NS5A Inhibitor Research Articles

Celastrol inhibits hepatitis C virus replication by upregulating heme oxygenase-1 via the JNK MAPK/Nrf2 pathway in human hepatoma cells

background and purposeCelastrol, a quinone methide triterpene isolated from the root extracts of Tripterygium wilfordii, can greatly induce the gene expression activity of heme oxygenase-1 (HO-1) to achieve disease prevention and control. HO-1 induction was recently shown to result in anti-HCV activity by inducing type I interferon and inhibiting hepatitis C virus (HCV) NS3/4A protease activity. The aim of the present study is to evaluate the anti-HCV activity of celastrol and characterize its mechanism of inhibition. MethodsThe anti-HCV activity of celastrol was evaluated using the HCV subgenomic replicon and HCVcc infection systems. The anti-HCV mechanism of celastrol targeting HO-1 expression was clarified using specific inhibitors against several signaling pathways. The transcriptional regulation of celastrol on target gene expression was determined using promoter-based reporter activity assay. The synergistic effect of celastrol and a numbers of clinically used anti-HCV drugs was determined via a drug combination assay. ResultsCelastrol inhibited HCV replication in both the HCV subgenomic and HCVcc infection systems with EC50 values of 0.37 ± 0.022 and 0.43 ± 0.019 μM, respectively. Celastrol-induced heme oxygenase 1 (HO-1) expression promoted antiviral interferon responses and inhibition of NS3/4A protease activity, thereby blocking HCV replication. These antiviral effects were abrogated by treatment with the HO-1-specific inhibitor SnMP or silencing of HO-1 expression by transfection of shRNA, which indicates that HO-1 induction contributes to the anti-HCV activity of celastrol. JNK mitogen-activated protein kinase and nuclear factor erythroid 2-related factor 2 (Nrf2) were confirmed to be involved in the inductive effect of celastrol on HO-1 expression. Celastrol exhibited synergistic effects in combination with interferon-alpha, the NS5A inhibitor daclatasvir, and the NS5B inhibitor sofosbuvir. ConclusionCelastrol can serve as a potential supplement for blocking HCV replication. Targeting the JNK/Nrf2/HO-1 axis presents a promising strategy against HCV infection.

Development of the Large-Scale Synthesis of Tetrahydropyran Glycine, a Precursor to the HCV NS5A Inhibitor BMS-986097

An efficient large-scale synthesis of acid 1, a penultimate precursor to the HCV NS5A inhibitor BMS-986097, along with the final API step are described. Three routes were devised for the synthesis of 1 at the various stages of the program. The third generation route, the one that proved scalable and is the main subject of this paper, features a one-step Michael addition of t-butyl 2-((diphenylmethylene)amino)acetate (24) to (E)-benzyl 4-(1-hydroxycyclopropyl)but-2-enoate (28) followed by cyclization and chiral separation to form 27c, the core skeleton of cap piece 1. The epimerization and chiral resolution of 27c followed by further synthetic manipulations involving the carbamate formation, lactone reduction and cyclization, afforded cyclopropyl pyran 1. A detailed study of diphenylmethane deprotection via acid hydrolysis as well as a key lactone to tetrahydropyran conversion, in order to avoid a side reaction that afforded an alternative cyclization product, are discussed. This synthesis was applied to the preparation of more than 100 g of the final API BMS-986097 for toxicology studies.

Searching for synergy: Identifying optimal antiviral combination therapy using Hepatitis C virus (HCV) agents in a replicon system

Direct acting antiviral agents (DAAs) are potent inhibitors of Hepatitis C virus (HCV) that have revolutionized the treatment landscape for this important viral disease. There are currently four classes of DAAs that inhibit HCV replication via distinct mechanisms of action: nonstructural protein (NS) 3/4a protease inhibitors, NS5A inhibitors, NS5B nucleoside polymerase inhibitors, and NS5B non-nucleoside polymerase inhibitors. Combination therapy with two or more DAAs has great potential to further enhance antiviral potency. The purpose of this study was to identify optimal combinations of DAAs against genotype 1 HCV replicons that maximized the inhibition of replicon replication. All possible two-drug combinations were evaluated against genotype 1a and 1b HCV replicons using a 96-well plate luciferase-based assay in triplicate. The Greco Universal Response Surface Area mathematical model was fit to the luciferase data to identify drug-drug interactions (i.e.: synergy, additivity, and antagonism) for antiviral effect against both genotypes. This information was used to rank-order combinations of DAAs based on their ability to inhibit replicon replication against genotype 1a and 1b HCV. These preclinical findings can provide information as to which antiviral regimens should move on in the development process.

Hepatitis C infection in renal transplantation: pathogenesis, current impact and emerging trends.

Prevalence of hepatitis C infection, which is associated with mortality and morbidity, is higher in chronic kidney disease patients on hemodialysis and transplant recipients when compared to non HCV infected patients. In addition to the conventional risk factors, HCV infection maybe an additional risk factor in the development of chronic kidney disease. HCV causes adverse effects leading to the poor long term outcome in renal transplant recipients; hepatitis C infection can cause both hepatic as well as extra hepatic complications. Prior evaluation and management of HCV infection is recommended for better long term outcome as there are chances of higher rejection rates with HCV treatment. However transplantation is not contraindicated in those patients who cannot be treated prior to the transplantation as patient survival is better when compared to dialysis patients. Kidney Disease Outcome Quality Initiative Clinical Practice Guidelines recommend interferon based therapy only when there is a rapid worsening of HCV related hepatic injury in transplant recipients. HCV treatment has been improved by the addition of direct acting antiviral, protease inhibitors and polymerase inhibitors. Combination therapies are showing improved sustained virological response rates. NS3-4A protease inhibitors, nucleotidic/nucleosidic NS5A and NS5B polymerase inhibitors are promising treatments which are under trials with different combinations. The focus of this review is to evaluate and optimize the treatment options of co-existing HCV infection in renal transplant recipients and discuss more promising alternative treatment regimen.

Natural NS5A inhibitor resistance associated substitutions in hepatitis C virus genotype 1 infected patients from Italy

ObjectivesGenetic variability in NS5A is associated with different levels of resistance to the currently licensed NS5A inhibitors. The aim of this study was to detect NS5A inhibitor resistance associated substitutions (RASs) in hepatitis C virus (HCV) genotype 1 (GT1) patients who are naive to direct-acting HCV antivirals. MethodsAmplification, Sanger sequencing and phylogenetic analysis of the HCV NS5A region were performed on plasma obtained from 122 consecutive patients with HCV chronic infection attending four different clinics in Italy. ResultsNS5A inhibitor RASs were detected in 14/61 (23.0%) HCV GT1b and 3/61 (4.9%) HCV GT1a infected patients (p 0.007). The pan-genotypic RAS Y93H was detected in 1 (1.6%) GT1a and 4 (6.6%) GT1b patients. GT1a sequences clustered into two different clades with RASs detected in 1/34 (2.9%) clade I and 2/27 (7.4%) clade II sequences. ConclusionsAlthough the impact of naturally occurring NS5A RASs might be limited with upcoming pan-genotypic treatment regimens, this information is still useful to map naturally occurring HCV variants in different geographic areas in the context of current HCV therapy.

Safety and efficacy of an 8-week regimen of grazoprevir plus ruzasvir plus uprifosbuvir compared with grazoprevir plus elbasvir plus uprifosbuvir in participants without cirrhosis infected with hepatitis C virus genotypes 1, 2, or 3 (C-CREST-1 and C-CREST-2, part A): two randomised, phase 2, open-label trials

New hepatitis C virus (HCV) therapies with pan-genotypic efficacy are needed. The goals of part A of C-CREST-1 and C-CREST-2 were to compare the efficacies of two doses (300 mg or 450 mg once daily) of uprifosbuvir (MK-3682; NS5B inhibitor) in an 8-week regimen combined with grazoprevir (NS3/4A inhibitor; 100 mg once daily) and an NS5A inhibitor, either elbasvir (50 mg once daily) or ruzasvir (MK-8408; 60 mg once daily), and to evaluate the safety and tolerability of these combination regimens in individuals infected with genotypes 1, 2, or 3. Part A of these phase 2, randomised, multicentre, open-label, clinical trials enrolled participants from 11 countries, aged 18 years or older, chronically infected with HCV genotypes 1, 2, or 3, with HCV RNA of at least 10 000 IU/mL, without evidence of cirrhosis, who had not received previous treatment for HCV infection. Within each HCV genotype, participants were randomly assigned (1:1:1:1) with a block size of 4, to open-label treatment to one of four treatment groups: grazoprevir (100 mg/day) plus ruzasvir (60 mg/day) plus uprifosbuvir (300 mg/day); grazoprevir (100 mg/day) plus ruzasvir (60 mg/day) plus uprifosbuvir (450 mg/day); grazoprevir (100 mg/day) plus elbasvir (50 mg/day) plus uprifosbuvir (300 mg/day); or grazoprevir (100 mg/day) plus elbasvir (50 mg/day) plus uprifosbuvir (450 mg/day), according to a computer-generated allocation schedule. Randomisation was centrally implemented using an interactive voice response system and integrated web response system. The primary endpoint was the proportion of participants achieving sustained virological response at 12 weeks (SVR12; HCV RNA less than the lower limit of quantitation at 12 weeks after the end of all study therapy) in the per-protocol analysis set, which included all participants who were randomised and received at least one dose of study drug. The trials are registered with ClinicalTrials.gov, numbers NCT02332707 and NCT02332720. 241 participants were randomised between Feb 18, 2015, and March 16, 2015. 240 participants completed 8 weeks of treatment and reached follow-up 12 weeks after the end of treatment. Of the four regimens, grazoprevir plus ruzasvir plus uprifosbuvir 450 mg had the most consistently high SVR12 (>90%) for participants infected with genotype 1 (21 [91%] of 23), genotype 2 (15 [94%] of 16), and genotype 3 (20 [91%] of 22). In particular, among those with genotype 2 infection, the grazoprevir plus ruzasvir plus uprifosbuvir 450 mg regimen had a higher SVR12 (15 [94%] of 16) than the grazoprevir plus ruzasvir plus uprifosbuvir 300 mg regimen (ten [71%] of 14), grazoprevir plus elbasvir plus uprifosbuvir 300 mg regimen (11 [69%] of 16), or grazoprevir plus elbasvir plus uprifosbuvir 450 mg regimen (nine [60%] of 15). Overall, the most common adverse events were headache (55 [23%] of 240), fatigue (47 [20%] of 240), and nausea (32 [13%] of 240). Two (<1%) of 240 participants had serious adverse events (pharyngeal abscess and keratitis), which were not considered drug related by the respective investigators. These results support further evaluation of the three-drug direct-acting antiviral agent regimen of grazoprevir 100 mg plus ruzasvir 60 mg plus uprifosbuvir 450 mg among a more diverse HCV-infected population, including those with compensated cirrhosis, previous treatment with an interferon-containing regimen, and HCV-HIV co-infection. Merck & Co, Inc.

Safety and efficacy of a fixed-dose combination regimen of grazoprevir, ruzasvir, and uprifosbuvir with or without ribavirin in participants with and without cirrhosis with chronic hepatitis C virus genotype 1, 2, or 3 infection (C-CREST-1 and C-CREST-2, part B): two randomised, phase 2, open-label trials

There is a need for hepatitis C virus (HCV) therapies with excellent efficacy across genotypes and in diverse populations. Part A of the C-CREST-1 and C-CREST-2 trials led to the selection of a three-drug regimen of grazoprevir (MK-5172; an HCV NS3/4A protease inhibitor; 100 mg/day) plus ruzasvir (MK-8408; an NS5A inhibitor; 60 mg/day) plus uprifosbuvir (MK-3682; an HCV NS5B polymerase inhibitor; 450 mg/day). Part B of the studies tested this combination as a single formulation in different treatment durations in a broader population. Part B of these randomised, phase 2, open-label clinical trials enrolled individuals from 15 countries who were chronically infected with HCV genotypes 1-6 (HCV RNA ≥10 000 IU/mL) with or without compensated cirrhosis. Those with genotype 1, genotype 2, genotype 4, or genotype 6 were treatment-naive; those with genotype 3 could be treatment-naive or treatment-experienced with pegylated interferon and ribavirin. Randomisation occurred centrally using an interactive voice response system and integrated web response system. Participants were randomly assigned to receive treatment for 8, 12, or 16 weeks with a fixed-dose combination of grazoprevir, ruzasvir, and uprifosbuvir with or without ribavirin. The primary endpoint was the proportion of participants achieving sustained virological response 12 weeks after the end of all study therapy (SVR12), defined as HCV RNA less than the lower limit of quantification (either target detected unquantifiable or target not detected [<15 IU/mL]). The trials are registered at ClinicalTrials.gov, numbers NCT02332707 and NCT02332720. 676 participants were randomly assigned between Feb 18, 2015, and Aug 16, 2016. In all 675 participants who received at least one dose of study drug (full analysis set), SVR12 for the 8-week regimen of grazoprevir, ruzasvir, and uprifosbuvir with and without ribavirin was achieved in 39 (93% [95% CI 81-99]) of 42 participants with genotype 1a, 45 (98% [88-100]) of 46 with genotype 1b, 54 (86% [75-93]) of 63 with genotype 2, 98 (95% [89-98]) of 103 with genotype 3, and seven (100% [59-100]) of seven participants with genotype 4. SVR12 for the 12-week regimen with and without ribavirin was achieved in 87 (99% [95% CI 94-100]) of 88 participants with genotype 1, 61 (98% [91-100]) of 62 with genotype 2, and four (100% [40-100]) of four with genotype 6. Among participants with cirrhosis who were infected with genotype 3, SVR12 for the 12-week regimen with and without ribavirin was achieved in 28 (97% [95% CI 82-100]) of 29 of those who were treatment-naive and 29 (100% [88-100]) of 29 who were treatment-experienced. SVR12 for the 16-week regimen with and without ribavirin was achieved in 26 (100% [95% CI 87-100]) of 26 participants with genotype 2 infection and 72 (96% [89-99]) of 75 participants with genotype 3 infection. The most common adverse events were headache (143 [22%] of 664), fatigue (129 [19%] of 664), and nausea (83 [13%] of 664). 16 (2%) of 664 participants had serious adverse events. The combined regimen of grazoprevir (100 mg/day), ruzasvir (60 mg/day), and uprifosbuvir (450 mg/day) has the potential to provide a simplified treatment for HCV that is effective and well tolerated in most individuals infected with HCV, as well as a shorter duration of treatment in many individuals. Merck & Co, Inc.

No one size fits all-Shortening duration of therapy with direct-acting antivirals for hepatitis C genotype 1 infection.

The advent of shorter duration, highly effective and well-tolerated interferon-free therapy now provides an opportunity for virtually all HCV-infected individuals to be cured. However, there continues to be a need to simplify and shorten treatment duration. Shortening therapy to 8weeks with sofosbuvir and ledipasvir can be considered in treatment patients with HCV genotype 1 infection and low baseline viral load. A number of other 8-week dual and triple therapy direct-acting antiviral (DAA) regimens are in advanced clinical development. Several small studies have further demonstrated the feasibility of 6weeks of sofosbuvir therapy in combination with an NS5A inhibitor and a protease inhibitor for HCV genotype 1. Four weeks of therapy with various combinations of the currently available DAAs appears to be suboptimal with poor response rates observed in phase 2 trials. Response-guided therapy is another promising tool that may allow for shorter therapy but require further research. Shortening therapy and retreating relapsers may be a viable cost-saving measure, but requires further cost-benefit analysis and more data on the impact of resistance on retreatment options.

An NS5A single optimized method to determine genotype, subtype and resistance profiles of Hepatitis C strains.

The objective was to develop a method of HCV genome sequencing that allowed simultaneous genotyping and NS5A inhibitor resistance profiling. In order to validate the use of a unique RT-PCR for genotypes 1–5, 142 plasma samples from patients infected with HCV were analysed. The NS4B-NS5A partial region was successfully amplified and sequenced in all samples. In parallel, partial NS3 sequences were analyzed obtained for genotyping. Phylogenetic analysis showed concordance of genotypes and subtypes with a bootstrap >95% for each type cluster. NS5A resistance mutations were analyzed using the Geno2pheno [hcv] v0.92 tool and compared to the list of known Resistant Associated Substitutions recently published. In conclusion, this tool allows determination of HCV genotypes, subtypes and identification of NS5A resistance mutations. This single method can be used to detect pre-existing resistance mutations in NS5A before treatment and to check the emergence of resistant viruses while undergoing treatment in major HCV genotypes (G1-5) in the EU and the US

Sofosbuvir–velpatasvir: A single-tablet treatment for hepatitis C infection of all genotypes

The pharmacology, pharmacokinetics, interaction potential, efficacy, and safety of the newest direct-acting antiviral (DAA) medication for the treatment of chronic hepatitis C are reviewed. Nonstructural proteins 5A (NS5A) and 5B (NS5B) are key drivers of hepatitis C virus (HCV) replication. Velpatasvir, an inhibitor of NS5A, was coformulated with the NS5B inhibitor sofosbuvir to provide a single-tablet combination DAA (Epclusa, Gilead Sciences). Sofosbuvir-velpatasvir was shown to have excellent activity against the 6 most prevalent HCV genotypes in the United States, with reported rates of sustained virological response at 12 weeks after treatment completion ranging from 95% to 100% in various HCV-infected populations, including patients with compensated cirrhosis and prior treatment failures. In patients with decompensated cirrhosis or HIV coinfection, reported cure rates are 85-100% and 92-100%, respectively. The duration of treatment with sofosbuvir-velpatasvir is 12 weeks regardless of the HCV genotype involved, previous treatment, and the presence of cirrhosis or baseline resistance-associated NS5A mutations. In patients with decompensated cirrhosis, sofosbuvir-velpatasvir must be used in combination with ribavirin. Sofosbuvir-velpatasvir was well tolerated in clinical trials; adverse effects reported at a rate of ≥10% were fatigue, headache, nausea, and nasopharyngitis. Sofosbuvir-velpatasvir is a DAA and the first single-tablet regimen to treat HCV infection caused by all genotypes. The efficacy and tolerability of sofosbuvir-velpatasvir have been observed in patients with types of HCV infection that traditionally have been difficult to treat.

Antiviral Activity and Resistance Analysis of NS3/4A Protease Inhibitor Grazoprevir and NS5A Inhibitor Elbasvir in Hepatitis C Virus GT4 Replicons.

Although genotype 4 (GT4)-infected patients represent a minor overall percentage of the global hepatitis C virus (HCV)-infected population, the high prevalence of the genotype in specific geographic regions coupled with substantial sequence diversity makes it an important genotype to study for antiviral drug discovery and development. We evaluated two direct-acting antiviral agents-grazoprevir, an HCV NS3/4A protease inhibitor, and elbasvir, an HCV NS5A inhibitor-in GT4 replicons prior to clinical studies in this genotype. Following a bioinformatics analysis of available GT4 sequences, a set of replicons bearing representative GT4 clinical isolates was generated. For grazoprevir, the 50% effective concentration (EC50) against the replicon bearing the reference GT4a (ED43) NS3 protease and NS4A was 0.7 nM. The median EC50 for grazoprevir against chimeric replicons encoding NS3/4A sequences from GT4 clinical isolates was 0.2 nM (range, 0.11 to 0.33 nM; n = 5). The difficulty in establishing replicons bearing NS3/4A resistance-associated substitutions was substantially overcome with the identification of a G162R adaptive substitution in NS3. Single NS3 substitutions D168A/V identified from de novo resistance selection studies reduced grazoprevir antiviral activity by 137- and 47-fold, respectively, in the background of the G162R replicon. For elbasvir, the EC50 against the replicon bearing the reference full-length GT4a (ED43) NS5A gene was 0.0002 nM. The median EC50 for elbasvir against chimeric replicons bearing clinical isolates from GT4 was 0.0007 nM (range, 0.0002 to 34 nM; n = 14). De novo resistance selection studies in GT4 demonstrated a high propensity to suppress the emergence of amino acid substitutions that confer high-potency reductions to elbasvir. Phenotypic characterization of the NS5A amino acid substitutions identified (L30F, L30S, M31V, and Y93H) indicated that they conferred 15-, 4-, 2.5-, and 7.5-fold potency losses, respectively, to elbasvir. The activity profiles of grazoprevir and elbasvir supported the testing of the direct-acting antivirals in clinical studies.

Efficacy of 12 or 18weeks of elbasvir plus grazoprevir with ribavirin in treatment-naïve, noncirrhotic HCV genotype 3-infected patients.

Elbasvir (EBR; HCV NS5A inhibitor) and grazoprevir (GZR; HCV NS3/4A protease inhibitor) are approved as a fixed-dose combination to treat patients chronically infected with HCV genotypes 1 and 4. During the development programme and supported by in vitro potency, the efficacy of EBR+GZR was assessed in HCV GT3-infected patients. This study's aim was to determine the efficacy and tolerability of 12 or 18weeks of EBR+GZR with ribavirin (RBV) in treatment-naïve, noncirrhotic HCV GT3-infected patients. Randomized patients received open-label EBR (50mg once daily) + GZR (100mg once daily) + RBV. The primary efficacy objective was to evaluate the sustained virologic response rates 12weeks after the end of all study therapy (SVR12). SVR12 rates (95% confidence interval) were 45.0% (23.1, 68.5) and 57.1% (34.0, 78.2) after treatment with EBR+GZR+RBV for 12weeks or 18weeks, respectively. On-treatment virologic failure was observed in 41% (17 of 41) of patients. At virologic failure, resistance-associated substitutions (RASs) with a >five-fold shift in potency occurred in the NS3 region in six (35%) patients and in the NS5A region in 16 (94%) patients. The most common RAS at virologic failure was Y93H in NS5A which was identified in 13 of 17 (76%) patients. The efficacy of EBR+GZR+RBV was suboptimal in HCV GT3-infected patients due to a high rate of on-treatment virologic failure and treatment-emergent RASs which demonstrates an inadequate barrier to the development of GT3 resistance. However, rapid viral clearance demonstrated the antiviral activity of EBR+GZR+RBV in GT3-infected patients.clinicaltrials.gov: NCT01717326.

Treatment of Hepatitis C Infection with Direct-Acting Antiviral Agents in Liver-Transplant Patients: A Systematic Review and Meta-Analysis

Context: Recurrence of hepatitis C virus (HCV) infection after liver transplantation (LT) can be prevented, using antiviral therapy and new treatment regimens. Combination of protease, NS5A, and NS5B inhibitors, with or without pegylated-interferon and ribavirin (PEG-IFN/RBV), results in significantly high rates of sustained virologic response (SVR) among post-LT patients with HCV infection. In this study, we aimed to assess the efficacy of direct-acting antiviral (DAA) regimens in post-LT patients with HCV infection. Evidence Acquisition: We conducted a systematic search in electronic databases to detect eligible studies on DAA treatments after LT. We evaluated English-language studies, including clinical trials and cohort studies, which used antiviral DAA regimens (with or without PEG-IFN/RBV) and reported SVR rates at 12 weeks after the end of treatment (SVR12). After data extraction, the pooled SVRs were calculated, using STATA version 11. Results: A total of 35 studies with various HCV genotypes were included in our analysis. Due to the small sample size and lack of suitable data on HCV genotypes 2 - 6, the meta-analysis was only conducted among patients with HCV genotype 1; the results of other studies were also obtained. SVR12 rates ranged from 91% to 97% in patients with 12- or 24-week sofosbuvir (SOF)/simeprevir (SMV) ± RBV, SOF/ledipasvir (LDV) ± RBV, and SOF/daclatasvir (DCV) ± RBV regimens. The minimum SVR12 rate was found in patients receiving SMV plus PEG-IFN/RBV (59%; 95% Confidence Interval, 49 - 68). Conclusions: Administration of new HCV DAA regimens can prevent post-LT HCV infection. The combination of SOF/DCV and SOF/LDV, with or without RBV, for 12 or 24 weeks can produce high rates of SVR12 in post-LT HCV patients in different settings.

Hepatitis C antiviral therapy: the next generation

In less than a decade, antiviral therapy for chronic hepatitis C (HCV) has undergone dramatic change. The sustained virologic response rate (SVR), defined as HCV RNA undetectability 12 weeks post-therapy, is recognized as being a virologic “cure” and has increased from 40–50%, with peginterferon and ribavirin, to 95–99% with the newest direct acting antiviral agents (DAA) (1). Unlike the non-specific antiviral and immunostimulatory effects of interferon, DAAs specifically target the HCV replicative machinery and include protease inhibitors, NS5a inhibitors and NS5b RNA dependent polymerase inhibitors.

Low frequency of NS5A relevant resistance-associated substitutions to Elbasvir among hepatitis C virus genotype 1a in Spain: a cross-sectional study

Relevant resistance-associated substitutions (RASs) to elbasvir, the new HCV NS5A inhibitor, may limit its efficacy and lead to virological failure in HCV-GT1a-infected patients. There are few data outside clinical trials evaluating their prevalence and impact of elbasvir/grazoprevir. A multicenter cross-sectional study of 617 HCV-GT1a-infected individuals attended in 84 Spanish hospitals from the 17 Autonomous Communities and two Autonomous cities was performed. HCV population sequencing was used to identify RASs to elbasvir and the mutational pattern and drug sensitivity were confirmed by geno2pheno[HCV]. Viruses bearing RASs to elbasvir were present in 6.2% of HCV-GT1a infected patients. The most common RASs were the Y93C/H/N and Q30E/H/R (2.4% and 2.3%; respectively). Only 3.4% of patients had viruses with RASs that confer reduced susceptibility to elbasvir by geno2pheno[HCV] that identified exclusively the positions Q30H/R (n = 7) and Y93C/H/N (n = 8) as single mutations and Q30H + Y93H (n = 4) and Q30R + Y93H (n = 2) as double mutations considered as RASs to elbasvir. Lower prevalence of RASs to elbasvir in our HCV-GT1a-Spanish cohort was observed than reported previously in clinical trials. This information may be essential to guiding the implementation of elbasvir/grazoprevir in Spain, expected at the beginning of 2017 and the management of GT1a-infected patients.

Sofosbuvir, Velpatasvir, and Voxilaprevir for Previously Treated HCV Infection

BackgroundPatients who are chronically infected with hepatitis C virus (HCV) and who do not have a sustained virologic response after treatment with regimens containing direct-acting antiviral agents (DAAs) have limited retreatment options.MethodsWe conducted two phase 3 trials involving patients who had been previously treated with a DAA-containing regimen. In POLARIS-1, patients with HCV genotype 1 infection who had previously received a regimen containing an NS5A inhibitor were randomly assigned in a 1:1 ratio to receive either the nucleotide polymerase inhibitor sofosbuvir, the NS5A inhibitor velpatasvir, and the protease inhibitor voxilaprevir (150 patients) or matching placebo (150 patients) once daily for 12 weeks. Patients who were infected with HCV of other genotypes (114 patients) were enrolled in the sofosbuvir–velpatasvir–voxilaprevir group. In POLARIS-4, patients with HCV genotype 1, 2, or 3 infection who had previously received a DAA regimen but not an NS5A inhibitor were randomly assigned in a 1:1 ratio to receive sofosbuvir–velpatasvir–voxilaprevir (163 patients) or sofosbuvir–velpatasvir (151 patients) for 12 weeks. An additional 19 patients with HCV genotype 4 infection were enrolled in the sofosbuvir–velpatasvir–voxilaprevir group.ResultsIn the three active-treatment groups, 46% of the patients had compensated cirrhosis. In POLARIS-1, the rate of sustained virologic response was 96% with sofosbuvir–velpatasvir–voxilaprevir, as compared with 0% with placebo. In POLARIS-4, the rate of response was 98% with sofosbuvir–velpatasvir–voxilaprevir and 90% with sofosbuvir–velpatasvir. The most common adverse events were headache, fatigue, diarrhea, and nausea. In the active-treatment groups in both trials, the percentage of patients who discontinued treatment owing to adverse events was 1% or lower.ConclusionsSofosbuvir–velpatasvir–voxilaprevir taken for 12 weeks provided high rates of sustained virologic response among patients across HCV genotypes in whom treatment with a DAA regimen had previously failed. (Funded by Gilead Sciences; POLARIS-1 and POLARIS-4 ClinicalTrials.gov numbers, NCT02607735 and NCT02639247.)

Virology analysis in HCV genotype 1-infected patients treated with the combination of simeprevir and TMC647055/ritonavir, with and without ribavirin, and JNJ-56914845

BackgroundIn study TMC647055HPC2001, a 3-direct-acting-antiviral (DAA) regimen combining NS3/4A protease inhibitor simeprevir (SMV), non-nucleoside NS5B inhibitor TMC647055/ritonavir (RTV) and NS5A inhibitor JNJ-56914845 resulted in high sustained virologic response 12 weeks after actual end of treatment (SVR12) in chronic hepatitis C virus (HCV) genotype 1-infected patients. SVR12 rates were generally lower in the 2-DAA regimen SMV + TMC647055/RTV with or without ribavirin. The objective of this study was to identify and characterise pre-existing and emerging resistance-associated variants (RAVs) in patients enrolled in study TMC647055HPC2001.MethodsHCV population sequencing analyses were performed on baseline isolates from all patients (n = 90) and post-baseline isolates from patients with virologic failure (n = 22). In addition, deep sequencing and phenotypic analyses were performed on selected baseline and post-baseline isolates.ResultsThe majority of patients with virologic failure had emerging RAVs to all study drugs at the time of failure: in all 22 patients SMV RAVs emerged at NS3 positions 80, 155, 156 and/or 168, consistent with the known SMV resistance profile. Emerging TMC647055 RAVs at NS5B position 495 were detected in the majority of patients (16/22), and all 5 patients who failed the 3-DAA regimen had emerging JNJ-56914845 RAVs at NS5A positions 30 and/or 31. While at the end of study emerging SMV and TMC647055 RAVs were no longer observed by population sequencing in 40% (8/20) and 62.5% (10/16) of patients with follow-up data available, respectively, emerging JNJ-56914845 RAVs were still detected in all (5/5) patients.ConclusionsVirologic failure in the 2- and 3-DAA combinations was, in the majority of patients, associated with the emergence of RAVs to all study drugs. While emerging SMV and TMC647055 RAVs became undetectable during follow-up, JNJ-56914845 RAVs in NS5A were still observed at end of study.Trial registration numberNCT01724086 (date of registration: September 26, 2012)

Efficient Hepatitis C Virus Genotype 1b Core-NS5A Recombinants Permit Efficacy Testing of Protease and NS5A Inhibitors.

Hepatitis C virus (HCV) strains belong to seven genotypes with numerous subtypes that respond differently to antiviral therapies. Genotype 1, and primarily subtype 1b, is the most prevalent genotype worldwide. The development of recombinant HCV infectious cell culture systems for different variants, permitted by the high replication capacity of strain JFH1 (genotype 2a), has advanced efficacy and resistance testing of antivirals. However, efficient infectious JFH1-based cell cultures of subtype 1b are limited and comprise only the 5' untranslated region (5'UTR)-NS2, NS4A, or NS5A regions. Importantly, it has not been possible to develop efficient 1b infectious systems expressing the NS3/4A protease, an important target of direct-acting antivirals. We developed efficient infectious JFH1-based cultures with genotype 1b core-NS5A sequences of strains DH1, Con1, and J4 by using previously identified HCV cell culture adaptive substitutions A1226G, R1496L, and Q1773H. These viruses spread efficiently in Huh7.5 cells by acquiring additional adaptive substitutions, and final recombinants yielded peak supernatant infectivity titers of 4 to 5 log10 focus-forming units (FFU)/ml. We subsequently succeeded in adapting a JFH1-based 5'UTR-NS5A DH1 recombinant to efficient growth in cell culture. We evaluated the efficacy of clinically relevant NS3/4A protease and NS5A inhibitors against the novel genotype 1b viruses, as well as against previously developed 1a viruses. The inhibitors were efficient against all tested genotype 1 viruses, with NS5A inhibitors showing half-maximal effective concentrations several orders of magnitude lower than NS3/4A protease inhibitors. In summary, the developed HCV genotype 1b culture systems represent valuable tools for assessing the efficacy of various classes of antivirals and for other virological studies requiring genotype 1b infectious viruses.

Frecuencia de sustituciones relevantes asociadas a resistencia en la región NS5A a elbasvir en el virus de la hepatitis C en pacientes con genotipo 1a en España

Resistance-associated substitutions (RASs) to the new HCV NS5A inhibitor elbasvir may limit its efficacy and lead to virological failure in HCV-GT1a-infected patients. There are no data outside clinical trials evaluating their prevalence and impact in grazoprevir/elbasvir in GT1a-infected patients in Spain. A multicentre cross-sectional study of 632 initial patients was conducted. In 13 of these patients, the sample could not be amplified or a consensus sequence by Sanger sequencing could not be performed. Ultimately, 617 HCV-G1a-infected individuals treated at 84 Spanish hospitals from the 17 autonomous communities plus the 2 autonomous cities of Spain were analysed. HCV population sequencing was used to identify RAS to elbasvir and the mutational pattern and drug sensitivity were confirmed by geno2pheno[HCV]. Viruses bearing RASs to elbasvir were present in 6.2% of HCV-G1a infected patients. The most common RASs were the Y93C/H/N and Q30E/H/R (2.4% and 2.3%, respectively). Only 3.4% of the identified RASs to elbasvir conferred reduced susceptibility to elbasvir by geno2pheno[HCV], which exclusively identified the positions Q30H/R (n=7) and Y93C/H/N (n=8) as single mutations and Q30H+Y93H (n=4) and Q30R+Y93H (n=2) as double mutations as the major RASs to elbasvir. A lower prevalence of RASs to elbasvir was observed in our HCV-G1a Spanish cohort than reported previously in clinical trials evaluating patients from the USA. This information may be essential to guide the implementation of grazoprevir/elbasvir in Spain and to manage G1a-infected patients.

Outcome of All-Oral Direct-Acting Antiviral Regimens on the Rate of Development of Hepatocellular Carcinoma in Patients with Hepatitis C Virus Genotype 1-Related Chronic Liver Disease

Objectives: There is little information on the risk factors for hepatocellular carcinoma (HCC) and outcome of treatment with an all-oral combination of direct-acting antiviral regimens following eradication of hepatitis C virus (HCV) RNA. Methods: The study subjects were 1,170 patients with HCV genotype 1-related chronic liver disease treated with either NS5A inhibitor plus NS3/4A protease inhibitor (n = 707), NS5A inhibitor plus NS5B polymerase inhibitor (n = 345), or NS5A inhibitor, NS3/4A protease inhibitor plus ritonavir (n = 118), for 12-24 weeks. All patients were free of HCC before and during therapy. Results: In this retrospective study, 22 patients developed HCC during the follow-up (time from the end of antiviral therapy until the last visit: 1.3 years). At 1 and 2 years after completion of the treatment, the cumulative HCC rates for the whole group were 1.8 and 2.3%, respectively, and 1.4 and 1.8%, respectively, for 1,065 patients who showed sustained virological response (SVR). The risk factors for HCC identified by multivariate analysis were hypoalbuminemia, thrombocytopenia, a high α-fetoprotein level, and non-SVR for all patients, and hypoalbuminemia and a high α-fetoprotein level for patients with SVR. Conclusion: Eradication of HCV RNA by direct-acting antiviral regimens might reduce the risk of HCC. Albumin and α-fetoprotein levels are significant risk factors for HCC.