Short-duration treatment for chronic hepatitis C virus with daclatasvir, asunaprevir, beclabuvir and sofosbuvir (FOURward study)

Treatment of chronic hepatitis C infection: strategies to address poor therapy adherence

INTRODUCTION

Non-adherence to any therapy may be related to skipping drug doses, discontinuation of therapy, or loss of follow-up. It leads to the ineffectiveness of treatment, which is associated with obvious individual health losses, significant social and financial costs, and, in the case of infectious diseases, epidemiological consequences resulting from the possibility of further spread of infection.

AREAS COVERED

This review article analyses the causes and effects of non-adherence to treatment in patients infected with the hepatitis C virus (HCV). It also presents strategies to reduce the risk of non-adherence, which can be implemented by simplifying the treatment process, improving the flow of information between the doctor and the patient, as well as improving patients' knowledge about hepatitis C infection, and facilitating the understanding of the risks associated with non-adherence.

EXPERT OPINION

Since the treatment of HCV infections is highly effective in almost all patients who complete medication, no new drugs are to be expected in the coming years. Therefore, the primary attention in the global elimination of HCV will be focused on screening programs, improving the availability of drugs, and reducing the risk of non-adherence.

Sustained Virological Response After Early Discontinuation of Hepatitis C Treatment

To date, the effectiveness of direct-acting antivirals (DAAs) discontinued before 4 weeks has not been analysed in routine clinical practice. The study aimed to determine whether such a short therapy will enable achieving a sustained virological response under real-world experience. The study population of 97 patients who discontinued DAA therapy and had data enabling analysis of patient and disease characteristics, and assessment of treatment effectiveness was selected from 16,815 patients registered in the EpiTer-2 database. The most common reason for discontinuation was hepatic decompensation (20.6%) or the patient's personal decision (18.6%). Patients who discontinued treatment were significantly older, more frequently therapy-experienced, more likely to have cirrhosis, a history of decompensation and a Child-Pugh B or C classification than those who completed treatment. SVR was achieved by 93.5% of patients who discontinued treatment after 4 weeks, 60.9% if discontinued at 3 or 4 week and 33.3% at Week 1 or 2. Patients receiving pangenotypic but not genotype-specific treatment who discontinued after 4 weeks were as likely to achieve SVR as those who completed therapy. Patients who responded to treatment that lasted no longer than 2 weeks had a low baseline viral load (<400,000 IU/mL). Despite discontinuation of therapy after Week 4, the chances of SVR are high. Very early discontinuation does not preclude therapeutic success, especially in patients with low baseline viral load.

Efficacy of ultra-short, response-guided sofosbuvir and daclatasvir therapy for hepatitis C in a single-arm mechanistic pilot study

Background

World Health Organization has called for research into predictive factors for selecting persons who could be successfully treated with shorter durations of direct-acting antiviral (DAA) therapy for hepatitis C. We evaluated early virological response as a means of shortening treatment and explored host, viral and pharmacokinetic contributors to treatment outcome.

Methods

Duration of sofosbuvir and daclatasvir (SOF/DCV) was determined according to day 2 (D2) virologic response for HCV genotype (gt) 1- or 6-infected adults in Vietnam with mild liver disease. Participants received 4- or 8-week treatment according to whether D2 HCV RNA was above or below 500 IU/ml (standard duration is 12 weeks). Primary endpoint was sustained virological response (SVR12). Those failing therapy were retreated with 12 weeks SOF/DCV. Host IFNL4 genotype and viral sequencing was performed at baseline, with repeat viral sequencing if virological rebound was observed. Levels of SOF, its inactive metabolite GS-331007 and DCV were measured on days 0 and 28.

Results

Of 52 adults enrolled, 34 received 4 weeks SOF/DCV, 17 got 8 weeks and 1 withdrew. SVR12 was achieved in 21/34 (62%) treated for 4 weeks, and 17/17 (100%) treated for 8 weeks. Overall, 38/51 (75%) were cured with first-line treatment (mean duration 37 days). Despite a high prevalence of putative NS5A-inhibitor resistance-associated substitutions (RASs), all first-line treatment failures cured after retreatment (13/13). We found no evidence treatment failure was associated with host IFNL4 genotype, viral subtype, baseline RAS, SOF or DCV levels.

Conclusions

Shortened SOF/DCV therapy, with retreatment if needed, reduces DAA use in patients with mild liver disease, while maintaining high cure rates. D2 virologic response alone does not adequately predict SVR12 with 4-week treatment.

Funding

Funded by the Medical Research Council (Grant MR/P025064/1) and The Global Challenges Research 70 Fund (Wellcome Trust Grant 206/296/Z/17/Z).

Cost-Effectiveness of Elbasvir/Grazoprevir for the Treatment of Chronic Hepatitis C: A Systematic Review

Objective

This study aims to systematically review recent economic evaluations of elbasvir/grazoprevir (EBR/GZR) for chronic hepatitis C (CHC), to critically appraise the reporting quality and to summarize the results.

Methods

A literature search was undertaken using Medline, Embase, the Cochrane Library, EconLit, China National Knowledge Infrastructure, Wanfang Data, and Chongqing VIP to identify original articles containing economic evaluations of EBR/GZR for CHC published between 1 January 2000 and 31 December 2020. The Consolidated Health Economic Evaluation Reporting Standards statement was used to assess the quality of reporting of the articles.

Results

Of 93 articles identified, 13 studies fulfilled the inclusion criteria. These studies were conducted in 4 countries, and 8 active interventions were assessed. The target population was patients infected with CHC genotype 1 infection in all studies. Eight out of 13 studies that compared EBR/GZR vs. other direct antiviral agents suggested that EBR/GZR was generally more cost-effective or dominant than daclatasvir/asunaprevir (DCV/ASV), sofosbuvir/velpatasvir (SOF/VEL), ledipasvir/sofosbuvir (LDV/SOF), ombitasvir/paritaprevir/ritonavir + dasabuvir (3D) but not more cost-effective than glecaprevir/pibrentasvir (GLE/PIB). Two studies from China and one study from the USA that compared EBR/GZR vs. pegylated interferon and ribavirin (PegIFN/RBV) consistently indicated that EBR/GZR was generally more cost-effective than PegIFN/RBV. One study from Italy compared EBR/GZR with SOF + PegIFN/RBV and suggested that EBR/GZR had a lower cost and higher effectiveness. One study from France and one study from the USA confirmed that compared with non-therapy for patients with chronic kidney disease, EBR/GZR was cost-effective at commonly accepted current standards. All included studies were of good quality of reporting, with an average score of 21.9 (range 19–23).

Conclusion

EBR/GZR for CHC genotype 1 might be cost-effective or dominant compared with PegIFN/RBV and other direct antiviral agents (SOF/VEL, 3D, DCV/ASV, LDF/SOF) or non-therapy. However, under certain assumptions, EBR/GZR was not a cost-effective alternative for CHC patients vs. GLE/PIB.

Four Weeks Treatment with Glecaprevir/Pibrentasvir + Ribavirin-A Randomized Controlled Clinical Trial

Enhancing treatment uptake for hepatitis C to achieve the elimination goals set by the World Health Organization could be achieved by reducing the treatment duration. The aim of this study was to compare the sustained virological response at week 12 (SVR12) after four weeks of glecaprevir/pibrentasvir (GLE/PIB) + ribavirin compared to eight weeks of GLE/PIB and to estimate predictors for SVR12 with four weeks of treatment through a multicenter open label randomized controlled trial. Patients were randomized 2:1 (4 weeks:8 weeks) and stratified by genotype 3 and were treatment naïve of all genotypes and without significant liver fibrosis. A total of 27 patients were analyzed for predictors for SVR12, including 15 from the first pilot phase of the study. In the ‘modified intention to treat’ group, 100% (7/7) achieved cure after eight weeks and for patients treated for four weeks the SVR12 was 58.3% (7/12). However, patients with a baseline viral load <2 mill IU/mL had 93% SVR12. The study closed prematurely due to the low number of included patients due to the COVID-19 pandemic. Our results suggest that viral load should be taken into account when considering trials of short course treatment.

Inferior cure rate in pilot study of 4-week glecaprevir/pibrentasvir treatment with or without ribavirin of chronic hepatitis C

BACKGROUND & AIMS

Shortening the treatment duration for chronic hepatitis C may increase feasibility and reduce the cost of cure. The aims of this study were to compare 4 weeks of glecaprevir/pibrentasvir (GLE/PIB) treatment with and without ribavirin for patients with chronic hepatitis C and favourable baseline characteristics and to monitor the development of resistance-associated substitutions (RAS) and re-treatment outcomes if treatment failed.

METHODS

We performed an open-label single-centre randomized controlled trial, in which patients with chronic hepatitis C were randomized 1:1 to GLE/PIB ± ribavirin, stratified by genotype 3. The main inclusion criteria were treatment-naive patients, aged 18-49 with all genotypes accepted, and absence of liver fibrosis, determined by liver stiffness measurement less than 8 kPa. Viral genome sequences were determined by deep sequencing at baseline and at the time of relapse.

RESULTS

A total of 32 patients started treatment. Sustained virological response at week 12 (SVR12) was 59% (10/17) for GLE/PIB without ribavirin and 73% (11/15) for GLE/PIB with ribavirin. Drug target-specific NS5A RAS were detected at baseline for 45% (5/11) of patients with treatment failure and for 14% (3/21) of patients who achieved SVR12. Ten failure patients were retreated 12 weeks with sofosbuvir-based regimens; all have been cured.

CONCLUSIONS

In this pilot study of 4-week treatment with GLE/PIB with and without ribavirin, we found that baseline RAS were more frequent in patients with virological failure. Development of RAS did occur after short treatment but did not result in retreatment failure with a different regimen. EudraCT no: 2017-005179-21.

High rates of sustained virological response despite premature discontinuation of directly acting antivirals in HCV-infected patients treated in a real-life setting

In routine clinical practice, hepatitis C virus-infected patients can prematurely discontinue the prescribed regimen for several reasons. The aim of our study was to investigate sustained virological response (SVR12) rates in patients who prematurely discontinued directly acting antiviral (DAA) regimens and to assess the shortest effective duration of DAA able to lead to SVR12. We retrospectively collected the SVR rates of patients, registered in the NAVIGATORE-Lombardia Network database from January 2015, who discontinued DAAs before the predefined end of treatment. Overall, we included 365 patients, males were the majority (213, 58.4%), mean age was 60.5 years, and 53 (14.5%) patients were HIV-co-infected. Liver cirrhosis was observed in 251 (68.8%) subjects, and the most represented genotypes were 1b (n = 168, 46%) and 3 (n = 59, 16.2%). DAA was discontinued a median of 1 (IQR 1-4) weeks before the predefined EOT, with 164 (44.9%) patients stopping DAAs at least 2 weeks before the planned schedule. In patients with F0-F3 liver fibrosis, lower rates of SVR12 were observed in patients treated for <4 weeks: 50% (n = 2/4) vs. 99.1% (n = 109/110) for ≥4 weeks, p = 0.003. In patients with liver cirrhosis, lower rates of SVR12 were observed in patients treated <8 weeks: 83.3% (n = 25/30) vs. 94.6% (n = 209/221) for ≥8 weeks, p = 0.038. Despite premature discontinuation of DAA, high SVR12 rates were observed in a real-life setting for treatment lasting at least 4 weeks in patients with liver fibrosis F0-F3 and 8 weeks in those with liver cirrhosis. On this basis, feasibility of reducing DAA treatment duration should be explored in randomized clinical trials.

Intrahepatic Viral Kinetics During Direct-Acting Antivirals for Hepatitis C in Human Immunodeficiency Virus Coinfection: The AIDS Clinical Trials Group A5335S Substudy

BACKGROUND

Direct-acting antivirals (DAAs) targeting hepatitis C virus (HCV) have revolutionized outcomes in human immunodeficiency virus (HIV) coinfection.

METHODS

We examined early events in liver and plasma through A5335S, a substudy of trial A5329 (paritaprevir/ritonavir, ombitasvir, dasabuvir, with ribavirin) that enrolled chronic genotype 1a HCV-infected persons coinfected with suppressed HIV: 5 of 6 treatment-naive enrollees completed A5335S.

RESULTS

Mean baseline plasma HCV ribonucleic acid (RNA) = 6.7 log10 IU/mL and changed by -4.1 log10 IU/mL by Day 7. In liver, laser capture microdissection was used to quantify HCV. At liver biopsy 1, mean %HCV-infected cells = 25.2% (95% confidence interval [CI], 7.4%-42.9%), correlating with plasma HCV RNA (Spearman rank correlation r = 0.9); at biopsy 2 (Day 7 in 4 of 5 participants), mean %HCV-infected cells = 1.0% (95% CI, 0.2%-1.7%) (P < .05 for change), and DAAs were detectable in liver. Plasma C-X-C motif chemokine 10 (CXCL10) concentrations changed by mean = -160 pg/mL per day at 24 hours, but no further after Day 4.

CONCLUSIONS

We conclude that HCV infection is rapidly cleared from liver with DAA leaving <2% HCV-infected hepatocytes at Day 7. We extrapolate that HCV eradication could occur in these participants by 63 days, although immune activation might persist. Single-cell longitudinal estimates of HCV clearance from liver have never been reported previously and could be applied to estimating the minimum treatment duration required for HCV infection.

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.

Factors influencing hepatitis C cure in the era of direct-acting antivirals

Direct-acting antiviral agents are highly potent drugs with a strong genetic barrier. Consequently, the factors influencing hepatitis C cure have been reduced and have progressively lost importance. Host factors, such as the presence of cirrhosis, race, and treatment adherence, influence sustained viral response. Adherence, together with treatment errors and drug interactions, are also important, especially in older patients. Viral factors, such as viral load, genotype, and the presence of baseline resistances affect the response rate but their influence can be minimised by using pan-genotypic regimens. Treatment simplification and the high efficacy of new antiviral treatments will allow treatment universalisation and will hopefully enable elimination of the infection in the next few decades. Supplement information: This article is part of a supplement entitled "The value of simplicity in hepatitis C treatment", which is sponsored by Gilead. © 2019 Elsevier España, S.L.U. All rights reserved.

Sustained Virologic Suppression After 4 Weeks of Ledipasvir/Sofosbuvir in Human Immunodeficiency Virus (HIV)/Hepatitis C Virus (HCV) Co-Infection

Patient: Male, 28-year-old

Final Diagnosis: HCV infection

Symptoms: Not applicable

Medication: —

Clinical Procedure: —

Specialty: Infectious Diseases

The design and statistical aspects of VIETNARMS: a strategic post-licensing trial of multiple oral direct-acting antiviral hepatitis C treatment strategies in Vietnam

BACKGROUND

Eliminating hepatitis C is hampered by the costs of direct-acting antiviral treatment and the need to treat hard-to-reach populations. Access could be widened by shortening or simplifying treatment, but limited research means it is unclear which approaches could achieve sufficiently high cure rates to be acceptable. We present the statistical aspects of a multi-arm trial designed to test multiple strategies simultaneously and a monitoring mechanism to detect and stop individual randomly assigned groups with unacceptably low cure rates quickly.

METHODS

The VIETNARMS trial will factorially randomly assign patients to two drug regimens, three treatment-shortening strategies or control, and adjunctive ribavirin or no adjunctive ribavirin with shortening strategies (14 randomly assigned groups). We will use Bayesian monitoring at interim analyses to detect and stop recruitment into unsuccessful strategies, defined by more than 0.95 posterior probability that the true cure rate is less than 90% for the individual randomly assigned group (non-comparative). Final comparisons will be non-inferiority for regimens (margin 5%) and strategies (margin 10%) and superiority for adjunctive ribavirin. Here, we tested the operating characteristics of the stopping guideline for individual randomly assigned groups, planned interim analysis timings and explored power at the final analysis.

RESULTS

A beta (4.5, 0.5) prior for the true cure rate produces less than 0.05 probability of incorrectly stopping an individual randomly assigned group with a true cure rate of more than 90%. Groups with very low cure rates (<60%) are very likely (>0.9 probability) to stop after about 25% of patients are recruited. Groups with moderately low cure rates (80%) are likely to stop (0.7 probability) before overall recruitment finishes. Interim analyses 7, 10, 13 and 18 months after recruitment commences provide good probabilities of stopping inferior individual randomly assigned groups. For an overall true cure rate of 95%, power is more than 90% to confirm non-inferiority in the regimen and strategy comparisons, regardless of the control cure rate, and to detect a 5% absolute difference in the ribavirin comparison.

CONCLUSIONS

The operating characteristics of the stopping guideline are appropriate, and interim analyses can be timed to detect individual randomly assigned groups that are highly likely to have suboptimal performance at various stages. Therefore, our design is suitable for evaluating treatment-shortening or -simplifying strategies.

TRIAL REGISTRATION

ISRCTN registry: ISRCTN61522291. Registered on 4 October 2019.

Hepatitis C virus (HCV) care in Canadian correctional facilities: Where are we and where do we need to be?

Approximately 25% of people in Canadian correctional facilities have been previously exposed to hepatitis C virus (HCV). Despite being a high-prevalence setting, most Canadian prisons have thus far failed to engage the majority of those with chronic HCV infection in care. Several factors, including the lack of systematic screening programs, lack of on-site and trained health care personnel to improve access to care and treatment during incarceration, and the absence of standardized procedures needed to facilitate linkage to care following release likely contribute to poor engagement along the HCV care cascade for people in prison. HCV screening and engagement in care for people in prison can be improved through the implementation of universal opt-out screening upon admission and consideration of multidisciplinary care models for the provision of care. As well, the dissemination of prison-based needle and syringe programs to avert new HCV infections and re-infections should be considered. To meet the World Health Organization (WHO) 2030 HCV elimination goals, engaging researchers, clinicians and other health care providers, policy makers, correctional officials, and members of community in dialogue will be an essential first step going forward.

Impact of pill burden on adherence to hepatitis C medication

Objective: To describe pill burden before and after hepatitis C virus (HCV) treatment initiation among patients newly treated for HCV infection, and to evaluate the association between HCV pill burden and gaps in HCV therapy. Methods: This was a retrospective administrative claims study of patients treated with direct-acting antivirals (DAAs) for HCV from 1 November 2013 to 31 July 2016. HCV pill burden was defined as the pill count per day for the index HCV regimen. Mean overall pill burden (HCV medications plus non-HCV medications) was calculated in the 90 days before and after DAA initiation. Gaps in the index HCV regimen were assessed in the 6 months after DAA initiation. Multivariable logistic regression was used to compare the odds of a gap in HCV therapy across HCV pill burden categories (1 pill/day, 2 pills/day, and ≥3 pills/day). Results: Among 9815 patients who met the study criteria, mean overall pill burdens before and after DAA treatment initiation were 5.4 and 7.7, respectively (p < .001). The adjusted odds ratio (OR) of a ≥15-day gap in HCV therapy was 1.75 (95% confidence interval [CI] = 1.38-2.22) for patients with 2 HCV pills/day and 2.11 (95% CI = 1.78-2.51) for patients with ≥3 pills/day, compared with patients with 1 HCV pill/day. Conclusions: Patients with HCV have a substantial pill burden even before initiating HCV treatment. As higher HCV pill burden was associated with lower medication adherence, pill burden should be an important consideration in HCV treatment selection.

Treatment optimisation for hepatitis C in the era of combination direct-acting antiviral therapy: a systematic review and meta-analysis

Background: Prior to direct-acting antiviral (DAA) therapy, personalised medicine played an important role in the treatment of hepatitis C virus (HCV). Whilst simplified treatment strategies are central to treatment scale-up, some patients will benefit from treatment optimisation. This systematic review and meta-analysis explores treatment optimisation strategies in the DAA era. Methods: We systematically searched Medline, Embase, and Web of Science for studies that adopted a stratified or personalised strategy using a licensed combination DAA regimen, alone or with additional agents. We performed a thematic analysis to classify optimisation strategies and a meta-analysis of sustained virologic response rates (SVR), exploring heterogeneity with subgroup analyses and meta-regression. Results: We included 64 studies (9450 participants). Thematic analysis found evidence of three approaches: duration, combination, and/or dose optimisation. We separated strategies into those aiming to maintain SVR in the absence of predictors of failure, and those aiming to improve SVR in the presence of predictors of failure. Shortened duration regimens achieve pooled SVR rates of 94.2% (92.3-95.9%) for 8 weeks, 81.1% (75.1-86.6%) for 6 weeks, and 63.1% (39.9-83.7%) for ≤4 weeks. Personalised strategies (100% vs 87.6%; p<0.001) and therapy shortened according to ≥3 host/viral factors (92.9% vs 81.4% or 87.2% for 1 or 2 host/viral factors, respectively; p=0.008) offer higher SVR rates when shortening therapy. Hard-to-treat HCV genotype 3 patients suffer lower SVR rates despite treatment optimisation (92.6% vs 98.2%; p=0.001). Conclusions: Treatment optimisation for individuals with multiple predictors of treatment failure can offer high SVR rates. More evidence is needed to identify with confidence those individuals in whom SVR can be achieved with shortened duration treatment.

A Cost-Effectiveness Analysis of Shortened Direct-Acting Antiviral Treatment in Genotype 1 Noncirrhotic Treatment-Naive Patients With Chronic Hepatitis C Virus

BACKGROUND

Direct-acting antivirals are successful in curing hepatitis C virus infection in more than 95% of patients treated for 12 weeks, but they are expensive. Shortened treatment durations, which may have lower cure rates, have been proposed to reduce costs.

OBJECTIVES

To evaluate the lifetime cost-effectiveness of different shortened treatment durations for genotype 1 noncirrhotic treatment-naive patients.

METHODS

Assuming a UK National Health Service perspective, we used a probabilistic decision tree and Markov model to compare 3 unstratified shortened treatment durations (8, 6, and 4 weeks) against a standard 12-week treatment duration. Patients failing shortened first-line treatment were re-treated with a 12-week treatment regimen. Parameter inputs were taken from published studies.

RESULTS

The 8-week treatment duration had an expected incremental net monetary benefit of £7737 (95% confidence interval £3242-£11 819) versus the standard 12-week treatment, per 1000 patients. The 6-week treatment had a positive incremental net monetary benefit, although some uncertainty was observed. The probability that the 8- and 6-week treatments were the most cost-effective was 56% and 25%, respectively, whereas that for the 4-week treatment was 17%. Results were generally robust to sensitivity analyses, including a threshold analysis that showed that the 8-week treatment was the most cost-effective at all drug prices lower than £40 000 per 12-week course.

CONCLUSIONS

Shortening treatments licensed for 12 weeks to 8 weeks is cost-effective in genotype 1 noncirrhotic treatment-naive patients. There was considerable uncertainty in the estimates for 6- and 4-week treatments, with some indication that the 6-week treatment may be cost-effective.

The Discovery and Early Clinical Evaluation of the HCV NS3/4A Protease Inhibitor Asunaprevir (BMS-650032)

The discovery of asunaprevir (1) began with the concept of engaging the small and well-defined S₁’ pocket of the hepatitis C virus (HCV) NS3/4A protease that was explored in the context of tripeptide carboxylic acid-based inhibitors. A cyclopropyl-acyl sulfonamide moiety was found to be the optimal element at the P₁-P₁’ interface enhancing the potency of carboxylic acid-based prototypes by 10- to >100-fold, dependent upon the specific background. Optimization for oral bioavailability identified a 1-substituted isoquinoline-based P₂* element that conferred a significant exposure advantage in rats compared to the matched 4-substituted quinoline isomer. BMS-605339 (30) was the first cyclopropyl-acyl sulfonamide derivative advanced into clinical trials that demonstrated dose-related reductions in plasma viral RNA in HCV-infected patients. However, 30 was associated with cardiac events observed in a normal healthy volunteer (NHV) and an HCV-infected patient that led to the suspension of the development program. Using a Langendorff rabbit heart model, a limited structure-cardiac liability relationship was quickly established that led to the discovery of 1. This compound, which differs from 30 only by changes in the substitution pattern of the P₂* isoquinoline heterocycle and the addition of a single chlorine atom to the molecular formula, gave a dose-dependent reduction in plasma viral RNA following oral administration to HCV-infected patients without the burden of the cardiac events that had been observed with 30. A small clinical trial of the combination of 1 with the HCV NS5A inhibitor daclatasvir (2) established for the first time that a chronic genotype 1 (GT-1) HCV infection could be cured by therapy with two direct-acting antiviral agents in the absence of exogenous immune-stimulating agents. Development of the combination of 1 and 2 was initially focused on Japan where the patient population is predominantly infected with GT-1b virus, culminating in marketing approval which was granted on July 4, 2014. In order to broaden therapy to include GT-1a infections, a fixed dose triple combination of 1, 2, and the allosteric NS5B inhibitor beclabuvir (3) was developed, approved by the Japanese health authorities for the treatment of HCV GT-1 infection on December 20, 2016 and marketed as Ximency^®.

Status of Direct-Acting Antiviral Therapy for Hepatitis C Virus Infection and Remaining Challenges

Chronic infection with hepatitis C virus is a major cause of liver disease and hepatocellular carcinoma worldwide. After the discovery of hepatitis C virus 3 decades ago, the identification of the structure of the viral proteins, combined with high-throughput replicon models, enabled the discovery and development of direct-acting antivirals. These agents have revolutionized patient care, with cure rates of more than 90%. We review the status of direct-acting antiviral therapies for hepatitis C virus infection and discuss remaining challenges. We highlight licensed compounds, discuss the potential to shorten therapy even further, and review different options for treatment failure and resistance. We also provide an overview of clinical experience with generic agents and evidence for their efficacy. Finally, we discuss the need for new drugs and outline promising targets for future therapies.

SVR 24 Achievement Two Weeks After a Tripled Dose of Daclatasvir in an HCV Genotype 3 Patient

Directly-acting antivirals (DAA) have changed the chronic hepatitis C virus (HCV) infection therapeutic scenario allowing virus eradication in more than 95% of patients, independently from the genotype, with 12 to 24-week treatment regimens. We describe a 51-year-old Pakistani man with a chronic HCV-genotype 3 (GT3a) infection with moderate liver fibrosis, who achieved sustained virological response (SVR) 24 after a tripled dose of Daclatasvir (DCV) taken erroneously associated to Sofosbuvir (SOF). The patient had a concomitant intestinal TB infection whose treatment had been delayed in order to firstly eradicate HCV to reduce the liver toxicity of anti-mycobacterial drugs. Thanks to the cultural mediator support, we explained to the patient the correct posology of each drug to take during the day consisting of 12 week SOF (400 mg daily) plus DCV (60 mg daily) regimen. He returned 13 days after for a programmed visit and we were surprised to learn that he had taken 3 pills of DCV (180 mg/daily) instead of one, thus ending DCV assumption after only 9 days while SOF was taken correctly. He complained no symptoms. We immediately performed blood test that showed alteration of lactate dehydrogenase, creatine phosphokinase, and creatin kinase MB activity. At day 15 we stopped SOF closely monitoring the patient. Blood test alterations returned normal after one week of treatment suspension, HCV viremia remained suppressed after 4, 12 and 24 weeks proving HCV eradication. If confirmed, these data could suggest that higher doses of DCV, if tolerated, might be employed in short-time HCV-GT3 treatment.

Association between alanine aminotransferase elevation and UGT1A1*6 polymorphisms in daclatasvir and asunaprevir combination therapy for chronic hepatitis C

BACKGROUND

Liver damage presented as alanine aminotransferase (ALT) elevation and high ALT-caused treatment discontinuation occurs with high frequency in Japanese patients receiving daclatasvir plus asunaprevir (DCV/ASV) therapy for hepatitis C virus (HCV) infection, and its mechanism is unknown.

METHODS

A total of 247 Japanese patients consisting of two independent cohorts with genotype-1b HCV infection receiving DCV/ASV therapy were included. The association of ALT levels during therapy and single nucleotide polymorphisms (SNP) of five drug-metabolizing enzyme loci selected for their possible influence on NS3/4A and NS5A inhibitors was investigated.

RESULTS

Among five SNPs, we found a significant correlation between the presence of the UGT1A1 rs4148323 A allele and ALT elevation (Grade 3 elevation in AA 57%, AG 18%, and GG 4%, P = 8.4E - 06) and drug discontinuation (AA 22%, AG 11%, and GG 2.5%, P = 8.7E - 04), while no association was observed with ALT values at baseline (Grade 3 elevation AA 0%, AG 4%, and GG 2%, P = 0.5). In contrast, patients with risk A allele for drug-induced ALT elevation had a tendency to respond more favorably to treatment (AA 100%, AG 93%, and GG 90%, P = 0.29).

CONCLUSIONS

Through the analysis we suggest that the A allele in UGT1A1 rs4148323 (UGT1A1*6), which is highly prevalent in the Japanese population, should be considered a risk for the development of DCV/ASV therapy-induced ALT elevation. Pretreatment SNP testing of UGT1A1*6 might be beneficial for the prediction of liver damage induced by DCV/ASV or even by DCV/ASV plus beclabuvir.

Efficacy and safety of 6 or 8 weeks of simeprevir, daclatasvir, sofosbuvir for HCV genotype 1 infection

The phase 2, open-label ACCORDION (ClinicalTrials.gov: NCT02349048) study investigated the efficacy, safety and pharmacokinetics of a 6- or 8-week regimen of simeprevir, daclatasvir and sofosbuvir in treatment-naïve patients with chronic hepatitis C virus (HCV) genotype (GT) 1 infection and either early-stage fibrosis or compensated cirrhosis. Patients were assigned to treatment groups according to their fibrosis stage. Early-stage fibrosis: simeprevir 150 mg, daclatasvir 60 mg, sofosbuvir 400 mg once daily for 6 weeks; compensated cirrhosis: same regimen for 8 weeks. The primary endpoint was sustained virologic response 12 weeks after the end of treatment (SVR12). Safety, tolerability and pharmacokinetics of simeprevir, daclatasvir and sofosbuvir were investigated. Sixty-eight patients were treated (6-week group: n = 59; 8-week group: n = 9). SVR12 was achieved by 86.4% (51/59) of patients with early-stage fibrosis and by 100% (9/9) of patients with cirrhosis. The main reason for not achieving SVR12 in the 6-week group was viral relapse (11.9%; 7/59). One patient had on-treatment failure due to an early withdrawal (lost to follow-up due to incarceration). One patient with SVR12 in the 6-week group had a late viral relapse at post-treatment week 24. No clinically significant drug-drug interactions were observed. Adverse events were reported in 63.2% of patients (43/68) and were mainly grade 1/2. None of these led to treatment discontinuation. The 3 direct-acting antiviral regimens of simeprevir, daclatasvir and sofosbuvir were safe and well tolerated in treatment-naïve, HCV GT1-infected patients with early-stage fibrosis or compensated cirrhosis.

Daclatasvir and sofosbuvir treatment of decompensated liver disease or post-liver transplant hepatitis C virus recurrence in patients with advanced liver disease/cirrhosis in a real-world cohort

We report the findings of an early access program providing treatment for chronic hepatitis C virus infection (any genotype) with daclatasvir and sofosbuvir with/without ribavirin to patients with Child‐Pugh class C cirrhosis or prior liver transplant recipients with recurrent hepatitis C virus infection and advanced fibrosis/cirrhosis. Patients had <12‐month life expectancies per the local investigator. Patients received daclatasvir 60 mg and sofosbuvir 400 mg once daily, with/without ribavirin, for 24 weeks. Sustained virologic response (SVR) at posttreatment week 12 (SVR12) was measured. Assessments adhered to local standards. One patient (prior Child‐Pugh class C who improved to class B) enrolled by exemption was included in the overall data but not the class C cohort efficacy/safety data. Of the 77 treated patients, including 62 liver transplant recipients (genotype 1, n = 43, 69%; genotype 3, n = 16, 26%) and 14 patients with Child‐Pugh class C cirrhosis (genotype 1, n = 4, 29%; genotype 3, n = 10, 71%), 63 (82%) completed treatment. SVR12 rates by modified intention‐to‐treat analysis (excluding nonvirologic failures lost to follow‐up and withdrawal [consent/no reason]) in the overall, liver transplant, and Child‐Pugh class C cohorts were 84% (n = 64/76), 90% (n = 56/62), and 62% (n = 8/13), respectively. Rates increased to 96% (n = 64/67), 97% (n = 56/58), and 89% (n = 8/9), respectively, in patients with available virologic data (including early discontinuations); 22/23 patients with genotype 3 (96%) achieved SVR12. Single cases of virologic nonresponse and relapse (both in liver transplant recipients with genotype 1) and viral breakthrough (Child‐Pugh class C; genotype 3) occurred. Six patients died, 10 had adverse events leading to discontinuation, and 30 experienced serious adverse events. Conclusion: Daclatasvir plus sofosbuvir, with/without ribavirin, provided high SVR12 rates and was generally well tolerated in patients with life‐threatening disease and high unmet needs. (Hepatology Communications 2018;2:354‐363)

NS5B polymerase inhibitors in phase II clinical trials for HCV infection

INTRODUCTION

Hepatitis C virus (HCV) infection might be the first chronic viral disease to be eradicated without the introduction of a prophylactic vaccine. This is essentially due to therapeutic revolution encapsulated by the advent of direct-acting antivirals (DAA) agents, whose efficacy, safety and tolerability (all oral regimens) have made the previous standard of care (interferon plus ribavirin) a vestige of the past. The new regimens achieve very high response rates and have an excellent tolerability profile. Notwithstanding, the first wave of DAAs has brought over problems regarding costs and failures which warrant research and development of further antiviral molecules.

AREAS COVERED

This review outlines the main clinical data concerning novel NS5B polymerase inhibitors currently in pipeline, focusing on the ones that have completed a phase 2 trial.

EXPERT OPINION

NS5B is one the main viral target for anti-HCV therapy. The large majority of the approved regimens so far include a NS5B inhibitor. Although not frequently, failure related to mutations can occur. The potential place in therapy in the mid-term of new NS5B inhibitors may be, in the first instance, the role of backbone in salvage combinations with DAAs of other classes.

HCV kinetic and modeling analyses project shorter durations to cure under combined therapy with daclatasvir and asunaprevir in chronic HCV-infected patients

BACKGROUND & AIMS

High cure rates are achieved in HCV genotype-1b patients treated with daclatasvir and asunaprevir, DCV/ASV. Here we analyzed early HCV kinetics in genotype-1b infected Japanese subjects treated with DCV/ASV and retrospectively projected, using mathematical modeling, whether shorter treatment durations might be effective.

METHODS

HCV RNA levels were measured frequently during DCV/ASV therapy in 95 consecutively treated patients at a single center in Japan. Mathematical modeling was used to predict the time to cure, i.e, <1 virus copy in the extracellular body fluid. Patients with HCV<15 IU/ml at week 1 (n = 27) were excluded from modeling analysis due to insufficient HCV RNA data points.

RESULTS

Eighty nine of the 95 included patients (94%) achieved cure, 3 (3%) relapsed due to treatment-emergent resistance, and 3 (3%) completed therapy but were lost during follow up. Model fits from 68 patients with sufficient data points indicate that after a short pharmacological delay (15.4 min [relative standard error, rse = 26%]), DCV/ASV effectiveness in blocking HCV production was 0.999 [rse~0%], HCV half-life in blood was t1/2 = 1.7 hr [rse = 21%], and HCV-infected cell loss rate was 0.391/d [rse = 5%]. Modeling predicted that 100% and 98.5% of patients who had HCV<15 IU/ml at days 14 and 28 might have been cured with 6 and 8 weeks of therapy, respectively. There was a trend (p = 0.058) between younger age and shorter time to cure.

CONCLUSION

Modeling early HCV kinetics under DCV/ASV predicts that most patients would achieve cure with short treatment durations, suggesting that 24 weeks of DCV/ASV treatment can be significantly shortened.

Shortening the duration of therapy for chronic hepatitis C infection

Combination direct-acting antiviral therapy of 8-24 weeks is highly effective for the treatment of chronic hepatitis C infection. However, shortening the treatment duration to less than 8 weeks could potentially reduce overall treatment costs and improve adherence. Here we explore the arguments for and against the development of short-duration regimens and existing data on treatment for 6 weeks or less among patients with chronic hepatitis C virus genotype 1 infection. Additionally, we identify potential predictors of response to short-course combination therapies with direct-acting antiviral drugs that might be explored in future clinical trials.

Adverse effects of direct acting antiviral-based regimens in chronic hepatitis C patients: a Brazilian experience

Background Direct-acting antivirals (DAA) are currently used for the treatment of chronic hepatitis C (HCV). However, few studies describe the adverse effects (AE) associated with DAA therapy in "real-word" cohorts. Aim To evaluate AE in Brazilian chronic HCV patients after DAA-therapy. Setting A reference center for hepatitis treatment in Rio de Janeiro, Brazil. Methods An observational "real-world" study was conducted with 102 chronic HCV patients undergoing DAA therapy for 12 or 24 weeks. The self-reported AE were correlated with cirrhosis status, genotype, age, current therapeutic schemes and comorbidities. Serious AE were also investigated. Main outcome measure Frequency of AE during DAA therapy. Results Overall, mean ± SD age was 60.9 ± 9.4 years, 67% were females, HCV-genotype 1 was the most prevalent (81%) and 74% were cirrhotic. Moreover, all patients reached sustained virological response. About 90% of patients reported at least one AE associated with current treatment, with a mean of 2.7 symptoms per patient. The most frequently reported AE were fatigue (43%), headache (42%), neuropsychiatric symptoms (30%) and nausea (26%). Furthermore, hemoglobin < 12 mg/dL was the most frequent (38%) laboratory abnormality observed. Neuropsychiatric symptoms were the only AE significantly different in treatment-experienced group when compared to naïve patients (41.7 vs. 12.5, P = 0.002). The higher frequency of AE did not correlate with the presence of previous treatment, cirrhosis, genotype, age, current therapeutic schemes with DAA or comorbidities. Conclusion DAA-based therapeutic regimens demonstrated safety in a Brazilian "real-world" cohort of chronic hepatitis C patients.

Response Tailored Protocol Versus the Fixed 12Weeks Course of Dual Sofosbuvir/Daclatasvir Treatment in Egyptian Patients With Chronic Hepatitis C Genotype-4 Infection: A Randomized, Open-label, Non-inferiority Trial

BACKGROUND

The most recent European Association for the Study of the Liver (EASL) 2016 Guidelines on treatment of hepatitis C (HCV), allowed for shortening the course of treatment for some subsets of patients with sofosbuvir/ledipasvir and with grazoprevir/elbasvir based on cutoff baseline HCV RNA values. We hypothesized that it would be prudent to also consider an objectively assuring very rapid, on-treatment, virologic response to therapy at week 2 (vRVR) before taking the decision of shortening the treatment duration. So we planned this study to test whether a dual sofosbuvir/daclatasvir (SOF/DCV) treatment duration tailored according to achieving vRVR to 8 or 12weeks is non-inferior to the recommended fixed 12weeks course in non-cirrhotic Egyptian chronic HCV genotype-4 patients.

METHODS

The study was conducted in an outpatient setting according to a prospective, randomized, open-label, comparative, non-inferiority study design. A hundred twenty eligible, non-cirrhotic, chronic HCV patients were randomly assigned (1:1) to receive daily doses in the form of one Gratisovir 400mg table (generic sofosbuvir produced by Pharco Pharmaceuticals, Alexandria, Egypt) plus one Daktavira 60mg tablet (generic daclatasvir produced by Dawood Pharm, Egypt) for either a fixed 12weeks duration (reference group) or a response tailored duration (test group). In the test group the treatment duration was tailored according to the virus load tested by real time PCR into 8weeks for patients who had undetectable HCV RNA level in their serum by the end of the second week of treatment (vRVR)), or 12weeks for those who did not show vRVR. The primary outcome of the trial was the proportions of patients achieving SVR12 (HCV RNA below lower level of quantification at week 12 after end of treatment). The comparison between groups was based on testing the null hypothesis of inferiority of the response-tailored group with a pre-specified margin of non-inferiority (NI-m) of 0.1 (10%). The protocol was registered with a WHO Clinical Trial Registration ID: ACTRN12617000263392. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372041 FINDINGS: Starting from Jun, 5 2016, a hundred twenty eligible patients from 4 outpatient clinics in Alexandria, Egypt were randomized to either a fixed duration group (reference group: n=60 patients) or a response tailored duration group (test group: n=60 patients). During the whole period of the study, only 1 patient dropped-out from each group. Both were lost to follow-up after the 4th week's visit. Baseline characteristics in both groups were almost matching. Fifty eight out of the total 60 intention-to-treat (ITT) patients in the reference group achieved SVR12 (96.67% (95% confidence interval (CI): 88.64-99%). Whereas, 59 out of the total 60 (ITT) patients in the test group achieved SVR12 (98.33% (CI: 91.14-99.71%). The per-protocol (PP) analysis, excluding patients who dropped-out before collecting their final result, showed that 58/59 (98.31% (CI: 91-99.7%)) of patients in the reference group and 59/59 (100% (CI: 93.89-100%) of the test group achieved SVR12. Non-inferiority was declared since the upper bound of the two-sided 95% CI for the difference in proportions of SVR12 between groups (P(reference)-P(test)) did not exceed the specified non-inferiority margin of +0.1 (10%), both in ITT population (-1.67%, CI: -9.8%-+5.9%), and in the PP population (-1.69%, CI: -9%-+4.58%). No fatalities or serious adverse events were reported during the period of the study. Similar rates of non-serious adverse events were reported in both groups with a trend of higher incidence rate in the fixed 12weeks group; all were mild in severity.

INTERPRETATION

Shortening the duration of therapy based on observed vRVR could provide a prudent basis to avoid unnecessary long treatment courses. This could not only reduce the drug exposure and the risk of adverse drug reactions, but also cut the cost of full treatment course with such expensive medications by one third. This could economize the treatment budget at the individual out-of-pocket level as well as the public health services and insurance levels and allow for better utilization of public health resources.

Why highly effective drugs are not enough: the need for an affordable solution to eliminating HCV

INTRODUCTION

Because of the rapid pace of development of new direct-acting antiviral (DAA) drugs, chronic hepatitis C virus (HCV) infection is now increasingly considered curable. However, the emphasis on DAA therapies disregards key issues related to cost, availability, and antiviral resistance. Areas covered: This perspective provides an overview of current HCV therapies and the development of DAAs, followed by a discussion of the limitations of DAA therapy. A literature search was used to select relevant studies, and a web search for relevant news articles and press releases was conducted. Expert commentary: Despite cure rates exceeding 90%, now is not the time to declare victory against HCV but to reinforce recent progress by addressing the issues of cost and availability as well as by developing strategies to manage antiviral resistance. Future drug development efforts should place greater emphasis on targeting host factors required for HCV replication, for which the barrier to resistance is higher, and effort should continue to develop a vaccine against HCV. Finally, efforts should be made to facilitate large-scale screening in endemic areas to identify and treat patients as early as possible to reduce long-term risks of advanced liver disease and their attendant costs of management.