Characterization of virologic escape in hepatitis C virus genotype 1b patients treated with the direct-acting antivirals daclatasvir and asunaprevir

Prognosis of Patients with Chronic Hepatitis C Genotype 1b Infection Treated Using Daclatasvir/Asunaprevir after Sustained Virologic Response: A 6-Year Multicenter Prospective Observational Study

Aim and Objectives: Direct-acting antiviral (DAA) therapy can cure chronic hepatitis C (CHC), and daclatasvir (DCV)/asunaprevir (ASV) was the first interferon-free DAA therapy introduced in Korea. Patients who achieve sustained virologic response (SVR) after DAA treatment are expected to have good prognoses. Therefore, in this study, we aimed to investigate the prognosis of these patients. Materials and Methods: This multicenter prospective observational study included patients with CHC who achieved SVR after DCV/ASV treatment. The primary endpoint was hepatocellular carcinoma (HCC) occurrence, which was reviewed annually. Results: We included 302 patients (median follow-up duration: 38 [16.5-60.0] months; median age: 58 [49-67] years) in the study. Cirrhosis was observed in 103 patients (34.1%), and the median Child-Pugh score was 5.0. HCC occurred in 16 patients (5.3%) within six years post-SVR; these patients were older and had higher cirrhosis prevalence, alpha-fetoprotein levels, and fibrosis-4 index scores than did those without HCC development. Cox proportional hazards analysis revealed that age > 71 years (p = 0.005) and cirrhosis (p = 0.035) were significant risk factors for HCC occurrence. Conclusions: Although the prognoses of patients who achieved SVR with DCV/ASV therapy were generally good, the risk for HCC was present, especially in older patients and in those with cirrhosis. Hence, early treatment at younger ages and regular follow-up surveillance after achieving SVR are warranted.

The role of IFNL4 in liver inflammation and progression of fibrosis

The discovery that genetic variation within the interferon lambda locus has a profound effect on the outcome of hepatitis C virus (HCV) treatment and spontaneous clearance of HCV is one of the great triumphs of genomic medicine. Subsequently, the IFNL4 gene was discovered and proposed as the causal gene underlying this association. However, there has been a lively debate within the field concerning the causality, which has been further complicated by a change in naming. This review summarizes the genetic data available for the IFNL3/IFNl4 loci and provides an in-depth discussion of causality. We also discuss a new series of interesting data suggesting that the genetic variation at the IFNL4 loci influences the evolution of the HCV virus and the implication this relationship between our genetic makeup and virus evolution has upon our understanding of the IFNL4 system. Finally, new data support an influence of the IFNL4 gene upon liver inflammation and fibrosis that is independent of etiology, thereby linking the IFNL4 gene to some of the major liver diseases of today.

Efficacy and safety of sofosbuvir and daclatasvir in patients with chronic hepatitis C virus induced cirrhosis with Child-Pugh class B

Background

This study aimed to evaluate the efficacy, safety and tolerability of SOF/DCV ± RBV in a cohort of Egyptian patients with chronic hepatitis C (CHC)-induced cirrhosis with decompensation (class B7–B9).

Results

After excluding the 9 patients who withdrew, SVR12 rate according to per protocol analysis was 82.9% (92/111), non-response and relapse rates were 2.7% (3/111) for each, 4 patients died secondary to hematemesis, and 8.1% stopped therapy due to worsening of Child’s class. SVR12 rate was significantly higher among patients with higher baseline WBCs count and lower among patients with Child-Pugh class B9. All treatment intolerant patients had ascites in pre-treatment assessment (P = 0.02). There was a significant decline in the levels of hemoglobin, ALT and AST, and serum bilirubin (P < 0.001) and a significant increase in albumin level (P < 0.001) at the end of treatment when compared to their pre-treatment levels. Follow-up of the three HCC did not show evidence of tumor recurrence.

Conclusions

The SOF/DCV combination ± ribavirin is an effective and safe regimen for patients with CHC induced cirrhosis with mild decompensation. Treatment did not increase the risk of HCC recurrence.

Non-invasive fibrosis markers are associated with mortality risk in both general populations and non-alcoholic fatty liver disease patients

AIM

We assessed the correlations between non-invasive fibrosis scores and mortality in both the general population and non-alcoholic fatty liver disease (NAFLD) patients.

METHODS

We used data from the US National Health and Nutrition Examination Survey 1988-2014. The NAFLD fibrosis score (NFS), Fibrosis-4 index (FIB-4) score, aspartate aminotransferase to platelet ratio index (APRI) score, and Forns index score were calculated at baseline. The associations of these scores with the risk of mortality were determined using additive Cox proportional hazard models. The area under the receiver operating characteristic curve (AUROC) was used to study the predictive capacity of each scoring system.

RESULTS

A total of 44 508 participants were included; among them, 9721 deaths occurred during a mean follow-up of 12.5 years. A "J"-shaped correlation pattern was observed for both the FIB-4 and APRI scores. A "U"-shaped correlation pattern was observed for both the Forns index and NFS. Similar correlation patterns were observed in 1955 NAFLD patients. For overall mortality, the AUROC values of the selected fibrosis scores were comparable between general population and NAFLD patients. The superior predictive capacity was found for FIB-4, with AUROC of 75.03% (95% confidence interval, 70.91% to 79.82%) in general population and 75.32% (95% confidence interval, 69.43% to 80.11%) in NAFLD patients, respectively.

CONCLUSIONS

Non-linear associations were shown between the fibrosis scoring systems and mortality risk. These scores could serve as indicators for mortality in people with or without NAFLD.

Phase 3, Multicenter Open-Label study to investigate the efficacy of elbasvir and grazoprevir fixed-dose combination for 8 weeks in treatment-naïve, HCV GT1b-infected patients, with non-severe fibrosis

BACKGROUND

Genotype 1b is the most common HCV genotype worldwide, accounting for the largest proportion of infections in Europe, Russia, Latin America and Asia. Reducing treatment duration can improve adherence, reduce drug exposure and cost. Accordingly, we evaluated the efficacy of 8 weeks fixed-dose combination of grazoprevir-elbasvir in treatment-naïve patients, with non-severe fibrosis.

METHODS

HCV mono-infected and treatment naïve patients with non-severe fibrosis (Fibroscan^® <9.5 kPa and Fibrotest^®  < 0.59) were enrolled in a study which included 117 patients. Genotyping by sequencing identified five patients with non-1b genotype (two GT1a, one GT1h, one GT1e and one GT1l). Thus, we included in the final analysis 112 GT1b patients. The primary end point was the proportion of patients with HCVRNA below the lower limit of quantification 12 weeks after treatment (SVR12).

FINDINGS

Mean age was 54 ± 13 years, 31% were men and viral load was higher than 800.000 IU/mL in 70 of 112 patients (63%). Using Fibroscan^® , 100 had F0-1 fibrosis score. FIB-4 lower than 1.45 and APRI less than 1 was found in 74/112 (66%) and 107/112 (95%) patients respectively. Relapse occurred in three patients by week 12. These three patients had a viral load higher than 6 million IU/mL and NS5A Y93H RAS (resistance-associated substitution). Then, modified intention-to-treat SVR12 for patients with genotype 1b was 109/112 (97%). By week 24; five relapses were observed and all had the Y93H RAS at relapse. SVR12 was achieved in 100% of patients with a baseline viral load below 6 million and decreased to 98% (98/100) by follow-up week 24.

INTERPRETATION

Naïve patients with genotype 1b and non-severe fibrosis can achieve an SVR12 of 97% and an SVR24 of 95%. Then, these patients can be treated with grazoprevir-elbasvir for 8 weeks.

Overview of hepatitis C infection, molecular biology, and new treatment

The World Health Organization estimates that 71 million people worldwide have chronic hepatitis C viral infection. A major challenge is overall lack of public awareness of hepatitis C, particularly among infected people of their infection status. Chronic hepatitis C infection is associated with advanced liver disease, is the main cause of hepatocellular carcinoma and causes many extra-hepatic manifestations. The existence of seven viral genotypes complicates targeting of treatment. Recent years have seen the approval of many direct acting antivirals targeted at hepatitis C virus non-structural proteins. These have revolutionized therapy as they allow achievement of extremely high sustained virologic responses. Of great significance is the development of pan-genotypic drug combinations, including the NS3/4A-NS5A inhibitor combinations sofosbuvir-velpatasvir and glecaprevir-pibrentasvir. However, resistance-associated mutations can result in failure of these treatments in a small number of patients. This, combined with the high costs of treatment, highlights the importance of continued research into effective anti-hepatitis C therapies, for example aimed at viral entry. Recent developments include identification of the potential of low-cost anti-histamines for repurposing as inhibitors of hepatitis C viral entry. In this review we focus on molecular biology of hepatitis C virus, and the new developments in hepatitis C treatment.

IFNL4: Notable variants and associated phenotypes. Gene 2019;730:144289. [PMID: 31846709 DOI: 10.1016/j.gene.2019.144289]

Interferon lambda proteins activate the JAK-STAT signalling pathway, resulting in upregulation of genes with antiviral effects. The interferon lambda family was initially thought to be redundant to the interferon alpha family, which signals through the same pathway, except for the more limited expression of the IFNLR1 receptor. However, recent studies show that interferon lambdas uniquely protect tissue barriers against a wide range of important viral infections. The interferon lambda 4 gene (IFNL4) was discovered in 2013. The IFNL4 protein is determined by the IFNL4-ΔG/TT (rs368234815) variant. The ancestral IFNL4-ΔG allele generates IFNL4, whereas IFNL4-TT causes pre-mature termination of the protein. Surprisingly, although interferons are generally antiviral proteins, the genotypes that generate the IFNL4 protein are strongly linked to impaired clearance of hepatitis C virus (HCV). IFNL4 genotype has also been linked to variation within the HCV genome, as well as risk of hepatic fibrosis, certain cancers and some infectious diseases. There has been very strong evolutionary selection against the ancestral IFNL4-ΔG allele, which is the major form in African populations, but the minor allele in Europeans and Asians. The reason for this selection and the biological mechanisms underlying observed phenotypic associations remain to be explained.

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.

Full-Genome Analysis of Hepatitis C Virus in Japanese and Non-Japanese Patients Coinfected With HIV-1 in Tokyo

BACKGROUND

Acute hepatitis C virus (HCV) infection is increasing among HIV-1-infected individuals in Tokyo. Appropriate clinical management is needed.

SETTING

To delineate the epidemiological status of HCV transmission, we analyzed stocked plasma samples of HCV/HIV-1-coinfected patients seen at the largest referral center for HIV care in Tokyo.

METHODS

HCV full-genome sequences were amplified and determined using next-generation sequencing. HCV genotyping and phylogenetic and phylodynamic analyses of thus obtained sequences were performed and combined with the analysis of HIV-1 reverse transcriptase sequences.

RESULTS

HCV phylogenetic analysis identified 3 dense clusters containing cases of men who have sex with men (MSM) and injection drug users (IDUs). Most of the confirmed acute infection cases were included within these clusters, indicating that the clustered viruses are currently being actively transmitted among HIV-1-infected MSM and IDU. Phylodynamic analysis indicated population expansion of one of these clusters from 2006 to 2008, during which the largest number of HIV-1-infected MSM was diagnosed in Tokyo. HIV-1 reverse transcriptase sequences of HCV-coinfected patients included in the same clusters did not converge together and did not form clusters, but rather diverged in the area of subtype B in the phylogenetic tree, indicating that they acquired HCV infection from individuals different from those from whom they had acquired HIV-1 infection. It is considered that these MSM changed their sexual partners and that IDU changed their drug use groups.

CONCLUSIONS

The results warrant careful monitoring of high-risk groups including MSM and IDU and early introduction of HCV treatment to prevent HCV epidemic.

Developments in the treatment of HCV genotype 3 infection

Introduction: Unlike other hepatitis C virus (HCV) genotypes (GTs), patients infected with GT3 are associated with an increased risk of accelerated liver disease progression. Although early immuno-modulator therapies yielded moderate sustained virologic response (SVR) rates, treatment of GT3 patients has proven more challenging in the era of direct-acting antivirals (DAAs). Areas covered: The review provides an overview of the evolution of therapies against GT3 since the approval of the first immunomodulatory agent nearly 30 years ago. Expert opinion: A greater choice of treatment options is now available for HCV GT3-infected patients. In treatment-naïve patients with or without compensated cirrhosis, SVR rates are comparably high approaching 100% irrespective of treatment option. For treatment-experienced patients, choosing the right therapy is important, especially for those with advanced liver disease. For the few patients who fail with multiple persistent highly resistant DAA substitutions, retreatment options are limited. Additional real-world treatment comparisons are required to confirm differences in SVR in these more difficult-to-treat patients. This also includes patients infected with GT3 subtypes such as GT3b where multiple DAA-resistant substitutions occur naturally. In the absence of new drugs with non-overlapping drug-resistant profiles, an interferon-based therapy may still be beneficial in select patient populations with high-level multiple DAA-resistant substitutions.

Active hepatocellular carcinoma is an independent risk factor of direct-acting antiviral treatment failure: A retrospective study with prospectively collected data

Background & aims

Previous studies from western countries have reported that active hepatocellular carcinoma (HCC) was associated with direct-acting antiviral (DAA) treatment failure. We sought to examine this issue in an Asian cohort.

Methods

A retrospective cohort study was conducted on hepatitis C virus (HCV)-infected patients with advanced fibrosis who were treated with DAAs at our hospital between January 2017 and June 2018.

Results

We treated 1021 HCV-infected patients during this period. A total of 976 of those patients were enrolled in a per-protocol analysis, including 556 (57.2%) who had genotype 1b infections, and 314 (32.3%) who had genotype 2 infections. The mean age of all 976 patients was 65.5 years, and 44.5% were male. 781 of the patients had no HCC, 172 had inactive HCC, and 23 had active HCC. Non-sustained virologic response (SVR) was noted in 10 (1.3%) patients without HCC, 5 (2.9%) patients with inactive HCC, and 4 (13.0%) patients with active HCC. After adjustment for confounders, active HCC (versus inactive HCC and non-HCC) was associated with non-SVR (adjusted odds ratio [AOR] = 24.5 (95% confidence interval [CI] = 4.4–136.9), P<0.001). Next, we excluded the 23 patients with active HCC from the multivariate analysis. After adjustment for confounders, inactive HCC (versus non-HCC) was not associated with non-SVR (AOR = 3.1 (95% CI = 0.94–9.95), P = 0.06).

Conclusion

Active HCC was associated with non-SVR, while inactive HCC was not. We thus suggest the deferral of DAA treatment until after the complete radiological response of HCCs to treatment.

Pooled analysis of HCV genotype 1 resistance-associated substitutions in NS5A, NS3 and NS5B pre-and post-treatment with 12 weeks of daclatasvir, asunaprevir and beclabuvir

BACKGROUND

Daclatasvir (DCV; non-structural [NS]5A inhibitor) plus asunaprevir (ASV; NS3 inhibitor) plus beclabuvir (BCV; non-nucleoside NS5B inhibitor) is an approved regimen for hepatitis C virus (HCV) genotype (GT)-1 treatment in Japan. A comprehensive analysis of pre-treatment and treatment-emergent HCV resistance to this regimen ± ribavirin (RBV) was performed.

METHODS

Data were pooled from five Phase 2/3 studies of DCV+ASV+BCV±RBV given for 12 weeks to GT-1a- or GT-1b-infected patients. The prevalence and impact of pre-treatment resistance-associated substitutions (RAS) in NS5A, NS3, and NS5B on sustained virological response (SVR) was assessed, as were emergent RAS and their post-treatment persistence.

RESULTS

Baseline NS5A RAS (GT-1a: M28T, Q30H/L/R/S, L31M, Y93C/H; GT-1b: L31I/M, Y93C/H) were present in 5% (26/561) of GT-1a and 16% (85/537) of GT-1b sequences. SVR12 for GT-1b without RBV was 100% (82/82) with RAS and >99% (427/428) without RAS. For GT-1a, SVR12 without RAS was 97% (85/88) with RBV and 92% (410/447) without RBV; SVR12 with RAS was 100% (2/2) with RBV and 54% (13/24) without RBV. Baseline NS3 (at R155 or D168) and NS5B (at P495) RAS were rare (≤1%). Treatment-emergent NS5A RAS (mostly Q30E/H/K/R±Y93H/N) in GT-1a persisted 60 weeks post-treatment, while NS3 RAS (mostly R155K) and NS5B-P495L/S were no longer detected after 48 or 24 weeks, respectively.

CONCLUSIONS

DCV+ASV+BCV±RBV was highly efficacious in HCV GT-1 infection, including HCV GT-1b with NS5A RAS. The fitness of treatment-emergent RAS post-treatment was NS5A > NS3 > NS5B; NS3 and NS5B RAS were generally replaced by wild-type sequence within 48 weeks.

Computational analysis of naturally occurring resistance-associated substitutions in genes NS3, NS5A, and NS5B among 86 subtypes of hepatitis C virus worldwide

Background and objective

Direct-acting antivirals (DAA) facing resistance continue to be used in some areas worldwide. Thus, identifying hepatitis C virus (HCV) genotypes/subtypes and loci with certain prevalent resistance-associated substitutions (RASs) deserves attention. We investigated the global and regional frequencies of naturally occurring RASs among all confirmed HCV subtypes (n=86) and explored co-occurring and mutually exclusive RAS pairs within and between genes NS3, NS5A, and NS5B.

Methods

A total of 213,908 HCV sequences available as of July 10, 2019 were retrieved from the NCBI nucleotide database. After curation, 17,312 NS3, 8,478 NS5A, and 25,991 NS5B sequence fragments from DAA-naïve patients were screened for RASs. MEGA 6.0 was used to translate aligned nucleotide sequences into amino acid sequences, and RAS pairs were identified by hypergeometric analysis.

Results

RAS prevalence varied significantly among HCV subtypes. For example, D168E, highly resistanct to all protease inhibitors except voxilaprevir, was nearly absent in all subtypes except in 43.48% of GT5a sequences. RASs in NS3 exhibiting significantly different global distribution included Q80K in GT1a with the highest frequency in North America (54.49%), followed by in Europe (22.66%), Asia (6.98%), Oceania (6.62%), and South America (1.03%). The prevalence of NS3 S122G in GT1b was highest in Asia (26.6%) and lowest in Europe (2.64%). NS5A L28M, R30Q, and Y93H in GT1b, L31M in GT2b, and NS5B C316N in GT1b was most prevalent in Asia. A150V in GT3a, associated with sofosbuvir treatment failure, was most prevalent in Asia (44.09%), followed by Europe (31.19%), Oceania (24.29%), and North America (19.05%). Multiple mutually exclusive or co-occurring RAS pairs were identified, including Q80K+R155K and R155K+D168G in GT1a and L159F+C316N and R30Q (NS5A)+C316N (NS5B) in GT1b.

Conclusion

Our data may be of special relevance for those countries where highly effective antivirals might not be available. Considering the specific RASs prevalence will help the clinicians to make optimal treatment choices. The RASs pairs would benefit anti-HCV drug development.

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.

The Prevalence of Mixed Hepatitis C Virus Genotype Infection and Its Effect on the Response to Direct-Acting Antivirals Therapy

BACKGROUND

The incidence of mixed hepatitis C virus (HCV) genotype infection is variable, and a few reports exist regarding the efficacy of direct-acting antivirals (DAA) therapy for mixed genotype. We aimed to investigate the prevalence of mixed genotype and its impact on the virologic response to DAA therapy.

METHODS

A total of 365 patients with chronic HCV infection who completed antiviral therapy were recruited. Nested polymerase chain reaction with universal and specific primers of genotypes 1b and 2 and direct sequencing were used for HCV genotyping.

RESULTS

Direct sequencing with universal primers defined genotypes 1b (n = 230), 2a (n = 95), and 2b (n = 40). Direct sequencing of genotype 2 was performed in patients with genotype 1b, and direct sequencing of genotype 1b in patients with genotype 2. Four patients with genotype 1b underwent amplification for genotype 2, and direct sequencing identified genotypes 1b (n = 1), 2a (n = 1), and 2b (n = 2). None with genotype 2 underwent amplification for genotype 1b. Three cases were confirmed to have mixed genotype.

CONCLUSIONS

Mixed genotype was rare, and hence the impact of mixed genotype on treatment outcome with DAA therapy is expected to be minimal.

Impact of novel NS5A resistance-associated substitutions of hepatitis C virus detected in treatment-experienced patients

Resistance-associated substitutions (RASs) of hepatitis C virus (HCV) in the NS5A region impair the efficacy of NS5A inhibitors. In this study, we evaluated the characteristics of the novel RASs observed in treatment-failure patients, A92K and a deletion at P32 (P32del), and the susceptibility of viruses with these RASs to various anti-HCV reagents by using JFH-1 based recombinant HCV with NS5A from a genotype 1b Con1 strain (JFH1/5ACon1). We introduced A92K or P32del solely or in combination with Q24K, L28M, R30Q or L31F into the NS5A of JFH1/5ACon1. Viruses harboring R30Q/A92K showed high extracellular core antigens and infectivity titers, whereas the other viruses with RASs showed low replication levels and infectivity titers. All the viruses with A92K or P32del were markedly resistant to ledipasvir, velpatasvir and elbasvir. Interestingly, viruses with R30Q/A92K were more susceptible to grazoprevir than viruses without RAS. All the viruses had a similar susceptibility to ribavirin and sofosbuvir. In conclusion, combination RASs R30Q/A92K enhanced virus production whereas other RASs impaired virus replication. Both A92K and P32del conferred severe resistance even to second generation NS5A inhibitors. However, these viruses were susceptible to grazoprevir, ribavirin and sofosbuvir. Thus, combination regimens with these reagents may eradicate viruses harboring A92K or P32del.

Subtype-Specific Prevalence of Hepatitis C Virus NS5A Resistance Associated Substitutions in Mainland China

Resistance associated substitutions (RASs) can reduce the efficacy of direct-acting antiviral agents (DAAs) targeting hepatitis C virus (HCV) and lead to treatment failure. Clinical data of HCV NS5A RASs prevalence are limited in China and need to be investigated. A total of 878 unique patient samples with different genotypes (GT) (1b: n = 489, 2a: n = 203, 3a: n = 60, 3b: n = 78, 6a: n = 48) were collected from around mainland China by KingMed Laboratory and analyzed for NS5A RASs distribution by Sanger sequencing. Phylogeographic analyses based on NS5A domain 1 sequences indicated circulation of both locally and nationally epidemic strains. Relatively high frequency of Y93H (14.1%) was only detected in GT1b but not in other subtypes. High frequency of L31M was found in both GT2a (95.6%) and GT3b (98.7%) sequences. Due to the overlapping incidence of A30K, 96% of GT3b isolates had NS5A RASs combination A30K + L31M, which confers high levels of resistance to most NS5A inhibitors. No RASs were detected in GT6a strains. Meanwhile, baseline NS5A RASs fingerprints were also evaluated in 185 DAA treatment-naive GT1b patients with next generation sequencing method. Patients presenting with Y93H had statistically higher entropy of HCV NS5A sequences. Taken together, subtype-specific distribution patterns of NS5A RASs were observed. GT1b patients with higher HCV complexity tend to have a greater chance of Y93H presence, while GT3b patients are naturally resistant to current NS5A inhibitors and their treatment may pose a challenge to real-world DAA application.

Efficacy and safety of elbasvir plus grazoprevir combination therapy in Japanese patients infected with hepatitis C virus genotype 1b

AIM

Treatment with all-oral direct-acting antiviral agents (DAAs) elbasvir/grazoprevir (EBR/GZR) is associated with high sustained virologic response (SVR). The aim of this study was to evaluate the safety and treatment efficacy of EBR/GZR in hepatitis C virus (HCV)-infected patients.

METHODS

This retrospective cohort study included 147 consecutive patients with chronic HCV genotype 1b infection who were treated with EBR (50 mg) plus GZR (100 mg) once daily for 12 weeks. The rates of SVR at 12 weeks after the end of treatment (SVR12) were evaluated based on patient baseline characteristics. Treatment efficacy was analyzed according to background chronic kidney disease (CKD), and retreatment efficacy in patients who failed to respond to previous DAAs.

RESULTS

The SVR12 was 94% (138 of 147 patients), based on intention-to-treat analysis. Rates of SVR12 were 97% (131 of 135) and 58% (7 of 12) in cases naïve to DAA treatment and failure to respond to prior DAAs, respectively. The SVR12 rates in patients with CKD stage 4-5 was 100% (8 of 8). All patients (4 of 4 patients) with stage 4-5 and advanced fibrosis (Fibrosis-4 index ≥3.25) also achieved SVR12. Multivariate analysis that included the above variables identified pretreatment with other DAAs as an independent factor that was significantly and independently associated with non-SVR12 (odds ratio, 97.5; P < 0.001). Relapsers of first DAAs, excluding the combination of ledipasvir and sofosbuvir, achieved SVR12. Characteristic novel non-structural protein 5A substitutions were not detected after failure of retreatment with EBR/GZR.

CONCLUSION

Treatment with EBR/GZR was highly efficacious with acceptable safety, even in patients with CKD stage 4-5. Retreatment of relapsers to prior DAAs, excluding ledipasvir and sofosbuvir, achieved SVR12.

Clinical outcomes after the introduction of direct antiviral agents for patients infected with genotype 1b hepatitis C virus depending on the regimens: A multicenter study in Korea

BACKGROUND

A real-life study is essential outside clinical trials. The aim is to evaluate the clinical outcomes of direct acting agents (DAA) for patients with chronic hepatitis C (CHC) in real practice.

METHODS

We analyzed 590 consecutively enrolled patients with CHC-1b who received DAAs since 2015, when DAAs were introduced in Korea. The patients were checked for resistance-associated variants (RAV) against nonstructural protein 5A inhibitors and then daclatasvir/asunaprevir or sofosbuvir based regimens were chosen.

RESULTS

The frequency of patients with cirrhosis and prior hepatocellular carcinoma (HCC) was 29.2% and 4.7%, respectively. For the RAV test, 10% were positive and in 3.6% the result was "indeterminate." Overall, 518 patients were treated with a 24-week regimen of daclatasvir/asunaprevir, 72 patients (RAV positive 75%) were treated with 12 weeks regimen of ledipasvir/sofosbuvir or daclatasvir/sofosbuvir. The SVR12 was 94.0% in the daclatasvir/asunaprevir, 98.2% in the ledipasvir/sofosbuvir, and 100% in the daclatasvir/sofosbuvir group. A total of 93.3% of SVR12 in the RAV-"indeterminate" patients was not difference 95.0% in the RAV-negative patients. Up to 1 year, de novo HCC occurrence and recurrence developed in 2.6% and 17.8%, respectively. HCC was more frequent in cirrhotic patients than in noncirrhotic patients (P = 0.000). α Fetoprotein (AFP) level at the end of treatment was a predicting factor for de novo HCC.

CONCLUSIONS

Optimizing the choice of DAAs according to RAV test resulted in high SVR among CHC-1b Korean patients. This real practice multicenter cohort study suggests the importance of AFP and HCC surveillance in cirrhotic patients even after successful HCV therapy.

Past history of hepatocellular carcinoma is an independent risk factor of treatment failure in patients with chronic hepatitis C virus infection receiving direct-acting antivirals

Direct-acting antiviral (DAA) treatment can achieve a high sustained virological response (SVR) rate in patients with hepatitis C virus (HCV) infection regardless of a history of hepatocellular carcinoma (HCC [+]). We examined 838 patients (370 men, median age: 69 years) who were treated with DAAs for comparisons of clinical findings between 79 HCC (+) (9.4%) and 759 HCC (-) (90.6%) patients and associations with treatment outcome. Male frequency was significantly higher in the HCC (+) group (60.8% vs 42.4%, P = 0.006). There were significant differences between the HCC (+) and HCC (-) groups for platelet count (115 vs 152 ×10⁹ /L, P < 0.001), baseline alpha fetoprotein (AFP) (9.9 vs 4.5 ng/mL, P < 0.001) and the established fibrosis markers of FIB-4 index (4.7 vs 3.0, P < 0.001), AST-to-platelet ratio index (APRI) (1.1 vs 0.7, P = 0.009), M2BPGi (3.80 vs 1.78 COI, P < 0.001) and autotaxin (1.91 vs 1.50 mg/L, P < 0.001). The overall SVR rate was 94.7% and significantly lower in the HCC (+) group (87.3 vs 95.5%, P = 0.001). Multivariate analysis revealed that a history of HCC was independently associated with DAA treatment failure (odds ratio: 3.56, 95% confidence interval: 1.32-9.57, P = 0.01). In conclusion, patients with chronic HCV infection and prior HCC tended to exhibit more advanced disease progression at DAA commencement. HCC (+) status at the initiation of DAAs was significantly associated with adverse therapeutic outcomes. DAA treatment for HCV should therefore be started as early as possible, especially before complicating HCC.

Late relapse of hepatitis C virus in patients with sustained virological response after daclatasvir and asunaprevir therapy

The optimal term of follow-up for patients who achieve sustained virological responses (SVR) is an important topic because of the widespread use of direct-acting antivirals (DAA), which achieve a high SVR rate. Investigations of long-term follow-up among patients with SVR after interferon (IFN) therapy have reported that approximately 80%-100% of patients maintained SVR. However, the long-term durability of SVR to DAA treatment is unknown. The aim of this study was to evaluate the incidence of late relapse in patients who achieved SVR with daclatasvir (DCV) and asunaprevir (ASV). Four hundred and thirteen patients infected with hepatitis C virus (HCV) genotype 1b who completed ASV and DCV treatment and achieved SVR were selected. Patients who were persistently negative for serum HCV RNA at 24 weeks after withdrawal of DCV and ASV were considered to have SVR24. Mean follow-up period was 21.5 months (range, 4.8-30.3 months) after SVR24. Four patients redeveloped HCV RNA in serum at 6, 12, 12 and 26 months, respectively, after achieving SVR24. Results of molecular analysis by phylogenetic tree of HCV nonstructural protein 3 and 5A regions from late relapse indicated that the same strain was present at pretreatment and late relapse. In conclusion, late relapse by the original HCV strain was confirmed by direct sequencing in 4 of 413 patients with SVR to ASV and DCV. Although a few patients may develop late relapse, SVR achieved with all oral DAA therapy is as durable as that with IFN therapy.

Evolution and persistence of resistance-associated substitutions of hepatitis C virus after direct-acting antiviral treatment failures

Daclatasvir plus asunaprevir (DCV+ASV) treatment is an all-oral direct-acting antiviral (DAA) therapy for the genotype 1b HCV-infected patients. In this study, we investigated how resistance-associated substitutions (RASs) evolved after treatment failures and assessed the effect of those substitutions on viral fitness. Sequencing of NS5A and NS3 revealed typical RASs after treatment failures. Interestingly, the RASs of NS3 reverted to the wild-type amino acid within 1 year after treatment failures. However, the RASs of NS5A were stable and did not change. The effect of NS5A and NS3 RASs on viral RNA replication was assessed after mutagenic substitution in the genotype 1b HCV RNA. Among single substitutions, the effect of D168V was more substantial than the others and the effect of the triple mutant combination (D168V+L31V+Y93H) was the most severe. The RAS at NS5A Y93 affected both viral RNA replication and virus production. Finally, the effect of trans-complementation of NS5A was demonstrated in our co-transfection experiments and these results suggest that such a trans-complementation effect of NS5A may help maintain the NS5A RASs for a long time even after cessation of the DAA treatment. In conclusion, the results from this investigation would help understand the emergence and persistence of RASs.

Evaluation of antiviral effects of novel NS5A inhibitors in hepatitis C virus cell culture system with full-genome infectious clones

Nonstructural protein 5A (NS5A) inhibitors of hepatitis C virus (HCV) are known to have potent anti-viral effects; however, these inhibitors have limited activities on strains with resistant-associated substitutions or non-genotype 1 strains. To overcome these shortcomings, novel NS5A inhibitors have been developed and approved for clinical application. The aim of this study was to evaluate the anti-viral effect of novel NS5A inhibitors (derivatives of odalasvir) on HCV genotype 2 strains in a cell culture system. Chimeric JFH-1 viruses replaced with NS5A of genotypes 1 and 2 were utilized to assess the genotype-specific potencies of NS5A inhibitors. We also examined full-genome infectious clones of JFH-1, J6cc, and J8cc to confirm the effects of NS5A inhibitors on genotype 2 strains. All chimeric viruses were capable of replication at similar levels in cell culture. We examined the anti-viral effects of derivatives of the novel NS5A inhibitor and compared with the first-generation NS5A inhibitor, daclatasvir (DCV). These compounds inhibited replication of chimeric JFH-1 viruses with NS5A of genotypes 1 and 2 at low concentrations in comparison with DCV. The EC₅₀ values of J6cc and J8cc to these compounds were more than 100-fold lower than that of DCV. By long-term culture in the presence of these compounds, we obtained highly resistant variants and identified the responsible substitutions. In conclusion, novel NS5A inhibitors displayed improved potency against HCV genotype 2 strains compared with DCV. However, the activity of these compounds was impaired by emerging resistance-associated substitutions.

Efficacy of daclatasvir plus asunaprevir in patients with hepatitis C virus infection undergoing and not undergoing hemodialysis

AIM

To evaluate the virologic responses and clinical course of daclatasvir plus asunaprevir treatment in non-hemodialysis (non-HD) and hemodialysis (HD) patients infected with genotype 1 hepatitis C virus (HCV).

METHODS

A total of 1113 non-HD patients and 67 HD patients were assessed. To evaluate pretreatment factors contributing to sustained virological response at 12 weeks (SVR12), univariate and multivariate analyses were carried out. To adjust for differences in patient background, propensity score matching was undertaken.

RESULTS

The overall SVR12 rates were 91.6% in non-HD patients and 95.5% in HD patients. Compared with non-HD patients, HD patients were younger, were more likely to be male, were less likely to have received interferon-based pretreatment, had a lower viral load, and had lower levels of alanine transaminase, hemoglobin, and α-fetoprotein. Multivariate analysis revealed that viral load, α-fetoprotein, L31 substitution negative, and Y93 substitution negative were independent predictive factors for SVR12 in non-HD patients. The proportion of patients with undetectable HCV-RNA during the initial 4 weeks was significantly higher in HD patients than in non-HD patients. The SVR12 rate was clearly higher in HD patients than in non-HD patients, although the difference was not statistically significant. After propensity score matching to adjust for viral load, α-fetoprotein, L31 substitution, and Y93 substitution, these trends disappeared.

CONCLUSIONS

For treatment of HCV genotype 1 infection, daclatasvir plus asunaprevir is useful not only in non-HD patients but also in HD patients. Viral load, α-fetoprotein levels, L31 substitution, and Y93 substitution influence treatment course and outcome.

Exposure-Response (Efficacy) Analysis of Daclatasvir and Asunaprevir in Japanese Patients With Hepatitis C Virus Infection

The treatment of hepatitis C virus (HCV) infection has been revolutionized by the development of all-oral combination regimens of direct-acting antiviral agents. The current analysis characterized the relationship between exposures of daclatasvir (DCV; tablets) and asunaprevir (ASV; capsules) and sustained virologic response (SVR) in Japanese patients who are HCV genotype (GT) 1b nonresponders to pegylated interferon (IFN) α/ribavirin or IFNβ/ribavirin, and IFN-based therapy-ineligible naive/intolerant patients receiving DCV and ASV, and provided insight into patient covariates that were most closely associated with efficacy. The relationship between the probability of achieving SVR at 12 weeks after treatment (SVR12) and average steady-state plasma concentrations estimated from population pharmacokinetic models for DCV and ASV is described using a logistic regression model with data from a phase 2 and a phase 3 study in Japanese patients infected with HCV GT 1b (N=265). The functional form characterization, which describes a relationship between DCV and ASV average steady-state plasma concentrations and SVR12, as well as covariate identification (demographic, laboratory, and prognostic and treatment covariates) were investigated during model development. The presence of the signature nonstructural protein 5A Y93H mutation at baseline was the only significant parameter of SVR12 in the final exposure-response model. Model evaluation plots demonstrate that the final model was able to predict the observed SVR rates. Exposure-response analysis supports the clinical utility of the combination regimen of 60-mg once-daily DCV and 100-mg twice-daily ASV in Japanese patients infected with HCV GT 1b.

The presence of multiple NS5A RASs is associated with the outcome of sofosbuvir and ledipasvir therapy in NS5A inhibitor-naïve patients with chronic HCV genotype 1b infection in a real-world cohort

It is unclear whether multiple nonstructural (NS) 5A resistance-associated substitutions (RASs) correlate with the outcome of sofosbuvir (SOF) and ledipasvir (LDV) therapy. We investigated the effects of multiple NS5A RASs in NS5A inhibitor-naïve patients with chronic hepatitis C virus genotype 1b infection treated with SOF/LDV. In 313 patients treated with SOF/LDV, we assessed the effects of multiple NS5A RASs on the sustained virological response (SVR). RASs at L28, R30, L31, Q54, P58, Q62, A92, and Y93 in the NS5A region were examined by direct sequencing. The prevalence of RASs was as follows: 2.6% at L28, 8.7% at R30, 6.1% at L31, 48.7% at Q54, 9.9% at P58, 9.9% at Q62, 5.1% at A92, 13.8% at Y93, and 19.2% at L31 or Y93. A total of 133 patients had no RASs. SVR was achieved in 98.7% of the patients. SVR rates significantly differed between patients with and without the L31 or Y93 RAS (93.0% [53/57] vs 100% [250/250], P = .0011). In addition, among patients with the L31 or Y93 RAS, 29.8%, 45.6% and 24.6% had one, two and three or more NS5A RASs, respectively. The SVR rate was significantly lower in patients with the L31 or Y93 RAS with more than three NS5A RASs compared to those with fewer than three NS5A RASs (71.4% [10/14] vs 100% [43/43], P = .0025). Although the prevalence of multiple NS5A RASs at baseline was low in NS5A inhibitor-naïve patients, the presence of multiple NS5A RASs was associated with the effectiveness of SOF/LDV therapy.

Differences in the Serum 4β-hydroxycholesterol Levels of Patients with Chronic Hepatitis C Virus (HCV) Infection: A Possible Impact on the Efficacy and Safety of Interferon (IFN)-free Treatment

Objective Since the majority of direct-acting antivirals (DAAs) that are used in the treatment of hepatitis C virus (HCV) infection are mainly metabolized by CYP3A4, it is hypothesized that inter-individual differences in CYP3A4 activity may be associated with the bioavailability of these agents. Methods The level of serum 4β-hydroxycholesterol (4βHC), a surrogate marker of CYP3A4 activity, was determined by LC-MS/MS in samples obtained from patients with HCV infection (CHCs) as well as healthy control subjects (CTLs). Serum samples obtained from patients treated with either asunaprevir/daclatasvir (ASV/DCV) or ombitasvir/paritaprevir/ritonavir (OTV/PTV/r) were used for additional assays. Results The serum 4βHC level in CHCs was significantly higher than that in CTLs, and a gender difference was seen among CHCs. In patients treated with OTV/PTV/r, the serum 4βHC level was observed to gradually decrease during the treatment period. In the cohort treated with ASV/DCV, 4 of 83 patients showed virological treatment failure. In pretreatment testing, an Invader assay detected a low prevalence of resistance-associated variants in these four patients. The average serum concentration of DCV/ASV in the treatment-failed group tended to be lower than that in the sustained virological response (SVR) group. The pretreatment serum 4βHC level in patients with treatment failure was significantly higher than that in patients with an SVR but in whom the prevalence of resistance-associated variants was low in the pretreatment setting. Conclusion The evaluation of CYP3A4 activity by measuring 4βHC before treatment may provide additional information that can potentially be used to select cost- and efficacy-optimized treatment of HCV.

Analysis of Naturally Occurring Resistance-Associated Variants to NS3/4A Protein Inhibitors, NS5A Protein Inhibitors, and NS5B Polymerase Inhibitors in Patients With Chronic Hepatitis C

The first NS3/4A hepatitis C virus (HCV) protease inhibitors telaprevir and boceprevir were approved in 2011, and both NS5A and NS5B polymerase inhibitors were launched. Recently, direct-acting antivirals (DAAs) have had a major impact on patients infected with HCV. HCV DAAs are highly effective antivirals with fewer side effects. DAAs have been developed for the treatment of HCV infection in combination with PEG-IFN-α/RBV as well as in IFN-free regimens. However, some drug resistance mutations occur when a single oral DAA is used for treatment, which indicates that there is a low-frequency drug resistance mutation in HCV patients before the application of antiviral drugs. Our research showed that natural resistance to HCV DAAs was found in treatment-naive CHC patients and that the drug resistance mutation rates differ in various HCV genotypes. Many challenges posed by natural resistance should be considered in the context of DAA therapies.

Retreatment with sofosbuvir/ledipasvir with or without lead-in interferon-β injections in patients infected with genotype 1b hepatitis C virus after unsuccessful daclatasvir/asunaprevir therapy

AIM

To improve the therapeutic efficacy of sofosbuvir/ledipasvir (SOF/LDV) for the retreatment of patients after daclatasvir/asunaprevir (DCV/ASV), a customized therapy with or without lead-in interferon (IFN)-β injections was formulated according to the types of resistance-associated substitutions (RAS) in the non-structural protein (NS)5A region of genotype 1b hepatitis C virus (HCV).

METHODS

Thirty-three patients failing prior DCV/ASV received SOF/LDV for 12 weeks. Patients with HCV carrying unfavorable NS5A-RAS and/or those previously treated with simeprevir were given lead-in IFN-β injections twice a day for 2 weeks; sequential changes in the NS5A-RAS during the injection period were evaluated using deep sequencing.

RESULTS

Lead-in injections were not undertaken in 27 patients; a sustained viral response (SVR) was achieved in 26 patients, while viral relapse occurred in 1 patient with HCV carrying NS5A-L28M/R30H/Y93H mutations. Among the 6 patients receiving lead-in injections, viral relapse occurred in 2 patients who had an unfavorable IFN-λ3-related gene single nucleotide polymorphism allele; both patients had been previously treated with simeprevir, and HCV carrying NS5A-L31V/Y93H mutations had emerged after DCV/ASV. Deep sequencing revealed no changes in the NS5A-RAS profiles during the lead-in injection period in either patient. In contrast, in a patient with a favorable allele who was infected with similar unfavorable HCV strains, NS5A-L31/Y93 wild-type strains appeared during the injection period, enabling an SVR.

CONCLUSION

Using customized therapies based on the NS5A-RAS profiles, a high SVR rate was obtained after SOF/LDV in patients failing prior DCV/ASV. Lead-in IFN-β injections did not improve the efficacy in patients with HCV carrying unfavorable NS5A-RAS except in those with a favorable IFN-λ3-related gene allele.

Usefulness of semiquantitative PCR-Invader assay for selecting candidates for daclatasvir plus asunaprevir combination therapy among patients with hepatitis C virus genotype 1b

AIMS

PCR-Invader is a highly sensitive assay for detecting non-structural protein 5A (NS5A) resistance-associated variants (RAVs) of hepatitis C virus (HCV). Here, we validated the accuracy of the semiquantitative PCR-Invader (SQ-PI) assay compared to direct sequencing (DS) for identifying NS5A RAVs, and we evaluated the treatment efficacy of daclatasvir plus asunaprevir (DCV + ASV) for patients judged to be non-positive for NS5A RAVs by SQ-PI.

METHODS

Detection rates of NS5A RAVs by SQ-PI and DS were compared for 204 patients with HCV genotype 1b. Patients with non-positive results for NS5A RAVs by SQ-PI were treated by DCV + ASV, and the efficacy of this treatment was examined.

RESULTS

All samples judged as negative for NS5A RAVs by SQ-PI were similarly judged by DS. However, 29.7% of samples judged as negative for Y93H by DS were judged as weakly positive or positive by SQ-PI. Among 108 patients who were judged as negative by SQ-PI and treated by DCV + ASV, rates of sustained virologic response at 24 weeks (SVR24) were 96.3% in intention-to-treat analysis and 99.0% in patients who completed treatment. Among patients who were weakly positive for Y93H on SQ-PI, the SVR24 rate was 95.0% (19/20). This rate was 100% (78/78) in patients who were negative for Y93H on SQ-PI and completed treatment.

CONCLUSION

Treatment efficacy of DCV + ASV was extremely high among patients who were non-positive for NS5A RAVs on SQ-PI, especially for patients with negative results.

Hepatitis C virus drug resistance associated substitutions and their clinical relevance: Update 2018

Nowadays, due to the development of potent Direct-Acting Antiviral Agents (DAAs) that specifically target NS3, NS5A and NS5B viral proteins, several new and highly efficacious options to treat chronic Hepatitis C virus (HCV) infection are available. The natural presence of resistance associated substitutions (RASs), as well as their rapid emergence during incomplete drug-pressure, are intrinsic characteristics of HCV that greatly affect treatment outcome and the chances to achieve a virolgical cure. To date, a high number of RASs in NS3, NS5A, and NS5B have been associated in vivo and/or in vitro with reduced susceptibility to DAAs, but no comprehensive RASs list is available. This review thus provides an updated, systematic overview of the role of RASs to currently approved DAAs or in phase II/III of clinical development against HCV-infection, discriminating their impact in different HCV-genotypes and DAAs, providing assistance for a fruitful use of HCV resistance testing in clinical practice.

Occurrence of late relapse of hepatitis C virus confirmed by molecular analysis after sustained virologic response to interferon-ribavirin-based therapy

AIM

The optimal duration of follow-up for patients who achieve sustained virologic responses (SVR) has become an important issue. Reports on long-term follow-up of SVR have indicated that 99% of patients maintained SVR. However, the limitations of a majority of studies include small patient numbers, short study periods, and lack of molecular analysis of hepatitis C virus (HCV) genome. The present study sought to evaluate the late relapse rate in long-term follow-up of patients who achieved SVR, with molecular analysis of HCV.

METHODS

A total of 224 patients with chronic hepatitis C who were treated by interferon and ribavirin-based therapy and achieved SVR were enrolled. All patients were recommended for follow-up every 6 or 12 months.

RESULTS

The mean follow-up period was 6.0 years (range, 1.0-13.6 years). Cumulative 5- and 10-year follow-up rates of the patients after SVR were 87.8% and 78.8%, respectively. Cumulative 5- and 10-year follow-up rates of serum HCV RNA after SVR were 85.5% and 52.6%, respectively. Two patients had detectable serum HCV RNA at 20 and 30 months, respectively, after SVR. Phylogenetic analyses of core, non-structural protein 3, and 5A regions of HCV strains from late relapse patients confirmed the same strain was present at baseline and late relapse.

CONCLUSIONS

Two of 224 patients developed late relapse of HCV by the original strain, which was confirmed by direct sequencing analysis. Although few patients may develop late relapse, SVR achieved with interferon and ribavirin-based therapy is durable for prolonged periods.

Nonstructural protein 5A resistance profile in patients with chronic hepatitis C treated with ledipasvir-containing regimens without sofosbuvir

The study aimed to evaluate the effects of baseline hepatitis C virus (HCV) nonstructural protein 5A (NS5A) resistance-associated substitutions (RASs) on sustained virologic response to ledipasvir (LDV)-containing regimens in the absence of sofosbuvir (SOF) in patients with HCV genotype (GT) 1 infection across 6 phase 2 clinical studies. We analysed data from 1103 patients who received either LDV + vedroprevir (NS3 protease inhibitor) + tegobuvir (NS5B inhibitor) ± ribavirin or LDV + ribavirin + pegylated interferon. Population sequencing of HCV NS5A was performed at baseline and at virologic failure from patient plasma samples. Of 1045 patients with available baseline sequences, 747 (67.7%) had GT1a, and 298 (26.9%) had GT1b infection. The overall prevalence of NS5A RASs at baseline was 9.4%; 7.6% (57/747) and 13.8% (41/298) of patients with GT1a and GT1b infection, respectively. The majority of GT1a-infected patients with NS5A RASs at baseline had a single NS5A RAS (78.9%) at NS5A positions K24R, M28T, Q30H/L, L31M and Y93H/N/C/S. The spectrum of NS5A RASs detected in GT1b patients was much less diverse compared to GT1a patients, with all patients harbouring a single NS5A RAS either L31M or Y93H/C. For patients treated with LDV-containing regimens in the absence of SOF, the presence of baseline NS5A RASs was associated with low SVR rates. In patients with virologic failure, nearly all had either pre-existing and/or emergent NS5A RASs: 287/287 (100%) and 40/42 (95.2%) patients with GT1a and GT1b infection, respectively. Three novel NS5A substitutions were identified as emergent NS5A RASs: K26E and S38F in GT1a; and L31I in GT1b. In conclusion, the presence of NS5A RASs at baseline reduced the SVR rate in patients treated with LDV in combination vedroprevir + tegobuvir ± ribavirin or ribavirin + pegylated interferon. Virologic failure was associated with the detection of NS5A RASs in nearly all patients. These results suggest that the resistance barrier may differ depending on HCV drug combination and may be more important than that of the individual DAAs.

Integrated pharmacokinetic/viral dynamic model for daclatasvir/asunaprevir in treatment of patients with genotype 1 chronic hepatitis C

In order to develop an integrated pharmacokinetic/viral dynamic (PK/VD) model to predict long-term virological response rates to daclatasvir (DCV) and asunaprevir (ASV) combination therapy in patients infected with genotype 1 (GT1) chronic hepatitis C virus (HCV), a systematic publication search was conducted for DCV and ASV administered alone and/or in combination in healthy subjects or patients with GT1 HCV infection. On the basis of a constructed meta-database, an integrated PK/VD model was developed, which adequately described both DCV and ASV PK profiles and viral load time curves. The IC₅₀ values of DCV and ASV were estimated to be 0.041 and 2.45 μg/L, respectively, in GT1A patients. A sigmoid E_max function was applied to describe the antiviral effects of DCV and ASV, depending on the drug concentrations in the effect compartment. An empirical exponential function revealed that IC₅₀ changing over time described drug resistance in HCV GT1A patients during DCV or ASV monotherapy. Finally, the PK/VD model was evaluated externally by comparing the expected and observed virological response rates during and post-treatment with DCV and ASV combination therapy in HCV GT1B patients. Both the rates were in general agreement. Our PK/VD model provides a useful platform for the characterization of pharmacokinetic/pharmacodynamic relationships and the prediction of long-term virological response rates to aid future development of direct acting antiviral drugs.

Comparison of direct sequencing and Invader assay for Y93H mutation and response to interferon-free therapy in hepatitis C virus genotype 1b

BACKGROUND AND AIM

Virologic failure of interferon-free therapy has been associated with Y93H mutation in the non-structure 5A region in hepatitis C virus (HCV) genotype 1b, and screening is recommended. A simple assay based on Q-Invader technology was developed for Y93H mutant screening to reduce cost and effort. The present study sought to compare two methods of detection of Y93H mutation and to evaluate the effect of Y93H mutation on response to interferon-free therapy.

METHODS

Y93H mutation was examined in 258 patients with HCV genotype 1b using both direct sequencing analysis and the polymerase chain reaction (PCR)-Invader assay. Daclatasvir and asunaprevir or ledipasvir and sofosbuvir therapy was administered to 205 patients whose sustained virological responses (SVR) were checked.

RESULTS

Hepatitis C virus was detected in 232 of 258 patients by direct sequencing and in 236 of 258 patients by the PCR-Invader assay. Forty of 231 cases were defined as Y93 mutation by direct sequencing, and 46 of 236 cases were defined as Y93 mutation by the PCR-Invader assay. SVR of patients who were Y93H by direct sequencing, Y93H by the PCR-Invader assay, and Y93H by both methods was 62.5%, 82.4%, and 50%, respectively.

CONCLUSIONS

The sensitivity of the PCR-Invader assay was similar to that of direct sequencing analysis; however, the PCR-Invader assay had a better ability to detect minor strains. Combination of the two assays would improve prediction of the response to daclatasvir and asunaprevir, but Y93H mutation had little effect on SVR in ledipasvir and sofosbuvir therapy.

Retreatment of patients with treatment failure of direct-acting antivirals: Focus on hepatitis C virus genotype 1b

The recent development of direct-acting antiviral agents (DAAs) against hepatitis C virus (HCV) infection could lead to higher sustained virological response (SVR) rates, with shorter treatment durations and fewer adverse events compared with regimens that include interferon. However, a relatively small proportion of patients cannot achieve SVR in the first treatment, including DAAs with or without peginterferon and/or ribavirin. Although retreatment with a combination of DAAs should be conducted for these patients, it is more difficult to achieve SVR when retreating these patients because of resistance-associated substitutions (RASs) or treatment-emergent substitutions. In Japan, HCV genotype 1b (GT1b) is founded in 70% of HCV-infected individuals. In this minireview, we summarize the retreatment regimens and their SVR rates for HCV GT1b. It is important to avoid drugs that target the regions targeted by initial drugs, but next-generation combinations of DAAs, such as sofosbuvir/velpatasvir/voxilaprevir for 12 wk or glecaprevir/pibrentasvir for 12 wk, are proposed to be potential solution for the HCV GT1b-infected patients with treatment failure, mainly on a basis of targeting distinctive regions. Clinicians should follow the new information and resources for DAAs and select the proper combination of DAAs for the retreatment of HCV GT1b-infected patients with treatment failure.

Clinical evaluation of sofosbuvir/ledipasvir in patients with chronic hepatitis C genotype 1 with and without prior daclatasvir/asunaprevir therapy

AIM

This study explored treatment outcomes of sofosbuvir (SOF)/ledipasvir (LDV) therapy for chronic hepatitis C patients with and without prior daclatasvir (DCV)/asunaprevir (ASV) therapy.

METHODS

Overall, 530 Japanese patients who were infected with hepatitis C virus genotype 1 received SOF/LDV therapy for 12 weeks, and resistance-associated variants (RAVs) in the hepatitis C virus non-structural protein (NS)5A and NS5B regions were assessed at baseline and virological relapse by direct sequencing.

RESULTS

Sustained virological response (SVR) rates did not significantly differ between patients with and without NS5A Y93H/N (94.2% [113/120] vs. 97.7% [345/353]), but the SVR rate was significantly lower in patients with prior DCV/ASV therapy compared to those without (69.2% [18/26] vs. 98.4% [496/504], P < 0.001). Among 26 patients with prior DCV/ASV therapy, the prevalence of NS5A multi-RAVs (≥2) was similar between responders and non-responders (61% [11/18] vs. 75% [5/8]), but all patients without RAVs achieved SVR. Multivariate analysis showed that prior DCV/ASV therapy and history of hepatocellular carcinoma were independently associated with treatment failure (odds ratio, 37.55; 95% confidence interval, 10.78-130.76; P < 0.001 for prior DCV/ASV therapy; odds ratio, 4.42; 95% confidence interval, 1.09-18.04; P = 0.03 for the history of HCC). All SOF/LDV failure patients (n = 8) with prior DCV/ASV treatment had two or more factors of cirrhosis, IL28B unfavorable genotype, and baseline NS5A multi-RAVs. The multiple NS5A RAVs had increased but NS5B substitutions, C316N/A207T/A218S or L159F, had not changed at the time of relapse.

CONCLUSIONS

Prior DCV/ASV therapy is associated with failure of SOF/LDV therapy due to multiple RAVs.

Prevalence of hepatitis C virus-resistant association substitutions to direct-acting antiviral agents in treatment-naïve hepatitis C genotype 1b-infected patients in western China

Background

Direct-acting antivirals (DAAs) against hepatitis C virus (HCV) are potent and highly efficacious. However, resistance-associated substitutions (RASs) relevant to DAAs can impair treatment effectiveness even at baseline. Moreover, the prevalence of baseline RASs in HCV genotype 1b-infected patients in western China is still unclear.

Materials and methods

Direct sequencing of the HCV NS3, NS5A, and NS5B regions was performed in baseline serum samples of 70 DAAs treatment-naïve HCV 1b-infected patients in western China. The sequences were analyzed with MEGA version 5.05 software. Evolutionary patterns of RASs and amino-acid covariance patterns in the NS3, NS5A, and NS5B genes were analyzed by MEGA and Cytoscape (version 3.2.1), respectively.

Results

The presence of at least one RAS in the NS3 region (C16S, T54S, Q80R/L, A87T, R117H, S122G, V132I, V170I) was observed in 85.48% (53 of 62) of patients, RASs in the NS5A region (L28M, R30Q, Q54H, P58S/T, Q62H/R, Y93H) were observed in 42.42% (28 of 66) of patients, and RASs in the NS5B region (N142S, A300T, C316N, A338V, S365A, L392I, M414L, I424V, A442T, V499A, S556G) were observed in 100% (44 of 44) of patients. Evolutionary patterns of RASs and amino-acid covariance patterns for the NS3, NS5A, and NS5B genes are reported.

Conclusion

The prevalence of RASs relevant to DAAs detected in the NS3, NS5A, and NS5B regions of HCV 1b from DAA treatment-naïve patients is high. Therefore, more attention should be paid to RASs associated with DAAs in the upcoming DAA-treatment era in China.

Asunaprevir and daclatasvir for recurrent hepatitis C after liver transplantation: A Japanese multicenter experience

The safety and efficacy of an IFN-free regimen using asunaprevir (ASV) and daclatasvir (DCV) for recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) have not been evaluated in Japan. A multicenter study of LT recipients (n = 74) with recurrent HCV genotype 1b infection treated with ASV-DCV for 24 weeks was performed. Medical history was positive for pegylated interferon and ribavirin (Peg-IFN/RBV) in 40 (54.1%) patients, and for simeprevir (SMV) with Peg-IFN/RBV in 12 (16.2%) patients. Resistance-associated variants (RAVs) were positive at D168 (n = 1) in the NS3, and at L31 (n = 4), Y93 (n = 4), and L31/Y93 (n = 1) in the NS5A region of the HCV genome. Sixty-one (82.4%) patients completed the 24-week treatment protocol. Although sustained viral response (SVR) was achieved in 49 (80.3%) patients, it was achieved in only two (16.7%) patients among those with histories of receiving SMV (n = 12). Univariate analysis showed that a history of SMV (P < .01) and the presence of mutations in NS5A (P = .02) were the significant factors for no-SVR. By excluding the patients with either a history of SMV-based treatment or RAVs in NS3/NS5A, the SVR rate was 96.4%. By excluding the patients with a history of SMV and those with RAVs in NS3/NS5A, viral clearance of ASV-DCV was favorable, with a high SVR rate.

The efficacy and safety of dual oral therapy with daclatasvir and asunaprevir for genotype 1b in Japanese real-life settings

BACKGROUND & AIMS

It is important to investigate the treatment outcomes in patients excluded from clinical trials (CTR). The aims of this study were to evaluate the efficacy and safety of a 24-week daclatasvir (DCV) and asunaprevir (ASV) therapy for patients with chronic hepatitis C virus (HCV)-1b infection.

METHODS

A total of 651 HCV-1b patients started dual oral therapy with DCV and ASV for 24 weeks in Toranomon Hospital, Tokyo. Among them, 276 patients met phase III CTR inclusion criteria. The sustained virological response (SVR) rate after treatment and the adverse events during therapy were compared between CTR-met (patients who met the inclusion criteria) and CTR-unmet (patients who did not meet the inclusion criteria) groups.

RESULTS

SVR12 was achieved in 87.0% (240/276) and 86.7% (325/375) in CTR-met and CTR-unmet patients respectively. SVR12 rate in simeprevir-experienced patients was 52.9% (9/17). SVR12 rate in patients without resistance-associated variant (RAV) of NS3 or NS5A loci was 93.7% (416/444). However, the SVR12 rates in patients with NS3-D168, NS5A-L31 and Y93 single RAV at baseline were 55.0% (11/20), 73.9% (17/23) and 65.6% (63/96) respectively. The safety profiles in both CTR-met and CTR-unmet patients were similar. The discontinuation rate as a result of alanine aminotransferase (ALT) elevation was only 2.9%. Seven (2.5%) patients in CTR-met group and 20 (5.3%) in CTR-unmet group discontinued therapy because of adverse events other than the ALT elevation.

CONCLUSIONS

Dual oral therapy with DCV and ASV in real-life settings was well tolerated with a similar safety profile and achieved similar SVR12 rates as that of CTR.

Hepatitis C Virus and Antiviral Drug Resistance

Since its discovery in 1989, hepatitis C virus (HCV) has been intensively investigated to understand its biology and develop effective antiviral therapies. The efforts of the previous 25 years have resulted in a better understanding of the virus, and this was facilitated by the development of in vitro cell culture systems for HCV replication. Antiviral treatments and sustained virological responses have also improved from the early interferon monotherapy to the current all-oral regimens using direct-acting antivirals. However, antiviral resistance has become a critical issue in the treatment of chronic hepatitis C, similar to other chronic viral infections, and retreatment options following treatment failure have become important questions. Despite the clinical challenges in the management of chronic hepatitis C, substantial progress has been made in understanding HCV, which may facilitate the investigation of other closely related flaviviruses and lead to the development of antiviral agents against these human pathogens.

Emergence of drug resistance-associated variants and changes in serum lipid profiles in sofosbuvir plus ledipasvir-treated chronic hepatitis C patients

Combination of sofosbuvir plus ledipasvir therapy has been expected to enhance sustained virological response (SVR) rates in hepatitis C virus (HCV) genotype 1 chronic infected patients. We analyzed the emergence of drug resistance-associated variants (RAVs) in treatment failure and changes in lipid profiles in sofosbuvir/ledipasvir-treated patients. A total of 176 patients with chronic HCV genotype 1 infection without decompensated liver cirrhosis were treated with sofosbuvir/ledipasvir for 12 weeks. NS5A and NS5B RAVs were determined by either Invader assay or direct sequencing. Serum lipid-related markers were measured at the start of treatment and at week 4 in patients who received sofosbuvir/ledipasvir and ombitasvir/paritaprevir/ritonavir therapies. SVR was achieved in 94.9% (167 out of 176) of patients. SVR12 rate was 97.1% for patietns with low frequncy (<25%) of baseline NS5A RAVs, but 82.8% for patients with high frequency (>75%) of NS5A RAVs. In multivariate regression analysis, higher albumin (odds ratio [OR] = 0.020 for presence; P = 0.007), and NS5A-L31/Y93 RAVs with a population frequency <75% (OR = 29.860 for presence; P = 0.023) were identified as significant independent predictors for SVR12. NS5A-Y93H substitutions were detected in all nine treatment failures at HCV relapse, and three out of six patients with NS5A inhibitor-naïve patients achieved additional NS5A RAVs. Serum low-density lipoprotein cholesterol and apolipoprotein B levels were significantly elevated at week 4 in sofosbuvir/ledipasvir-treated patients. These elevations were greater than in ombitasvir/paritaprevir/ritonavir-treated patients. In conclusion, NS5A multi-RAVs are likely to develop in patients who fail to respond to sofosbuvir/ledipasvir therapy. Inhibition of HCV replication with sofosbuvir might affect lipid metabolism.

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

BACKGROUND & AIMS

The phase 2, FOURward study (NCT02175966) investigated short-duration therapy (4/6 weeks) with four direct-acting antivirals (DAAs) with distinct mechanisms of action in patients infected with hepatitis C virus (HCV) genotype-1.

METHODS

Non-cirrhotic patients were randomized 1:1 to DCV-TRIO (fixed-dose daclatasvir 30 mg, asunaprevir 200 mg and beclabuvir 75 mg) twice-daily + sofosbuvir 400 mg once-daily for 4 or 6 weeks. The primary endpoint was sustained virological response at post-treatment Week 12 (SVR12). Patients without SVR12 were offered retreatment based on the DAA resistance profile at failure; patients with resistance to ≤1 DCV-TRIO component received DCV-TRIO + RBV for 12 weeks.

RESULTS

Twenty-eight patients with HCV genotype-1 were enrolled; 79% had genotype-1a infection and median baseline HCV-RNA levels were high (9 × 10⁶  IU/mL). Most patients had undetectable HCV-RNA at end of treatment (96% [n=27/28]); however, relapse occurred in 77% (n=10/13) and 43% (n=6/14) treated for 4 and 6 weeks, leading to SVR12 rates of 29% (n=4/14) and 57% (n=8/14) respectively. SVR12 was higher in patients with lower baseline HCV-RNA (<2 million IU/mL, 71% [n=5/7]; ≥2 million IU/mL, 33% [n=7/21]). None of the 16 non-SVR12 patients had NS3 or NS5B resistance-associated substitutions (RAS) detected at failure. All 15 patients retreated with DCV-TRIO + RBV for 12 weeks achieved SVR12. All regimens were well tolerated.

CONCLUSIONS

Short-duration treatment with four DAAs with distinct mechanisms of action was insufficient for most patients with genotype-1 infection and high baseline viraemia. Non-SVR12 was not associated with emergence of NS3 or NS5B RAS and retreatment with DCV-TRIO + RBV for 12 weeks led to SVR in all patients.

Long-Term Follow-Up of Resistance-Associated Substitutions in Hepatitis C Virus in Patients in Which Direct Acting Antiviral-Based Therapy Failed

We evaluated the transition of dominant resistance-associated substitutions (RASs) in hepatitis C virus during long-term follow-up after the failure of DAAs (direct acting antivirals)-based therapy. RASs in non-structure (NS)3/4A, NS5A, NS5B, and deletions in NS5A from 20 patients who failed simeprevir/pegylated-interferon/ribavirin (SMV/PEG-IFN/RBV) and 25 patients who failed daclatasvir/asunaprevir (DCV/ASV) treatment were examined by direct sequencing. With respect to SMV/PEG-IFN/RBV treatment, RAS was detected at D168 in NS3/4A but not detected in NS5A and NS5B at treatment failure in 16 of 20 patients. During the median follow-up period of 64 weeks, the RAS at D168 became less dominant in 9 of 16 patients. Among 25 DCV/ASV failures, RASs at D168, L31, and Y93 were found in 57.1%, 72.2%, and 76.9%, respectively. NS5A deletions were detected in 3 of 10 patients treated previously with SMV/PEG-IFN/RBV. The number of RASs in the breakthrough patients exceeded that in relapsers (mean 3.9 vs. 2.7, p < 0.05). RAS at D168 in NS3/4A became less dominant in 6 of 15 patients within 80 weeks. Y93H emerged at the time of relapse, then decreased gradually by 99% at 130 weeks post-treatment. Emerged RASs were associated with the clinical course of treatment and could not be detected during longer follow-up.

Interferon-free therapy with sofosbuvir plus ribavirin for successful treatment of genotype 2 hepatitis C virus with lichen planus: a case report

Hepatitis C virus (HCV) infection remains the main cause of liver disease and can lead to chronic hepatitis, cirrhosis, and hepatocellular carcinoma. HCV may also develop extrahepatic manifestations in the skin, eyes, joints, kidneys, nervous system, and immune system. In fact, several studies reported that up to 70% of HCV patients experienced extrahepatic manifestations. Lichen planus (LP), which is an immune system disorder that is triggered by viral infections, allergens, and stress, can affect the skin, mouth, nails, and scalp. The association of LP with HCV has been reported, but the effect of HCV treatment on LP remission is controversial. We encountered a 53-year-old man with HCV genotype 2a and LP that were successfully treated with sofosbuvir and ribavirin for 12 weeks. After treatment, he achieved sustained virological response against HCV and remission of erosive LP lesions on the lip. In the era of interferon (IFN)-based treatment for HCV, exacerbation of autoimmune diseases is a common adverse event. Therefore, use of an IFN-free regimen of direct-acting antivirals for HCV might prevent the extrahepatic manifestation of an immune disorder.

Safety and efficacy of dual therapy with daclatasvir and asunaprevir for older patients with chronic hepatitis C

BACKGROUND

Daclatasvir and asunaprevir combination therapy has shown a high virological response for chronic genotype 1 hepatitis C virus (HCV)-infected patients. However, the safety and efficacy of the therapy for older patients are unknown.

METHODS

One hundred seventy patients younger than 75 years and 139 patients aged 75 years or older with genotype 1 HCV infection were treated for 24 weeks with daclatasvir plus asunaprevir. Pretreatment drug-resistance-associated variants at NS5A-L31 and NS5A-Y93 were determined by the Invader assay. Virological response and adverse events according to age were analyzed.

RESULTS

The sustained virological response (SVR) rate for older patients was similar to that for younger patients (97.1 and 92.4 % respectively). In multivariate regression analysis, prior simeprevir treatment (odds ratio 56.6 for absence; P < 0.001) was identified as a significant independent predictor of SVR. The SVR rate for patients with pretreatment resistance-associated variants (RAVs) at a low population frequency (less than 25 %) was similar to that for patients with no detectable RAVs. The frequency of adverse events was similar between younger and older patients. All 19 very elderly patients (85 years or older) completed the 24 weeks of treatment and achieved SVR.

CONCLUSIONS

Older patients have a virological response and tolerance of daclatasvir plus asunaprevir therapy similar to those of younger patients. Even though RAVs were detected, virological response similar to that for patients with no detectable RAVs may still be expected for patients with RAVs as long as the population frequency is low.