NS5A-P32 deletion as a factor involved in virologic failure in patients receiving glecaprevir and pibrentasvir

Ledipasvir/Sofosbuvir Is Effective for Relapsed Genotype 1b Hepatitis C Virus Patients after Achieving a Sustained Virological Response at Post-treatment Week 12 with Glecaprevir/Pibrentasvir

A patient with genotype 1b chronic hepatitis C virus who had been treated with pegylated interferon and ribavirin (RBV) was treated with glecaprevir/pibrentasvir (GLE/PIB) for 12 weeks. A sustained virological response at post-treatment week 12 (SVR12) was achieved, but relapse occurred approximately 31 weeks after the end of treatment. The patient had a history of allergy to RBV and was treated with ledipasvir/sofosbuvir (LDV/SOF), achieving SVR12 and remaining hepatitis C virus-negative until 24 weeks after the completion of treatment. LDV/SOF can thus be a secondary treatment for GLE/PIB.

Real-world efficacy and safety of glecaprevir/pibrentasvir in Japanese adolescents with chronic hepatitis C: a prospective multicenter study

BACKGROUND

Part 1 of the DORA study, a 2019 international clinical trial of glecaprevir and pibrentasvir (G/P) treatment in adolescents with chronic hepatitis C virus (HCV) infection, demonstrated high efficacy and safety. However, few reports have considered real-world experience with G/P treatment in adolescents with chronic HCV. The present prospective multicenter study assessed real-world efficacy and safety of G/P treatment in Japanese adolescents with chronic HCV.

METHODS

Subjects between 12 and 17 years old who were treatment-naïve or previously managed with interferon-based regimens were prospectively enrolled and treated with G/P (300 mg/120 mg) once daily for 8 or 12 weeks. The primary efficacy endpoint was sustained virologic response at 12 weeks after treatment completion (SVR12). Adverse effects and laboratory abnormalities were assessed.

RESULTS

Twenty-five Japanese patients (15 female) were enrolled from 13 pediatric centers in Japan. Median age was 13 years (range 12-17). Numbers of patients with genotypes 1b, 2a, 2b, and 2b/1b were 6, 12, 6, and 1, respectively. Twenty-two were treatment-naïve, while three had experienced interferon-based treatments. All patients completed G/P treatment (24 for 8 weeks and 1 for 12). Twenty-four achieved SVR12 (96%). Most adverse events were mild. None were serious. G/P significantly decreased serum alanine aminotransferase, γ-glutamyltransferase, and Wisteria floribunda agglutinin-positive Mac-2-binding protein concentrations. No negative effects on growth or maturation were apparent at 12 weeks.

CONCLUSIONS

Under real-world conditions, G/P treatment of Japanese adolescents with chronic HCV was highly efficacious and well tolerated.

Direct antiviral agents (DAAs) and their use in pregnant women with hepatitis C (HCV)

INTRODUCTION

Direct-Acting Antiviral Agents (DAAs) provide safer, efficacious, tolerable, and curative therapy for women with hepatitis C. Their preferred safety and efficacy profile make them potential therapies for the elimination of perinatal transmission of hepatitis C virus (HCV). However, DAAs are not currently recommended for use during pregnancy due to limited pharmacokinetic and safety data.

AREAS COVERED

This review covers the different DAA drug combinations, the available data on their pharmacodynamic and pharmacokinetic properties, how the physiology in pregnancy can potentially affect DAA drug disposition, known drug-drug interactions with DAAs, and available and planned epidemiological and pharmacokinetic studies on DAA use during pregnancy. Although no large randomized clinical trials or prospective cohort studies involving DAAs have been completed in pregnancy, the currently available studies demonstrate no significant changes in pharmacokinetics, and no major safety concerns in women with hepatitis C.

EXPERT OPINION

Initial pharmacokinetic and safety data suggest that DAAs have high efficacy and a low risk of adverse events during pregnancy. As more pharmacokinetic and epidemiologic data become available, DAAs could become a preferred option for treating HCV during pregnancy and elimination of perinatal transmission of hepatitis C virus.

Mutational spectrum of hepatitis C virus in patients with chronic hepatitis C determined by single molecule real-time sequencing

The emergence of hepatitis C virus (HCV) with resistance-associated substitution (RAS), produced by mutations in the HCV genome, is a major problem in direct acting antivirals (DAA) treatment. This study aimed to clarify the mutational spectrum in HCV-RNA and the substitution pattern for the emergence of RASs in patients with chronic HCV infection. HCV-RNA from two HCV replicon cell lines and the serum HCV-RNA of four non-liver transplant and four post-liver transplant patients with unsuccessful DAA treatment were analyzed using high-accuracy single-molecule real-time long-read sequencing. Transition substitutions, especially A>G and U>C, occurred prominently under DAAs in both non-transplant and post-transplant patients, with a mutational bias identical to that occurring in HCV replicon cell lines during 10-year culturing. These mutational biases were reproduced in natural courses after DAA treatment. RASs emerged via both transition and transversion substitutions. NS3-D168 and NS5A-L31 RASs resulted from transversion mutations, while NS5A-Y93 RASs was caused by transition substitutions. The fidelity of the RNA-dependent RNA polymerase, HCV-NS5B, produces mutational bias in the HCV genome, characterized by dominant transition mutations, notably A>G and U>C substitutions. However, RASs are acquired by both transition and transversion substitutions, and the RASs-positive HCV clones are selected and proliferated under DAA treatment pressure.

HCV genome-wide analysis for development of efficient culture systems and unravelling of antiviral resistance in genotype 4

OBJECTIVE

HCV-genotype 4 infections are a major cause of liver diseases in the Middle East/Africa with certain subtypes associated with increased risk of direct-acting antiviral (DAA) treatment failures. We aimed at developing infectious genotype 4 cell culture systems to understand the evolutionary genetic landscapes of antiviral resistance, which can help preserve the future efficacy of DAA-based therapy.

DESIGN

HCV recombinants were tested in liver-derived cells. Long-term coculture with DAAs served to induce antiviral-resistance phenotypes. Next-generation sequencing (NGS) of the entire HCV-coding sequence identified mutation networks. Resistance-associated substitutions (RAS) were studied using reverse-genetics.

RESULT

The in-vivo infectious ED43(4a) clone was adapted in Huh7.5 cells, using substitutions identified in ED43(Core-NS5A)/JFH1-chimeric viruses combined with selected NS5B-changes. NGS, and linkage analysis, permitted identification of multiple genetic branches emerging during culture adaptation, one of which had 31 substitutions leading to robust replication/propagation. Treatment of culture-adapted ED43 with nine clinically relevant protease-DAA, NS5A-DAA and NS5B-DAA led to complex dynamics of drug-target-specific RAS with coselection of genome-wide substitutions. Approved DAA combinations were efficient against the original virus, but not against variants with RAS in corresponding drug targets. However, retreatment with glecaprevir/pibrentasvir remained efficient against NS5A inhibitor and sofosbuvir resistant variants. Recombinants with specific RAS at NS3-156, NS5A-28, 30, 31 and 93 and NS5B-282 were viable, but NS3-A156M and NS5A-L30Δ (deletion) led to attenuated phenotypes.

CONCLUSION

Rapidly emerging complex evolutionary landscapes of mutations define the persistence of HCV-RASs conferring resistance levels leading to treatment failure in genotype 4. The high barrier to resistance of glecaprevir/pibrentasvir could prevent persistence and propagation of antiviral resistance.

Efficacy of Glecaprevir/Pibrentasvir for Real-World HCV Infected Patients in the Northern Part of Tokyo, Japan

Hepatis virus C (HCV) infection causes liver cirrhosis and hepatocellular carcinoma (HCC) worldwide. The objective of our study was to examine the effects of the HCV nonstructural protein (NS) 3/4A inhibitor glecaprevir/NS5A inhibitor pibrentasvir on real-world HCV patients in the northern part of Tokyo, Japan. Although 106 patients were consecutively included, a total of 102 HCV-infected patients with chronic hepatitis or compensated cirrhosis, who received 8- or 12-week combination treatment with glecaprevir/pibrentasvir and were followed up to week 12 after the end of treatment were analyzed retrospectively. Only three patients discontinued treatment due to adverse events; however, they achieved a sustained virologic response at 12 weeks (SVR12). Finally, SVR rates were 99.0% (101/102). Only one patient without liver cirrhosis was a treatment relapser who received hepatic resection for HCC approximately two years after commencement of the 8-week combination treatment with glecaprevir/pibrentasvir. After the exclusion of patients with HCV genotype 1b and P32 deletion in the HCV NS5A region, a 12-week combination of glecaprevir/pibrentasvir led to SVR12 in all nine direct-acting antiviral-experienced patients. Glecaprevir/pibrentasvir had a high efficacy and an acceptable safety profile for real-world HCV patients in a single hospital in Japan.

Sofosbuvir/Velpatasvir Plus Ribavirin Combination Therapy for Patients with Hepatitis C Virus Genotype 1a, 2a, or 3b after Glecaprevir/Pibrentasvir Therapy Failed

Glecaprevir/pibrentasvir (GLE/PIB) is a pan-genotype anti-hepatitis C virus (HCV) therapy with high efficacy and safety. However, evidence supporting retreatment following failure of the GLE/PIB regimen is limited. We herein report 3 non-cirrhotic cases involving two men aged 51 and 58 years old and a woman aged 68 years old infected with HCV genotype 1a, 2a, and 3b respectively who failed anti-HCV therapies including GLE/PIB therapy. With combination therapy of sofosbuvir/velpatasvir plus ribavirin (SOF/VEL+RBV) for 24 weeks, all 3 patients had achieved a sustained viral response (SVR) at 24 weeks after completing treatment. SOF/VEL+RBV therapy was effective for retreatment of HCV after failure of GLE/PIB therapy.

Treatment progress and expansion in Japan: From interferon to direct-acting antiviral

Hepatitis C virus (HCV) was first discovered in 1989, and patients infected with HCV were initially treated with interferon (IFN) monotherapy. In the 2000s, pegylated IFN combined with ribavirin was the mainstay of therapy for infected patients, but the sustained virologic response (SVR) rate was less than 50% for patients with HCV genotype 1. To further improve the therapeutic effect, direct-acting antiviral (DAA) was developed, and combination therapy with DAA and IFN has been available since 2011. In addition, IFN-free DAA therapy became available in 2014, and SVR was achieved in more than 95% of patients with chronic hepatitis and compensated cirrhosis. Thus, in just 30 years since the discovery of HCV, we aim to eliminate HCV in almost all patients. However, there are remaining issues to be addressed. Many of the patients who achieved SVR with DAA therapy had advanced liver fibrosis, and it is necessary to verify to what extent DAA therapy improves their prognosis in terms of liver function, hepatocellular carcinoma occurrence, and mortality. Resistance-associated substitutions can cause failure of DAA therapy, and the search for an effective therapy for high-level resistant viruses such as P32 deletion is particularly important. DAA therapy was approved for use in patients with decompensated cirrhosis in Japan in 2019, which is an unmet need so far. It is also important to verify the efficacy and safety in real-world settings. The World Health Organization aims to eliminate HCV by 2030, and Japan must tackle its remaining issues to achieve this goal.

Prevalence of resistance-associated substitutions and retreatment of patients failing a glecaprevir/pibrentasvir regimen

OBJECTIVES

To investigate resistance-associated substitutions (RASs) as well as retreatment efficacies in a large cohort of European patients with failure of glecaprevir/pibrentasvir.

METHODS

Patients were identified from three European Resistance Reference centres in Spain, Italy and Germany. Sequencing of NS3, NS5A and NS5B was conducted and substitutions associated with resistance to direct antiviral agents were analysed. Clinical and virological parameters were documented retrospectively and retreatment efficacies were evaluated.

RESULTS

We evaluated 90 glecaprevir/pibrentasvir failures [3a (n = 36), 1a (n = 23), 2a/2c (n = 20), 1b (n = 10) and 4d (n = 1)]. Ten patients were cirrhotic, two had previous exposure to PEG-interferon and seven were coinfected with HIV; 80 had been treated for 8 weeks. Overall, 31 patients (34.4%) failed glecaprevir/pibrentasvir without any NS3 or NS5A RASs, 62.4% (53/85) showed RASs in NS5A, 15.6% (13/83) in NS3 and 10% (9/90) in both NS5A and NS3. Infection with HCV genotypes 1a and 3a was associated with a higher prevalence of NS5A RASs. Patients harbouring two (n = 34) or more (n = 8) RASs in NS5A were frequent. Retreatment was initiated in 56 patients, almost all (n = 52) with sofosbuvir/velpatasvir/voxilaprevir. The overall sustained virological response rate was 97.8% in patients with end-of-follow-up data available.

CONCLUSIONS

One-third of patients failed glecaprevir/pibrentasvir without resistance. RASs in NS5A were more prevalent than in NS3 and were frequently observed as dual and triple combination patterns, with a high impact on NS5A inhibitor activity, particularly in genotypes 1a and 3a. Retreatment of glecaprevir/pibrentasvir failures with sofosbuvir/velpatasvir/voxilaprevir achieved viral suppression across all genotypes.

Efficacy and Safety of Glecaprevir/Pibrentasvir in Patients with Chronic HCV Infection

Hepatitis C virus (HCV) infection is a major cause of end-stage liver disease, including decompensated cirrhosis and hepatocellular carcinoma. Over 95% of patients with HCV infection have achieved sustained virologic response at 12 weeks under the treatment of several pan-genotypic regimens approved for patients with HCV infection. The glecaprevir/pibrentasvir (G/P) regimen has some features that distinguish it from others and is the only 8-week regimen approved for treatment-naive patients and patients experienced in regimens containing (peg)interferon, ribavirin, and/or sofosbuvir, without an HCV NS3/4A protease inhibitor or NS5A inhibitor (except those with genotype 3). This review aims to summarize the efficacy and safety of G/P in HCV-infected patients from clinic trials and real-world studies, including those who have historically been considered difficult to cure.

Efficacy and Safety of Glecaprevir/Pibrentasvir in HCV Patients With Previous Direct-Acting Antiviral Therapy Failures: A Meta-Analysis

Background: Since a greater number of hepatitis C virus (HCV) patients have access to direct-acting antiviral (DAA) based therapies, the number of patients not properly responding to prior DAA regimens is increasing. The objective of this comprehensive analysis was to assess the efficacy and safety of glecaprevir/pibrentasvir (GLE/PIB) in HCV patients who experienced previous DAA therapy failures.

Methods: Bibliographic databases were systematically searched for relevant articles published by November 2020. The main endpoints were sustained viral response after 12 weeks (SVR12), adverse events (AEs; any grade) and severe adverse events (SAEs). Publication bias assessment was performed using funnel plots and the Egger's test.

Results: Fourteen studies consisting of a total of 1,294 subjects were included in this study and the pooled estimate of SVR12, AEs and SAEs rates were 96.8% (95%CI: 95.1–98.2), 47.1% (95%CI: 26.0–69.3), and 1.8% (95%CI: 0.7–3.4), respectively. Subgroup analysis showed that pooled SVR12 rates were 97.9% (95%CI: 96.7–98.9) for Japan and 91.1% (95%CI: 87.3–94.3) for the United States; 95.8% (95%CI: 93.9–97.4) for genotype (GT)1 and 100.0% (95%CI: 99.6–100.0) for GT2; 95.3% (95%CI: 92.4–97.2) for cirrhosis and 96.3% (95%CI: 94.2–97.7) for non-cirrhosis cases. There was no publication bias included this study.

Conclusion: This comprehensive analysis revealed that GLE/PIB is an effective and secure retreatment option for patients who did not optimally respond to DAA treatment, especially the Asian population with GT1-2.

Insights into the unique characteristics of hepatitis C virus genotype 3 revealed by development of a robust sub-genomic DBN3a replicon

Hepatitis C virus (HCV) is an important human pathogen causing 400 000 chronic liver disease-related deaths annually. Until recently, the majority of laboratory-based investigations into the biology of HCV have focused on the genotype 2 isolate, JFH-1, involving replicons and infectious cell culture systems. However, genotype 2 is one of eight major genotypes of HCV and there is great sequence variation among these genotypes (>30 % nucleotide divergence). In this regard, genotype 3 is the second most common genotype and accounts for 30 % of global HCV cases. Further, genotype 3 is associated with both high levels of inherent resistance to direct-acting antiviral (DAA) therapy, and a more rapid progression to chronic liver diseases. Neither of these two attributes are fully understood, thus robust genotype 3 culture systems to unravel viral replication are required. Here we describe the generation of robust genotype 3 sub-genomic replicons (SGRs) based on the adapted HCV NS3-NS5B replicase from the DBN3a cell culture infectious clone. Such infectious cell culture-adaptive mutations could potentially promote the development of robust SGRs for other HCV strains and genotypes. The novel genotype 3 SGRs have been used both transiently and to establish stable SGR-harbouring cell lines. We show that these resources can be used to investigate aspects of genotype 3 biology, including NS5A function and DAA resistance. They will be useful tools for these studies, circumventing the need to work under the biosafety level 3 (BSL3) containment required in many countries.

Efficacy and safety of glecaprevir and pibrentasvir combination therapy in old-aged patients with chronic hepatitis C virus infection

Objective: Combination therapy with glecaprevir and pibrentasvir (G/P) has been shown to provide a sustained virologic response (SVR) rate of >97% in patients with chronic hepatitis C virus (HCV) infection in the first published real-world Japanese data. However, a recently published study showed that the treatment was often discontinued in patients ≥75 years old, resulting in low SVR in intention-to-treat (ITT) analysis. Thus, our aim was to evaluate real-world data for G/P therapy in patients ≥75 years of age, the population density of which is high in “rural” regions.

Patients and Methods: We conducted a multicenter study to assess the efficacy and safety of G/P therapy for chronic HCV infection, in the North Kanto area in Japan.

Results: Of the 308 patients enrolled, 294 (95.5%) completed the treatment according to the protocol. In ITT and per-protocol analyses, the overall SVR12 rate was 97.1% and 99.7%, respectively. The old-aged patients group consisted of 59 participants, 56 of whom (94.9%) completed the scheduled protocol. Although old-aged patients tended to have non-SVR factors such as liver cirrhosis, history of HCC, and prior DAA therapies, the SVR12 rates in old-aged patients were 98.3% and 100% in the ITT and PP analyses, respectively. Of 308 patients enrolled, adverse events were observed in 74 patients (24.0%), with grade ≥3 events in 8 patients (2.6%). There was no significant difference in any grade and grade ≥3 adverse events between the old-aged group and the rest of the study participants. Only one patient discontinued the treatment because of adverse events.

Conclusion: G/P therapy is effective and safe for old-aged patients.

Efficacy and Safety of Glecaprevir/Pibrentasvir for Chronic Hepatitis C Patients: A Systematic Review and Meta-analysis

Background and Aims: Glecaprevir/pibrentasvir is a pangenotypic regimen recently approved for the treatment of chronic hepatitis C virus (HCV) infection. The objective of the present review was to summarize the findings from clinical trials to understand how patient-related factors influence glecaprevir/pibrentasvir efficacy (sustained virologic response rates at 12 weeks' after treatment [referred to as SVR12]) and safety. Methods: Data from 21 phase III clinical trials were analyzed. Results: The integrated efficacy analysis included 4,817 patients. Findings showed 97.5% of all included patients with chronic HCV achieved SVR12 in the intention-to-treat population. SVR12 rate was >95% across subgroups of interest. The integrated safety analysis included 4,015 patients. Findings showed that 64.1% of patients reported an adverse event, and <0.1% of patients reported a serious adverse event related to glecaprevir/pibrentasvir. Conclusions: These results indicate that the 8- or 12-week glecaprevir/pibrentasvir treatment is effective for patients infected with HCV genotypes 1-6 without or with compensated cirrhosis, with good safety profiles, irrespective of treatment-experience. Glecaprevir/pibrentasvir is a good option for patients with human immunodeficiency virus/HCV coinfection and comorbid HCV and severe renal impairment.

Real-word efficacy of sofosbuvir, velpatasvir plus ribavirin therapy for chronic hepatitis patients who failed to prior DAA therapy with NS5A-P32 deletion mutated HCV infection

The hepatitis C virus (HCV) NS5A-P32 deletion (P32del) confers potent resistance to NS5A inhibitors. Chronic hepatitis C patients in whom NS5A-P32del variants had emerged during prior direct-acting antiviral (DAA) therapy with an NS5A inhibitor show poor response to DAA retreatment. Here, we report three patients with HCV NS5A-P32del infection who were treated with sofosbuvir, velpatasvir plus ribavirin (SOF/VEL + RBV) in a real-world setting. The patients developed HCV NS5A-P32del, L31F + P32del, or L31V + P32del variants following failure of daclatasvir plus asunaprevir (DCV/ASV) therapy. One of the patients failed to respond to subsequent DCV/ASV and beclabuvir therapy, and the remaining two patients failed to respond to subsequent glecaprevir and pibrentasvir therapy. All three patients completed 24-week SOF/VEL + RBV therapy. Serum HCV RNA became negative at the end of the therapy in all three patients. Two patients with NS5A-P32del and NS5A-L31F + P32del achieved sustained virological response 12 weeks after completion of treatment (SVR12), but HCV relapsed in the remaining NS5A-L13V + P32del patient. Direct sequence analysis detected no additional variants within either the NS5A or NS5B regions at the time of relapse. In conclusion, three patients with prior NS5A-P32del-associated DAA treatment failure received 24 weeks of SOF/VEL + RBV therapy, and two of the patients achieved SVR12.

Japan Society of Hepatology guidelines for the management of hepatitis C virus infection: 2019 update

The Drafting Committee for Hepatitis Management Guidelines established by the Japan Society of Hepatology (JSH) drafted the first version of the clinical practice guidelines for the management of hepatitis C virus (HCV) infection in 2012. Since then, we have been publishing updates as new drugs for hepatitis C become available and new indications for existing drugs are added. The new approval of sofosbuvir/velpatasvir prompted us to publish the seventh version of the guidelines in Japanese in March 2019. We also published the first English-language version of the JSH guidelines in 2013 and English versions of updates made to the Japanese-language guidelines in 2014 and 2016. In 2020, the Committee has decided to publish a new English version, covering general information about treatment for hepatitis C, drugs used, recommended treatments for chronic hepatitis and cirrhosis, and special populations, such as patients who have renal impairment, are on dialysis, or have developed recurrence of hepatitis C after liver transplantation. Furthermore, the Committee has released a separate publication covering the protective effect of antiviral therapy against hepatocarcinogenesis.

Features of resistance-associated substitutions after failure of multiple direct-acting antiviral regimens for hepatitis C

Background & Aims

We aimed to clarify the features of resistance-associated substitutions (RASs) after failure of multiple interferon (IFN)-free regimens in HCV genotype 1b infections.

Methods

A total of 1,193 patients with HCV for whom direct-acting antiviral (DAA) treatment had failed were enrolled from 67 institutions in Japan. The RASs in non-structural protein (NS)3, NS5A, and NS5B were determined by population sequencing.

Results

Failure of 1, 2, and 3 regimens was observed in 1,101; 80; and 12 patients, respectively. Among patients with failure of 1 regimen, Y56H and D168V in NS3 were more frequently detected after failure of paritaprevir, whereas D168E was more frequently detected after failure of regimens including asunaprevir. R30H and L31-RAS in NS5A were frequently detected after failure of regimens including daclatasvir. The prevalence of Y93-RAS was high irrespective of the regimen. S282T RAS in NS5B was detected in 3.9% of ledipasvir/sofosbuvir failures. The prevalence of D168-RAS increased significantly according to the number of failed regimens (p <0.01), which was similar to that seen with L31-RAS and Y93-RAS. The prevalence of patients with RASs in either NS3 or NS5A, or in both, increased significantly with increasing numbers of failed regimens. The P32del, which is unique to patients for whom DAA had failed, was linked to the absence of Y93H, the presence of L31F, and previous exposure to IFN plus protease inhibitor regimens.

Conclusions

Failure of multiple DAA regimens can lead to the generation of multiple RASs in the NS3 and NS5A regions of the HCV 1b genome. These mutations contribute to viral resistance to multiple treatment regimens and, therefore, should be considered during decision making for treatment of chronic HCV.

Lay summary

Resistance-associated substitutions (RAS) in the genome of the hepatitis C virus are 1 of the major causes for failed treatment. We investigated RASs after failure of various treatments for chronic hepatitis C, and found that more complicated RASs accumulated in the viral genome with successive failed treatments. The highly resistant P32del RAS at NS5A region was uniquely found in patients for whom DAA treatments had failed, and was linked to the presence and absence of specific RASs.

2020 Taiwan consensus statement on the management of hepatitis C: part (I) general population

Hepatitis C virus (HCV) infection remains a major public health issue with high prevalence in Taiwan. Recently, the advent of direct-acting antiviral (DAA) agents, with higher efficacy, excellent safety profile, and truncated treatment duration, has revolutionized the paradigm of hepatitis C treatment and made HCV elimination possible. To provide timely guidance for optimal hepatitis C management, the Taiwan Association for the Study of the Liver (TASL) established an expert panel to publish a 2-part consensus statement on the management of hepatitis C in the DAA era. After comprehensive literature review and a consensus meeting, patient-oriented, genotype-guided recommendations on hepatitis C treatment for the general and special populations have been provided based on the latest indications and scientific evidence. In the first part of this consensus, we present the epidemiology and treatment situation of hepatitis C in Taiwan, the development of DAA, pre-treatment evaluation, post sustained virologic response (SVR) monitoring, and most importantly the treatment recommendations for the general population with compensated liver disease. The second part will focus on the treatment recommendations for the special populations.

Effectiveness of Glecaprevir/Pibrentasvir for Hepatitis C: Real-World Experience and Clinical Features of Retreatment Cases

Glecaprevir/pibrentasvir (G/P) are direct-acting antivirals (DAAs) that achieve a high sustained virological response (SVR) rate for hepatitis C virus (HCV) infection. We investigated G/P effectiveness for HCV patients based on real-world experience and the clinical features of retreatment cases. HCV patients (n = 182) were compared for clinical features and outcomes between first treatment (n = 159) and retreatment (n = 23) G/P groups. Overall, 77 patients (42.3%) were male, the median age was 68 years, and 86/66/1/4 cases had genotype 1/2/1 + 2/3, respectively. An SVR was achieved in 97.8% (178/182) of cases by intention-to-treat analysis and 99.4% (178/179) of cases by per-protocol analysis. There were no remarkable differences between the first treatment and retreatment groups for male (42.8% vs. 39.1%, p = 0.70), median age (68 vs. 68 years, p = 0.36), prior hepatocellular carcinoma (5.8% vs. 8.7%, p = 0.59), or the fibrosis markers AST-to-platelet ratio index (APRI) (0.5 vs. 0.5, p = 0.80) and fibrosis-4 (FIB-4) index (2.2 vs. 2.6, p = 0.59). The retreatment group had a significantly more frequent history of interferon treatment (12.3% vs. 52.2%, p < 0.01) and the Y93H mutation (25.0% vs. 64.7%, p = 0.02). The number of retreatment patients who had experienced 3, 2, and 1 DAA treatment failures was 1, 3, and 19, respectively, all of whom ultimately achieved an SVR by G/P treatment. In conclusion, G/P was effective and safe for both HCV first treatment and retreatment cases despite the retreatment group having specific resistance mutations for other prior DAAs. As G/P treatment failure has been reported for P32 deletions, clinicians should consider resistance mutations during DAA selection.

Involvement of portosystemic shunts in impaired improvement of liver function after direct-acting antiviral therapies in cirrhotic patients with hepatitis C virus

AIM

Factors responsible for impaired improvement of liver function despite sustained viral response after direct-acting antiviral agents therapies in cirrhotic patients with hepatitis C virus need to be elucidated.

METHODS

Liver function and the extent of portosystemic shunting were evaluated for 79 patients with compensated cirrhosis, in whom sustained viral response had been achieved after direct-acting antiviral agents therapies for hepatitis C virus at least 3 years earlier.

RESULTS

Portosystemic shunts were observed in 63 patients (80%). Improvement and worsening, as compared with the baseline, of esophageal/gastric varices after direct-acting antiviral agents therapies was seen in three patients (4%) and 10 patients (13%), respectively. Portal hypertension-related events, such as varices and ascites requiring treatment, were observed in six patients (8%), in whom three patients showing worsening of Child-Pugh scores were included. Multivariate analysis showed that maximal diameter of the shunts (P = 0.012) and serum Mac-2 binding protein glycosylation isomer levels at the end of treatment (P = 0.005) were associated with the development of portal hypertension-related events, with cut-off values of 5.25 mm (P = 0.001) and 6.84 cut-off index (P < 0.001), respectively. The increase of serum albumin levels at 3 years, as compared with the baseline, was smaller in 22 patients having shunts with maximal diameters of ≥5 mm than in the remaining 57 patients (P = 0.034), whereas no such difference was seen between the patients with and without elevation of serum Mac-2 binding protein glycosylation isomer level of ≥6.8 cut-off index.

CONCLUSIONS

A large size of portosystemic shunts was found to be a crucial determinant of impaired improvement of liver function, as well as of the development of portal hypertension-related events, even after sustained viral response in patients with compensated cirrhosis.

Viral and host factors are associated with retreatment failure in hepatitis C patients receiving all-oral direct antiviral therapy

AIM

Direct-acting antiviral (DAA) therapy for hepatitis C virus is associated with high sustained virologic response rates. However, patients for whom DAA therapy fails acquire resistance-associated substitutions (RASs). We therefore evaluated the efficacy of DAA retreatment and factors associated with retreatment failure.

METHODS

Non-structural 5A RASs were investigated at the start of DAA therapy and at treatment failure in 64 patients with hepatitis C virus genotype 1b for whom DAA combination therapy had failed. A total of 59 patients were introduced to DAA retreatment. The factors associated with retreatment failure were investigated.

RESULTS

A total of 20 of 43 (46.5%) daclatasvir + asunaprevir-treated patients with virologic failure had no RASs at baseline, and three (15%) acquired P32 deletion RASs. Four of seven sofosbuvir/ledipasvir-treated patients with virologic failure had more than two RASs of NS5A at baseline. The sustained virologic response rates on retreatment were as follows: sofosbuvir/ledipasvir, 81.8%; with elbasvir + grazoprevir, 0%; and glecaprevir/pibrentasvir, 87.5%. Patients for whom sofosbuvir/ledipasvir or elbasvir + grazoprevir failed achieved sustained virologic response with glecaprevir/pibrentasvir. Two of three patients for whom glecaprevir/pibrentasvir retreatment failed had Q24/L28/R30 and A92K RASs; the other had P32 deletion RAS at baseline. Interestingly, 10 of 11 patients with retreatment failure had the interleukin (IL)-28B single-nucleotide polymorphism (SNP) minor allele. A multivariate analysis showed that the IL28B SNP minor allele (P = 0.005, odds ratio 28.291) was an independent risk factor for retreatment failure.

CONCLUSIONS

In addition to viral factors (e.g. Q24, L28, R30, and A92 or P32 deletion RASs), host factors (e.g. IL28B SNP) are associated with DAA retreatment failure.

The effectiveness and safety of glecaprevir/pibrentasvir in chronic hepatitis C patients with refractory factors in the real world: a comprehensive analysis of a prospective multicenter study

BACKGROUND

Direct-acting anti-virals (DAAs) have markedly improved the effectiveness of anti-viral therapy for chronic hepatitis C (CHC) patients. In a phase III trial in Japan, treatment with the NS3/4A protease inhibitor glecaprevir and the NS5A inhibitor pibrentasvir (G/P) resulted in a small number of patients with refractory factors. We aimed to evaluate the effectiveness and safety of G/P, especially among patients with these refractory factors, and the influence of these factors on treatment.

METHODS

In a prospective, multicenter study involving 33 medical institutions, 1439 patients were treated with G/P, and their efficacy, safety, and most frequent adverse effects (AEs) were analyzed.

RESULTS

Overall SVR12 rates were 99.1% (1397/1410) in the per-protocol-analysis, and genotype sustained virologic response SVR12 rates were: genotype 1, 99.4% (707/711); genotype 2, 99.4% (670/674); genotype 3, 80.0% (16/20). DAA-naïve patients (p = 0.008) with HCV genotype except 3 (genotype 1 vs. 3, p = 2.68 × 10^-5; genotype 2 vs. 3, p = 3.28 × 10^-5) had significantly higher SVR12 rates. No significant difference was observed between CKD stage 1-3 (99.1% [1209/1220]) and chronic kidney disease (CKD) stage 4-5 (98.9% [188/190]) patients, or between cirrhotic (99.0% [398/402]) and non-cirrhotic (99.1% [999/1008]) patients. Multiple logistic regression analysis revealed that genotype 3 [OR 33.404, 95% CI (7.512-148.550), p value (p = 4.06 × 10^-5)] and past experience of IFN-free DAAs [OR 3.977, 95% CI (1.153-13.725), p value (p = 0.029)] were both significantly independent predictors of non-SVR12. AEs were reported in 28.2% of patients, and 1.6% discontinued treatment owing to drug-related AEs. AEs were significantly higher in CKD stage 4-5 (41.6% [79/190]) than CKD stage 1-3 (26.1% [319/1220]) patients (p = 2.00 × 10^-5). AEs were also significantly higher in cirrhotic (38.6% [155/402]) than in non-cirrhotic (24.1% [243/1008]) (p = 2.91 × 10^-18) patients.

CONCLUSIONS

G/P regimen is highly effective and safe to treat CHC patients even with refractory factors such as CKD and advanced liver fibrosis. However, patients with past experience of IFN-free DAA treatment and genotype 3, CKD stage 4 or 5, and advanced liver fibrosis should be more closely observed.

Single-molecular real-time deep sequencing reveals the dynamics of multi-drug resistant haplotypes and structural variations in the hepatitis C virus genome

While direct-acting antivirals (DAAs) for hepatitis C virus (HCV) have dramatically progressed, patients still suffer from treatment failures. For the radical eradication of HCV, a deeper understanding of multiple resistance-associated substitutions (RASs) at the single-clone level is essential. To understand HCV quasispecies and their dynamics during DAA treatment, we applied single-molecule real-time (SMRT) deep sequencing on sera from 12 patients with genotype-1b HCV infections with DAA treatment failures, both pre- and post-treatment. We identified >3.2 kbp sequences between NS3 and NS5A genes of 187,539 clones in total, classifying into haplotype codes based on the linkage of seven RAS loci. The number of haplotype codes during the treatment, per sample, significantly decreased from 14.67 ± 9.12 to 6.58 ± 7.1, while the number of nonsynonymous codons on the seven RAS loci, per clone, significantly increased from 1.50 ± 0.92 to 3.64 ± 0.75. In five cases, the minority multi-drug resistant haplotypes at pre-treatment were identical to the major haplotypes at relapse. Moreover, various structural variations (SVs) were detected and their dynamics analysed. These results suggest that SMRT deep sequencing is useful for detecting minority haplotypes and SVs, and to evaluate the dynamics of viral genomes at the single-clone level.

Intention-to-treat assessment of glecaprevir + pibrentasvir combination therapy for patients with chronic hepatitis C in the real world

AIMS

We assessed the problems and efficacy of glecaprevir + pibrentasvir (GLE/PIB) therapy for patients infected with hepatitis C virus (HCV) in the real world.

METHOD

A total of 423 patients infected with HCV who started treatment at eight different centers in Japan were enrolled in the study. Glecaprevir (300 mg) and pibrentasvir (120 mg) were given once daily for 8 weeks to 246 non-cirrhotic direct-acting antiviral (DAA)-naive patients with HCV genotype (GT)-1 or -2, and for 12 weeks to patients who: were DAA-naive cirrhotic (n = 55), had experienced DAA failure (n = 78), were cirrhotic and had DAA failure (n = 37), and were other GT-1/2 (n = 7). Anti-HCV efficacy was defined as a sustained virologic response 12 weeks post-treatment (SVR12). The evaluation was undertaken in an intention-to-treat (ITT) population and in patients who were assessed at SVR12 (modified ITT population).

RESULTS

In the ITT population, 220 (89%) patients on the 8-week regimen and 164 (93%) patients on the 12-week regimen achieved SVR12. The 30 dropout patients were predominantly men and with GT-2. All other DAA-naive GT-1 patients achieved SVR12. The 12-week regimen resulted in 100% SVR12 in 41 GT-2 patients. Nine patients did not achieve SVR12: two DAA naive with GT-2a, two GT-3b patients, two GT-1 patients with discontinuation, and three other GT-1 patients with a history of DAA failure. Four of seven patients who discontinued treatment due to severe adverse effects were more than 75 years old.

CONCLUSIONS

Glecaprevir + pibrentasvir had a remarkable anti-HCV effect in GT-1 and GT-2 patients, but not in GT-3b patients. Although this therapy was reasonably safe, it is necessary to carefully consider elderly and dropout patients.

Effects of resistance-associated variants in genotype 2 hepatitis C virus on viral replication and susceptibility to antihepatitis C virus drugs

AIMS

Development of direct-acting antivirals (DAAs) has made antihepatitis C virus (HCV) treatment highly safe and effective. However, the emergence of resistant-associated variants (RAVs) after failure of DAA therapy affects retreatment outcomes. In particular, genotype 1 HCV with P32 deletion has been reported to be highly resistant to all approved non-structural protein (NS)5A inhibitors. However, analysis of RAVs in genotype 2 HCV has been limited. Accordingly, in this study, we evaluated the roles of genotype 2 HCV variants in antiviral drug efficacy.

METHODS

We utilized HCV-2b/2a (JFH-1) chimeric virus (genotype 2a), which replicates more robustly than JFH-1. We constructed various genotype 2a JFH-1-based HCV cell culture systems with NS3 (D168E), NS5A (F28S, F28S/M31I, P32 deletion, and Y93H), and NS5B (S282 T) RAVs and analyzed the replication ability and sensitivity to various anti-HCV reagents.

RESULTS

Genotype 2a-based HCV with NS5A-P32 deletion could not replicate even in long-term cultures. Genotype 2a-based HCV with NS5A-F28S/M31I showed significantly higher replication ability than the wild-type strain, and replication could not be suppressed, even with high concentrations of NS5A inhibitors, including pibrentasvir and velpatasvir (<1000-10 000 fold-resistance compared with the wild-type strain). However, genotype 2a-based HCV with NA5A-F28S/M31I was sensitive to HCV protease inhibitor, NS5B inhibitor, interferon-α, and ribavirin. Genotype 2a-based HCV with NS5B-S282 T was resistant to sofosbuvir, but was highly sensitive to ribavirin compared with the control.

CONCLUSIONS

When undertaking retreatment for genotype 2a HCV-infected patients who fail to respond to DAAs, the optimized retreatment should be chosen according to the sensitivity of the emerging RAVs to anti-HCV drugs.

Consensus recommendations for resistance testing in the management of chronic hepatitis C virus infection: Public Health England HCV Resistance Group

The treatment of hepatitis C virus (HCV) infection has been revolutionised by the advent of oral, well-tolerated, direct acting antiviral therapies (DAA), with high cure rates. However, in some scenarios, HCV resistance to antiviral therapies may have an impact on treatment success. Public Health England's HCV Resistance Group was established to support clinicians treating people with HCV, where the issue of resistance may be a factor in clinical decision-making, and this review includes the Group's current recommendations on the use of HCV resistance testing. The authors describe the principles behind and approach to HCV resistance testing and consider evidence from in vitro studies, clinical trials and real world cohorts on the impact of HCV resistance on treatment outcomes for particular DAA regimens. Five scenarios are identified in the UK and similar settings, where, in the Group's opinion, resistance testing should be performed.

Management of HCV patients in cases of direct-acting antiviral failure

Introduction: Over 70 million people are infected with hepatitis C virus (HCV), increasing the risk of cirrhosis and hepatocellular carcinoma. Areas covered: Since the approval of the first interferon-free direct-acting antiviral (DAA) therapy in 2011, a number of DAAs have been approved, and HCV is now considered curable. Until recently, however, there were no clear guidelines on how to re-treat patients who fail DAA therapy. Current protease inhibitors (PIs) are generally unaffected by earlier resistance-associated variants (RAVs), but many NS5A inhibitors continue to have overlapping resistance profiles, and NS5A RAVs can persist even in the absence of DAAs. Expert opinion: Fortunately, RAVs affecting NS5B polymerase inhibitors are rare, making sofosbuvir a safe choice as the backbone of re-treatment therapies. Recent re-treatment guidelines that take into account genotype, fibrosis, treatment history, and RAV suggest that >90% of patients with prior treatment failures can be successfully re-treated with sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir or glecaprevir/pibrentasvir.

Exploring the hepatitis C virus genome using single molecule real-time sequencing

Single molecular real-time (SMRT) sequencing, also called third-generation sequencing, is a novel sequencing technique capable of generating extremely long contiguous sequence reads. While conventional short-read sequencing cannot evaluate the linkage of nucleotide substitutions distant from one another, SMRT sequencing can directly demonstrate linkage of nucleotide changes over a span of more than 20 kbp, and thus can be applied to directly examine the haplotypes of viruses or bacteria whose genome structures are changing in real time. In addition, an error correction method (circular consensus sequencing) has been established and repeated sequencing of a single-molecule DNA template can result in extremely high accuracy. The advantages of long read sequencing enable accurate determination of the haplotypes of individual viral clones. SMRT sequencing has been applied in various studies of viral genomes including determination of the full-length contiguous genome sequence of hepatitis C virus (HCV), targeted deep sequencing of the HCV NS5A gene, and assessment of heterogeneity among viral populations. Recently, the emergence of multi-drug resistant HCV viruses has become a significant clinical issue and has been also demonstrated using SMRT sequencing. In this review, we introduce the novel third-generation PacBio RSII/Sequel systems, compare them with conventional next-generation sequencers, and summarize previous studies in which SMRT sequencing technology has been applied for HCV genome analysis. We also refer to another long-read sequencing platform, nanopore sequencing technology, and discuss the advantages, limitations and future perspectives in using these third-generation sequencers for HCV genome analysis.

Glecaprevir/pibrentasvir for the treatment of chronic hepatitis C: design, development, and place in therapy

Direct-acting antiviral (DAA) therapy has changed the landscape of hepatitis C virus (HCV) management and has changed the focus to the possibility of HCV elimination in the near future. Glecaprevir, an NS3/4A protease inhibitor, and pibrentasvir, an HCV NS5A inhibitor, have addressed many of the existing shortcomings in the DAA therapy spectrum. This combination has proven to be a highly efficacious pan-genotypic DAA with a high barrier to resistance as a once-daily, all-oral medication. This review explores the design and development of glecaprevir and pibrentasvir, its place in current HCV management in the midst of a myriad of DAA therapy options, and also remaining challenges.