coefficients of variation ranged from 0.09% to 5.61%, and 1.05% to 3.65%, respectively. The study of serum specimens from patients infected with HCV genotypes 1 to 6 showed a satisfactory relationship between HCV RNA levels measured by the Aptima HCV Quant Dx assay, and both real-time PCR comparators (Abbott RealTime HCV and Cobas AmpliPrep/Cobas TaqMan HCV Test, version 2.0, assays).

CONCLUSIONS

the new Aptima HCV Quant Dx assay is rapid, sensitive, reasonably specific and reproducible and accurately quantifies HCV RNA in serum samples from patients with chronic HCV infection, including patients on antiviral treatment. The Aptima HCV Quant Dx assay can thus be confidently used to detect and quantify HCV RNA in both clinical trials with new anti-HCV drugs and clinical practice in Europe and the US.

A European multicentre study on the comparison of HCV viral loads between VERIS HCV assay and COBAS® TaqMan® HCV Test and RealTime HCV Assay

BACKGROUND

Beckman Coulter has developed the VERIS HCV Assay for use on the new fully automated DxN VERIS Molecular Diagnostic System^¥ for HCV viral load monitoring.

OBJECTIVES

Evaluate the clinical performance of the new quantitative VERIS HCV Assay.

STUDY DESIGN

Comparison was performed on 279 plasma specimens from HCV infected patients tested with the VERIS HCV Assay and COBAS^® Ampliprep/COBAS^® Taqman^® HCV Test and 369 specimens tested with the VERIS HCV Assay and RealTime HCV Assay. Patient monitoring sample results from four time points were also compared.

RESULTS

The average bias between the VERIS HCV Assay and the COBAS^® Ampliprep/COBAS^® Taqman^® HCV Test was 0.04 log₁₀IU/mL, while between the VERIS HCV Assay and the RealTime HCV Assay average bias was 0.21 log₁₀IU/mL. Bias, however, was not consistent across the measuring range. Analysis at the lower end of quantification levels 50, 100, and 1000IU/mL showed a predicted bias for VERIS HCV Assay versus COBAS^® Ampliprep/COBAS^® Taqman^® HCV Test between -0.42 and -0.22 log₁₀IU/mL and for VERIS HCV Assay versus RealTime HCV Assay between 0.00 and 0.13 log₁₀IU/mL. Patient monitoring of HCV viral load over time demonstrated similar levels between VERIS HCV Assay results and COBAS^® Ampliprep/COBAS^® Taqman^® HCV Test (52 samples from 13 patients) and RealTime HCV Assay (112 samples from 28 patients).

CONCLUSIONS

VERIS HCV Assay for use on the DxN VERIS Molecular Diagnostic System represents a reliable new tool for easy sample to result HCV RNA viral load monitoring.

European Multicenter Study on Analytical Performance of DxN Veris System HCV Assay

The analytical performance of the Veris HCV Assay for use on the new and fully automated Beckman Coulter DxN Veris Molecular Diagnostics System (DxN Veris System) was evaluated at 10 European virology laboratories. Precision, analytical sensitivity, specificity, and performance with negative samples, linearity, and performance with hepatitis C virus (HCV) genotypes were evaluated. Precision for all sites showed a standard deviation (SD) of 0.22 log₁₀ IU/ml or lower for each level tested. Analytical sensitivity determined by probit analysis was between 6.2 and 9.0 IU/ml. Specificity on 94 unique patient samples was 100%, and performance with 1,089 negative samples demonstrated 100% not-detected results. Linearity using patient samples was shown from 1.34 to 6.94 log₁₀ IU/ml. The assay demonstrated linearity upon dilution with all HCV genotypes. The Veris HCV Assay demonstrated an analytical performance comparable to that of currently marketed HCV assays when tested across multiple European sites.

Usefulness of Dried Blood Spots (DBS) to perform hepatitis C virus genotyping in drug users in Senegal

The aim of this pilot study was to analyze the Hepatitis C Virus (HCV) genotypes circulating in Senegal among Drug User (DUs), using Dried Blood Spots (DBS) as RNA source for molecular assays. Heroin and/or cocaine users (n = 506) were recruited in Dakar from April to July 2011, using a Respondent Driven Sampling (RDS) method. DBS preparation consisted of five drops of whole blood from finger applied to a Whatman paper card. HCV infection was screened by the detection of anti-HCV antibodies, using a rapid immune-chromatographic test. HCV RNA was quantified on anti-HCV positive DBS, using the Abbott RealTime HCV® Genotyping was performed on DBS with detectable viral load with Versant® HCV Genotype 2.0 Assay (LiPA) and Abbott RealTime HCV Genotype II assay®. Among the 506 participants, 120 were tested as positive for anti-HCV antibodies and their samples were analyzed for HCV RNA viral load and genotype. Out of the 120 DBS tested, HCV RNA was detected on 25 (20.8%). The median viral load was 15,058 IU/ml (ranging from 710 to 766,740 IU/ml). All positive DBS were suitable for the genotyping assay, that showed a predominance of genotype 1 (21/25) including 16 genotypes 1a and 5 genotypes 1b. HCV genotype 1 prevails in a DU population in Dakar. DBS could be useful for HCV RNA genotyping, but optimal storage conditions should required avoiding RNA impairment. Acknowledging this limitation, DBS could be a great interest for detecting and genotyping HCV viremic patients. J. Med. Virol. 89:484-488, 2017. © 2015 Wiley Periodicals, Inc.

Hepatitis C RNA assay differences in results: Potential implications for shortened therapy and determination of Sustained Virologic Response

Approval of Ledipasvir/Sofosbuvir for the treatment of chronic hepatitis C (HCV) includes the truncation of therapy from 12 to 8 weeks in treatment naïve, non-cirrhotic patients with baseline HCV RNA levels <6 million IU/mL (6.8 log10 IU/mL). The aim of this study was to evaluate this clinical cutoff with a different widely used commercially available HCV RNA test. Results from samples tested prospectively with Roche High Pure TaqMan HCV 2.0 test (HPS) were compared to those tested retrospectively with the Abbott RealTime HCV RNA test (ART). Using 6 million IU/mL as the cut-off, pre-treatment results were concordant in 70.4% of cases. When results with the same test measured at screening and baseline, clinical decisions could be impacted in 14.4% and 6.2% of cases for HPS and ART respectively. Using only HCV RNA cutoff of 6 million IU/mL, 29.55% of subjects would receive a different and potentially incorrect treatment duration based solely on HCV RNA test method used. A further 6-14% of subjects would have treatment decision change based on the day the sample was taken.

Analytical performance of the VERIS MDx system HCV assay for detecting and quantifying HCV RNA

BACKGROUND

The diagnosis of HCV relies on the detection of viral RNA.

OBJECTIVE

To evaluate the performance of the VERIS/MDx System HCV Assay, a new automated system for quantifying HCV RNA, and to compare with the COBAS^® Ampliprep/COBAS^® Taqman™ (CAPCTM) HCV Test version 2.0.

STUDY DESIGN

The limit of detection was determined by Probit analysis with the 3rd International WHO HCV standard and precision by assaying in duplicate control samples with HCV RNA concentrations of 7.9; 5.0; 3.4; 1.6 and 0logIU/ml over 20 days. Analytical specificity was assessed by assaying 180 samples from negative anti-HCV and HCV RNA blood donors and linearity with replicates of serial dilutions of a clinical plasma (6.4-0.6logIU/ml). We compared the VERIS MDx HCV and CAPCTM HCV assays by testing 209 samples.

RESULTS

The limit of detection was 6.1IU/ml [CI 95%: 5.0-8.3] and the precision, given by the standard deviation, was ≤0.11logIU/ml. Specificity was 100%. The linearity ranged from 1.5 to 6.4logIU/ml. Passing-Bablok regression analysis gave: VERIS logIU/ml=-0.33+[1.04× CAPCTM] logIU/ml, with biases for the 25th, 50th, 75th percentiles of 0.18, -0.10 and -0.06logIU/ml. The two assays were well correlated (ρ=0.92, p<0.001) and Bland-Altman analysis gave biases of 0.12, logIU/ml for genotype 1, -0.19 for genotype 2, -0.26 for genotype 3, and -0.77 for genotype 4.

CONCLUSION

The VERIS MDx HCV assay performed well. But, we observed an under-quantification of the genotype 4 samples.

Applicability of Hepatitis C Virus RNA Viral Load Thresholds for 8-Week Treatments in Patients With Chronic Hepatitis C Virus Genotype 1 Infection

BACKGROUND

Interferon-free treatment of chronic hepatitis C virus (HCV) genotype 1 infection may be shortened to 8 weeks in treatment-naive, noncirrhotic patients with baseline HCV RNA levels of <4 or <6 million (M) IU/mL based on post-hoc analyses of phase 3 trial data. The applicability of these viral load thresholds in clinical practice is unknown.

METHODS

Pretreatment and on-treatment serum samples (n = 740) from patients with HCV genotype 1 infection were included for HCV RNA analysis with 2 widely used assays, Cobas AmpliPrep/CobasTaqMan (CAP/CTM) and Abbott RealTime HCV (ART) assays.

RESULTS

HCV RNA levels were significantly higher with CAP/CTM than with ART (overall difference, +0.11 log10 IU/mL; P < .001). In treatment-naive, noncirrhotic patients, discordance rates around the clinical cutoffs at 4M and 6M IU/mL were 23% and 18%, respectively. The mean differences between assays in discordant samples were 0.38 (4M) and 0.41 (6M) log10 IU/mL, respectively. Overall, 87% and 95% of treatment-naive, noncirrhotic patients, respectively, had baseline HCV RNA levels below 4M and 6M IU/mL with ART. These rates were significantly higher than those measured with CAP/CTM (64% and 78%, respectively; P < .001). Finally, discordance rates around the proposed thresholds in 2 consecutive samples of the same patient were in the range of 1%-2% for ART and 13%-17% for CAP/CTM.

CONCLUSIONS

Selection of patients for 8-week regimens on the basis of a single HCV RNA determination may not be reliable because viral load levels around the proposed clinical thresholds show significant interassay and intrapatient variability.

Impact of HCV kinetics on treatment outcome differs by the type of real-time HCV assay in NS3/4A protease inhibitor-based triple therapy

Repeated measurement of the HCV RNA level is essential for properly monitoring treatment efficacy. The aim of this study was to determine the utility of two HCV real-time assays in the evaluation of the impact of hepatitis C virus (HCV) kinetics on the outcome of triple therapy with NS3/4A protease inhibitors (PIs), telaprevir or simeprevir. This study consisted of 171 Japanese patients infected with HCV genotype 1. All 3266 serum samples taken during and post treatment were tested with both the COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) HCV Test v2.0 and the Abbott RealTime (ART) HCV Test. Of the 2597 samples undetectable (lower limit of detection [<LOD]) for HCV RNA by the CAP/CTM assay from the on and post treatment, 400 (15.4%) (369 detectable/less than the lower limitation of quantification [<LLOQ] and 31 quantifiable) were detectable by the ART assay. HCV RNA < LOD within the first four weeks by ART was associated with sustained virological response (SVR) for the difficult-to-treat group that included patients with advanced fibrosis or prior partial/null response. In contrast, for the non-difficult-to-treat group, almost all of the late responders by ART achieved SVR, unlike by CAP/CTM. Despite HCV RNA being once < LOD by ART, 33.1% patients experienced the reappearance of residual HCV RNA (detectable/<LLOQ) during treatment. This event in the first 12 weeks (with PI-treatment period) was not related to treatment failure, however, relapse was observed in all patients with a reappearance of residual HCV RNA after 12 weeks (without PI-treatment period). The superior ability to detect low-level HCV RNA by ART could be useful for predicting SVR by difficult-to-treat patients in the early period and relapse in the late period.

Early virological assessment during telaprevir- or boceprevir-based triple therapy in hepatitis C cirrhotic patients who failed a previous interferon based regimen - The ANRS CO20-CUPIC study

BACKGROUND AND OBJECTIVE

To assess within the ANRS CO20-CUPIC cohort whether the viral load (VL) at week 2/week 6 for telaprevir/boceprevir-based triple therapy, respectively, was predictive of sustained virological response (SVR) in patients with hepatitis C virus (HCV) infection and to study the relevance of this measurement to early diagnose drug resistance.

METHODS

Observational study of HCV genotype 1 patients with compensated cirrhosis (Child-Pugh A), non-responders to a prior course of interferon (IFN)-based therapy and who started triple therapy. Patients received either 12 weeks of telaprevir in combination with PEG-IFN/ribavirin (RBV), then 36 weeks of PEG-IFN/RBV, or 4 weeks of PEG-IFN/RBV, then 44 weeks of PEG-IFN/RBV and boceprevir.

RESULTS

A total of 262 patients were analyzed. For telaprevir-treated patients, 28% had undetectable VL at W2 of whom 81% achieved SVR12 whereas 67% had undetectable VL at W4 of whom 67% achieved SVR12. For boceprevir-treated patients 20% had undetectable VL at W6 and 86% of them achieved SVR12 whereas 36% had undetectable VL at W8 among whom 73% achieved SVR12. Five telaprevir-treated patients had a VL increase between W2 and W4 after a decrease between D0 and W2. Four of them did not achieve SVR12. Similarly, six boceprevir-treated patients had a VL increase between W6 and W8 after a decrease between D0 and W6. Five did not reach SVR12.

CONCLUSIONS

The assessment of HCV RNA level after two weeks of triple therapy in cirrhotic non-responder patients is a good predictor of SVR. This assessment was useful to do an early diagnosis of viral breakthrough.

Performance characteristics of the VERSANT hepatitis C virus RNA 1.0 (kPCR) assay

HCV RNA assays are of central importance for virological diagnostics and for clinical planning and monitoring of an antiviral combination treatment of chronic HCV infections. The objective of the pre-market evaluation of the VERSANT HCV RNA 1.0 Assay (kPCR) was to collect analytical performance data for this new method of HCV RNA quantification and to compare them with the high standards that exist in this context. The assay exhibited a specificity of 100%. The mean intra- and inter-assay imprecision was 14.1% and 14.6%, respectively. The detection limit was determined to be 16IU/ml (95% confidence interval: 11.9-30.6IU/ml) and consequently corresponded to the manufacturer's claims (i.e. 15IU/ml). The test exhibited linearity for all HCV genotypes in a broad range from 15 to 10(8)IU HCV RNA/ml. Hence, the kPCR assay in general is well suitable for HCV RNA determinations in clinical practice. However, in a methodological comparison, a considerable under-quantification of the concentrations of HCV genotype 2 and 3 isolates was detected. Provided that the assay's manufacturer will quickly remedy this shortcoming, the VERSANT HCV RNA 1.0 (kPCR) can be called a completely reliable technique for HCV RNA quantification in routine virological diagnostics.

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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Plasma apolipoprotein H limits HCV replication and associates with response to NS3 protease inhibitors-based therapy

BACKGROUND & AIMS

Chronic infection with HCV remains a public health problem with approximately 150 million people infected worldwide. HCV intersects with lipid metabolism for replication and entry; and plasma concentrations of apolipoproteins have been identified as predictors for response to therapy. Herein, we conducted a screen of plasma proteins, including all apolipoproteins, to identify correlates of response to pegylated-interferon/ribavirin (PR) and HCV non-structural protein 3 (NS3) inhibitors (i.e., telaprevir/boceprevir) therapy in treatment-experienced cirrhotic patients from the ANRS CUPIC cohort.

METHODS

We analysed 220 baseline plasma protein concentrations in 189 patients using Luminex technology and analyzed results.

RESULTS

We identified baseline levels of apolipoprotein H (apoH) as a surrogate marker for sustained virological response (SVR). Notably, increased plasma concentration of apoH, used in combination with known clinical parameters, established a robust model with improved classification of patients as likely to achieve SVR (AUC = 0.77, Se = 66%, Sp = 72%, NRI = 39%). Moreover, we provide mechanistic information that indicates a previously unidentified role for apoH during viral entry. Using a human liver slices HCV infection model, we demonstrate that apoH limits replication.

CONCLUSION

These data support testing of new biomarker strategies for the management of cirrhotic HCV patients and expand our understanding of how apoH may intersect with HCV infection.

Biomarkers in HCV Infection

Liver-related biomarkers have been developed and validated mainly in patients with chronic hepatitis C for the prediction of liver fibrosis or cirrhosis, which is a final pathway of chronic liver injury. They are noninvasive, traceable, and easy-to-use. Biomarkers provide implications related to screening, diagnosis, treatment, and prognosis of chronic hepatitis. For the improvement of performance and coverage, biomarker panels, imaging biomarkers, and even genetic biomarkers have been developed. With the advancement of genomics and proteomics, earlier and more precise prediction is expected in the near future. In this review, multiple biomarker panels for the estimation of the degree of fibrosis in chronic hepatitis C, biomarkers for the screening and diagnosis of hepatitis C, biomarkers for the treatment of hepatitis C, biomarkers for the prediction of complications related to the chronic hepatitis C, and future perspectives will be summarized.

Hepatitis C virus infection in the human immunodeficiency virus infected patient

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same transmission routes; therefore, coinfection is frequent. An estimated 5-10 million individuals alone in the western world are infected with both viruses. The majority of people acquire HCV by injection drug use and, to a lesser extent, through blood transfusion and blood products. Recently, there has been an increase in HCV infections among men who have sex with men. In the context of effective antiretroviral treatment, liver-related deaths are now more common than Acquired Immune Deficiency Syndrome-related deaths among HIV-HCV coinfected individuals. Morbidity and mortality rates from chronic HCV infection will increase because the infection incidence peaked in the mid-1980s and because liver disease progresses slowly and is clinically silent to cirrhosis and end-stage-liver disease over a 15-20 year time period for 15%-20% of chronically infected individuals. HCV treatment has rapidly changed with the development of new direct-acting antiviral agents; therefore, cure rates have greatly improved because the new treatment regimens target different parts of the HCV life cycle. In this review, we focus on the epidemiology, diagnosis and the natural course of HCV as well as current and future strategies for HCV therapy in the context of HIV-HCV coinfection in the western world.

Effectiveness of telaprevir or boceprevir in treatment-experienced patients with HCV genotype 1 infection and cirrhosis

BACKGROUND & AIMS

We investigated the effectiveness of the protease inhibitors peginterferon and ribavirin in treatment-experienced patients with hepatitis C virus (HCV) genotype 1 infection and cirrhosis.

METHODS

In the Compassionate Use of Protease Inhibitors in Viral C Cirrhosis study, 511 patients with HCV genotype 1 infection and compensated cirrhosis who did not respond to a prior course of peginterferon and ribavirin (44.3% relapsers or patients with viral breakthrough, 44.8% partial responders, and 8.0% null responders) were given either telaprevir (n = 299) or boceprevir (n = 212) for 48 weeks. We assessed percentages of patients with sustained viral responses 12 weeks after therapy and safety. This observational study did not allow for direct comparison of the 2 regimens.

RESULTS

Among patients given telaprevir, 74.2% of relapsers, 40.0% of partial responders, and 19.4% of null responders achieved SVR12. Among those given boceprevir, 53.9% of relapsers, 38.3% of partial responders, and none of the null responders achieved SVR12. In multivariate analysis, factors associated with SVR12 included prior response to treatment response, no lead-in phase, HCV subtype 1b (vs 1a), and baseline platelet count greater than 100,000/mm(3). Severe adverse events occurred in 49.9% of cases, including liver decompensation, severe infections in 10.4%, and death in 2.2%. In multivariate analysis, baseline serum albumin level less than 35 g/L and baseline platelet counts of 100,000/mm(3) or less predicted severe side effects or death.

CONCLUSIONS

Relatively high percentages of real-life, treatment-experienced patients with HCV genotype 1 infection and cirrhosis respond to the combination of peginterferon and ribavirin with telaprevir or boceprevir. However, side effects are frequent and often severe. Baseline levels of albumin and platelet counts can be used to guide treatment decisions. ClinicalTrials.gov number: NCT01514890.

Performance characteristics of the COBAS Ampliprep/COBAS TaqMan v2.0 and the Abbott RealTime hepatitis C assays - implications for response-guided therapy in genotype 1 infections

BACKGROUND

With the advent of the protease inhibitors boceprevir and telaprevir a novel therapy approach for HCV genotype 1 infected subjects has become standard of care. Quantification of HCV viral load (VL) represents an important predictor of treatment response.

METHODS

Two different real-time PCR platforms, the COBAS Ampliprep/COBAS TaqMan v2.0 (CAP-CTM v2.0) and the Abbott RealTime (ART) HCV assay are most widely used. We performed a comparative evaluation of both systems focusing on genotype 1 HCV quantification using clinical specimens, the fourth WHO International Standard for HCV and the Paul Ehrlich National Standard, respectively.

RESULTS

The HCV VL assays showed an excellent overall agreement in the clinical specimens studied (R(2)=0.912). Discrepant results were obtained at the low VL end. Four samples tested negative with CAP-CTM v2.0 but were detectable with ART and two samples were undetectable with ART but tested positive with CAP-CTM v2.0. The coefficient of variation in replicate measurements of both reference materials was higher for CAP-CTM v2.0 as compared with ART at the clinical decision point for boceprevir (≥100 IU/ml), but was similar for the two assays at the clinical decision point for telaprevir (≥1,000 IU/ml). The tendency for underestimation of the diluted standards was higher for ART than for CAP-CTM v2.0.

CONCLUSIONS

Although both assays allowed accurate determination of VL levels in clinical samples, careful interpretation of results at the low VL end is essential. Furthermore, discontinuation of therapy based on single HCV RNA measurement should be carefully reconciled, unless the issue of assay variability has been addressed adequately.

Performance of a new rapid test for the detection of hepatitis B surface antigen in various patient populations

BACKGROUND

Rapid diagnostic tests (RDT) have been developed for the detection of hepatitis B surface antigen (HBsAg). They represent a promising alternative to enzyme immunoassays and a powerful tool for large-scale screening and diagnosis of HBV infection, especially in regions without easy access to serological and molecular testing.

OBJECTIVES

The aims of the present study were to evaluate the characteristics and clinical performance of a new CE-marked HBsAg RDT, DRW-HBsAg v2.0 assay (Diagnostics for the Real World™, Ltd., USA), in various patient populations, including those chronically infected with HBV, patients with severe acute hepatitis of unknown origin and pregnant women with unknown HBV serological status at delivery.

RESULTS

The lower limit of detection of the assay, evaluated in 21 clinical samples, ranged from 0.30 ± 0.07 to 0.97 ± 0.26 international units/mL (using Abbott Architect as a reference), depending on the HBV genotype. The assay tested positive in 100% of patients with chronic hepatitis B, 96.3% of HBsAg-positive acute hepatitis patients, and 95.2% of HBsAg-positive pregnant women. Its specificity was 98.8% in HBsAg-negative patients, 98.7% in HBsAg-negative patients with acute hepatitis of unknown origin and 97.8% in HBsAg-negative pregnant women. Amino acid substitutions in the HBsAg major hydrophilic region did not affect HBsAg detection by DRW-HBsAg v2.0.

CONCLUSIONS

The new DRW-HBsAg v2.0 assay is a simple, rapid, easy-to-run and highly sensitive assay that can be used in both high- and low-risk populations for the diagnosis of HBsAg carriage. It appears to be a promising new tool for large-scale screening and diagnosis of HBV infection.

The importance of HCV RNA measurement for tailoring treatment duration

The introduction of telaprevir and boceprevir in the treatment of chronically HCV genotype 1 infected patients has led to substantially improved sustained virologic response rates and shorter treatment duration for a growing group of patients. Management and monitoring of patients receiving protease inhibitor-based triple therapy is of major importance and has become more complicated. Close monitoring of HCV RNA levels for patients on protease inhibitor-based therapy to identify subjects who are eligible for shortening of treatment duration, are virological non-responders or are in danger of experiencing a viral breakthrough is strongly recommended. Several virological tools including qualitative and quantitative HCV RNA assays for detection and quantification of HCV RNA are commercially available. We review these methods and their implications for HCV therapy as well as current sustained virologic response definition, stopping rules and recommendations for protease inhibitor-based treatment durations.

Triple therapy in treatment-experienced patients with HCV-cirrhosis in a multicentre cohort of the French Early Access Programme (ANRS CO20-CUPIC) - NCT01514890

BACKGROUND & AIMS

In phase III trials, the safety profile of triple therapy (pegylated interferon/ribavirin with boceprevir or telaprevir) seems to be similar in HCV treatment-experienced cirrhotic and non-cirrhotic patients, but few cirrhotics were included. We report the week 16 safety and efficacy analysis in a cohort of compensated cirrhotics treated in the French Early Access Programme.

METHODS

674 genotype 1 patients, prospectively included, received 48 weeks of triple therapy. The analysis is restricted to 497 patients reaching week 16.

RESULTS

A high incidence of serious adverse events (40.0%), and of death and severe complications (severe infection or hepatic decompensation) (6.4%), and a difficult management of anaemia (erythropoietin and transfusion use in 50.7% and 12.1%) were observed. Independent predictors of anaemia < 8 g/dl or blood transfusion were: female gender (OR 2.19, 95% CI 1.11-4.33, p=0.024), no lead-in phase (OR 2.25, 95% CI 1.15-4.39, p=0.018), age ≥ 65 years (OR 3.04, 95% CI 1.54-6.02, p=0.0014), haemoglobin level (≤ 12 g/dl for females, ≤ 13 g/dl for males) (OR 5.30, 95% CI 2.49-11.5, p=0.0001). Death or severe complications were related to platelets count ≤ 100,000/mm(3) (OR 3.11, 95% CI 1.30-7.41, p=0.0105) and albumin <35 g/dl (OR 6.33, 95% CI 2.66-15.07, p=0.0001), with a risk of 44.1% in patients with both. However, the on-treatment virological response was high.

CONCLUSIONS

The safety profile was poor and patients with platelet count ≤ 100,000/mm(3) and serum albumin <35 g/L should not be treated with the triple therapy.

Treatment of hepatitis C: how will we use viral kinetics, response-guided therapy?

Hepatitis C virus (HCV) RNA level monitoring is currently used to guide the duration of interferon-containing treatment regimens. Nowadays, HCV RNA level quantification is based on real-time polymerase chain reaction assays that are both sensitive and accurate. Assessing the virological response to therapy is used to shorten treatment duration in early responders, in order to reduce the cost and burden of adverse events of therapy without impacting the chance of success. Whether response-guided therapy will still be useful in the era of all-oral, interferon-free regimens remains uncertain.

Second-generation Cobas AmpliPrep/Cobas TaqMan HCV quantitative test for viral load monitoring: a novel dual-probe assay design

Hepatitis C virus (HCV) RNA viral load (VL) monitoring is a well-established diagnostic tool for the management of chronic hepatitis C patients. HCV RNA VL results are used to make treatment decisions with the goal of therapy to achieve an undetectable VL result. Therefore, a sensitive assay with high specificity in detecting and accurately quantifying HCV RNA across genotypes is critical. Additionally, a lower sample volume requirement is desirable for the laboratory and the patient. This study evaluated the performance characteristics of a second-generation real-time PCR assay, the Cobas AmpliPrep/Cobas TaqMan HCV quantitative test, version 2.0 (CAP/CTM HCV test, v2.0), designed with a novel dual-probe approach and an optimized automated extraction and amplification procedure. The new assay demonstrated a limit of detection and lower limit of quantification of 15 IU/ml across all HCV genotypes and was linear from 15 to 100,000,000 IU/ml with high accuracy (<0.2-log(10) difference) and precision (standard deviation of 0.04 to 0.22 log(10)). A specificity of 100% was demonstrated with 600 HCV-seronegative specimens without cross-reactivity or interference. Correlation to the Cobas AmpliPrep/Cobas TaqMan HCV test (version 1) was good (n = 412 genotype 1 to 6 samples, R(2) = 0.88; R(2) = 0.94 without 105 genotype 4 samples). Paired plasma and serum samples showed similar performance (n = 25, R(2) = 0.99). The sample input volume was reduced from 1 to 0.65 ml in the second version. The CAP/CTM HCV test, v2.0, demonstrated excellent performance and sensitivity across all HCV genotypes with a smaller sample volume. The new HCV RNA VL assay has performance characteristics that make it suitable for use with currently available direct-acting antiviral agents.

New virologic tools for management of chronic hepatitis B and C

Molecular biology techniques are routinely used to diagnose and monitor treatment of patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. These tools can detect and quantify viral genomes and analyze their sequence to determine their genotype or subtype and to identify nucleotide or amino acid substitutions associated with resistance to antiviral drugs. They include real-time target amplification methods, which have been standardized and are widely used in clinical practice to diagnose and monitor HBV and HCV infections, and next-generation sequencing techniques, which are still restricted to research laboratories. In addition, new enzyme immunoassays can quantify hepatitis B surface and hepatitis C core antigens, and point-of-care tests and alternatives to biologic tests that require whole-blood samples obtained by venipuncture have been developed. We review these new virologic methods and their clinical and research applications to HBV and HCV infections.

Performance of the Abbott RealTime and Roche Cobas TaqMan hepatitis C virus (HCV) assays for quantification of HCV genotypes

We evaluated the Abbott RealTime (ART) and Roche Cobas TaqMan Hepatitis C virus (HCV) viral load assays for quantification of HCV genotypes in patient specimens. The ART HCV assay was a more sensitive and precise tool for accurate HCV viral load quantification across the HCV genotypes tested, especially genotype 1b.

Optimal follow-up time to determine the sustained virological response in patients with chronic hepatitis C receiving pegylated-interferon and ribavirin

BACKGROUND AND AIM

This study evaluated whether the assessment of hepatitis C virus (HCV)-RNA at 12 weeks (FW+12) post-treatment follow-up was as applicable as FW+24 to evaluate sustained virological response (SVR) using the highly sensitive real-time polymerase chain reaction (PCR) HCV assay.

METHODS AND RESULTS

Two hundred and twenty-two patients with chronic hepatitis C were included in this study. Pegylated interferon (Peg-IFN) and ribavirin were administered for 24-72 weeks based on the genotype and viral load. Serum HCV-RNA was measured using real-time PCR at pretreatment, the end of treatment, FW+4, FW+8, FW+12, FW+16, FW+20 and FW+24. Two hundred patients had a virological response at the end of treatment. One hundred and forty-eight of 200 (74.0%) patients with a virological response at the end of treatment had an SVR at the FW+24. The positive predictive value (PPV) to identify patients with SVR at FW+4, FW+8, FW+12 was 87.1, 96.1, 98.0%, respectively. The viral load showed a reversion to the basal level as early as 8 weeks in relapse patients. There were only three patients who relapsed after FW+12 and all three of these patients were females with genotype Ib and a high viral load.

CONCLUSION

The assessment of serum HCV-RNA FW+12, using the highly sensitive real-time PCR assay, is almost as effective as FW+24 to predict SVR. However, there are false negatives in female patients with a high viral load of genotype Ib when the SVR is predicted by FW+12. The current standard with FW+24 is reasonable, but the assessment of serum HCV-RNA FW+12 may be effective in most patients.

Liver stiffness diminishes with antiviral response in chronic hepatitis C

BACKGROUND

Transient elastography measures liver stiffness, which correlates with the hepatic fibrosis stage and has excellent accuracy for the diagnosis of cirrhosis in patients with chronic hepatitis C.

AIM

To assess prospectively the kinetics of liver stiffness in treated patients with chronic hepatitis C and compare them with the viral kinetics on treatment and with the final outcome of therapy.

METHODS

91 patients with chronic hepatitis C with significant fibrosis (>7.0kPa) at baseline were included. They received therapy with pegylated interferon-α and ribavirin. The kinetics of liver stiffness were characterized during therapy and thereafter by means of Fibroscan, and compared with the virological responses at weeks 4, 12, 24, end of treatment and 12 and 24weeks after.

RESULTS

A significant liver stiffness decrease was observed during therapy, which continued after treatment only in patients who achieved a sustained virological response. In this group, the median intra-patient decrease relative to baseline at the end of follow-up was -3.4kPa, vs-1.8kPa in the patients who did not achieve an SVR. Similar dynamics were observed in cirrhotic and non-cirrhotic patients. In multivariate analysis, only the SVR was associated with long-term improvement of liver stiffness (odds ratio: 3.10; 95% confidence interval: 1.20-8.02, P=0.019).

CONCLUSIONS

In patients with advanced fibrosis at the start of therapy, liver stiffness is significantly reduced during treatment, but improvement continues off treatment only in patients who achieve a sustained virological response. Liver stiffness assessment earlier than 6months after the end of therapy does not appear to be clinically meaningful.

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.

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.

Development of a new duplex real-time polymerase chain reaction assay for hepatitis B viral DNA detection

BACKGROUND

Quantification of hepatitis B virus (HBV) DNA can be used for diagnosing HBV infection and monitoring the effect of antiviral therapy. However, probably because of mismatches between the template and primer/probe, HBV DNA in some HBV infections could not be detected using currently available commercial assays with single primer/probe. By aligning the HBV sequences, we developed a duplex real-time polymerase chain reaction (PCR) assay using two sets of primers/probes and a specific armored DNA as internal control (IC).

RESULTS

The limit of the duplex real-time PCR assay was 29.5 IU/ml, whereas the specificity was 100%. The within-run precision coefficient of variation (CV) ranged from 1.02% to 2.73%, while the between-run CV ranged from 0.83% to 1.25%. The optimal concentration of armored DNA IC in the HBV DNA duplex real-time PCR assay was 1 000 copies/ml. Data from 69 serum samples with HBV infection showed that the performance of the duplex real-time PCR assay was comparable to that of the COBAS Ampliprep/Cobas Taqman (CAP/CTM) HBV assay and was superior to those of the domestic commercial HBV assays.

CONCLUSIONS

The duplex real-time PCR assay is sufficiently sensitive, specific, accurate, reproducible and cost-effective for the detection of HBV DNA. It is suitable for high throughput screening and frequent HBV DNA level monitoring.

Performance of two Real-Time RT-PCR assays for quantitation of hepatitis C virus RNA: evaluation on HCV genotypes 1-4

Accuracy for monitoring of the concentration of hepatitis C virus (HCV) RNA represents a major challenge throughout the management of patients with chronic hepatitis C. To investigate the genotype-independent efficiency and the accuracy of two real-time detection reverse transcription-polymerase chain reaction (RT-PCR) assays; the Cobas Ampliprep/Cobas TaqMan (CAP/CTM); and the Abbott RealTime HCV (ART), a total of 184 samples with different HCV subtypes were examined; 1b (n=58), 2a (n=39), 2b (n=26), 3a (n=20), and 4 (n=41). A robust linear correlation was observed between the two assays applied to genotypes 1b, 2a, 2b, and 3a [the correlation coefficient (R) ranged from 0.99 to 0.98], but not to genotype 4 specimens (R=0.78). A significant difference in measurements of HCV RNA using CAP/CTM and ART in serum samples with genotypes 1b and 4 was observed (0.72, -0.53 log IU/ml, P<0.0001, 0.01, respectively). A robust correlation was observed between the HCV core antigen and HCV RNA values by either of the HCV RNA quantitation assays applied to all genotypes with exception of genotype 4, for which R was higher with ART (R=0.95) than with CAP/CTM (R=0.80). The lower limit of detection of CAP/CTM and ART were 41.4 and 28.5 IU/ml using the WHO standards, respectively. In conclusion, two RT-PCR assays had a high efficiency and accuracy for quantitation of HCV RNA of genotypes 2a, 2b, and 3a, but the mean values of HCV RNA differed for genotype 1b and 4.