Review

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

Benjamin Maasoumy1, Johannes Vermehren2,⇑

Summary

Keywords: Response-guided

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therapy; Pegylated interferon;Direct-acting; Antivirals;On-treatment HCV RNA; HCV RNAassay.

Received 25 May 2016; received inrevised form 20 July 2016; accepted21 July 2016

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 todetermine optimal treatment duration and to early identify patients not responding to futiletherapies. RGT helped to improve sustained virologic response (SVR) rates and lower the ratesof adverse effects. RGT was of particular importance for telaprevir- and boceprevir-based tripletherapies. RGT strategies are dependent on highly sensitive and reproducible HCV RNAquantification. However, different HCV RNA assays are used in routine clinical practice andthese differ significantly in their performance characteristics. The development of IFN-freetherapies 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 treat-ment individualization has decreased. However, shorter treatment durations may still bedesirable, particularly with respect to the high costs of current IFN-free direct-acting antiviralagents (DAAs). Moreover, some difficult-to-treat patients remain, e.g., those infected with HCVgenotype 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 fea-sible. However, current data on the predictive value of on-treatment HCV RNA are limited andhave shown conflicting results. As more potent DAAs become available, the role of responseprediction may diminish further. Currently, shorter treatment duration is only based onbaseline HCV RNA whereas no RGT strategy is recommended for any of the approved DAA reg-imens available.� 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rightsreserved.

Introduction

1Medizinische Hochschule Han-nover, Klinik für Gastroenterologie,Hepatologie und Endokrinologie,Hannover, Germany;2Universitätsklinikum Frankfurt,Medizinische Klinik 1, Frankfurt amMain, Germany

⇑ Corresponding author. Address:Medizinische Klinik 1, Univer-sitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt amMain, Germany. Tel.: +49 69 63015122; fax: +49 69 6301 83112.E-mail address:Johannes.vermehren@kgu.de(J. Vermehren).

Hepatitis C virus (HCV) infection is a major cause ofchronic liver disease that can progress to cirrhosisand hepatocellular carcinoma [1]. Chronic HCVinfection accounts for approximately 500,000deaths each year [2]. Following the discovery ofHCV in the late 1980s, development of molecularmethods for the detection of nucleic acids was amilestone towards successful treatment of HCVinfection [3]. Until today, direct detection andquantification of viral nucleic acid (HCV RNA) isgenerally regarded as the definite diagnostic crite-rion to document active HCV infection, regardlessof the presence of anti-HCV antibodies and/or ele-vated liver enzymes [4,5]. Moreover, the primarygoal of HCV therapy is the achievement of a sus-tained virologic response (SVR), defined as unde-tectable HCV RNA by a sensitive assay 12 or24 weeks after treatment completion [5].

Qualitative assays were the first nucleic acidassays available. However, with these assays only

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the presence or absence of active HCV infectioncan be confirmed. Development of quantitativeassays also allowed for on-treatment response mon-itoring and SVR prediction. This became an integralpart of pegylated interferon (PegIFN)-based treat-ment, which was the mainstay of antiviral therapyuntil 2013 [6]. On-treatment HCV RNA levels wereused to determine optimal treatment duration andto early identify patients not responding to antiviraltherapy who were advised to stop treatment due tofutility [7]. The paradigm of response-guided treat-ment (RGT) also became a key concept of HCV ther-apy following the approval of first generation HCVprotease inhibitors (PIs) in 2011. With PI-basedtriple therapies, higher SVR rates could be achievedusing shorter treatment durations compared withPegIFN/RBV alone [8–11]. RGT was further facili-tated by the increase in sensitivity and accuracy ofreal-time PCR-based assays. Today, highly sensitiveassays with a limit of detection (LOD) 615

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Key point

-Highly sensitive real-timePCR-based assays are reco-mmended to be used tomonitor HCV RNA duringand after therapy.-Several commercially avail-able assays are approved fortreatment monitoring.-Differences in assays sensi-tivities and quantificationmust be addressed whencomparing and interpretingHCV RNA results.

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International Units (IU)/ml are universally recom-mended for monitoring treatment response [5].However, several quantitative nucleic acid testswith different sensitivities and different ranges ofquantification are commercially available [12].These differences in performance characteristicsmust be addressed when comparing assay resultsin a given clinical setting.

PegIFN-based dual and triple therapies are asso-ciated with severe side effects that can sometimeseven be fatal [12–15]. The concept of RGT wasimplemented not only to increase SVR but also toshorten treatment, which may be associated withbetter tolerability and patient compliance. In2014, the first IFN-free regimens became available.Currently, IFN-free treatment with direct-actingantiviral agents (DAAs) is the standard of care inmany countries. These treatments are generallysafe and well tolerated, and viral eradication canbe achieved in the vast majority of patients [16].DAA treatment durations are mostly short, rangingfrom 8–24 weeks only, with most patients achiev-ing undetectable HCV RNA relatively early duringantiviral therapy. This has fundamentally changedthe role of on-treatment HCV RNA monitoring.Indeed, the original concept of RGT is now verymuch in question as on-treatment HCV RNA mayno longer be used to increase SVR significantly.Instead, RGT may still be useful for other reasons,in particular for its cost-saving potential.

In this review we discuss the role of on-treatment HCV RNA quantification to guide treat-ment duration in light of the therapeutic advancesthat have evolved over the past years.

Virologic tools for HCV RNA quantification

Molecular assays for HCV RNA detection and quan-tification are routinely used to diagnose and moni-tor treatment of patients with chronic HCVinfection. These assays have evolved over the past20 years in parallel with the tremendous advancesin the therapeutic field. Currently, several HCVRNA assays are commercially available that use dif-ferent combinations of amplification and detectionmethods (Table 1). These include signal amplifica-tion techniques, such as branched DNA amplifica-tion, and target amplification techniques, such aspolymerase chain reaction (PCR) or transcription-mediated amplification (TMA) [12,17].

Real-time PCR technology

The classic PCR technique involves thermal cyclingand a thermostable DNA polymerase that has bothreverse transcriptase and polymerase activity.During the process, HCV RNA is transcribed intocomplimentary DNA, which serves as a templatein the PCR reaction. The number of DNA copies is

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doubled with each PCR cycle. However, the numberof amplicons can only be analysed at the end of thePCR reaction. Quantification is based on competitiveamplification of the HCV target sequence and aknown amount of a quantification standard that isadded to each reaction tube.

The limitations of classic end-point PCR assays,such as relatively low sensitivity, narrow dynamicrange and lack of automation have been largelyovercome with the advent of real-time PCR technol-ogy [18–20]. Real-time PCR relies on the detectionand quantification of a fluorescent reporter that islinked to a quencher and annealed to the targetsequence. The reporter signal is released duringeach PCR cycle and increases in direct proportionto the amount of the PCR product. By measuringthe amount of fluorescence emission at each cycle,it is possible to collect the PCR data during the expo-nential growth phase in real-time as opposed toend-point detection.

Commercially available real-time HCV RNA assays

Several real-time PCR assays are commerciallyavailable. The two most widely used assays theCOBAS AmpliPrep/COBAS TaqMan (CAP/CTM; RocheDiagnostics, Rotkreuz, Switzerland) and the AbbottRealTime HCV assay (ART; Abbott Molecular, DesPlaines, IL, USA) as well as the COBAS TaqMan foruse with the High Pure System (HPS/CTM; RocheDiagnostics), which is used in most clinical trials,are discussed herein. All three assays have receivedConformité Européenne (CE) marking and UnitedStates Food and Drug Administration (FDA) approvalfor monitoring HCV RNA during antiviral therapy.

For assay standardization purposes, a WHOinternational standard for HCV was established.The standard comprises genotype 1a HCV RNA pos-itive plasma and has been calibrated in IU/ml [21].All assays are calibrated against this standard, whichis currently available in its 5th version (https://www.nibsc.org/documents/ifu/14-150.pdf). How-ever, despite calibration to the standard material,significant differences between assays have beenreported, i.e., lower quantification by ART andhigher quantification by CAP/CTM [22,23]. Thismay result from different reasons, including inter-individual and genotype-specific sequence variabil-ity, even within the highly conserved 5’-UTR whichcommonly serves as the primer binding region,and differences in assay properties, such as theinternal control [23,24].

The COBAS TaqMan HCV assay was the first real-time PCR assay to be approved for the guidance ofantiviral therapy. The assay is highly sensitive andlinear over a broad dynamic range [25,26]. A com-mon misconception is that there is only one COBASassay available. However, for HCV RNA extractioneither the manual HPS viral nucleic acid kit that usesglass fibre columns or the fully automated COBASAmpliPrep (CAP) instrument that uses magnetic

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Table 1. Commercially available real-time HCV RNA assays.

Assay Manufacturer Extraction device Amplification device IVD approval status

Limit of detection (LOD) in IU/ml

Range of quantificationin IU/ml

COBAS TaqMan HCV Test v2.0 For Use With The High Pure System (HPS/CTM)

Roche molecular diagnostics

High pure system (manual)

COBAS TaqMan CE (Europe)FDA (USA)

8.8-9.3 (GT1; Europe)20 (all GTs; USA)

25-3.91×108

(GT1; Europe)25-3×108 (all GTs; USA)

COBAS AmpliPrep/COBAS TaqMan HCV Test, v2.0 (CAP/CTM)

Roche molecular diagnostics

Roche molecular diagnostics

COBAS AmpliPrep

COBAS TaqMan CE (Europe)FDA (USA)

15 15-1.0×108

RealTime HCV Abbott molecular m2000SP m2000RT CE (Europe)FDA (USA)

12 12-1.0×108

Artus HCV QS-RGQ assay Qiagen QIAsymphony SP/AS

Rotor-Gene Q CE (Europe) 36.2 67.6-17.7×106

Versant HCV 1.0 kPCR Assay

Siemens healthcare

kPCR sample Prep

kPCR amplification and detection (AD) module

CE (Europe) 15 15-1.0×108

Xpert HCV Viral Load Cepheid GeneXpert system CE (Europe) 4-6.1 10-1.0×108

Aptima HCV Quant Dx Assay Hologic Panther system CE (Europe) 3.9-4.3 10-1.0×108

VERIS HCV Assay Beckman coulter DxN VERIS molecular diagnostics System

CE (Europe) 12 12-1.0×109

COBAS HCV test COBAS 6800/8800 systems CE (Europe) 10 15-1.0×108

CE, Conformité européenne; FDA, Food and Drug Administration; GT, genotype; IVD, in vitro diagnostics.

Key point

-The lower limit of quantifi-cation (LLOQ) representsthe lowest HCV RNA resultwithin the linear range of agiven assay.-The limit of detection (LOD)represents the lowest HCVRNA level detected P95% ofthe time.

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microparticles for the purification of nucleic acidsare combined with the COBAS TaqMan assay(HPS/CTM and CAP/CTM, respectively). Each assayhas distinct performance characteristics withregard to the LOD and dynamic range of HCV RNAquantification (Table 1). The HPS/CTM assay hasbeen commonly used in clinical trials, particularlyin most approval studies involving DAAs. In thesestudies, an HCV RNA result <25 IU/ml has beenused to determine on-treatment and post-treatment response [8–11,27–35]. With the firstversion of the fully automated CAP/CTM assay, sig-nificant underestimation of clinical genotype 4samples was reported [36]. However, with use ofa new dual probe design, the following second ver-sion has been shown to accurately quantify all 6genotypes over the full dynamic range [24,26,37].

The ART assay is also highly sensitive and showsa linear quantification range across all 6 genotypes[23,38]. Interestingly, the assay is more sensitivearound the lower limit of quantification (LLOQ)when compared to the CAP/CTM and HPS/CTMassays. This has led to the observation that manyon-treatment or even post-treatment specimensthat had results reported as ‘‘target not detected”by HPS/CTM or CAP/CTM showed detectable/notquantifiable or even quantifiable results by theART assay [22,39–42].

Lower limit of quantification and limit ofdetection

As mentioned above, HCV RNA <25 IU/ml assessedwith HPS/CTM has been widely used to determineon-treatment and post-treatment response in

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clinical trials. However, while 25 IU/ml representsthe lowest HCV RNA level that is within the linearrange of the HPS/CTM assay (LLOQ), it is not thelowest possible HCV RNA result that can be detectedby this assay. Any positive PCR signal below theLLOQ will be reported as ‘‘detectable, <25 IU/ml” ordetectable/not quantifiable” and this also holds truefor the other available assays with their respectivecut-offs (Table 2). Thus, HCV RNA results can bereported in three different ways with regard to thelower end of quantification: i) quantifiable, showinga specific number in IU/ml within the linear range ofthe respective assay; ii) detectable/not quantifiable,representing any detectable result that lies belowthe LLOQ (i.e., <25 IU/ml for HPS/CTM; <15 IU/mlfor CAP/CTM; <12 IU/ml for ART), and iii) an unde-tectable HCV RNA result, also known as ‘‘target notdetected”, with no PCR amplification possible(Fig. 1).

The lower limit of detection (LOD) represents astatistical threshold. That is, the lowest HCV RNAlevel detected P95% of the time as a positive PCRsignal. It is important to note that HCV RNA levelsbelow the LOD may therefore still be detectable in<95% of the time. Thus, in samples with HCV RNAlevels below the respective assay LOD it can simplybe a matter of chance, whether or not HCV RNA isreported to be detectable or undetectable. CAP/CTM, for example, has a LOD of 15 IU/ml but it hasbeen shown to detect HCV RNA levels of 2.5 IU/mlin approximately 50% of the time, which will thenbe reported as ‘‘detectable/not quantifiable(<15 IU/ml)” [26,43]. Similarly, in one study thatassessed on-treatment HCV RNA of patients under-going telaprevir-based triple therapy, samples weretested in triplicate by the first and second version of

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Key point

-Response-guided therapywas used to individualizetreatment duration in pati-ents treated with pegylatedinterferon/ribavirin.-Shorter and longer treat-ment durations were deter-mined based on baselineHCV RNA and on-treatmentresponse at treatment weeks4, 12 and 24 of antiviraltherapy.

Key point

The majority of treatment-naïve patients with HCVgenotype 1 were eligible toreceive a shorter course oftelaprevir/boceprevir-basedtherapy based on attainingan extended rapid virologicresponse.

Table 2. Definitions of commonly used assay cut-off values.

Cut-off DefinitionLimit of detection (LOD) The lowest HCV-RNA level that can be qualitatively

detected by a given assay ≥95% of the time

Lower limit of quantification (LLOQ)

The lowest HCV-RNA level that can be quantitatively detected within the linear range of a given assay

Upper limit of quantification (ULOQ)

The highest HCV-RNA level that can be quantitatively detected within the linear range of a given assay

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CAP/CTM and with HPS/CTM. In samples that hadundetectable HCV RNA according to one assay,retesting with the respective other assays resultedin detectable HCV RNA in 32–50% of cases [44].

The role of HCV RNA quantification duringpegylated interferon/ribavirin dual therapy

The likelihood of achieving SVR to treatment withPegIFN/RBV is directly related to when the patientbecomes HCV RNA undetectable during therapy[7]. Patients with HCV genotype 1, 2 or 3 infection,who became HCV RNA undetectable within4 weeks after initiating treatment (defined as arapid virologic response; RVR) had high SVR ratesin the range of 86–88% compared to patients whoonly cleared the virus at treatment week 12 (SVR:54–68%) [45]. Based on a combination of low base-line viral load (<600–800,000 IU/ml) and attain-ment of RVR, patients can be identified whoqualify for shorter-than-standard treatment dura-tions: Patients who meet both criteria and whodo not have any negative response predictors atbaseline (e.g., cirrhosis or diabetes) can receive 16or 24 weeks of treatment in HCV genotypes 2/3and 1, respectively, instead of the standard dura-tions of 24 and 48 weeks, without compromisingSVR rates [46–50].

Measurement of on-treatment HCV RNA at latertime points during treatment has been mostly usedto predict futility [51,52]. In contrast, it was alsoshown that patients with a >2 log decline at treat-ment week 12 but detectable HCV RNA benefitfrom treatment extension to 72 weeks [53–55].

The role of HCV RNA quantification duringprotease inhibitor-based triple therapy

Following the approval of the first two HCV PIstelaprevir (TVR) and boceprevir (BOC) in 2011, theconcept of RGT was readily incorporated as a cen-tral element in treating patients with HCV geno-type 1 infection. With these new therapies, SVRrates were significantly higher compared toPegIFN/RBV alone (67–75% vs. 40–44% intreatment-naïve patients) [9,10]. The TVR/BOC-specific RGT paradigm was based on phase III data

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that had shown in treatment-naïve patients andthose who had experienced relapse following a priorcourse of PegIFN/RBV therapy that duration of ther-apy could be safely shortened to 24 weeks (TVR) or28 weeks (BOC) provided the patient achieved unde-tectable HCV RNA at week 4 and 8 through week 12and 24 of triple therapy with TVR and BOC, respec-tively [6,10,56]. Given the relatively high antiviralactivity of the new PIs, shorter treatment durationsare applicable in 44%-65% of patients [10,56].

In a retrospective analysis of the TVR and BOCregistration trials, patients who had detectable/<25 IU/ml HCV RNA measured by HPS/CTM at week4, had an approximately 20% lower SVR rate com-pared to patients with undetectable HCV RNA. Thus,eligibility for shortened therapy should be based onattainment of undetectable HCV RNA at week 4 only,whereas patients with detectable/not quantifiable(<25 IU/ml) HCV RNA should receive a full courseof therapy [43]. However, the HPS/CTM assay thatwas used in these trials has been shown to be lesssensitive compared to CAP/CTM and ART, whichare mostly used in clinical routine [39,44,57].Indeed, some data suggest that assay-specific RGTcriteria may be required given the significantperformance differences among HCV RNA assays.In one study, week 4 samples of patients undergoingresponse-guided triple therapy with TVR using theCAP/CTM assay were re-tested with ART. In thisstudy, 58% of patients who received shortened treat-ment based on RGT criteria using the CAP/CTM assayhad detectable HCV RNA according to the ART assayand all but one of these patients achieved SVR. Thus,an undetectable HCV RNA result obtained with theART assay should not be a requirement for short-ened treatment durations as this will likely lead toovertreatment in a significant portion of patients,and an HCV RNA result <12 IU/ml at week 4 maytherefore be the better threshold [42].

By implementing RGT guidelines and stoppingrules to patients who are treated with TVR- orBOC-based triple therapies, potentially seriousadverse effects and high costs of futile treatmentscan be avoided. However, correct use of such criteriarequires close patient monitoring and knowledge ofthe performance characteristics and limitations ofthe assay in use. Not surprisingly, adherence toRGT guidelines was less than 33%, and adherenceto stopping rules was less than 50% in a recent ret-rospective real-world analysis [58].

In 2014, the second generation NS3 PI simeprevir(SMV) was approved for the treatment of patientswith HCV genotype 1 or 4 infection. In patientstreated with SMV and PegIFN/RBV, all medicationshould be stopped if HCV RNA levels are P25 IU/ml at week 4 [59–61]. As seen with the firstgeneration PIs, SVR rates were approximately 30%lower in patients who had detectable/<25 IU/mlHCV RNA at week 4 when compared to those withan undetectable viral load [60–62]. In a retrospec-tive analysis of week 4 results, substantially

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HCV RNA never detectable (0%)

HCV RNA detectable/not quantifiable(>0%; <95%)

HCV RNA detectable and quantifiable(≥95%)

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LOD

LOB

LLOQ

Fig. 1. Summary of different HCV RNA levels during antiviraltherapy. The limit of blank (LOB) represents the thresholdwhere no PCR amplification is possible. The limit of detection(LOD) represents the lowest HCV RNA level detected P95% ofthe time as a positive PCR signal. The lower limit of quantifi-cation (LLOQ) represents the lowest HCV RNA levels that lieswithin the linear range of the respective assay.

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different RVR rates were observed among the threewidely used assays, HPS/CTM, CAP/CTM, and ART.However, patients with undetectable HCV RNA atweek 4 had SVR rates >90%, regardless of the assayin use [63].

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The IFN-free era: Is there a need forindividualized treatments or does one size fit all?

The approval of IFN-free therapies has fundamen-tally changed the role of RGT. An important steptowards HCV eradication is the overall highantiviral efficacy of these new regimens. In therespective phase 3 studies, almost all patientsachieved HCV RNA <LLOQ at some point duringtreatment, often within the first 4 weeks of therapy[27,28,30,32,34,64–69]. SVR rates >90% have nowbecome reality for the majority of patientsubgroups. As virological failures during therapyare rare, no stopping criteria have yet been estab-lished. Moreover, these regimens are far bettertolerated than any of the former IFN-containingtreatments [14,33,70,71]. Thus, there seems to beno major interest in shortened treatment durationswith respect to drug safety. However, despite thegood tolerability and high efficacy, individualizedtreatment durations may still be beneficial for var-ious reasons (Fig. 2):

1) Reducing treatment costFrom an economic perspective, short DAAtreatments are highly desirable. Indeed, thehigh costs of DAA treatments and theirpotential impact on the access to HCV carehave sparked an intensive debate. UnlikeIFN-based therapies, there are rarely absolutecontraindications to the currently approvedDAAs [5]. Thus, the number of patientseligible to receive HCV treatment hasdramatically increased in the past two years[71]. In order to address this economicchallenge, access to DAA therapy has been

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restricted to patients with advanced liver dis-eases or significant extrahepatic manifesta-tions in many countries. However, differentepidemiological models have clearly shownthat only a significant increase in treatmentuptake can achieve a meaningful reductionin HCV prevalence and HCV associated mor-bidity and mortality. Thus, treatment of allHCV patients should be considered but mayonly be realistic if treatments costs can bereduced significantly [72,73].

2) Preventing DAA side effects:Although DAA-related side effects are infre-quent and usually mild to moderate, this doesnot mean that they are entirely absent. Thus,shorter DAA treatments may even be desir-able with regard to treatment safety, particu-larly in the presence of advanced cirrhosis.There is at least some evidence that SOF-based treatments may be associated withincreased adverse effects in patients withadvanced liver disease [74]. Reports of hep-atic decompensations during treatment withombitasvir (NS5A inhibitor; OBT), paritapre-vir (NS3 PI; PTV/ritonavir (r)) and dasabuvir(non-nucleoside NS5B inhibitor; DSV) inpatients with advanced cirrhosis have evenled to a post-marketing label change thatrestricts this regimen to patients with com-pensated liver disease only [5,75].

3) Limiting the risk of drug-drug-interactions:The challenge of drug-drug interactions(DDIs) should be addressed while consideringtreatment safety. Recent data show that up to66% of HCV patients can be at considerablerisk for DDIs if treated with one of the avail-able IFN-free regimens [76]. The risks for DDIsmay increase with longer treatment dura-tions, in particular if due to the good tolera-bility treatment access is expanded topatients with several co-morbidities.

Thus, even with current DAA regimens, treat-ment duration should be as short as possible toavoid unnecessary drug exposure. With currentDAAs the standard treatment duration is 12 weeksfor the majority of patients. For PegIFN-based regi-mens the optimal treatment duration as well asthe concept of a RGT was widely based on viralkinetics modeling estimating the time until viraleradication could be reached [77]. In contrast, thereis no scientific base to assume that a 12-week treat-ment duration is necessary using IFN-free DAA reg-imens. Indeed, there is increasing evidence that a12-week regimen with two or more DAA representsovertreatment in a significant number of patients.Easy-to-treat patients, i.e., those without cirrhosisand no previous treatment failure, may require only8 weeks of treatment without compromising SVRrates [32,65] and even shorter treatment durationsmay be possible in well-selected patients.

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Motivation for response-guided

treatmentin the IFN era

Motivation forresponse-guided

treatmentin the IFN-free era

IncreaseSVR rates

Limitadverseeffects

IncreaseSVR rates

Limitadverseeffects Reduce

treatmentcosts

Reducetreatment

costsImprovetreatmentadherence

Improvetreatmentadherence

Fig. 2. Motivation for response-guided therapy (RGT) in the era of interferon-based therapy vs.direct-acting antiviral (DAA) therapy. Changing motivation for RGT: From SVR being the highestpriority in the era of interferon-based therapies to a reduction in treatment costs being the highestmotivator with current highly efficacious DAAs.

Key point

On-treatment HCV RNA isnot a strong predictor oftreatment outcome in themajority of highly effica-cious DAA combinationtherapies, in particular ifSVR rates exceed 90–95%.

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At present, only an eight-week regimen of ledi-pasvir (NS5A inhibitor; LDV) in combination withsofosbuvir (NS5B polymerase inhibitor; SOF) isapproved. However, this treatment was not estab-lished based on RGT criteria. Eight weeks of LDV/SOF is recommended for treatment-naïve, non-cirrhotic patients with genotype 1 infection pro-vided they have a viral load <6 million IU/ml atbaseline [78]. The label was based on a post-hocanalysis of patients treated for 8 weeks in theION-3 study which showed that only an HCV RNAconcentration below 6 million IU/ml at baselinewas associated with a low rate of relapse thatwas comparable to the overall study population[32]. This label has been controversially discussedas it lacks a scientific basis [80]. Moreover, thecut-off may show significant variation dependingon the assay that is used [79]. Interestingly, ‘‘Real-world” data suggest that in patients who receive8 weeks of LDV/SOF without consideration of assaydifferences and without strict adherence to the cut-off show comparable SVR rates to the SVR seen inthe ION-3 study in the subgroup of patients withbaseline HCV RNA <6 million IU/ml [81]. Robustcriteria to select patients that qualify for shortertreatment still need to be better defined. However,these data also clearly show that shorter treatmentregimens are certainly possible in a large propor-tion of the patient population.

On the other hand, there are still some patientswho may benefit from extension of treatment dura-tion or addition of ribavirin. This seems to be par-ticularly true in patients with HCV genotype 3infection and those with decompensated cirrhosis[82–84]. For example, in cirrhotic patients withHCV genotype 3 who also failed a prior course ofPegIFN/RBV therapy, triple therapy with daclatasvir(NS5A inhibitor, DCV) and SOF plus addition of RBVfor 24-week is recommended [5]. Achieving SVR inthese patients with the first course of IFN-freetreatment is of particular importance as patients

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who fail a first course of DAA therapy are at high riskof developing resistance-associated variants (RAVs).This holds particularly true for patients who fail anNS5A inhibitor-containing regimen as these drugshave a relatively low barrier to resistance. NS5ARAVs can be found in the majority of treatment fail-ures and these RAVs may persist for several yearsthereafter, thereby limiting re-treatment options[85,86]. While the presence of baseline RAVs maynot have a significant influence on overall SVRchances to a first course of DAA therapy, few dataexist on their impact on re-treatment in patientswho failed a DAA treatment [87,88]. Thus, failureto DAAs should be avoided by choosing the best reg-imen and treatment duration available for each indi-vidual patient, particularly in the presence ofadditional negative response predictors such as cir-rhosis and prior failure to PegIFN-based therapy.

In conclusion, a fixed treatment duration (‘‘onesize fits all”) may either lead to overtreatment in asignificant proportion of easy-to-treat patientswhereas the risk of treatment failure may beincreased in more difficult-to-treat patients(Fig. 3). Individualized treatment durations havethe potential to reduce treatment costs and increaseSVR rates. However, at present, the level of treat-ment individualization is relatively low with respectto IFN-free DAA therapies. On-treatment HCV RNAmay have the potential to add an important aspecttowards more individualized treatment durations.

HCV RNA quantification for the prediction of SVRduring IFN-free therapy

RGT strategies have not (yet) been established forIFN-free DAA therapies. Accordingly, on-treatmentHCV RNA measurements are not recommended inthe respective DAA package inserts. Despite this,the European Association for the Study of the Liver(EASL) treatment guidelines recommend quantita-tive HCV RNA testing at treatment weeks 2, 4 andat the end of antiviral therapy in order to ensurepatient compliance and treatment efficacy [5]. How-ever, these guidelines neither provide stopping rulesnor criteria for a response-guided modification oftreatment duration based on results generated atthe respective on-treatment time points [5]. It couldbe argued that viral load testing may be too costintensive to simply document treatment adherenceand/or on-treatment efficacy, particularly if it is ofno consequence to the patient. For this purpose,the cheaper HCV core antigen (HCV Ag) test maybe of clinical use [89,90]. However, as the sensitivityof the HCV Ag assay is comparably low, RGT strate-gies may not be performed with this assay [90]. Forthis purpose, HCV RNA is likely to be more useful.Implementation of RGT algorithms to further indi-vidualize and optimize DAA treatments would, how-ever, require a meaningful predictive value of on-treatment response (reflected by HCV RNA levels)

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Easy-to-treat4-6 wks required for SVR

Standard8-12 wks required for SVR

Difficult-to-treat12-24 wks required for SVR

Standard treatment duration12 wks

Suboptimal therapyTreatment failure

OvertreatmentUnnecessary costs

Easy-to-treat4-6 wks required for SVR

Standard8-12 wks required for SVR

Difficult-to-treat12-24 wks required for SVR

Long treatment duration24 wks

OvertreatmentUnnecessary costs

OvertreatmentUnnecessary costs

Easy-to-treat4-6 wks required for SVR

Standard8-12 wks required for SVR

Difficult-to-treat12-24 wks required for SVR

Short duration6 wks

Suboptimal therapyTreatment failure

Suboptimal therapyTreatment failure

Easy-to-treat4-6 wks required for SVR

Standard8-12 wks required for SVR

Difficult-to-treat12-24 wks required for SVR

24 wks12 wks6 wks

Individualized treatment duration

One size fits all1. Standard duration for all

2. Long duration for all

3. Short duration for all

Fig. 3. One size fits all vs. individualized treatment. The model is based on the assumption that a fictional HCV population consists of three different groups: an easy-to-treat group, a standard group and a difficult-to-treat group. Using the same DAA regimen different minimal treatment duration is needed for each group to achieve SVR inthe majority of patients. If one standard duration is used for all patients this results either in overtreatment of the easier to treat cohorts or in a suboptimal therapy in themore difficult-to-treat groups. Individualized treatment duration in each of the three groups reduces overtreatment without compromising SVR rates.

Key point

Early on-treatment HCV RNAmay be predictive oftreatment outcome in somedifficult-to-treat patientsubgroups, including pati-ents with advanced cirrhosisand those infected with HCVgenotype 3

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for SVR. Overall, data regarding the associationbetween on-treatment HCV RNA levels duringIFN-free therapies and SVR are still relatively scarceand viral kinetics that were assessed in many of theDAA approval studies were often incompletelystudied. In the following, available data on on-treatment HCV RNA for SVR prediction in DAA reg-imens will be summarized.

HCV RNA quantification for the prediction of SVRduring sofosbuvir/ribavirin treatment

The combination of SOF and RBV was the first IFN-free therapy that was approved for the treatment ofHCV infection. On-treatment HCV RNA levels seemto be predictive of SVR with this regimen as long asthere is a significant risk of treatment failure in agiven patient cohort resulting in a considerablenumber of relapsers.

SOF/RBV given for 24 weeks was used directlyafter SOF-approval in patients with chronic HCVgenotype 1 infection and urgent need for immedi-ate therapy. This regimen is now considered too

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ineffective for genotype 1 patients as SVR could beachieved in only 50–70% [40,41,91,92]. However,we found that on-treatment HCV RNA levels atweeks 1, 2 and 4 were significantly higher in relap-sers compared to patients with SVR. The greatestdifference in HCV RNA levels between patients withrelapse and those who achieved SVR was found attreatment week 2 [40] (Table 3). In another study,patients with an undetectable HCV RNA with theART assay or HCV RNA <LLOQ with the CAP/CTMassay at treatment week 4 had higher chances toachieve SVR (88% vs. 61% and 70 vs. 50%, respec-tively). However, this was not statistical significant.HCV RNA results at week 2 were not investigated inthis study [41] (Table 3).

In the era of IFN-free treatments, HCV genotype 3has evolved as the most difficult genotype to cure[93]. In the VALENCE study, genotype 3 patientswere treated with SOF/RBV for 24 weeks andachieved an overall SVR rate of 85%. However,among those who were treatment-experienced andalso had cirrhosis, the SVR rate was only 62% [35].A post-hoc analysis found that SVR rates varied

of Hepatology 2016 vol. 65 j S67–S81 S73

Table 3. Predictive value of on-treatment HCV RNA results during IFN-free therapy.

Regimen Genotype Treatment duration

Study/author Study population OverallSVR rate

SVR prediction by on-treatmentHCV RNA response (selected cut-offs)

Sofosbuvir +ribavirin

1 24 weeks Steinebrunner et al. [92] All patients (n = 12) 50% Week 4: <LLOQ/≥LLOQ: 67%/33%Sidharthan et al. [41] All patients (n = 55) 69% Week 4:

CTM v.1.0:<LLOQ/≥LLOQ: 70%/50%TND vs. detectable: 70%/68%ART:<LLOQ/≥LLOQ: 71%/67%TND vs. detectable: 88%/61%

Maasoumy et al. [40] All patients (n = 31) 52% Week 1:CTM: <225 IU/ml vs. ≥225 IU/ml: 93%/8%ART: <270 IU/ml vs. ≥270 IU/ml: 93%/8%Week 2: CTM: <35 IU/ml vs. ≥35 IU/ml: 93%/13%ART: <70 IU/ml vs. ≥70 IU/ml: 93%/13%Week 4:CTM: TND vs. detectable: 77%/35%ART: <LLOQ vs. ≥LLOQ: 92%/28%

2 12 weeks FISSION + POSITRON, Wyles et al. [96]

All patients (n = 176) 96% Week 1: TND/detectable: 100%/96%Week 2: <LLOQ/≥LLOQ: 97%/85%Week 4: TND/detectable: 98%/83%

FUSION, Wyles et al. [96] Prior PegIFN/RBV failure (n = 36)

86% Week 1: <LLOQ/≥LLOQ: 90%/85%Week 2: <LLOQ/≥LLOQ: 87%/83%

VALENCE, Zeuzem et al. [94] All patients (n = 73) 93% Week 1: <LLOQ/≥LLOQ: 88%/96%Week 2: <LLOQ/≥LLOQ: 89%/100%Week 4: TND/detectable: 93%/92%

Maasoumy et al. [40] All patients (n = 32) 88% Week 1:CTM: <70 IU/ml vs. ≥70 IU/ml: 93%/63%ART: <70 IU/ml vs. ≥70 IU/ml: 92%/67%Week 2: CTM: <LLOQ vs. ≥LLOQ: 90%/83%ART: <LLOQ vs. ≥LLOQ: 94%/80%Week 4:CTM: TND vs. detectable: 91%/75%ART: TND vs. detectable: 88%/86%

16 weeks FUSION, Wyles et al. [96] Prior PegIFN/RBV failure (n = 32)

94%

60%

31%

62%

Week 1: <LLOQ/≥LLOQ: 100%/93%Week 2: <LLOQ/≥LLOQ: 96%/75%Week 4: TND/detectable: 96%/83%

3 12 weeks FISSION + POSITRON, Wyles et al. [96]

All patients (n = 272) Week 1: <LLOQ/≥LLOQ: 72%/50%Week 2: <LLOQ/≥LLOQ: 62%/38%Week 4: TND/detectable: 62%/48%

FUSION, Wyles et al. [96] Prior PegIFN/RBV failure (n = 61)

Week 1: <LLOQ/≥LLOQ: 38%/29%Week 2: <LLOQ/≥LLOQ: 37%/8%Week 4: TND/detectable: 38%/9%

16 weeks FUSION, Wyles et al. [96] Prior PegIFN/RBV failure (n = 63)

Week 1: <LLOQ/≥LLOQ: 70%/58%Week 2: TND/detectable: 72%/55%Week 4: TND/detectable: 65%/44%

24 weeks Maasoumy et al. [40] All patients (n = 33) 64% Week 1:CTM: <270 IU/ml vs. ≥270 IU/ml: 88%/40%ART: <190 IU/ml vs. ≥190 IU/ml: 89%/33%Week 2: CTM: <45 IU/ml vs. ≥45 IU/ml: 100%/33%ART: <60 IU/ml vs. ≥60 IU/ml: 100%/29%Week 4:CTM: TND vs. detectable: 79%/53%ART: <LLOQ vs. ≥LLOQ: 82%/44%

VALENCE, Zeuzem et al. [94] All patients (n = 248) 86% Week 1: <LLOQ/≥LLOQ: 99%/80%Week 2: <LLOQ/≥LLOQ: 90%/61%Week 4: TND/detectable: 91%/67%

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Table 3 (Continued)

Regimen Genotype Treatment duration

Study/author Study population OverallSVR rate

SVR prediction by on-treatmentHCV RNA response (selected cut-offs)

Sofosbuvir + simeprevir

1 12 weeks OPTIMIST-2, Lawitz et al. [67]

Cirrhosis (n = 103) 83% Week 4: TND/detectable: 86%/76%

Sofosbuvir +daclatasvir +ribavirin

1, 2, 3 and 4

12 weeks ALLY-1, Poordad et al. [83] Advanced cirrhosis (CHILD A-C)

83% Week 4: TND/detectable: 94%/71%

Sofosbuvir +daclatasvir

3 12 weeks ALLY-3, Kowdley et al. [104] Cirrhosis (n = 32) 63% Week 1: <LLOQ/≥LLOQ: 40%/67%Week 2: <LLOQ/≥LLOQ: 70%/50%Week 4: <LLOQ/≥LLOQ: 66%/33%

Sofosbuvir +ledipasvir ±ribavirin

1 12 or 24 weeks

ION 1 + 2, Welzel et al. [101] Only patients with cirrhosis (n = 224)

96% Week 1: <LLOQ/≥LLOQ: 96%/96%Week 2: <LLOQ/≥LLOQ: 98%/91%Week 4: TND/detectable: 98%/91%

SOLAR-1, Welzel et al. [103] CHILD B+C cirrhosisPatients after liver transplantatation (n = 310)

96% Week 2: TND/detectable: 96%/96%<LLOQ/≥LLOQ: 98%/94%Week 4: TND/detectable: 98%/94%<LLOQ/≥LLOQ: 96%/98%

Ombitasvirparitraprevir +ritonavir +dasabuvir ±ribavrin

1 12 or 24 weeks

SAPPHIRE I + IIPEARL II + III + IVTURQUOISE IISulkowski et al. [105]

Without cirrhosis (n = 1650)

98% SVR by first time HCV RNA TNDWeek 1: 98%; Week 2: 98%Week 4: 98%; Week 8: 100%

TURQUOISE II, Sulkowski et al. [105]

Cirrhosis (n = 372) 96% SVR by first time HCV RNA TNDWeek 1: 100%; Week 2: 94%Week 4: 97%; Week 8: 100%

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significantly depending on the week 1 or week 2HCV RNA result. Overall, only seven patients (3%)were HCV RNA undetectable at week 1 and all ofthese patients achieved SVR. However, 76 patients(30%) achieved HCV RNA <LLOQ, while 172 (69%)had a result PLLOQ, and SVR rates were 99%(n = 75/76) and 80% (n = 138/172), respectively.Similarly, SVR rates among patients with week 2HCV RNA <LLOQ achieved SVR in 90%(n = 191/212) but in only 61% (n = 22/38) if HCVRNA was PLLOQ [94]. We have reported similarresults in a ‘‘real-world” cohort. In 33 genotype 3patients treated with SOF/RBV, HCV RNA levels atweek 1 and 2 were significantly lower in patientsachieving SVR compared to those with treatmentfailure. Again, the largest difference was found atweek 2. We retrospectively identified optimal week2 HCV RNA cut-offs to predict treatment outcome.All patients with HCV RNA <45 IU/ml according toCAP/CTM or <60 IU/ml according to the ART assayachieved SVR, while patients with a week 2 HCVRNA above the respective cut-offs achieved SVR in33% and 29% only [40] (Table 3).

SOF/RBV is widely considered as standard ofcare in genotype 2 patients and high SVR ratesexceeding 88% have been reported [35,95]. As aresult, on-treatment HCV RNA was not predictiveof SVR in genotype 2 patients treated with SOF/RBV for 12 weeks in the VALENCE study [94]. Thiswas recently confirmed in a ‘‘real-world” study[40]. Data from the FISSION + POSITRON trials sug-gest that patients with a slower HCV RNA declineduring treatment have response rates that are12–15% lower compared to those with faster HCVRNA elimination [96] (Table 3). However, the

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overall number of relapsers was relatively low inthese studies, which limits the impact of HCV RNAdecline on SVR prediction.

HCV RNA quantification for the prediction of SVRduring simeprevir/sofosbuvir treatment

In the era of IFN-based treatments, patients with cir-rhosis were considered the most difficult-to-cureand treatment was even contraindicated in thosewith advanced disease. In the OPTIMIST-2 study,patients with HCV genotype 1 infection and cirrho-sis were treated with SMV and SOF for 12 weeksand only 83% achieved SVR. The considerable num-ber of virologic failures in this study sparked theinterest in on-treatment SVR prediction. However,patients with undetectable HCV RNA at week 4had only slightly higher SVR compared to those withdetectable HCV RNA at this time point (86% vs. 76%)[67] (Table 3). Other studies support the notion thaton-treatment HCV RNA alone may not be a goodpredictor of SVR with this DAA regimen [40,97–99].

HCV RNA quantification for the prediction of SVRduring daclatasvir/sofosbuvir and ledipasvir/sofosbuvirtreatment

Combination of a NS5A inhibitor with SOF has beenproven to be a highly efficient treatment option. Thefixed combination of LDV/SOF is currently one of themost widely used regimens for HCV genotype 1infection and high SVR rates can be achieved, evenin patients with advanced cirrhosis [100]. In aretrospective analysis of the LDV/SOF ION-1 andION-2 phase III trials, 224 patients with compen-

of Hepatology 2016 vol. 65 j S67–S81 S75

V

70%

30%

50%

% S

VR

HCV RNASensitivity: 70%Specificity: 70%

Fig. 4. Impact of SVR rates on prepredictors diminishes with the propoHCV RNA cut-off is able to identify SVoverall SVR rate was 50%, patients wachieve SVR in 70% compared to onlycut-off. The difference between the tw32% (relative risk 1,6) and 9% (relativ

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sated cirrhosis were identified and only 9 of thesepatients had experienced virologic relapse. Inter-estingly, these patients had significantly higherHCV RNA levels at weeks 1, 2 and 4 compared tothe SVR patients. Furthermore, patients with aweek 1 and 2 viral load PLLOQ had significantlybetter chances to achieve SVR if they were treatedfor 24 weeks instead of the standard 12-week dura-tion. This observation may give support to the ideaof a RGT concept in cirrhotic patients treated withthis regimen. However, the predictive value of on-treatment HCV RNA was limited even in thesedifficult-to-cure patients, which is not surprisinggiven the overall SVR rate of >95%. The highest neg-ative predictive value (NPV) affecting more thanone patient was seen in the ION-2 study. Here,HCV RNA PLLOQ at week 2 and detectable HCVRNA at week 4 had NPVs of 17% and 20%, respec-tively, to predict post-treatment relapse [101].

Treating patients with decompensated cirrhosisis still one of the most challenging tasks with thecurrent DAAs available. Patients with Child-Pughscore A, B and C cirrhosis treated with DCV andSOF + RBV for 12 weeks in the ALLY-1 studyachieved SVR in 92%, 94% and 56%, respectively.In total, 8 out of 10 patients who failed to achieveSVR had detectable HCV RNA at week 4. In patientswith undetectable HCV RNA at week 4, SVR wasachieved in 94% whereas only 71% of patients withdetectable HCV RNA achieved SVR [83]. In a similaranalysis from the SOLAR-1 study that investigatedLDV/SOF + RBV in decompensated cirrhotic andpost-transplant patients, no association could befound between on-treatment HCV RNA and SVR,which may be explained by the very low numberof virologic failures in this study [102,103].

SOF + DCV is now widely used for the treatmentof genotype 3 patients. In the ALLY-3 study, geno-

Overall SVR

alue of SVR predictors

88%98%

56%

89%

75% 95%Overall SVR

<cut-off HCV RNA >cut-off

dictive value of on-treatment HCV RNA. The value of SVRrtion of patients achieving SVR. In this model an on-treatmentR patients with a sensitivity of 70% and a specificity of 70%. If theith an on-treatment HCV RNA result below the cut-off would30% among those with an HCV RNA result above the selectedo groups is 40% (relative risk 2,3). This difference diminishes toe risk 1,1) if the overall SVR rate is 75% and 95%, respectively.

Journal of Hepatology 2016 vol. 65 j S

type 3 patients were treated with SOF and DCV for12 weeks. In this study, patients without cirrhosisand patients with cirrhosis achieved SVR in 96%and 63%, respectively. Despite this striking differ-ence, the predictive value of on-treatment HCVRNA was still very low in the subgroup of patientswith cirrhosis. The highest difference in SVR rateswas seen with week 2 HCV RNA <LLOQ vs. PLLOQ(SVR: 70% vs. 50%) and again at week 4 (SVR: 66%vs. 33%; n = 3) [104] (Table 3).

HCV RNA quantification for the prediction of SVRduring paritaprevir/ombitasvir + dasabuvir treatment

The combination of ritonavir-boosted PTV/OBT andDSV ± RBV is the only approved DAA triple therapythat is intended for patients with HCV genotype 1infection without decompensated cirrhosis. In a ret-rospective analysis of the six phase 3 studies com-prising more than 2000 patients, time to firstundetectable HCV RNA (week, 1, 2, 4, 6 or 8) wasnot associated with SVR. Overall, SVR was achievedin 96% and 98% of patients with and without cirrho-sis, respectively [105].

Approach towards a response-guided treatmentstrategy in the DAA era

The predictive value of on-treatment HCV RNAseems to be limited in the setting of currently avail-able DAA regimens. Importantly, lower SVR rateswere only observed in patients with a significantrisk for relapse either because they had genotype 3infection or in case a less effective DAA regimenwas used. The value of on-treatment HCV RNA forthe prediction of SVR is clearly lower compared towhat was seen with PegIFN-containing regimens,mainly because these regimens are so efficacious.Even for some less effective DAA regimens such asSMV in combination with SOF, on-treatment HCVRNA does not seem to be significantly associatedwith SVR [67]. For any DAA regimen that is givenin a fixed duration and which shows SVR ratesexceeding 95%, HCV RNA is of no use for responseprediction. However, if higher relapse rates dooccur, on-treatment HCV RNA may still play a con-siderable role (Fig. 4). This may be the case if muchshorter treatment durations are used (e.g.,66 weeks) or if RBV is not added to current DAA reg-imens in difficult-to-cure patient populations. How-ever, response prediction has not been studied inthese patients. Interestingly, recent modeling datasuggest that the use of early HCV RNA kineticsmay be feasible to individualize treatment duration.Dahari and co-workers retrospectively studied acohort of 58 patients who had been treated withDCV/SOF, LDV/SOF or SMV/SOF. In this cohort, onlyone patient relapsed after 12 weeks of LDV/SOF.Based on a modeling analysis, relapse could havebeen prevented in this patient by one additional

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Easy-to-treat patient

HCV RNA at day 2

Ultra-short regimen (4-6 weeks)

HCV RNA at week 2 (day 14)

Standard treatment duration

Eligible for ultra-short regimenPredicted SVR >70%

Screening RAVs, gender,baseline viral load?

Predicted SVR<90%

Predicted SVR>90%

Predicted SVR>95%

Response-guidedtreatment

Predicted SVR<95%

Difficult-to-treat patient

HCV RNA at day 2

Complete standard treatment

HCV RNA at week 2 (day 14)

Add another DAAExpand treatment duration

Eligible for standard treatmentPredicted SVR >70%

Screening RAVs, platelets,baseline viral load?

Predicted SVR<90%

Predicted SVR>90%

Predicted SVR>95%

Predicted SVR<95%

Response-guidedtreatment

A

B

Fig. 5. Possible algorithms for response-guided strategies in the DAA era. Among the easy-to-treatgroup patients are identified who achieve SVR in >70% if they are treated for 4 or 6 weeks with a potentIFN-free regimen. Selection of patients is could be based on different baseline parameters like thepresence of resistant-associated variants (RAVs), gender or baseline viral load. At day 2 of therapy on-treatment HCV RNA is used to predict SVR. Only patients with a predicted SVR rate >90% continue in theRGT arm. The remaining patients are treated for the standard duration (e.g., 12 weeks). At week 2 on-treatment HCV RNA is used again to predict SVR. Patients that are predicted to achieve SVR in less than95% after the ultra-short regimen are treated for the standard duration (A). In difficult-to-treat patients asimilar approach is used. Patients that may not need RBV or a second DAA or those who might be curedwith the standard treatment duration are selected using baseline predictors. At day 2 and week 2on-treatment HCV RNA is used as response predictor. The respective HCV RNA cut-offs need to identifypatients with lower SVR chances in whom a second DAA or RBV can be added or treatment durationneeds to be expanded (B).

Key point

Preliminary data suggest thatvery early on-treatment HCVRNAmaybeused to individu-alize treatment durationwith DAAs.

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week of therapy. More interestingly, the authorsestimated that treatment could have been short-ened in the majority of patients without compro-mising SVR. Based on the use of early viralkinetics they predicted that 43%, 30% and 13% ofpatients would have required only 6, 8, and10 weeks of treatment, respectively [106].

Ferenci and co-workers recently suggested aRGT concept for all patients with cirrhosis treatedwith SOF and either DCV, SMV or LDV but withoutthe addition of RBV. According to preliminary datafrom their own center, all cirrhotic patients weretreated with only 12 weeks of therapy if HCV RNAat week 8 was undetectable with the ART assay.The remaining patients were treated for 16 to24 weeks and all patients achieved SVR. However,this was not a randomized study and data havenot yet been fully published [107]. In our ownstudy, detectable/<12 IU/ml HCV RNA was fre-quently seen with the ART assay even at the endof therapy. However, SVR rates were still very highin these patients, which argues against treatmentextension due to detectable HCV RNA at late stagesof antiviral therapy [40]. Other groups have pub-lished similar data [41,108]. It has been speculatedthat the detection of HCV RNA at the end of therapymay not be infectious virus but residual RNA parti-cles [40,41]. Another possible explanation would bethat any remaining virus is cleared by the host’srestored immune system after treatment cessation[109,110]. However, this requires furtherinvestigation.

Given the high antiviral efficacy of currentDAAs, response prediction should most likely neverbe based on week 4 viral load, as the majority ofpatients is already HCV RNA negative at this stage.Instead, earlier time points such as week 2 or evenafter only a few days of therapy may be more usefulfor response prediction. Indeed, in our study thehighest predictive value for SVR was documentedfor the HCV RNA result at week 2 of SOF/RBV treat-ment [40]. In a pilot study from China, viralresponse was assessed after only 2 days of therapy.Treatment-naïve, non-cirrhotic Chinese patientswith HCV genotype 1b infection were assigned toone of 3 highly potent regimens involving 3 DAAs.Patients were treated with either LDV/SOF+ asunaprevir (ASV), DCV/SOF + SMV or DCV/SOF+ ASV. In patients who achieved a pre-definedcut-off of <500 IU/ml at day 2, all treatment wasstopped after only 3 weeks of therapy. This pre-defined goal was achieved by 18/26 (69%) patientsand all of these patients achieved SVR. Of note,according to a modeling analysis from the samestudy, no patient should have been cured in thisstudy as treatment was predicted to be too shortto hit the viral cure boundary, defined as <1 virionin extracellular body fluid [111]. Such a RGT strat-egy should certainly be explored in a largerprospective trial. Treatment duration could be sig-nificantly shortened in easy-to-treat patients who

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have an ultrarapid on-treatment response withinthe first one or two weeks of therapy. Alternatively,treatment could be started with a cheap and simpleDAA regimen, which is later further escalated bylonger treatment duration or the addition of moreDAAs in case of a suboptimal early treatmentresponse (Fig. 5). However, given the difficulties ofresponse prediction with current viral kinetics mod-els there is still a considerable risk for treatmentfailure, which may be associated with the emer-

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References

[1] Maasoumy B, Wedemeyer H. NaBest Pract Res Clin Gastroentero

[2] Lozano R, Naghavi M, Foremanand regional mortality from 23and 2010: a systematic analysisLancet 2012;380:2095–2128.

[3] Gretch DR. Use and interpretasetting. Clin Liver Dis 1997;1:54

[4] Diseases AAFTSOL, America IDSand treating hepatitis C, 2016.

[5] European Association for the Stfice@easloffice.eu. EASL RecommJ Hepatol 2015;63:199–236.

[6] European AFTSOTL. EASL Clinhepatitis C virus infection. J He

[7] Kau A, Vermehren J, Sarrazin C.response in hepatitis B and C. J

[8] Bacon BR, Gordon SC, Lawitz EBoceprevir for previously treateMed 2011;364:1207–1217.

[9] Jacobson IM, McHutchison JG, DNH, et al. Telaprevir for previnfection. N Engl J Med 2011;36

[10] Poordad F, McCone J, Bacon BRBoceprevir for untreated chron2011;364:1195–1206.

[11] Zeuzem S, Andreone P, Pol S, Lawretreatment of HCV infection. N

[12] Chevaliez S, Rodriguez C, Pawloof chronic hepatitis B and C. Ga

[13] Hézode C, Fontaine H, DorivaEffectiveness of telaprevir or bwith HCV genotype 1 in2014;147:132–142 e4.

[14] Maasoumy B, Port K, DeterdinRogalska-Taranta M, et al. Limitinhibitor-based triple therapy

Ass

ess

me

nt

of

HC

V D

ise

ase

Review

S78

gence of multidrug-resistant variants. Based oncurrent knowledge, RGT is not recommended withcurrently approved DAAs and treatment durationsshould not be altered based on on-treatment HCVRNA levels in a given patient.

Conclusion – Is this the end of response-guidedtherapy?

RGT was a cornerstone of HCV therapy in the era ofPegIFN-based therapy. RGT resulted in a remark-able improvement in SVR rates and reduction ofadverse effects. However, with the approval ofIFN-free DAA regimens, the role of on-treatmentHCV RNA for SVR prediction has diminished signif-icantly given the high efficacy and overall excellenttolerability of these regimens.

Given the perspective of approval of even morepotent regimens over the next few years, RGTstrategies with the aim to increase SVR may nolonger be desirable. Despite this, individualizedtreatment durations may still have considerablebenefits, in particular with respect to cost and pos-sibly some difficult-to-treat patient subgroups.However, due to the lack of sufficient data, RGT

tural history of acute and chronic hepatitis C.l 2012;26:401–412.K, Lim S, Shibuya K, Aboyans V, et al. Global5 causes of death for 20 age groups in 1990for the Global Burden of Disease Study 2010.

tion of HCV diagnostic tests in the clinical3–557, vi.O. Recommendations for testing, managing,

udy of the Liver. Electronic address: easlof-endations on treatment of hepatitis C 2015.

ical Practice Guidelines: management ofpatol 2011;55:245–264.Treatment predictors of a sustained virologicHepatol 2008;49:634–651., Marcellin P, Vierling JM, Zeuzem S, et al.d chronic HCV genotype 1 infection. N Engl J

usheiko G, Di Bisceglie AM, Reddy KR, Bzowejiously untreated chronic hepatitis C virus4:2405–2416., Bruno S, Manns MP, Sulkowski MS, et al.ic HCV genotype 1 infection. N Engl J Med

itz E, Diago M, Roberts S, et al. Telaprevir forEngl J Med 2011;364:2417–2428.

tsky JM. New virologic tools for managementstroenterology 2012;142:1303–1313 e1.l C, Zoulim F, Larrey D, Canva V, et al.oceprevir in treatment-experienced patientsfection and cirrhosis. Gastroenterology

g K, zu Siederdissen C Höner, Markova AA,ed effectiveness and safety profile of proteaseagainst chronic hepatitis C in a real-world

cohort withHepatol 20

[15] Manns MPside effects

[16] Pawlotskyto hepatitis

[17] Scott JD, Gsystematic

[18] Bustin SA.scription2000;25:16

[19] Lockey C, Omolecule. B

[20] Orlando C,Chem Lab

[21] Saldanha J,Health Orginternationtechnology

[22] Maasoumyet al. Perfotriple thera2014;9 e11

[23] Vermehrenbetween twHCV and Co(Versant H2008;46:38

[24] Chevaliez SJM. The Coassay accur2013;51:10

[25] Colucci G,Improvedthe Highperforman2007;45:35

[26] Zitzer H, HSecond-gen

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concepts are currently not recommended for anyof the approved DAA regimens. Future studies needto address whether additional response predictorsmay be combined with on-treatment HCV RNA topredict SVR and whether these can be incorporatedinto RGT algorithms and lead to shorter and less costintensive therapies for some patient subgroups.

Conflict of interest

BM received speaker and/or consulting fees fromAbbott Molecular, AbbVie, Bristol-Myers Squibb,Fujirebio, Janssen-Cilag, Merck/MSD, and Roche. Healso received research support from Abbott Molecu-lar and Roche.

JV received speaker and/or consulting fees fromAbbott Molecular, AbbVie, Bristol-Myers Squibb,Gilead, and Medtronic.

Authors’ contributions

BM and JV wrote and approved the final version ofthe manuscript.

a high proportion of advanced liver disease. Eur J Gastroenterol14;26:836–845., Wedemeyer H, Cornberg M. Treating viral hepatitis C: efficacy,, and complications. Gut 2006;55:1350–1359.JM, Feld JJ, Zeuzem S, Hoofnagle JH. From non-A, non-B hepatitisC virus cure. J Hepatol 2015;62:S87–S99.

retch DR. Molecular diagnostics of hepatitis C virus infection: areview. JAMA 2007;297:724–732.Absolute quantification of mRNA using real-time reverse tran-polymerase chain reaction assays. J Mol Endocrinol9–193.tto E, Long Z. Real-time fluorescence detection of a single DNAiotechniques 1998;24:744–746.Pinzani P, Pazzagli M. Developments in quantitative PCR. Clin

Med 1998;36:255–269.Heath A, Aberham C, Albrecht J, Gentili G, Gessner M, et al. Worldanization collaborative study to establish a replacement WHOal standard for hepatitis C virus RNA nucleic acid amplificationassays. Vox Sang 2005;88:202–204.B, Hunyady B, Calvaruso V, Makara M, Vermehren J, Haragh A,rmance of two HCV RNA assays during protease inhibitor-basedpy in patients with advanced liver fibrosis and cirrhosis. PLoS One0857.J, Kau A, Gärtner BC, Göbel R, Zeuzem S, Sarrazin C. Differenceso real-time PCR-based hepatitis C virus (HCV) assays (RealTimebas AmpliPrep/Cobas TaqMan) and one signal amplification assayCV RNA 3.0) for RNA detection and quantification. J Clin Microbiol80–3891., Bouvier-Alias M, Rodriguez C, Soulier A, Poveda JD, Pawlotskybas AmpliPrep/Cobas TaqMan HCV test, version 2.0, real-time PCRately quantifies hepatitis C virus genotype 4 RNA. J Clin Microbiol78–1082.Ferguson J, Harkleroad C, Lee S, Romo D, Soviero S, et al.

COBAS TaqMan hepatitis C virus test (Version 2.0) for use withPure system: enhanced genotype inclusivity and

ce characteristics in a multisite study. J Clin Microbiol95–3600.eilek G, Truchon K, Susser S, Vermehren J, Sizmann D, et al.eration Cobas AmpliPrep/Cobas TaqMan HCV quantitative test

67–S81

for viral load monitoring: a novel dual-probe assay design. J Clin Microbiol2013;51:571–577.

[27] Afdhal N, Reddy KR, Nelson DR, Lawitz E, Gordon SC, Schiff E, et al. Ledipasvirand sofosbuvir for previously treated HCV genotype 1 infection. N Engl J Med2014;370:1483–1493.

[28] Afdhal N, Zeuzem S, Kwo P, Chojkier M, Gitlin N, Puoti M, et al. Ledipasvir andsofosbuvir for untreated HCV genotype 1 infection. N Engl J Med2014;370:1889–1898.

[29] Feld JJ, Kowdley KV, Coakley E, Sigal S, Nelson DR, Crawford D, et al.Treatment of HCV with ABT-450/r-ombitasvir and dasabuvir with ribavirin.N Engl J Med 2014;370:1594–1603.

[30] Ferenci P, Bernstein D, Lalezari J, Cohen D, Luo Y, Cooper C, et al. ABT-450/r-ombitasvir and dasabuvir with or without ribavirin for HCV. N Engl J Med2014;370:1983–1992.

[31] Jacobson IM, Gordon SC, Kowdley KV, Yoshida EM, Rodriguez-Torres M,Sulkowski MS, et al. Sofosbuvir for hepatitis C genotype 2 or 3 in patientswithout treatment options. N Engl J Med 2013;368:1867–1877.

[32] Kowdley KV, Gordon SC, Reddy KR, Rossaro L, Bernstein DE, Lawitz E, et al.Ledipasvir and sofosbuvir for 8 or 12 weeks for chronic HCV withoutcirrhosis. N Engl J Med 2014;370:1879–1888.

[33] Lawitz E, Mangia A, Wyles D, Rodriguez-Torres M, Hassanein T, Gordon SC,et al. Sofosbuvir for previously untreated chronic hepatitis C infection. N EnglJ Med 2013;368:1878–1887.

[34] Poordad F, Hezode C, Trinh R, Kowdley KV, Zeuzem S, Agarwal K, et al. ABT-450/r-ombitasvir and dasabuvir with ribavirin for hepatitis C with cirrhosis.N Engl J Med 2014;370:1973–1982.

[35] Zeuzem S, Dusheiko GM, Salupere R, Mangia A, Flisiak R, Hyland RH, et al.Sofosbuvir and ribavirin in HCV genotypes 2 and 3. N Engl J Med2014;370:1993–2001.

[36] Chevaliez S, Bouvier-Alias M, Brillet R, Pawlotsky JM. Overestimation andunderestimation of hepatitis C virus RNA levels in a widely used real-timepolymerase chain reaction-based method. Hepatology 2007;46:22–31.

[37] Vermehren J, Yu ML, Monto A, Yao JD, Anderson C, Bertuzis R, et al. Multi-center evaluation of the Abbott RealTime HCV assay for monitoring patientsundergoing antiviral therapy for chronic hepatitis C. J Clin Virol2011;52:133–137.

[38] Michelin BD, Muller Z, Stelzl E, Marth E, Kessler HH. Evaluation of the AbbottRealTime HCV assay for quantitative detection of hepatitis C virus RNA. J ClinVirol 2007;38:96–100.

[39] Fevery B, Susser S, Lenz O, Cloherty G, Perner D, Picchio G, et al. HCV RNAquantification with different assays: implications for protease inhibitor-based response-guided therapy. Antivir Ther 2014;19:559–567.

[40] Maasoumy B, Vermehren J, Welker MW, Bremer B, Perner D, Zu Siederdis-sen CH, et al. Clinical value of on-treatment HCV RNA levels duringdifferent approved sofosbuvir-based antiviral regimens. J Hepatol 2016;65:473–482.

[41] Sidharthan S, Kohli A, Sims Z, Nelson A, Osinusi A, Masur H, et al. Utility ofhepatitis C viral load monitoring on direct-acting antiviral therapy. ClinInfect Dis 2015;60:1743–1751.

[42] Vermehren J, Aghemo A, Falconer K, Susser S, Lunghi G, Zeuzem S, et al.Clinical significance of residual viremia detected by two real-time PCR assaysfor response-guided therapy of HCV genotype 1 infection. J Hepatol2014;60:913–919.

[43] Harrington PR, Zeng W, Naeger LK. Clinical relevance of detectable but notquantifiable hepatitis C virus RNA during boceprevir or telaprevir treatment.Hepatology 2012;55:1048–1057.

[44] Maasoumy B, Cobb B, Bremer B, Luk K, Halfon P, Aslam S, et al. Detection oflow HCV viraemia by repeated HCV RNA testing predicts treatment failure totriple therapy with telaprevir. Aliment Pharmacol Ther 2014;39:85–92.

[45] Fried MW, Hadziyannis SJ, Shiffman ML, Messinger D, Zeuzem S. Rapidvirological response is the most important predictor of sustained virologicalresponse across genotypes in patients with chronic hepatitis C virusinfection. J Hepatol 2011;55:69–75.

[46] Ferenci P, Laferl H, Scherzer TM, Maieron A, Hofer H, Stauber R, et al.Peginterferon alfa-2a/ribavirin for 48 or 72 weeks in hepatitis C genotypes 1and 4 patients with slow virologic response. Gastroenterology2010;138:503–512 512.e1.

[47] Jensen DM, Morgan TR, Marcellin P, Pockros PJ, Reddy KR, Hadziyannis SJ, et al.Early identification of HCV genotype 1 patients responding to 24 weekspeginterferon alpha-2a (40 kd)/ribavirin therapy. Hepatology 2006;43:954–960.

[48] Shiffman ML, Suter F, Bacon BR, Nelson D, Harley H, Sola R, et al.Peginterferon alfa-2a and ribavirin for 16 or 24 weeks in HCV genotype 2or 3. N Engl J Med 2007;357:124–134.

[49] von Wagner M, Huber M, Berg T, Hinrichsen H, Rasenack J, Heintges T, et al.Peginterferon-alpha-2a (40KD) and ribavirin for 16 or 24 weeks in patients

with genotype 2 or 3 chronic hepatitis C. Gastroenterology2005;129:522–527.

[50] Zeuzem S, Buti M, Ferenci P, Sperl J, Horsmans Y, Cianciara J, et al. Efficacy of24 weeks treatment with peginterferon alfa-2b plus ribavirin in patientswith chronic hepatitis C infected with genotype 1 and low pretreatmentviremia. J Hepatol 2006;44:97–103.

[51] Davis GL, Wong JB, McHutchison JG, Manns MP, Harvey J, Albrecht J. Earlyvirologic response to treatment with peginterferon alfa-2b plus ribavirin inpatients with chronic hepatitis C. Hepatology 2003;38:645–652.

[52] Fried MW, Shiffman ML, Reddy KR, Smith C, Marinos G, Gonçales FL, et al.Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection. NEngl J Med 2002;347:975–982.

[53] Mangia A, Minerva N, Bacca D, Cozzolongo R, Ricci GL, Carretta V, et al.Individualized treatment duration for hepatitis C genotype 1 patients: Arandomized controlled trial. Hepatology 2008;47:43–50.

[54] Pearlman BL, Ehleben C, Saifee S. Treatment extension to 72 weeks ofpeginterferon and ribavirin in hepatitis c genotype 1-infected slow respon-ders. Hepatology 2007;46:1688–1694.

[55] Sánchez-Tapias JM, Diago M, Escartín P, Enríquez J, Romero-Gómez M,Bárcena R, et al. Peginterferon-alfa2a plus ribavirin for 48 versus 72 weeks inpatients with detectable hepatitis C virus RNA at week 4 of treatment.Gastroenterology 2006;131:451–460.

[56] Sherman KE, Flamm SL, Afdhal NH, Nelson DR, Sulkowski MS, Everson GT,et al. Response-guided telaprevir combination treatment for hepatitis C virusinfection. N Engl J Med 2011;365:1014–1024.

[57] Kessler HH, Cobb BR, Wedemeyer H, Maasoumy B, Michel-Treil V, Cec-cherini-Nelli L, et al. Evaluation of the COBAS(�) AmpliPrep/COBAS(�)TaqMan(�) HCV Test, v2.0 and comparison to assays used in routine clinicalpractice in an international multicenter clinical trial: The ExPECT study. J ClinVirol 2015;67:67–72.

[58] Harris JB, Ward MA, Schwab P. Is response-guided therapy being applied inthe clinical setting? The hepatitis C example. Am Health Drug Benefits2015;8:22–28.

[59] Forns X, Lawitz E, Zeuzem S, Gane E, Bronowicki JP, Andreone P, et al.Simeprevir with peginterferon and ribavirin leads to high rates of SVR inpatients with HCV genotype 1 who relapsed after previous therapy: a phase3 trial. Gastroenterology 2014;146:1669–1679 e3.

[60] Jacobson IM, Dore GJ, Foster GR, Fried MW, Radu M, Rafalsky VV, et al.Simeprevir with pegylated interferon alfa 2a plus ribavirin in treatment-naive patients with chronic hepatitis C virus genotype 1 infection (QUEST-1):a phase 3, randomised, double-blind, placebo-controlled trial. Lancet2014;384:403–413.

[61] Manns M, Marcellin P, Poordad F, de Araujo ES, Buti M, Horsmans Y, et al.Simeprevir with pegylated interferon alfa 2a or 2b plus ribavirin intreatment-naive patients with chronic hepatitis C virus genotype 1 infection(QUEST-2): a randomised, double-blind, placebo-controlled phase 3 trial.Lancet 2014;384:414–426.

[62] Reddy KR, Zeuzem S, Zoulim F, Weiland O, Horban A, Stanciu C, et al.Simeprevir versus telaprevir with peginterferon and ribavirin in previousnull or partial responders with chronic hepatitis C virus genotype 1 infection(ATTAIN): a randomised, double-blind, non-inferiority phase 3 trial. LancetInfect Dis 2015;15:27–35.

[63] Fevery B, Susser S, Lenz O, Cloherty G, Perner D, Gilles L, et al. Comparison ofthree quantitative HCV RNA assays in samples from HCV genotype 1- or 4-infected patients treated with the NS3/4A protease inhibitor simeprevir. JClin Virol 2015;72:133–140.

[64] Andreone P, Colombo MG, Enejosa JV, Koksal I, Ferenci P, Maieron A, et al.ABT-450, ritonavir, ombitasvir, and dasabuvir achieves 97% and 100%sustained virologic response with or without ribavirin in treatment-experi-enced patients with HCV genotype 1b infection. Gastroenterology2014;147:359–365 e1.

[65] Kwo P, Gitlin N, Nahass R, Bernstein D, Etzkorn K, Rojter S, et al. Simeprevirplus sofosbuvir (12 and 8 weeks) in HCV genotype 1-infected patientswithout cirrhosis: OPTIMIST-1, a phase 3. randomized study. Hepatology2016;64:370–380.

[66] Lawitz E, Gane E, Pearlman B, Tam E, Ghesquiere W, Guyader D, et al. Efficacyand safety of 12 weeks versus 18 weeks of treatment with grazoprevir (MK-5172) and elbasvir (MK-8742) with or without ribavirin for hepatitis C virusgenotype 1 infection in previously untreated patients with cirrhosis andpatients with previous null response with or without cirrhosis (C-WORTHY):a randomised, open-label phase 2 trial. Lancet 2015;385:1075–1086.

[67] Lawitz E, Matusow G, DeJesus E, Yoshida EM, Felizarta F, Ghalib R, et al.Simeprevir plus sofosbuvir in patients with chronic hepatitis C virusgenotype 1 infection and cirrhosis: A Phase 3 study (OPTIMIST-2). Hepatol-ogy 2015;64:360–369.

Ass

ess

me

nt

of

HC

V D

ise

ase

JOURNAL OF HEPATOLOGY

Journal of Hepatology 2016 vol. 65 j S67–S81 S79

[68] Roth D, Nelson DR, Bruchfeld A, Liapakis A, Silva M, Monsour H, et al.Grazoprevir plus elbasvir in treatment-naive and treatment-experiencedpatients with hepatitis C virus genotype 1 infection and stage 4–5 chronickidney disease (the C-SURFER study): a combination phase 3 study. Lancet2015;386:1537–1545.

[69] Sulkowski M, Hezode C, Gerstoft J, Vierling JM, Mallolas J, Pol S, et al. Efficacyand safety of 8 weeks versus 12 weeks of treatment with grazoprevir (MK-5172) and elbasvir (MK-8742) with or without ribavirin in patients withhepatitis C virus genotype 1 mono-infection and HIV/hepatitis C virus co-infection (C-WORTHY): a randomised, open-label phase 2 trial. Lancet2015;385:1087–1097.

[70] Dore GJ, Conway B, Luo Y, Janczewska E, Knysz B, Liu Y, et al. Efficacy andsafety of ombitasvir/paritaprevir/r and dasabuvir compared to IFN-contain-ing regimens in genotype 1 HCV patients: The MALACHITE-I/II trials. JHepatol 2016;64:19–28.

[71] Höner zu Siderdissen C, Maasoumy B, Deterding K, Port K, Sollik L, Mix C,et al. Eligibility and safety of the first interferon-free therapy againsthepatitis C in a real-world setting. Liver Int 2015;35:1845–1852.

[72] Razavi H, Waked I, Sarrazin C, Myers RP, Idilman R, Calinas F, et al. Thepresent and future disease burden of hepatitis C virus (HCV) infection withtoday’s treatment paradigm. J Viral Hepat 2014;21:34–59.

[73] Wedemeyer H, Duberg AS, Buti M, Rosenberg WM, Frankova S, Esmat G, et al.Strategies to manage hepatitis C virus (HCV) disease burden. J Viral Hepat2014;21:60–89.

[74] Welker MW, Luhne S, Lange CM, Vermehren J, Farnik H, Herrmann E, et al.Lactic acidosis in patients with hepatitis C virus cirrhosis and combinedribavirin/sofosbuvir treatment. J Hepatol 2016;64:790–799.

[75] Viekirax package insert.[76] zu Siederdissen C Höner, Maasoumy B, Marra F, Deterding K, Port K, Manns

MP, et al. Drug-drug interactions with novel all oral interferon-free antiviralagents in a large real-world cohort. Clin Infect Dis 2016;62:561–567.

[77] Neumann AU, Lam NP, Dahari H, Gretch DR, Wiley TE, Layden TJ, et al.Hepatitis C viral dynamics in vivo and the antiviral efficacy of interferon-alpha therapy. Science 1998;282:103–107.

[78] Harvoni package insert.[79] Vermehren J, Maasoumy B, Maan R, Cloherty G, Berkowski C, Feld JJ, et al.

Applicability of Hepatitis C Virus RNA Viral Load Thresholds for 8-WeekTreatments in Patients With Chronic Hepatitis C Virus Genotype 1 Infection.Clin Infect Dis 2016;62:1228–1234.

[80] O’Brien TR, Feld JJ, Kottilil S, Pfeiffer RM. No scientific basis to restrict 8 weeksof treatment with ledipasvir/sofosbuvir to patients with hepatitis C virusRNA 6,000,000 IU/ml. Hepatology 2016;63:28.

[81] Buggisch P, Peterson J, Mauss S, Kowdley K, Curry M, Ruane P et al.Ledipasvir/sofosbuvir (LDV/SOF) for 8 wks in genotype 1 (Gt1) treatment-naïve (Tn) non-cirrhotic (NC) patients with HCV Viral Load (Vl) <6 Million IU/ml (6m); A Comparative Analysis of the Phase-3 Ion-3 Data to Real WorldEffectiveness (RWE). EASL – The International Liver Congress 2016, 51thannual Meeting of the European association for the Study of the LiverBarcelona, Spain 2016.

[82] Saxena V, Nyberg L, Pauly M, Dasgupta A, Nyberg A, Piasecki B, et al. Safetyand efficacy of simeprevir/sofosbuvir in hepatitis C-infected patients withcompensated and decompensated cirrhosis. Hepatology 2015;62:715–725.

[83] Poordad F, Schiff ER, Vierling JM, Landis C, Fontana RJ, Yang R, et al.Daclatasvir with sofosbuvir and ribavirin for HCV infection with advancedcirrhosis or post-liver transplant recurrence. Hepatology2016;63:1493–1505.

[84] Leroy V, Angus P, Bronowicki JP, Dore GJ, Hezode C, Pianko S, et al.Daclatasvir, sofosbuvir, and ribavirin for hepatitis C virus genotype 3 andadvanced liver disease: a randomized phase III study (ALLY-3+). Hepatology2016;63:1430–1441.

[85] Wyles D, Mangia A, Cheng W, Shafran S, Schwabe C, Ouyang W et al. Long-Term Persistence of HCV NS5A Variants After Treatment With NS5A InhibitorLedipasvir. EASL – The International Liver Congress 2015, 50th annualMeeting of the European association for the Study of the Liver, Vienna,Austria, april 22–26 2015 2015.

[86] Sarrazin C. The importance of resistance to direct antiviral drugs in HCVinfection in clinical practice. J Hepatol 2016;64:486–504.

[87] Lawitz E, Flamm S, Yang JC, Pang PS, Zhu Y, Svarovskaia E et al. Retreatmentof Patients Who Failed 8 or 12 Weeks of Ledipasvir/Sofosbuvir-BasedRegimens With Ledipasvir/Sofosbuvir for 24 Weeks. EASL - The InternationalLiver Congress 2015, 50th annual Meeting of the European association for theStudy of the Liver, Vienna, Austria, april 22–26 2015.

[88] Vermehren J, Susser, S, Dietz J, von Hahn T, Petersen J, Hinrichsen H et al.Retreatment of Patients who Failed DAA-Combination Therapies: RealworldExperience from a large Hepatitis C Resistance Database. EASL - The

International Liver Congress 2016, 51th annual Meeting of the Europeanassociation for the Study of the Liver, Barcelona, Spain 2016 2016.

[89] Chevaliez S, Feld J, Cheng K, Wedemeyer H, Sarrazin C, Maasoumy B, et al.Clinical utility of HCV core antigen detection and quantification in thediagnosis and management of patients with chronic hepatitis Creceiving an all-oral, interferon-free regimen. Antivir Ther 2016, [Epubahead of print].

[90] Aghemo A, Degasperi E, De Nicola S, Bono P, Orlandi A, D’Ambrosio R, et al.Quantification of core antigen monitors efficacy of direct-acting antiviralagents in patients with chronic hepatitis C virus infection. Clin GastroenterolHepatol 2016, [Epub ahead of print].

[91] Martinello M, Schteinman A, Alavi M, Williams K, Dore GJ, Day R, et al. Theimpact of ribavirin plasma concentration on the efficacy of the interferon-sparing regimen, sofosbuvir and ribavirin. Antivir Ther 2016;21:127–132.

[92] Steinebrunner N, Sprinzl MF, Zimmermann T, Wörns MA, Zimmerer T, GallePR, et al. Early virological response may predict treatment response insofosbuvir-based combination therapy of chronic hepatitis c in a multi-center ‘‘real-life” cohort. BMC Gastroenterol 2015;15:97.

[93] Goossens N, Negro F. Is genotype 3 of the hepatitis C virus the new villain.Hepatology 2014;59:2403–2412.

[94] Zeuzem S, Dusheiko GM, Colombo M, Flisiak R, Hyland RH, Illeperuma A et al.Early Viral Kinetics Do Not Predict Treatment Outcome With Sofosbuvir +Ribavirin for 12 or 24 Weeks in HCV Genotype 2/3 Patients in the VALENCETrial. 49th Annual Meeting of the European, Association for the Study of theLiver, London, United Kingdom April 9–13 2014.

[95] Welzel TM, Nelson DR, Morelli G, Di Bisceglie A, Reddy RK, Kuo A, et al.Effectiveness and safety of sofosbuvir plus ribavirin for the treatment of HCVgenotype 2 infection: results of the real-world, clinical practice HCV-TARGETstudy. Gut 2016, [Epub ahead of print].

[96] Wyles DL, Nelson DR, Swain MG, Gish RG, Ma J, McNally J, et al. On treatmentHCV RNA as a predictor of virologic response in sofosbuvir-containingregimens for genotype 2/3 HCV infection: Analysis of the FISSION, POSITRON,and FUSION studies. Hepatology 2013;58:140A.

[97] Aqel BA, Pungpapong S, Leise M, Werner KT, Chervenak AE, Watt KD, et al.Multicenter experience using simeprevir and sofosbuvir with or withoutribavirin to treat hepatitis C genotype 1 in patients with cirrhosis. Hepatol-ogy 2015;62:1004–1012.

[98] Shiffman ML, James AM, Long AG, Alexander PC. Treatment of chronic HCVwith sofosbuvir and simeprevir in patients with cirrhosis andcontraindications to interferon and/or ribavirin. Am J Gastroenterol2015;110:1179–1185.

[99] Pillai AA, Wedd J, Norvell JP, Parekh S, Cheng N, Young N, et al. Simeprevirand sofosbuvir (SMV-SOF) for 12 weeks for the treatment of chronic hepatitisc genotype 1 infection: a real world (Transplant) hepatology practiceexperience. Am J Gastroenterol 2016;111:250–260.

[100] Manns M, Samuel D, Gane EJ, Mutimer D, McCaughan G, Buti M, et al.Ledipasvir and sofosbuvir plus ribavirin in patients with genotype 1 or 4hepatitis C virus infection and advanced liver disease: a multicentre, open-label, randomised, phase 2 trial. Lancet Infect Dis 2016;16:685–697.

[101] Welzel TM, Herrmann E, Marcellin P, Afdhal NH, Kowdley KV, Stamm LMet al. On-Treatment HCV RNA as a Predictor of Virologic Response in theLedipasvir/Sofosbuvir Phase 3 Program for HCV Genotype 1 Infection:Analysis of the ION-1, ION-2, and ION-3 Studies. 65th Annual Meeting ofthe American Association for the Study of Liver Diseases, Boston, MA 2014.

[102] Charlton M, Everson GT, Flamm SL, Kumar P, Landis C, Brown RS, et al.Ledipasvir and sofosbuvir plus ribavirin for treatment of HCV infection inpatients with advanced liver disease. Gastroenterology 2015;149:649–659.

[103] Welzel TM, Reddy KR, Flamm SL, Denning J, Lin M, Hyland R, et al.On-treatment HCV RNA in patients with varying degrees of fibrosis andcirrhosis in the SOLAR-1 trial. Antivir Ther 2016, [Epub ahead of print].

[104] Kowdley K, Nelson D, Lalezari J, Box, T, Gitlin N, Poleynard G et al.On-Treatment HCV RNA as a Predictor of Sustained Virologic Response inHCV Genotype 3-Infected Patients Treated With Daclatasvir and Sofosbuvir:A subanalysis of the Phase 3 ALLY-3 Study. 50th annual Meeting of theEuropean association for the Study of the Liver, Vienna, Austria April 22–262015.

[105] Sulkowski M, Fried MW, Ozaras R, Isakov V, Wyles D, Ferenci P et al. Time toViral Suppression [week 2/4] Is Not Related to Achievement of SVR12 in HCVGT1-infected Patients Treated With ABT-450/Ritonavir/Ombitasvir andDasabuvir With or Without Ribavirin. 65th Annual Meeting of the AmericanAssociation for the Study of Liver Diseases, Boston, MA Nov 7–11; 2014.

[106] Dahari H, Canini L, Graw F, Uprichard SL, Araújo ES, Penaranda G, et al. HCVkinetic and modeling analyses indicate similar time to cure among sofos-buvir combination regimens with daclatasvir, simeprevir or ledipasvir. JHepatol 2016;64:1232–1239.

Ass

ess

me

nt

of

HC

V D

ise

ase

Review

S80 Journal of Hepatology 2016 vol. 65 j S67–S81

[107] Ferenci P, Kozbial K, Mandorfer M, Hofer H. HCV targeting of patients withcirrhosis. J Hepatol 2015;63:1015–1022.

[108] Sarrazin C, Wedemeyer H, Cloherty G, Cohen DE, Chevaliez S, Herman C, et al.Importance of very early HCV RNA kinetics for prediction of treatmentoutcome of highly effective all oral direct acting antiviral combinationtherapy. J Virol Methods 2015;214:29–32.

[109] Martin B, Hennecke N, Lohmann V, Kayser A, Neumann-Haefelin C, Kukolj G,et al. Restoration of HCV-specific CD8+ T cell function by interferon-freetherapy. J Hepatol 2014;61:538–543.

[110] Meissner EG, Wu D, Osinusi A, Bon D, Virtaneva K, Sturdevant D, et al.Endogenous intrahepatic IFNs and association with IFN-free HCV treatmentoutcome. J Clin Invest 2014;124:3352–3363.

[111] Lau G, Benhamou Y, Chen G, Li J, Shao Q, Ji D, et al. Efficacy and safety of3-week response-guided triple direct-acting antiviral therapy for chronichepatitis C infection: a phase 2, open-label, proof-of-concept study. LancetGastroenterol Hepatol 2016. http://dx.doi.org/10.1016/S2468-1253(16)30015-2, [Epub ahead of print].

Ass

ess

me

nt

of

HC

V D

ise

ase

JOURNAL OF HEPATOLOGY

Journal of Hepatology 2016 vol. 65 j S67–S81 S81