Publications by authors named "Ed Marins"

15 Publications

  • Page 1 of 1

Classification of HIV-1 virological treatment failure using the Roche cobas plasma separation card on cobas 8800 compared to dried blood spots on Abbott RealTime HIV-1.

J Clin Virol 2021 Apr 23;140:104839. Epub 2021 Apr 23.

University of the Witwatersrand, School of Pathology, Department of Molecular Medicine and Haematology, Johannesburg, South Africa; National Health Laboratory Service, Johannesburg, South Africa.

Background: Measurement of HIV-1 viral load (VL) is essential for monitoring antiretroviral treatment (ART) efficacy. In remote settings, dried blood spots (DBS) may be used as the specimen type. However, cellular components in DBS not present in the gold standard specimen type, plasma, may result in low specificity i.e., over-estimation of VL results from DBS compared to plasma. The Abbott RealTime HIV-1 assay system has been reported to have improved specificity using DBS compared to other tests. A new specimen collection matrix, the cobas plasma separation card (PSC, Roche Molecular Systems), enables specimen collection from a finger prick or venous blood, using a multi-layer absorption and filtration design that results in a specimen similar to plasma.

Objectives And Study Design: We performed a direct comparison between VL results from PSC tested with the cobas 6800/8800 assay (c8800) and DBS tested with the Abbott RealTime HIV-1 assay.

Results: Overall concordance between PSC and plasma around the 1000 copies/mL threshold was high (>97%). Compared to VL measured using DBS and the RealTime assay, PSC and c8800 showed improved sensitivity (96.9% vs 90.6%) and specificity (97.4% vs. 87.2%) using plasma as the reference, as there were fewer patients with VL below 1000 copies/mL in plasma in whom VL was over this threshold using PSC compared to DBS. The limit of detection for PSC was lower than for DBS (575 vs. 2314 copies/mL).

Conclusions: cobas PSC represents a promising specimen type for use with the cobas 6600/8800 system in settings where plasma cannot be used.
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http://dx.doi.org/10.1016/j.jcv.2021.104839DOI Listing
April 2021

HBV-RNA Co-amplification May Influence HBV DNA Viral Load Determination.

Hepatol Commun 2020 Jul 26;4(7):983-997. Epub 2020 May 26.

Department of Gastroenterology, Hepatology and Endocrinology Hannover Medical School Hannover Germany.

Despite effective hepatitis B virus (HBV)-DNA suppression, HBV RNA can circulate in patients receiving nucleoside/nucleotide analogues (NAs). Current assays quantify HBV DNA by either real-time polymerase chain reaction (PCR), which uses DNA polymerase, or transcription-mediated amplification, which uses reverse-transcriptase (RT) and RNA polymerase. We assessed the effect of RT capability on HBV-DNA quantification in samples from three cohorts, including patients with quantified HBV RNA. We compared the HBV-DNA levels by real-time PCR (cobas HBV, Roche 6800/8800; Xpert HBV, Cepheid), transcription-mediated amplification (Aptima HBV, Hologic), and real-time PCR with added RT capability (cobas HBV+RT). In the first cohort (n = 45) followed over 192 weeks of NA therapy, on-treatment HBV-DNA levels were higher with cobas HBV+RT than cobas HBV (mean difference: 0.14 log IU/mL). In a second cohort (n = 50) followed over 96 weeks of NA therapy, HBV-DNA viral load was significantly higher with the cobas HBV+RT and Aptima HBV compared with the cobas HBV test at all time points after initiation of NA therapy (mean difference: 0.65-1.16 log IU/mL). A clinically significant difference was not detected between the assays at baseline. In a third cohort (n = 53), after a median of 2.2 years of NA therapy, we detected HBV RNA (median 5.6 log copies/mL) in 23 patients (43.4%). Median HBV-DNA levels by Aptima HBV were 2.4 versus less than 1 log IU/mL in samples with HBV RNA and without HBV RNA, respectively ( = 0.0006). In treated patients with HBV RNA, Aptima HBV measured higher HBV-DNA levels than Xpert HBV and cobas HBV. Tests including an RT step may overestimate HBV DNA, particularly in samples with low viral loads as a result of NA therapy. This overestimation is likely due to amplification of HBV RNA and may have an impact on clinical decisions.
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http://dx.doi.org/10.1002/hep4.1520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327219PMC
July 2020

Evaluation of the cobas® HCV test for quantifying HCV RNA in dried plasma spots collected using the cobas® Plasma Separation Card.

J Virol Methods 2020 04 13;278:113820. Epub 2020 Jan 13.

Roche Molecular Systems, Inc., 4300 Hacienda Drive, Pleasanton, CA, 94588, USA.

Objective: This study evaluated the performance of the cobas® hepatitis C virus (HCV) Test for use on the cobas® 6800/8800 Systems for the detection and quantification of HCV RNA collected using the cobas® Plasma Separation Card (PSC) compared with plasma samples.

Methods: Whole EDTA-venous blood was collected from 50 HCV-positive donors and 140 μL from each donor was spotted onto a PSC and stored either frozen or at ambient temperature. These were compared with matched EDTA-plasma samples. The limit of detection (LoD) of the assay for PSC samples was determined using serial dilutions of the Roche HCV secondary calibration standard. The stability of the PSC samples across a range of timepoints was also assessed.

Results: The mean titer difference between ambient and -10 °C storage of PSC samples was 0.04 log10 IU/mL (95% CI: 0.00, 0.07). The mean titer difference between frozen PSC samples and EDTA plasma samples was -1.59 log10 IU/mL (95% CI: -1.66, -1.53) and between ambient PSC samples and EDTA samples was -1.64 log10 IU/mL (95% CI: -1.70, -1.57). Correlation between PSC samples and EDTA plasma was linear in both cases (frozen: slope = 1.039, intercept=-1.839, R = 0.89; ambient: slope = 1.012, intercept=-1.712, R = 0.88). The LoD of the cobas® HCV Test using the PSC was 866 IU/mL (95% CI: 698, 1153 IU/mL) and 408 IU/mL (95% CI: 336, 544 IU/mL) using an optimized Assay Specific Analysis Package.

Conclusions: PSC samples correlate well with plasma viral load and demonstrate a LoD below 1000 IU/mL and good stability at ambient temperature for 28 days. A correction factor would allow quantification of HCV viral RNA load from samples collected using a PSC.
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http://dx.doi.org/10.1016/j.jviromet.2020.113820DOI Listing
April 2020

Evaluation of Contamination Risk by the cobas e 602 Serology Module Before Viral Load Testing on the cobas 6800 System.

Sex Transm Dis 2020 05;47(5S Suppl 1):S32-S34

Medical and Scientific Affairs, Roche Molecular Systems, Pleasanton, CA.

Background: Diagnosis of HCV, HBV, and HIV involves antibody screening followed by confirmation and/or treatment decision using nucleic acid tests. However, minimal data exist evaluating the risk of nucleic acid cross-contamination on serology devices upstream of molecular testing despite the potential clinical and laboratory workflow advantages of single specimen vial testing for both procedures.

Methods: We conducted a checkerboard study investigating the potential risk of HCV, HBV, and HIV nucleic acid cross-contamination on 480 negative specimens by a serology screening instrument that uses disposable tips for sample transfer, rather than a fixed needle, before molecular testing.

Results: Nucleic acid contamination was observed in 0 of 480 negative specimens when processed with alternating high-titer HCV, HBV, or HIV specimens on the serology platform.

Conclusions: This study suggests that specimens analyzed by a serology instrument using disposable tips for sample transfer may be suitable for direct primary specimen reflex testing by a sensitive nucleic acid confirmatory test.
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http://dx.doi.org/10.1097/OLQ.0000000000001125DOI Listing
May 2020

Utility of the new cobas HCV test for viral load monitoring during direct-acting antiviral therapy.

PLoS One 2019 18;14(11):e0224751. Epub 2019 Nov 18.

Department of Internal Medicine 1, University Hospital Frankfurt, Frankfurt am Main, Germany.

Background: The COBAS AmpliPrep/COBAS TaqMan assay HCV (CAP/CTM) is widely used in clinical routine for HCV testing. Recently, the new cobas HCV test was established for high throughput testing with minimal operator intervention. As different assays may yield different quantitative/qualitative results that possibly impact treatment decisions, the aim of this study was to externally evaluate the cobas HCV test performance in comparison to CAP/CTM in a clinically relevant setting.

Methods: Serum samples were obtained from 270 patients who received direct acting antiviral therapy with different treatment regimens at two study sites (Hannover and Frankfurt) in 2016. Overall, 1545 samples (baseline, on-treatment and follow-up) were tested in parallel by both assays.

Results: The mean difference between cobas HCV and CAP/CTM for the quantification of HCV RNA was 0.008 log10 IU/ml HCV RNA (95% limits of agreement: -0.02-0.036) showing excellent agreement of both assays. With respect to clinical cut offs (HCV RNA detectable vs. target not detected and HCV RNA above the lower limit of quantification (LLOQ) vs.
Conclusion: The performance of the new cobas HCV test was comparable to CAP/CTM in a clinical setting representing a large patient population with HCV GT 1 and 3 treated with DAAs.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0224751PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6860929PMC
April 2020

Generating timely molecular diagnostic test results: workflow comparison of the cobas® 6800/8800 to Panther.

Expert Rev Mol Diagn 2019 10 17;19(10):951-957. Epub 2019 Sep 17.

Department of Molecular Diagnostics, Labor Stein , Monchengladbach , Germany.

: Molecular diagnostic tests for HBV, HCV and HIV-1 and other pathogens are widely used for clinical management. Practical issues related to workflow and labor requirements need to be characterized to inform selection of the most appropriate system. : We compared the workflow of two high-throughput systems: cobas 6800 (Roche) and Panther (Hologic), using average mid-size laboratory test volumes for five different assays (HIV-1, HBV, HCV, HPV or TV, and CT/NG). : Set-up time, time to first results, time to last results, and total hands-on time for cobas 6800 was 0.40, 2.47, 7.12, and 0.98 hours, respectively; on the Panther system, these times were 0.75, 2.7, 9.1, and 1.48 hours. Fifty-seven samples had results available at the first time point on cobas 6800 compared to 5 samples on the Panther system. The Panther system required more manual steps including several with potential risks of contamination or error. The number of reagents items required was 5 for cobas 6800 and 40 for the Panther system. : Both systems provided a high level of automation. The cobas 6800 platform had shorter start up, time to first result, time to last result and hands-on times than the Panther system.
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http://dx.doi.org/10.1080/14737159.2019.1665999DOI Listing
October 2019

Analytical performance of four molecular platforms used for HIV-1, HBV and HCV viral load determinations.

Expert Rev Mol Diagn 2019 10 19;19(10):941-949. Epub 2019 Jun 19.

Department of Molecular Diagnostics, Labor Stein , Monchengladbach , Germany.

: Viral load (VL) quantification is important for the management of HBV, HCV, and HIV-1-infected patients. Several semi- or fully automated systems and assays are available that can be used to measure VL for these and other targets. : We assessed the accuracy, genotype/subtype inclusivity, and precision of four VL assays for three viral targets: cobas 4800 (Roche), cobas 6800 (Roche), Aptima (Hologic) and VERIS (Beckman), using WHO standards, cell culture supernatants and clinical samples. : Most results were close to expected values, except for significant under-quantification of HIV-1 group O, HBV genotype C, and D at high VL, and HCV genotype 3 by Aptima, and of HIV-1 CRF01_AE and group N and HCV genotype 3 by VERIS. Precision was comparable between tests except for VERIS HCV, which showed more variability. Aptima and cobas 6800 results agreed well with each other except HBV VL at lower VL (<10,000 IU/mL) where Aptima results tended to be higher. : Results from different VL assays may not always agree in certain subsets of patients. Clinicians should we aware of these findings when making treatment decisions.
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http://dx.doi.org/10.1080/14737159.2019.1624162DOI Listing
October 2019

Multicenter evaluation of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system for the quantification of HIV-1 plasma viral load.

J Clin Virol 2019 05 16;114:43-49. Epub 2019 Mar 16.

Department of Infection and Immunity, Luxembourg Institute of Health, Luxembourg. Electronic address:

Background And Objectives: Measurement of HIV-1 viral load (VL) is necessary to monitor treatment efficacy in patients receiving antiretroviral therapy. We evaluated the performance of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system ("cobas 4800 HIV-1").

Methods: Limit of detection, linearity, accuracy, precision, and specificity of cobas 4800 HIV-1, COBAS® AmpliPrep/COBAS® Taqman® HIV-1 version 2.0 (CAP/CTM HIV-1 v2) and Abbott RealTime HIV-1 were determined in one or two out of three sites.

Results: The limit of detection of the cobas 4800 HIV-1 for 400 μL and 200 μL input volumes was 14.2 copies/mL (95% CI: 12.5-16.6 copies/mL) and 43.9 copies/mL (37.7-52.7 copies/mL), respectively. Cobas 4800 HIV-1 demonstrated 100% specificity, and results were linear for all analyzed group M HIV-1 subtypes. Precision was high (SD < 0.19 log) across all measured ranges, reagent lots and input volumes. Correlation between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was high (R ≥ 0.95). Agreement between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 was 96.5% (95.0%-97.7%) at a threshold of 50 copies/mL, and 97.2% (95.8%-98.3%) at 200 copies/mL. Agreement between cobas 4800 HIV-1 and RealTime HIV-1 was 96.6% (93.4%-98.5%) at 50 copies/mL, and 97.0% (94.0%-98.8%) at 200 copies/mL. The mean difference between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was -0.10 log or 0.01 log, respectively.

Conclusions: The cobas 4800 HIV-1 test is highly sensitive, accurate and correlated well with other assays, including agreement around clinically relevant thresholds, indicating minimal overall VL quantification differences between tested platforms.
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http://dx.doi.org/10.1016/j.jcv.2019.03.008DOI Listing
May 2019

Diagnosis and monitoring of HCV infection using the cobas HCV test for use on the cobas 6800/8800 systems.

J Clin Virol 2018 05 24;102:63-69. Epub 2018 Feb 24.

Division of Medical Microbiology, Department of Pathology, The Johns Hopkins Hospital, Baltimore, MD 21287, United States. Electronic address:

Background And Objectives: Accurate, sensitive, and specific tests for detection and monitoring of hepatitis C virus (HCV) RNA concentrations are essential for diagnosis and management of HCV infections. We evaluated the next-generation reverse-transcription real-time PCR test, cobas HCV test for use with the cobas 6800/8800 systems ("cobas HCV") by determining its analytical performance characteristics and clinical utility for the diagnosis and therapeutic monitoring of chronic HCV infections.

Methods: The limit of detection (LOD), linearity, precision, specificity, matrix equivalence of plasma and serum, and quantitative agreement with the COBAS AmpliPrep/COBAS TaqMan HCV Test version 2.0 ("CAP/CTM HCV v2") were evaluated. Clinical utility for the diagnosis of chronic HCV infection was demonstrated by testing plasma from HCV seropositive individuals and comparing results to a nucleic acid amplification test (NAAT) approved for use in the diagnosis of chronic hepatitis C. Clinical specificity was investigated by testing plasma from HCV antibody negative subjects with non-HCV related liver diseases. Utility for monitoring treatment response was defined by testing plasma collected during treatment of HCV genotypes (GT) 1, 2, and 3 and determining positive predictive value (PPV), negative predictive value (NPV) and the odds ratio (OR) for predicting cure (sustained virologic response 12 weeks after treatment cessation, "SVR12").

Results: The cobas HCV test demonstrated an LOD of at least 15 IU/mL and measurable range from 15 to at least 1.0E + 08 IU/mL (1.2-8.0 log IU/mL) for GT 1-6, with high accuracy (≤0.16 log difference) and precision (standard deviation 0.04-0.14 log) throughout the linear range. Paired plasma and serum samples showed highly correlated performance (R = 0.97). Quantification was 100% specific for HCV in analytical studies. Correlation with CAP/CTM HCV v2 was high in patient samples (mean titer difference: 0.05 log with a 95% CI: 0.03-0.06 log). For the diagnosis of chronic HCV, positive and negative percent agreement between cobas HCV and the comparator NAAT were 98.8-100% on the cobas 6800 and 8800 systems. Clinical specificity of cobas HCV using samples from HCV antibody negative subjects with non-HCV related liver diseases was 99.6% and 100% on cobas 6800 and 8800 systems. In therapeutic monitoring and SVR12 prediction during experimental treatment for chronic HCV GT 1 infections, undetectable HCV RNA by cobas HCV at different on-treatment weeks had a PPV 76.8%-79.4%, NPV 29.9%-100%, and OR 1.64-47.52. During therapy of HCV GT 2 and GT 3, treatment week 4 and 12 results were: PPV, 84.7% and 75.3%; NPV, 47.8% and 50.0%; OR, 5.09 and 3.05.

Conclusions: The cobas HCV test is highly sensitive, specific, and accurate HCV RNA test for GT 1-6. It demonstrates excellent correlation with the FDA-approved CAP/CTM HCV v2 test. It is useful clinically for detection of active HCV infection in individuals that have had a positive anti-HCV antibody test result and in monitoring treatment response.
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http://dx.doi.org/10.1016/j.jcv.2018.02.017DOI Listing
May 2018

Commutability and concordance of four hepatitis B virus DNA assays in an international multicenter study.

Therap Adv Gastroenterol 2017 Aug 7;10(8):609-618. Epub 2017 Aug 7.

Hannover Medical School, Hanover, Germany.

Background: HBV DNA is the most important molecular marker in hepatitis B, used to determine treatment indication and monitoring. Most patients require lifelong hepatitis B virus (HBV) management, thus viral load (VL) monitoring may be performed at different laboratories, with different HBV assays, which may result in different VL results. This multicenter study compares the commutability and concordance of results from four different HBV DNA assays: CAP/CTM HBVv2, HPS/CTM HBVv2 and the new cobas 6800/8800 HBV and cobas 4800 HBV assays.

Methods: Across all four assays, HBV limit of detection (LoD) and linearity at lower concentrations were assessed using panels traceable to the World Health Organization international standard, and concordance was investigated at the important medical decision cutoffs 2000 and 20,000 IU/ml, using specimens from HBV-positive patients.

Results: The calculated LoD a probit curve was 2.7 IU/ml for cobas 6800/8800 HBV, 2.8 IU/ml for cobas 4800 HBV, 9.6 IU/ml for CAP/CTM HBVv2, and 6.2 IU/ml for HPS/CTM HBVv2. The average accuracy was comparable between cobas 6800/8800 HBV, cobas 4800 HBV and CAP/CTM HBVv2 (0.04-0.05 log IU/ml), while a slightly lower accuracy was documented for HPS/CTM HBVv2 (-0.16 log IU/ml). A total of 211-245 clinical samples were used for a pairwise comparison. Mean paired log differences ranged from -0.17 log IU/ml to -0.01 log IU/ml. Coefficient of determination was over 98% for all pairs with high overall percent agreement at the 2000 and 20,000 IU/ml cutoffs (from 91.7% to 96.3%). In a subset of samples with VL±0.5 log to the 2000 and 20,000 IU/ml thresholds, concordance was still 72% and 82%, respectively.

Conclusions: The new cobas 6800/8800 HBV and 4800 HBV assays show high accuracy in samples with low-level viremia and a high concordance with the established HBV tests, CAP/CTM HBVv2 and HPS/CTM HBVv2, at 2000 and 20,000 IU/ml. Thus, all four HBV assays have high commutability and may be used interchangeably in routine clinical practice.
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http://dx.doi.org/10.1177/1756283X17722745DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5557192PMC
August 2017

First identification of a recombinant form of hepatitis C virus in Austrian patients by full-genome next generation sequencing.

PLoS One 2017 25;12(7):e0181273. Epub 2017 Jul 25.

Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria.

Hepatitis C virus (HCV) intergenotypic recombinant forms have been reported for various HCV genotypes/subtypes in several countries worldwide. In a recent study, four patients living in Austria had been identified to be possibly infected with a recombinant HCV strain. To clarify results and determine the point of recombination, full-genome next-generation sequencing using the Illumina MiSeq v2 300 cycle kit (Illumina, San Diego, CA, USA) was performed in the present study. Samples of all of the patients contained the recombinant HCV strain 2k/1b. The point of recombination was found to be within the HCV NS2 gene between nucleotide positions 3189-3200 based on H77 numbering. While three of four patients were male and had migration background from Chechnya (n = 2) and Azerbaijan (n = 1), the forth patient was a female born in Austria. Three of the four patients including the female had intravenous drug abuse as a risk factor for HCV transmission. While sequencing techniques are limited to a few specialized laboratories, a genotyping assay that uses both ends of the HCV genome should be employed to identify patients infected with a recombinant HCV strain. The correct identification of recombinant strains also has an impact considering the tailored choice of anti-HCV treatment.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0181273PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5526534PMC
October 2017

Evaluation of the COBAS AmpliPrep/COBAS TaqMan HCV Test v2.0 for HCV viral load monitoring using dried blood spot specimens.

J Virol Methods 2017 09 30;247:77-80. Epub 2017 May 30.

Roche Molecular Systems, 4300 Hacienda Dr, Pleasanton, CA, 94588, United States.

This study evaluated the use of dried blood spot (DBS) for HCV viral load quantification using the COBAS AmpliPrep/COBAS Taqman HCV Quantitative Test v2.0 (CAP/CTM HCV v2), and compared two different procedures for preparation of DBS samples with a Specimen Pre-Extraction (SPEX) reagent (either heated [SPEX with SH] for 10min at 56°C on a thermomixer, or incubated for 1h at room temperature [SPEX at RT]) against the standard plasma input. Whole blood specimens from 48 patients with chronic HCV infection and Whatman 903 Protein Saver Cards were used to prepare 35μL DBS. An aliquot of plasma was spun and frozen from each draw. Mean DBS viral load results were compared to the corresponding results from plasma. Correlation between DBS to plasma was linear for both SPEX with SH (R=0.96) and SPEX at RT (R=0.97) procedures, with a constant negative offset of approximately 2.0logIU/mL between whole blood DBS without any adjustments and plasma results. After volume corrections, the mean offset to plasma decreased to -0.39 and -0.36 for the two procedures, respectively. The study demonstrated the use of DBS for HCV viral load correlates well with plasma with a constant offset.
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http://dx.doi.org/10.1016/j.jviromet.2017.05.016DOI Listing
September 2017

Advancing the regulatory path on hepatitis B virus treatment and curative research: a stakeholders consultation.

J Virus Erad 2017 Jan 1;3(1):1-6. Epub 2017 Jan 1.

Forum for Collaborative Research , Washington DC , USA.

Hepatitis B infection remains a significant disease burden around the world, with an estimated two billion individuals infected and 350 million living with chronic hepatitis B. Current antivirals are efficacious, but require lifelong treatment for the majority of infected individuals. The field is galvanised to improve diagnostics and treatment with the goal to develop shorter, finite treatments leading to viral control after treatment discontinuation. Achievement of complete and functional cure is challenged by the complexity of the virus life cycle, the lack of adequate preclinical models, the cccDNA-mediated persistence of HBV in liver cells, the lack of validated biomarkers to predict viral control and cure, and the probable need for combination treatment involving antiviral- and immune-based strategies. Experts from diverse stakeholder groups participating in the HBV Forum (a project of the Forum for Collaborative Research) contributed their expertise and perspective to resolving issues and overcoming barriers in the regulatory path for novel HBV therapeutic strategies; addressing gaps in preclinical models, diagnostics, clinical trial design, biomarkers and endpoints, and public health efforts. Interviewees highlighted the need for open and collaborative ongoing dialogues among stakeholders in a neutral space as a critical process to move the field forwards. The Forum model facilitates dialogue and deliberation of this nature, with dedicated experts from all stakeholder groups participating. The promise of an HBV cure is exciting. Now is the time to work together toward that goal.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5337416PMC
January 2017

Multicenter Comparison Study of both Analytical and Clinical Performance across Four Roche Hepatitis C Virus RNA Assays Utilizing Different Platforms.

J Clin Microbiol 2017 04 25;55(4):1131-1139. Epub 2017 Jan 25.

Institut für Hygiene, Mikrobiologie und Umweltmedizin, Medizinische Universität Graz, Graz, Austria

The efficacy of antiviral treatment for chronic hepatitis C virus (HCV) infection is determined by measuring HCV RNA at specific time points throughout therapy using highly sensitive and accurate HCV RNA assays. This study compared the performances of two recently developed real-time PCR HCV RNA assays, cobas HCV for use on the cobas 6800/8800 systems (cobas 6800/8800 HCV) and cobas HCV for use on the cobas 4800 system (cobas 4800 HCV), with those of two established assays, the Cobas AmpliPrep/Cobas TaqMan HCV quantitative test, version 2 (CAP/CTM v2) and the Cobas TaqMan HCV test, version 2 for use with the High Pure system (HPS/CTM v2). The limits of detection (LODs) and linearity at lower concentrations (5 to 1000 IU/ml) were assessed for cobas 6800/8800 HCV and cobas 4800 HCV using WHO standard traceable panels representing HCV genotypes (GT) 1 to 4. Pairwise assay comparisons were also performed using 245 clinical samples representing HCV GT 1 to GT 4. Results from cobas 6800/8800 HCV and cobas 4800 HCV were linear at low HCV RNA concentrations (<0.3 log IU/ml difference between expected and observed results) with LODs of 8.2 IU/ml and 11.7 IU/ml, respectively, for GT 1. The new assays showed excellent agreement with results from CAP/CTM v2 and HPS/CTM v2 in samples with quantifiable viral loads. The concordances using the 6 million IU/ml cutoff were high among all four assays (90 to 94%). In conclusion, the cobas 6800/8800 HCV and cobas 4800 HCV tests are sensitive and linear and correlate well with the established Roche assays used in clinical practice.
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http://dx.doi.org/10.1128/JCM.02193-16DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5377840PMC
April 2017

Evaluation of the new cobas® HCV genotyping test based on real-time PCRs of three different HCV genome regions.

Clin Chem Lab Med 2017 Mar;55(4):517-521

Background: Determination of the hepatitis C virus (HCV) genotype and discrimination between HCV subtypes 1a and 1b is still mandatory prior to anti-HCV treatment initiation. The aim of this study was to evaluate the performance of the recently introduced cobas® HCV GT assay (Roche) and to compare it to two comparator assays.

Methods: The cobas® HCV GT assay is based on primer-specific real-time polymerase chain reaction (PCR). For comparison, the TRUGENE® HCV 5'NC Genotyping Kit (Siemens) and the VERSANT® HCV Genotype 2.0 Assay (Siemens) were employed. Accuracy of the new assay was determined using proficiency panels. For clinical evaluation, 183 residual clinical samples obtained from patients with chronic hepatitis C infection were included.

Results: When accuracy was tested, panel members containing HCV subtypes 1a, 1b, and 3a were identified as expected; however, the new assay failed to identify low titer panel members containing HCV subtype 5a correctly. Of 183 clinical samples, 160 gave concordant results. For seven samples, an indeterminate result was reported with the cobas® HCV GT assay and the remaining 16 samples were found discordant with one of the comparator assays. When time-to-results of the assays were compared, the new assay showed shorter total time and similar hands-on time per sample.

Conclusions: The cobas® HCV GT assay showed a good performance and proved to be suitable for use in the routine diagnostic laboratory. Due to the high level of automation, fast and reliable results are obtained with short hands-on time.
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http://dx.doi.org/10.1515/cclm-2016-0620DOI Listing
March 2017