Clinical significance of residual viremia detected by two real-time PCR assays for response-guided therapy of HCV genotype 1 infection

Does a detectable HCV RNA at the end of DAA therapy herald treatment failure?

BACKGROUND & AIMS

The study aimed to assess the phenomenon of achieving sustained virologic response (SVR) in patients with detectable ribonucleic acid (RNA) of hepatitis C virus (HCV) at the end of treatment (ET) with direct-acting antivirals (DAA), find how this is affected by the type of regimen, and how patients experiencing this differed from non-responders with detectable HCV RNA at the ET.

METHODS

The study included all consecutive patients with detectable HCV RNA at the ET selected from the EpiTer-2 database, a retrospective national multicentre project evaluating antiviral treatment in HCV-infected patients in 2015-2023.

RESULTS

Of the 16106 patients treated with IFN-free regimens with available HCV RNA assessment at the ET and at follow-up 12 weeks after treatment completion (FU), 1253 (7.8%) had detectable HCV RNA at the ET, and 1120 of them (89%) finally achieved SVR. This phenomenon was significantly more frequent in pangenotypic regimens, 10.3% vs. 4.7% in genotype-specific options (p < 0.001), and the highest proportion was documented for glecaprevir/pibrentasvir (13.7%), and velpatasvir/sofosbuvir ± ribavirin (6.9%). Patients ET + FU- treated with these two pangenotypic regimens (n = 668) had less advanced liver disease, were less frequently infected with genotype (GT) 3, and were significantly more likely to be treatment-naïve than 61 non-responders.

CONCLUSIONS

We documented 7.8% rate of patients with detectable HCV RNA at the ET, of whom 89% subsequently achieved SVR, significantly more frequently in the population treated with pangenotypic regimens. Less severe liver disease, more often GT3 infection, and a higher percentage of treatment-naive patients distinguished this group from non-responders.

Breakthroughs in hepatitis C research: from discovery to cure

In the 1970s, an unknown virus was suspected for documented cases of transfusion-associated hepatitis, a phenomenon called non-A, non-B hepatitis. In 1989, the infectious transmissible agent was identified and named hepatitis C virus (HCV) and, soon enough, the first diagnostic HCV antibody test was developed, which led to a dramatic decrease in new infections. Today, HCV infection remains a global health burden and a major cause of liver cirrhosis, hepatocellular carcinoma and liver transplantation. However, tremendous advances have been made over the decades, and HCV became the first curable, chronic viral infection. The introduction of direct antiviral agents revolutionized antiviral treatment, leading to viral eradication in more than 98% of all patients infected with HCV. This Perspective discusses the history of HCV research, which reads like a role model for successful translational research: starting from a clinical observation, specific therapeutic agents were developed, which finally were implemented in national and global elimination programmes.

Response guided therapy for reducing duration of direct acting antivirals in chronic hepatitis C infected patients: a Pilot study

The advent of direct-acting antivirals (DAAs) has transformed the landscape of hepatitis C virus (HCV) management. We aimed to prospectively (real-time) evaluate the feasibility of using a response-guided therapy approach, based on mathematical modeling of early viral kinetics, to reduce the duration of DAAs therapy. Patients were treated with DAAs according to the physicians' preference. HCV was measured at baseline and at day 2 and weeks 1, 2 and 4 after treatment initiation. The primary endpoint was the proportion of patients with sustained-virological response (SVR) at 12 and/or 24 weeks post-treatment. Twenty-nine patients (mean age 54 ± 16, 44% females, 73% with HCV genotype 1), were enrolled and all completed therapy. Treatment duration was shortened in 11 of the 29 patients (38%). SVR was achieved in 28 of the 29 patients (97%). Relapse occurred post treatment in a single case of a non-cirrhotic male with genotype 3, who was treated with sofosbuvir/velpatasvir for 6 weeks. Virus sequencing did not identify baseline or treatment emergent resistance associated substitutions. Real-time mathematical modeling of early HCV kinetics can be utilized for shortening DAAs duration in approximately 40% of patients without compromising treatment efficacy.Clinical trial registration: ClinicalTrials.gov Identifier: NCT03603327.

Clinical significance of detectable and quantifiable HCV RNA at the end of treatment with ledipasvir/sofosbuvir in GT1 patients

BACKGROUND & AIMS

AASLD/IDSA treatment guidelines for hepatitis C virus (HCV) infection state that testing for quantitative HCV RNA can be considered at the end of antiviral treatment (EOT) with interferon-free regimens. However, it remains unclear how to respond to a detectable or even quantifiable HCV RNA result. The aim of this study was to analyse the frequency and predictive value of detectable and quantifiable HCV RNA results at the EOT in patients with HCV genotype 1 infection treated with ledipasvir (LDV) and sofosbuvir (SOF) ± ribavirin (RBV) in a large real-world cohort.

METHODS

A retrospective analysis of the DHC-R (Deutsches Hepatitis C-Register, German Hepatitis C-Registry) cohort was performed including all patients who were treated with LDV/SOF ± RBV and in whom HCV RNA testing was done with either the Roche COBAS AmpliPrep/COBAS TaqMan (CAP/CTM) or the Abbott RealTime HCV assay (ART).

RESULTS

The frequency of detectable HCV RNA at the EOT was 7% in this real-world study involving 471 patients. Furthermore, 3% of the patients (n = 14/471) even had quantifiable viral load at the EOT. Detectable and quantifiable results were more frequent if the ART was used for testing. However, SVR was achieved by 32/33 patients (97%) with detectable and even by all 14 patients (100%) with quantifiable HCV RNA results at the EOT.

CONCLUSION

Detectable and even quantifiable HCV RNA results are quite frequent if highly sensitive HCV RNA assays are used. However, treatment prolongation is not indicated, as SVR rates remain high in these patients.

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.

Comparison of on-treatment HCV RNA during direct antiviral therapy using two different COBAS TaqMan HCV assays

BACKGROUND

Repeated measurements of hepatitis C virus (HCV) RNA levels during antiviral therapy are recommended to monitor treatment efficacy and adherence. Throughout most direct antiviral agent (DAA) approval studies, HCV RNA cutoffs and endpoints were established with the COBAS TaqMan assay for use with the High Pure System (HPS/CTM). Different assays used in clinical practice may yield different quantitative results and possibly impact treatment decisions.

OBJECTIVES

The concordance of the fully-automated COBAS AmpliPrep/COBAS TaqMan assay (CAP/CTM) with HPS/CTM and its ability to predict response to DAA-treatment with ledipasvir/sofosbuvir was assessed in cirrhotic patients with HCV genotype-1-infection who had failed prior treatment with protease inhibitor-based regimens.

STUDY DESIGN

Serum samples from patients (n=154) treated in the phase-2 SIRIUS-study were collected at baseline and during antiviral therapy (weeks 1-8), and were tested in parallel by both assays.

RESULTS

The mean difference between HPS/CTM and CAP/CTM at baseline (n=153) was 0.32 log₁₀ IU/mL HCV RNA. Discordant results were observed in 12% of samples collected at treatment weeks 1-8, with the greatest differences observed at weeks 2 and 4 (14% and 29%, respectively, for undetectable HCV RNA). SVR rates were 96%-97% in the study and were not significantly different between patients with detectable vs. undetectable HCV RNA according to both assays at weeks 1-4 of antiviral therapy.

CONCLUSIONS

CAP/CTM and HPS/CTM showed significantly different response rates during the early stages of ledipasvir/sofosbuvir treatment. However, on-treatment response was not predictive of SVR with either assay, indicating that determination of on-treatment HCV RNA levels may not be useful to guide treatment decisions.

Point -of -care testing (POCT) in molecular diagnostics: Performance evaluation of GeneXpert HCV RNA test in diagnosing and monitoring of HCV infection

BACKGROUND

Molecular testing at the point-of-care may turn out to be game changer for HCV diagnosis and treatment monitoring, through increased sensitivity, reduced turnaround time, and ease of performance. One such assay GeneXpert^® has recently been released.

OBJECTIVES

Comparative analysis between performances of GeneXpert^® and Abbott HCV-RNA was done.

STUDY DESIGN

174 HCV infected patients were recruited and, one time plasma samples from 154 patients and repeated samples from 20 patients, obtained at specific treatment time-points (0, 4, 12 and 24) weeks were serially re-tested on Xpert^®.

RESULTS

Genotype 3 was the commonest, seen in 80 (66%) of the cases, genotype 1 in 34 (28.3%), genotype 4 in 4 (3.3%) and genotypes 2 and 5 in 1 (0.8%) each. Median HCV RNA load was 4.69 log₁₀ (range: 0-6.98log₁₀) IU/ml. Overall a very good correlation was seen between the two assays (R²=0.985), concordance of the results between the assays was seen in 138 samples (89.6%). High and low positive standards were tested ten times on Xpert^® to evaluate the precision and the coefficient of variation was 0.01 for HPC and 0.07 for the LPC. Monitoring of patients on two different regimes of treatment, pegylated interferon plus ribavirin and sofosbuvir plus ribavirin was done by both the systems at baseline, 4, 12 and 24 weeks. Perfect correlation between the assays in the course of therapy at different treatment time- point in genotypes 3 and 1 was seen.

CONCLUSION

The study demonstrates excellent performance of the Xpert^® HCV assay in viral load assessment and in treatment course monitoring consistency.

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

Prevalence of end of treatment RNA-positive/sustained viral response in HCV patients treated with sofosbuvir combination therapies

BACKGROUND

Some chronic hepatitis C virus (HCV), genotype 1 infected patients treated with direct antiviral agents (DAAs) remain viremic at end of treatment (EOT+), yet go on to achieve sustained virological response 12 weeks after completion of therapy (SVR₁₂). The incidence of EOT+/SVR in patients with genotype 1 and other genotypes, as well as whether such patients achieve SVR₂₄ remain in question. The aims of this study were to evaluate the frequency and durability of EOT+/SVR_12&24 and other response categories in HCV genotype 1, 2, or 3 infected patients treated with DAA in clinical practice.

METHODS

Data from patients treated with all oral sofosbuvir-based regimens at a university hepatology practice by 1 July 2015 were reviewed retrospectively. Responses were categorized based on virus levels during and post DAA treatment. HCV RNA levels were measured by Abbott RealTime HCV (ART) or by Roche CobasTaqMan v2.0 (RCTM) assays.

RESULTS

The study population included 89 patients. Participants were 62% genotype 1, 19% genotype 2 and 19% genotype 3, 54% cirrhotic and 46% treatment-experienced. A total of 45 received sofosbuvir-simeprevir, 38 sofosbuvir-ribavirin and 6 sofosbuvir-ledipasvir. The SVR₁₂ rate was 82%. A total of 5 patients (6%), all with genotype 1, had EOT+ by ART assay and each achieved SVR_12&24.

CONCLUSIONS

A total of 9% of genotype 1 patients (6% overall) treated with DAAs were EOT+ by ART and all EOT+ cases achieved SVR₂₄. EOT+/SVR was not observed with genotype 2 or 3 or by the RCTM assay. In patients treated with DAAs, EOT+ by the ART assay does not indicate treatment failure.

Diagnostics in hepatitis C: The end of response-guided therapy?

On-treatment hepatitis C virus (HCV) RNA has been used to predict response to interferon (IFN)-based therapy. The concept of response-guided treatment (RGT) was established to determine optimal treatment duration and to early identify patients not responding to futile therapies. RGT helped to improve sustained virologic response (SVR) rates and lower the rates of adverse effects. RGT was of particular importance for telaprevir- and boceprevir-based triple therapies. RGT strategies are dependent on highly sensitive and reproducible HCV RNA quantification. However, different HCV RNA assays are used in routine clinical practice and these differ significantly in their performance characteristics. The development of IFN-free therapies has fundamentally changed the role of on-treatment HCV RNA for SVR prediction. Given the high efficacy and excellent tolerability of IFN-free regimens, the interest in treatment individualization has decreased. However, shorter treatment durations may still be desirable, particularly with respect to the high costs of current IFN-free direct-acting antiviral agents (DAAs). Moreover, some difficult-to-treat patients remain, e.g., those infected with HCV genotype 3 in whom the current standard of care may not always be sufficient to achieve SVR, especially in treatment-experienced patients with cirrhosis. Here, a RGT extension may be feasible. However, current data on the predictive value of on-treatment HCV RNA are limited and have shown conflicting results. As more potent DAAs become available, the role of response prediction may diminish further. Currently, shorter treatment duration is only based on baseline HCV RNA whereas no RGT strategy is recommended for any of the approved DAA regimens available.

Hepatitis C virus: life cycle in cells, infection and host response, and analysis of molecular markers influencing the outcome of infection and response to therapy

Hepatitis C virus (HCV) is a major global health burden accounting for around 170 million chronic infections worldwide. Since its discovery, which dates back to about 30 years ago, many details of the viral genome organization and the astonishing genetic diversity have been unveiled but, owing to the difficulty of culturing HCV in vitro and obtaining fully susceptible yet immunocompetent in vivo models, we are still a long way from the full comprehension of viral life cycle, host cell pathways facilitating or counteracting infection, pathogenetic mechanisms in vivo, and host defences. Here, we illustrate the viral life cycle into cells, describe the interplay between immune and genetic host factors shaping the course of infection, and provide details of the molecular approaches currently used to genotype, monitor replication in vivo, and study the emergence of drug-resistant viral variants.

Clinical value of on-treatment HCV RNA levels during different sofosbuvir-based antiviral regimens

BACKGROUND & AIMS

The European Association for the Study of the Liver (EASL) guidelines recommend HCV RNA measurements at specific time points during sofosbuvir(SOF)-therapy. However, it remains unclear, how these results should be interpreted. We aimed to analyze whether on-treatment HCV RNA levels predict relapse comparing the CobasAmpliPrep/CobasTaqMan v2.0 (CAP/CTM) and Abbott RealTime HCV (ART) assays.

METHODS

Samples were collected from 298 patients (HCV genotypes; GT1-5) at weeks (w) 0, 1, 2, 4, 8, 12, 16, 20 and 24 during SOF-based therapy at two university clinics and tested for HCV RNA level by CAP/CTM and ART. Patients were treated with SOF/ribavirin (RBV) 12/24 w (n=99), pegylated-interferon-alfa (PegIFN)/SOF/RBV 12 w (n=51), SOF/simeprevir (SMV)±RBV 12 w (n=69) or SOF/daclatasvir±RBV 12/24 w (n=79).

RESULTS

HCV RNA levels during the first 4weeks of SOF/RBV therapy were significantly lower in GT3 patients who achieved SVR compared with those who relapsed. All GT3 patients with a week 2 result <45IU/ml by CAP/CTM achieved SVR but only 33% of those with ⩾45IU/ml (p=0.0003). Similar results were documented with ART and 60IU/ml as cut-off (SVR: 100% vs. 29%; p=0.0002). In contrast, HCV RNA levels during early treatment phases were not significantly related to relapse in patients treated with other SOF-based regimens. Residual HCV RNA was frequently detected by ART at later stages of therapy. However, SVR rates remained high in these patients. At the end of SOF/SMV±RBV therapy HCV RNA was detectable with ART in 20% of patients, of whom 92% achieved SVR.

CONCLUSIONS

HCV RNA levels assessed at week 2 of SOF/RBV therapy can predict relapse in GT3-patients. Detectable HCV RNA results at later stages during SOF-based therapy may occur frequently with the more sensitive ART. However, this should not lead to treatment extension.

LAY SUMMARY

We analyzed the predictive value of hepatitis C virus (HCV) RNA levels measured at different time points for treatment efficacy. We found that the level of HCV RNA measured at week 2 of antiviral therapy can be used to predict treatment success in patients with HCV genotype 3 infection treated with sofosbuvir and ribavirin but not in patients treated with other sofosbuvir-based regimens. Low level HCV RNA is frequently detected by the RealTime HCV assay during later stages of antiviral therapy. However, this is not associated with reoccurrence of HCV RNA after the end of treatment.

Ultrasensitive HCV RNA Quantification in Antiviral Triple Therapy: New Insight on Viral Clearance Dynamics and Treatment Outcome Predictors

OBJECTIVES

Identifying the predictive factors of Sustained Virological Response (SVR) represents an important challenge in new interferon-based DAA therapies. Here, we analyzed the kinetics of antiviral response associated with a triple drug regimen, and the association between negative residual viral load at different time points during treatment.

METHODS

Twenty-three HCV genotype 1 (GT 1a n = 11; GT1b n = 12) infected patients were included in the study. Linear Discriminant Analysis (LDA) was used to establish possible association between HCV RNA values at days 1 and 4 from start of therapy and SVR. Principal component analysis (PCA) was applied to analyze the correlation between HCV RNA slope and SVR. A ultrasensitive (US) method was established to measure the residual HCV viral load in those samples which resulted "detected <12IU/ml" or undetectable with ABBOTT standard assay, and was retrospectively used on samples collected at different time points to establish its predictive power for SVR.

RESULTS

According to LDA, there was no association between SVR and viral kinetics neither at time points earlier than 1 week (days 1 and 4) after therapy initiation nor later. The slopes were not relevant for classifying patients as SVR or no-SVR. No significant differences were observed in the median HCV RNA values at T0 among SVR and no-SVR patients. HCV RNA values with US protocol (LOD 1.2 IU/ml) after 1 month of therapy were considered; the area under the ROC curve was 0.70. Overall, PPV and NPV of undetectable HCV RNA with the US method for SVR was 100% and 46.7%, respectively; sensitivity and specificity were 38.4% and 100% respectively.

CONCLUSION

HCV RNA "not detected" by the US method after 1 month of treatment is predictive of SVR in first generation Protease inhibitor (PI)-based triple therapy. The US method could have clinical utility for advanced monitoring of virological response in new interferon based DAA combination regimens.

Significance of HCV RNA monitoring in the era of new potent therapies

INTRODUCTION

The development and approval of direct-acting-antivirals (DAA) has revolutionized the treatment of hepatitis C within a few years and opened the door to a new era of shorter, well-tolerated but also highly expensive treatment options.

AREAS COVERED

Nowadays, reductions of viral load below quantification limits may often be achieved within the first weeks of therapy. Viral breakthroughs during treatment are rarely observed and unfavourable viral genotypes or an advanced liver disease do not necessarily lower the prospect of eradication. For this reason, pan-genotypic DAA-only therapies are about to replace interferon/ribavirin-regimens as the standard of care worldwide. Expert commentary: Consequently, it has become essential to reevaluate the utility of HCV RNA quantification in predicting treatment outcomes and to guide clinical decisions. Is there still a need for a close-meshed monitoring or is it reasonable to limit HCV RNA monitoring to baseline and post-treatment results? This review discusses the pro- and contra arguments in this regard.

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

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

Multicentric performance analysis of HCV quantification assays and its potential relevance for HCV treatment

An accurate quantification of low viremic HCV RNA plasma samples has gained importance since the approval of direct acting antivirals and since only one single measurement predicts the necessity of a prolonged or shortened therapy. As reported previously, HCV quantification assays such as Abbott RealTime HCV and Roche COBAS AmpliPrep/COBAS TaqMan HCV version 2 (CTM v2) may vary in sensitivity and precision particularly in low-level viremia. Importantly, substantial variations were previously demonstrated between some of these assays compared to the Roche High Pure System/COBAS TaqMan assay (HPS) reference assay, which was used to establish the clinical decision points in clinical studies. In this study, the reproducibility of assay performances across several laboratories was assessed by analysing quantification results generated by six independent laboratories (3× RealTime, 3× CTM v2) in comparison with one HPS reference laboratory. The 4th WHO Standard was diluted to 100, 25 and 10 IU/ml, and aliquots were tested in triplicates in 5 independent runs by each assay in the different laboratories to assess assay precision and detection rates. In a second approach, 2 clinical samples (GT 1a & GT 1b) were diluted to 100 and 25 IU/ml and tested as described above. While the result range for WHO 100 IU/ml replicates across all laboratories was similar in this analysis, the CVs of each laboratory ranged from 19.3 to 25.6 % for RealTime laboratories and were lower than CVs of CTM v2 laboratories with a range of 26.1-47.3 %, respectively, and also in comparison with the CV of the HPS reference laboratory (34.9 %). At WHO standard dilution of 25 IU/ml, 24 replicates were quantified by RealTime compared to 8 replicates with CTM v2. Results of clinical samples again revealed a higher variation of CTM v2 results as compared to RealTime values. (CVs at 100 IU/ml: RealTime: 13.1-21.0 % and CTM v2: 15.0-32.3 %; CVs at 25 IU/ml: RealTime 17.6-34.9 % and CTM v2 28.2-54.9 %). These findings confirm the superior precision of RealTime versus CTM v2 at low-level viremia even across different laboratories including the new clinical decision point at 25 IU/ml. A highly precise monitoring of HCV viral load during therapy will remain crucial for patient management with regard to futility rules, therapy efficacy and SVR.

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.

COBAS ® AmpliPrep/COBAS ® Taqman ® HCV Quantitative Test, version 2.0: an in vitro test for hepatitis C virus RNA quantification

The COBAS(®) AmpliPrep/COBAS(®) Taqman(®) HCV Quantitative Test, version 2.0, is an in vitro, fully automated, real-time, nucleic acid amplification test indicated for quantifying hepatitis C virus (HCV) RNA levels in the plasma/serum of patients infected with HCV of genotypes 1-6 who are receiving anti-viral therapy. By quantifying levels of HCV RNA in these patients, the test can be used early in the course of treatment to predict the likelihood of a sustained virologic response being achieved and can also be used to assess virologic response during treatment as part of response-guided therapy. The test has excellent sensitivity, high specificity and a broad linear range of quantitation. It correlates well with version 1.0 of the same test, but has the benefit of better sensitivity and genotype inclusivity and a smaller sample input volume. It also correlates well with other available HCV tests, including other quantitative real-time PCR tests (specifically the COBAS(®) Taqman(®) HCV Test, version 2.0, used with the high pure system, and the Abbott Realtime and Artus HCV QS-RGQ tests), the Versant(®) branched DNA quantitative test, the COBAS(®) Amplicor HCV Qualitative PCR Test and the Versant(®) HCV qualitative transcription-mediated amplification assay. The test is not indicated for HCV infection diagnosis or to screen for the presence of HCV in blood/blood products.

Comparison of three quantitative HCV RNA assays in samples from HCV genotype 1- or 4-infected patients treated with the NS3/4A protease inhibitor simeprevir

BACKGROUND

Monitoring HCV RNA levels during treatment is an important tool for managing protease-inhibitor-based regimens, and different assays used in clinical practice can impact treatment decisions.

OBJECTIVES

The concordance of three HCV RNA assays was determined, and their impact on treatment decisions assessed using samples from HCV genotype (GT) 1- and GT4-infected patients treated with the NS3/4A inhibitor simeprevir in combination with pegylated interferon-α/ribavirin.

STUDY DESIGN

Plasma samples collected during the simeprevir Phase III studies QUEST-1 and QUEST-2 (GT1), and RESTORE (GT4) were analyzed with the Roche High-Pure-System COBAS(®) TaqMan(®) HCV v2.0 (HPS), the Roche AmpliPrep COBAS(®) TaqMan(®) HCV v2.0 (CAP), and the Abbott RealTime HCV (ART) assay.

RESULTS

In GT1, of the 440 samples, 81% were undetectable (rapid virological response; RVR) by HPS at Week 4, 76% by CAP and 44% by ART. In GT4 (103 samples), RVR rates were 67% by HPS and 24% by ART. HCV RNA <25IU/mL at Week 4 was observed for 95-96% and 92% GT1 samples and 86% and 74% GT4 samples by HPS/CAP and ART, respectively. At Week 12, assay concordance for undetectability was high in GT1 and GT4, (95-98% and 93%, respectively).

CONCLUSIONS

While different HCV RNA assays can lead to substantially different RVR rates, a good concordance was observed with a cut-off of 25IU/mL. Sustained virologic response rates among GT1 patients achieving RVR or <25IU/mL at Week 4 were high and similar between assays used. At later time points, when viremia is low, assay concordance was high.

HCV targeting of patients with cirrhosis

Interferon (IFN)-free treatments are now the treatment of choice for patients with chronic hepatitis C. Previously difficult to treat patients by IFN-containing treatments can now be treated safely by IFN-free therapies. More than 90% of hepatitis C genotype 1 and 4 patients with compensated cirrhosis or after orthotopic liver transplantation (OLT) can be cured by sofosbuvir combined with simeprevir, daclatasvir or ledipasvir, or by the paritaprevir/ritona-vir/ombitasvir/±dasabuvir (3D) combination. Addition of ribavirin confers to a minimal, if any, benefit to increase SVR. The need for ribavirin is controversial and remains to be studied. The optimal length of treatment is still unknown, and an individual approach may be needed. Most patients require only 12weeks of therapy. The safety of these drugs is not fully explored in patients with decompensated cirrhosis (Child-Pugh C), who should not be treated with protease inhibitors. In cirrhosis hepatitis C virus eradication does not necessarily mean a cure of the disease and patients regularly require follow-up. Drug-drug interactions with immunosuppressant in patients after OLT are easier to manage but still require attention. Better drugs are needed for genotype 3 patients.

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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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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Collaborators Collapse

Variation analysis of six HCV viral load assays using low viremic HCV samples in the range of the clinical decision points for HCV protease inhibitors

In the range of clinical decision points for response-guided therapy of HCV, there is still insufficient data concerning the conformity of quantification results obtained by different assays and their correlation with the HPS/CTM v2 assay which was used for initial clinical studies. In a head-to-head comparison, assay accuracy and detection rates of six quantitative assays [artus HCV QS-RGQ, COBAS Ampliprep/COBAS TaqMan HCV v1/v2, High Pure System/COBAS TaqMan (HPS), RealTime HCV, and Versant HCV1.0] were assessed by measuring WHO and PEI standards at dilution steps near clinical decision points. Detection rates and mean differences between assays were evaluated by analyzing twenty clinical samples at 10, 100, and 1,000 IU/mL. Ten replicates from specimens with different HCV genotypes were used to analyze pan-genotypic intra-assay variation. At ≤ 25 IU/mL, RealTime demonstrated the highest detection rates. With 0.1 log difference when testing clinical samples, results obtained from the Versant and RealTime assays matched best with results from HPS. Mean difference analysis across all assay results revealed wide differences between 0.01 and 0.75 log IU/mL. RealTime showed the lowest intra-assay variation across genotypes 1-4 (25, 100, 1,000 IU/mL). There are substantial analytical differences between viral load assays clinicians should be aware of. These variations may have impact on clinical decisions for patients on HCV triple therapy and may argue for assay-specific decision points equivalent to reference values established in studies using HPS. A comparison of quantification is recommended prior to a switch of assays during ongoing therapy.

Treatment of hepatitis C in difficult-to-treat patients

Interferon-free regimes are now the treatment of choice for patients with chronic hepatitis C; previously patients who were 'difficult-to-treat' using interferon-containing treatments can now safely be treated with such therapies. More than 90% of patients infected with HCV genotype 1 or 4, compensated cirrhosis, or who have had liver transplantation, can be cured with the use of sofosbuvir combined with simeprevir, daclatasvir or ledipasvir, or by the combination of paritaprevir with ritonavir, ombitasvir and with or without dasabuvir. Addition of ribavirin seems to shorten treatment duration. However, the safety of these drugs is not fully explored in patients with decompensated cirrhosis (that is, those with Child-Pugh class C disease), and protease inhibitors should not be used in this group. The optimal use of interferon-free regimes in patients with renal failure or after kidney transplantation is currently being studied. However, new and improved drugs are needed to treat patients infected with HCV genotype 3. Unfortunately, the broad application of new HCV treatments is limited by their high costs. In this Review, I discuss the treatment of patients with hepatitis C with compensated and decompensated cirrhosis, before and after orthotopic liver transplantation and in patients with impaired kidney function.

An OPTIMIZE study retrospective analysis for management of telaprevir-treated hepatitis C virus (HCV)-infected patients by use of the Abbott RealTime HCV RNA assay

Protease inhibitor (PI)-based response-guided triple therapies for hepatitis C virus (HCV) infection are still widely used. Noncirrhotic treatment-naive and prior relapser patients receiving telaprevir-based treatment are eligible for shorter, 24-week total therapy if HCV RNA is undetectable at both weeks 4 and 12. In this study, the concordance in HCV RNA assessments between the Roche High Pure System/Cobas TaqMan and Abbott RealTime HCV RNA assays and the impacts of different HCV RNA cutoffs on treatment outcome were evaluated. A total of 2,629 samples from 663 HCV genotype 1 patients receiving telaprevir/pegylated interferon/ribavirin in OPTIMIZE were analyzed using the High Pure System and reanalyzed using Abbott RealTime (limits of detection, 15.1 IU/ml versus 8.3 IU/ml; limits of quantification, 25 IU/ml versus 12 IU/ml, respectively). Overall, good concordance was observed between the assays. Using undetectable HCV RNA at week 4, 34% of the patients would be eligible for shorter treatment duration with Abbott RealTime versus 72% with the High Pure System. However, using <12 IU/ml for Abbott RealTime, a similar proportion (74%) would be eligible. Of the patients receiving 24-week total therapy, 87% achieved a sustained virologic response with undetectable HCV RNA by the High Pure System or <12 IU/ml by Abbott RealTime; however, 92% of the patients with undetectable HCV RNA by Abbott RealTime achieved a sustained virologic response. Using undetectable HCV RNA as the cutoff, the more sensitive Abbott RealTime assay would identify fewer patients eligible for shorter treatment than the High Pure System. Our data confirm the <12-IU/ml cutoff, as previously established in other studies of the Abbott RealTime assay, to determine eligibility for shortened PI-based HCV treatment. (The study was registered with ClinicalTrials.gov under registration no. NCT01241760.).

Virological outcomes and treatment algorithms utilisation in observational study of patients with chronic hepatitis C treated with boceprevir or telaprevir

BACKGROUND

HCV-TARGET is a longitudinal observational study of chronic hepatitis C virus (HCV) patients treated with direct-acting anti-viral agents (DAAs) in a US consortium of 90 academic and community medical centres.

AIM

To assess utilisation of response-guided therapy (RGT) and sustained virological response (SVR) of a large cohort of patients.

METHODS

Patients received peginterferon (PEG-IFN), ribavirin and either telaprevir or boceprevir. Demographical, clinical and virological data were collected during treatment and follow-up. RGT and treatment futility stopping rules was assessed at key time points.

RESULTS

Of 2084 patients, 38% had cirrhosis and 56% had received prior treatment for HCV. SVR rates were 31% (95% CI: 24-40) and 50% (95% CI: 44-56) in boceprevir patients with and without cirrhosis, respectively. SVR rates were 46% (95% CI: 42-50) and 60% (95% CI: 57-64) in telaprevir patients with and without cirrhosis, respectively. Early clearance of virus, IL28B genotype, platelet counts and diabetes were identified as predictors of SVR among boceprevir patients, while early clearance of virus, IL28B, cirrhosis, HCV subtype, age, haemoglobin, bilirubin and albumin levels were identified as predictors of SVR for telaprevir patients.

CONCLUSIONS

In academic and community centres, triple therapy including boceprevir or telaprevir led to SVR rates somewhat lower than those noted in large phase 3 clinical trials. Response rates were consistently higher among patients without cirrhosis compared to those with cirrhosis regardless of DAA used and prior treatment response. Trial registration clinicaltrials.gov NCT01474811.

Evaluation of the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HCV Test, v2.0 and comparison to assays used in routine clinical practice in an international multicenter clinical trial: The ExPECT study

BACKGROUND

The COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v2.0 (CAP/CTM2) is used for HCV RNA viral load monitoring.

OBJECTIVES

The performance of the CAP/CTM2 was compared to other widely used tests, including a manual version of the assay (the COBAS(®) TaqMan(®) HCV Test, v2.0 for use with the High Pure System, HPS/CTM2) predominantly used during phase III clinical trials for the new direct acting antiviral therapies.

STUDY DESIGN

Low HCV RNA level comparisons were performed across tests (Abbott Realtime HCV Test, ART; COBAS(®) AmpliPrep(®)/COBAS(®) TaqMan(®) HCV Test, v1.0, CAP/CTM1; CAP/CTM2; and HPS/CTM2) using dilutions of the 2nd HCV WHO International Standard. Additionally, the clinical performance of the CAP/CTM2 was evaluated with 421 leftover HCV RNA-positive routine clinical samples.

RESULTS

All quantifiable WHO dilutions were within ±0.3log10IU/mL of the expected results across tests and the analytical sensitivity resulted in a limit of detection of 12IU/mL (95% confidence interval, 10, 15). When clinical samples were tested the results for 87% (367 of 421) of all sample comparisons were within ±0.5log10IU/mL. When low viral load results (25-3500IU/mL) were compared, values obtained by the ART assay were significantly lower (p<0.0001) than those obtained with the CAP/CTM2.

CONCLUSIONS

The new CAP/CTM2 showed good accuracy with comparable sensitivity to comparator assays. The new kit is well-suited for use in the routine diagnostic laboratory, especially for accurate monitoring of patients receiving triple therapy or interferone-free regimens.

Importance of very early HCV RNA kinetics for prediction of treatment outcome of highly effective all oral direct acting antiviral combination therapy

Interferon-free combination therapies lead to rapid suppression of HCV RNA early during treatment. The potential to predict virologic response and failure as well as to guide treatment duration with measurement of HCV RNA very early during treatment by highly sensitive assays is not well known. In 11 IL28B CC (rs12979860) patients infected with HCV genotype 1, who received DAA combination therapy with the NS3 protease inhibitor ABT-450/r together with the non-nucleoside NS5B polymerase inhibitor ABT-072 and ribavirin for 12 weeks, HCV RNA was assessed frequently by the RealTime HCV (ART) and the High-Pure-System/Cobas TaqMan (HPS) assays during and after treatment. Overall, at 33 of 131 time points during treatment residual HCV RNA was detectable by ART but undetectable by HPS while the converse was observed in only two samples. Of the two patients who experienced virologic relapse, one patient had residual viremia at week 6 of treatment by ART only while the other patient never had undetectable HCV RNA by the ART assay. However, residual viremia was also observed by ART as late as therapy weeks 9, 10 and 12 in patients with subsequent sustained virologic response. In patients with sustained response no viremia was observed at multiple time points during post-treatment follow up by either assay. The higher sensitivity of the ART in comparison to the HPS assay may be associated with more frequent detection of residual viremia during highly effective, interferon-free combination therapies. However, the significance of this finding in predicting virologic failure appears to be limited.

Performance of two HCV RNA assays during protease inhibitor-based triple therapy in patients with advanced liver fibrosis and cirrhosis

Introduction

On-treatment HCV RNA measurements are crucial for the prediction of a sustained virological response (SVR) and to determine treatment futility during protease inhibitor-based triple therapies. In patients with advanced liver disease an accurate risk/benefit calculation based on reliable HCV RNA results can reduce the number of adverse events. However, the different available HCV RNA assays vary in their diagnostic performance.

Aim

To investigate the clinical relevance of concordant and discordant results of two HCV RNA assays during triple therapy with boceprevir and telaprevir in patients with advanced liver fibrosis/cirrhosis.

Methods

We collected on-treatment samples of 191 patients with advanced liver fibrosis/cirrhosis treated at four European centers for testing with the Abbott RealTime (ART) and COBAS AmpliPrep/COBAS TaqMan HCV v2.0 (CTM) assays.

Results

Discordant test results for HCV RNA detectability were observed in 23% at week 4, 17% at week 8/12 and 9% at week 24 on-treatment. The ART detected HCV RNA in 41% of week 4 samples tested negative by the CTM. However, the positive predictive value of an undetectable week 4 result for SVR was similar for both assays (80% and 82%). Discordance was also found for application of stopping rules. In 27% of patients who met stopping rules by CTM the ART measured levels below the respective cut-offs of 100 and 1000 IU/ml, respectively, which would have resulted in treatment continuation. In contrast, in nine patients with negative HCV RNA by CTM at week 24 treatment would have been discontinued due to detectable residual HCV RNA by the ART assay. Importantly, only 4 of these patients failed to achieve SVR.

Conclusion

Application of stopping rules determined in approval studies by one assay to other HCV RNA assays in clinical practice may lead to over and undertreatment in a significant number of patients undergoing protease inhibitor-based triple therapy.

Molecular diagnostics in the management of chronic hepatitis C: key considerations in the era of new antiviral therapies

Molecular tests that detect and/or quantify HCV RNA are important in the diagnosis and management of patients with chronic hepatitis C (CHC) undergoing anti-viral therapy. The primary goal of anti-HCV therapy is to achieve a sustained virologic response (SVR) defined as "undetectable" Hepatitis C Virus (HCV) RNA in the serum or plasma at 12 to 24 weeks following the end of treatment.