Prevalence of hepatitis C virus subgenotypes 1a and 1b in Japanese patients: ultra-deep sequencing analysis of HCV NS5B genotype-specific region. PLoS One. 2013;8:e73615. [PMID: 24069214 PMCID: PMC3775835 DOI: 10.1371/journal.pone.0073615]

Real-world Safety and Effectiveness of 24-week Sofosbuvir and Ribavirin Treatment in Patients Infected with Rare Chronic Hepatitis C Virus Genotypes 3, 4, 5, or 6 in Japan

Objectives Real-world evidence on the safety and effectiveness of direct-acting antivirals in patients infected with chronic hepatitis C virus (HCV) genotypes (GTs) 3, 4, 5, or 6 in Japan is limited. This prospective observational study assesses the real-world safety profile and treatment effectiveness among patients prescribed sofosbuvir with ribavirin (SOF+RBV) for HCV GT3-6 infection in Japan. Methods Adults receiving 24-week SOF+RBV treatment for HCV GT3-6 infection were prospectively enrolled and observed through 24 weeks post-treatment for treatment-emergent adverse events (AEs) considered related to SOF and/or RBV by treating physicians and for a sustained virologic response at 12 and 24 weeks post-treatment (SVR12, SVR24). Incidence rates of related AEs and serious AEs (SAEs) were calculated. Proportions of patients experiencing related AEs/SAEs and those achieving SVR12 and SVR24 were assessed overall and by baseline characteristics, including treatment experience and cirrhosis status. Results Among the 50 patients included in the safety analysis, 92% had GT3 infection. The incidence rates of related AEs and SAEs were low overall (1.52 and 0.25 per 100 person-weeks, respectively), with 6.0% and 14.0% patients experiencing AEs related to SOF or RBV, respectively. There were no marked differences in the occurrence of related AEs/SAEs by patient baseline characteristics. SVR12 and SVR24 were achieved in 83.7% (41/49) and 82.2% (37/45) of patients, respectively. Lower effectiveness was observed among treatment-experienced patients and patients with cirrhosis at baseline. Conclusions This study demonstrated that SOF+RBV treatment for HCV GT3-6 infection was safe, effective, and an important treatment option for this difficult-to-treat patient population in Japan.

Distribution of naturally -occurring NS5B resistance-associated substitutions in Egyptian patients with chronic Hepatitis C

Background

NS5B polymerase inhibitors represent the cornerstone of the present treatment of Hepatitis C virus infection (HCV). Naturally occurring substitution mutations to NS5B inhibitors have been recorded. The current study intended to demonstrate possible natural direct acting antiviral (DAA)—mutations of the HCV NS5B region in HCV patients in Minia governorate, Egypt.

Methods

Samples were collected from 27 treatment-naïve HCV patients and 8 non-responders. Out of 27 treatment-naïve patients, 17 NS5B sequences (amino acids 221–345) from treatment-naïve patients and one sample of non-responders were successfully amplified. Nucleotide sequences have been aligned, translated into amino acids, and compared to drug resistance mutations reported in the literature.

Results

NS5B amino acid sequence analysis ensures several novel NS5B mutations existence (more than 40 substitution mutations) that have not been previously documented to be correlated with a resistant phenotype. It was found that K304R (82.4%), E327D and P300T (76.5% each) substitutions were the most distributed in the tested samples, respectively. S282T, the major resistance mutation that induces high sofosbuvir-resistance level in addition to other reported mutations (L320F/C) and (C316Y/N) were not recognized. Q309R mutation is a ribavirin-associated resistance, which was recognized in one strain (5.9%) of genotype 1g sequences. Besides, one substitution mutation (E237G) was identified in the successfully amplified non-responder sample.

Conclusion

Our study showed various combinations of mutations in the analyzed NS5B genes which could enhance the possibility of therapy failure in patients administered regimens including multiple DAA.

Phylogenetic and phylodynamic analyses of hepatitis C virus subtype 1a in Okinawa, Japan

Okinawa Island, located in Southern Japan, has a higher prevalence rate of hepatitis C virus subtype 1a (HCV-1a) infection than that in mainland Japan. Okinawa has a history of US military occupation after World War II. To elucidate the transmission history of HCV-1a in Okinawa, 26 whole-genome sequences were obtained from 29 patients during 2011-2016. Phylogenetic trees were reconstructed to identify the origin and characteristics of HCV-1a in Okinawa with epidemiological information. A phylogenetic tree based on whole-genome sequencing revealed that all of the samples were located below the US branches. Additionally, we identified one cluster comprised of 17 strains (Okinawa, n = 16; United States, n = 1). The majority of the patients in this cluster were people who inject drugs (PWID), indicating the presence of a people who inject drugs (PWID) cluster. Subsequently, Bayesian analyses were employed to reveal viral population dynamics. Intriguingly, a phylodynamic analysis uncovered a substantial increase in effective population size of HCV-1a from 1965 to 1980 and a slight increase in mid-2000, which were associated with an increase in illicit drug use in Okinawa. The estimated divergence time of the PWID cluster was 1967.6 (1964.2-1971.1). These findings suggest that HCV-1a was introduced into Okinawa from the United States in the late 1960s, coincident with the Vietnam War. Subsequently, HCV-1a might have spread among the Japanese population with the spread of injecting drug use. Our study provides an understanding of HCV transmission dynamics in Okinawa, as well as the key role of PWID in HCV transmission.

Efficacy and safety of sofosbuvir and ledipasvir in Japanese patients aged 75 years or over with hepatitis C genotype 1

AIM

To evaluate the efficacy and safety of a regimen containing sofosbuvir (SOF) and ledipasvir (LDV) in Japanese patients aged ≥ 75 years with hepatitis C genotype 1.

METHODS

This multicenter, retrospective study consisted of 246 Japanese patients with HCV genotype 1 at nine centers in Miyazaki prefecture in Japan. Demographic, clinical, virological, and adverse effects (AE)-related data obtained during and after SOF/LDV therapy were collected from medical records. These patients were divided into two groups, younger (aged < 75 years) and elderly (aged ≥ 75 years). Virological data and AEs were analyzed by age group.

RESULTS

The sustained virological response (SVR) rates at 12 wk after treatment were 99.2%, 99.4%, and 98.7% in the overall population and in patients aged < 75 and ≥ 75 years, respectively. Common AEs during therapy were headache, pruritus, constipation, and insomnia. These occurred in fewer than 10% of patients, and their incidence was not significantly different between the younger and elderly groups. Two patients discontinued treatment, one due to a skin eruption and the other due to cerebral bleeding.

CONCLUSION

Compared with younger patients, elderly patients had a similar virological response and tolerance to SOF/LDV 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.

Real-World Experiences with the Combination Treatment of Ledipasvir plus Sofosbuvir for 12 Weeks in HCV Genotype 1-Infected Japanese Patients: Achievement of a Sustained Virological Response in Previous Users of Peginterferon plus Ribavirin with HCV NS3/4A Inhibitors

The aim of this study was to characterize the treatment response and serious adverse events of ledipasvir plus sofosbuvir therapies in Japanese patients infected with hepatitis C virus (HCV) genotype 1 (GT1). This retrospective study analyzed 240 Japanese HCV GT1 patients treated for 12 weeks with 90 mg of ledipasvir plus 400 mg of sofosbuvir daily. Sustained virological response at 12 weeks post-treatment (SVR12) was achieved in 236 of 240 (98.3%) patients. Among treatment-naïve patients, SVR12 was achieved in 136 of 138 (98.6%) patients, and among treatment-experienced patients, SVR12 was achieved in 100 of 102 (98.0%) patients. In patients previously treated with peginterferon plus ribavirin with various HCV NS3/4A inhibitors, 100% SVR rates (25/25) were achieved. Two relapsers had HCV NS5A resistance-associated variants (RAVs), but no HCV NS5B-S282 was observed after they relapsed. We experienced two patients with cardiac events during treatment. In conclusion, combination of ledipasvir plus sofosbuvir for 12 weeks is a potential therapy for HCV GT1 patients. Caution is needed for HCV NS5A RAVs, which were selected by HCV NS5A inhibitors and cardiac adverse events.

Discrepancy between Hepatitis C Virus Genotypes and NS4-Based Serotypes: Association with Their Subgenomic Sequences

Determination of hepatitis C virus (HCV) genotypes plays an important role in the direct-acting agent era. Discrepancies between HCV genotyping and serotyping assays are occasionally observed. Eighteen samples with discrepant results between genotyping and serotyping methods were analyzed. HCV serotyping and genotyping were based on the HCV nonstructural 4 (NS4) region and 5'-untranslated region (5'-UTR), respectively. HCV core and NS4 regions were chosen to be sequenced and were compared with the genotyping and serotyping results. Deep sequencing was also performed for the corresponding HCV NS4 regions. Seventeen out of 18 discrepant samples could be sequenced by the Sanger method. Both HCV core and NS4 sequences were concordant with that of genotyping in the 5'-UTR in all 17 samples. In cloning analysis of the HCV NS4 region, there were several amino acid variations, but each sequence was much closer to the peptide with the same genotype. Deep sequencing revealed that minor clones with different subgenotypes existed in two of the 17 samples. Genotyping by genome amplification showed high consistency, while several false reactions were detected by serotyping. The deep sequencing method also provides accurate genotyping results and may be useful for analyzing discrepant cases. HCV genotyping should be correctly determined before antiviral treatment.

Assessing the Budget Impact and Economic Outcomes of the Introduction of Daclatasvir + Asunaprevir and Sofosbuvir/Ledipasvir for the Treatment of Chronic Hepatitis C Virus Infection in Japan

BACKGROUND

The advent of highly efficacious, well-tolerated, all-oral direct-acting antiviral regimens has revolutionized the standard of care for patients chronically infected with hepatitis C virus. As efficacy and safety rates converge, prescribers and payers need to consider value for money.

OBJECTIVES

To evaluate the health economic value of daclatasvir + asunaprevir versus sofosbuvir/ledipasvir via a cost-effectiveness analysis, and determine the optimal treatment considering both costs and health outcomes in Japan.

METHODS

A previously published Markov model was used to estimate the cost-effectiveness of daclatasvir + asunaprevir compared with sofosbuvir/ledipasvir on the basis of a matching-adjusted indirect comparison of pivotal trials and modeling inputs specific to the Japanese setting. A de novo budget impact model was developed and used to predict the cost implications of differing treatment sequences.

RESULTS

Cost-effectiveness results demonstrated minimal difference in terms of benefit (0.037 fewer QALYs and 0.014 fewer life-years with daclatasvir + asunaprevir); nevertheless, a significant difference in cost was predicted (estimated ¥2,299,700 [US $21,695] reduction with daclatasvir + asunaprevir). The budget impact analysis estimated that treatment with daclatasvir + asunaprevir is expected to be less expensive than treatment with sofosbuvir/ledipasvir (as the proportion of patients initially treated with sofosbuvir/ledipasvir increased from 0% to 100%, total costs increased from ¥206 to ¥403 billion [US $1.94 billion to US $3.80 billion]).

CONCLUSIONS

On the basis of results from an established cost-effectiveness model and a conventional budget impact analysis, treatment with daclatasvir + asunaprevir is expected to be cost-saving compared with treatment with sofosbuvir/ledipasvir in Japan with similar health outcomes, regardless of treatment sequence.

Ultra-Deep Sequencing Characterization of HCV Samples with Equivocal Typing Results Determined with a Commercial Assay

Hepatitis C virus (HCV) is classified into seven phylogenetically distinct genotypes, which are further subdivided into related subtypes. Accurate assignment of genotype/subtype is mandatory in the era of directly acting antivirals. Several molecular methods are available for HCV genotyping; however, a relevant number of samples with indeterminate, mixed, or unspecified subtype results, or even with misclassified genotypes, may occur. Using NS5B direct (DS) and ultra-deep pyrosequencing (UDPS), we have tested 43 samples, which resulted in genotype 1 unsubtyped (n = 17), mixed infection (n = 17), or indeterminate (n = 9) with the Abbott RealTime HCV Genotype II assay. Genotype 1 was confirmed in 14/17 samples (82%): eight resulted in subtype 1b, and five resulted in subtype 1a with both DS and UDPS, while one was classified as subtype 1e by DS and mixed infection (1e + 1a) by UDPS. Three of seventeen genotype 1 samples resulted in genotype 3h with both sequencing approaches. Only one mixed infection was confirmed by UDPS (4d + 1a), while in 88% of cases a single component of the mixture was detected (five genotype 1a, four genotype 1b, two genotype 3a, two genotype 4m, and two genotype 4d); 44% of indeterminate samples resulted genotype 2c by both DS and UDPS, 22% resulted genotype 3a; one indeterminate sample by Abbott resulted in genotype 4d, one resulted in genotype 6n, and one was classified as subtype 3a by DS, and resulted mixed infection (3a + 3h) by UDPS. The concordance between DS and UDPS was 94%, 88%, and 89% for genotype 1, co-infection, and indeterminate results, respectively. UDPS should be considered very useful to resolve ambiguous HCV genotyping results.

Daclatasvir plus Asunaprevir Treatment for Real-World HCV Genotype 1-Infected Patients in Japan

Background. All-oral combination of direct-acting antivirals could lead to higher sustained virologic response (SVR) in hepatitis C virus (HCV)-infected patients. In the present study, we examined the efficacy and safety of the dual oral treatment with HCV nonstructural protein (NS) 5A inhibitor daclatasvir (DCV) plus HCV NS3/4A inhibitor asunaprevir (ASV) for 24 weeks in real-world HCV genotype 1-infected Japanese individuals. Methods. After screening for HCV NS5A resistance-associated variants (RAVs) by PCR invader assay, a total of 54 Japanese patients infected with HCV genotype 1 treated with DCV plus ASV were retrospectively analyzed. SVR12 was used for evaluation of the virologic response. Results. Of the total 54 patients, 46 patients (85.2%) were treated with DCV plus ASV for 24 weeks and achieved SVR12. The other 8 patients (14.8%) discontinued this treatment before 24 weeks due to adverse events. Of these 8 patients, 5 and 3 patients did and did not achieve SVR12, respectively. Finally, 51 of 54 (94.4%) patients achieved SVR12. Conclusion. Treatment with DCV and ASV after screening for HCV NS5A RAVs by PCR invader assay is effective and safe in the treatment of real-world HCV genotype 1-infected patients in Japan.

Exposure-Response Relationship for Ombitasvir and Paritaprevir/Ritonavir in Hepatitis C Virus Subgenotype 1b-Infected Japanese Patients in the Phase 3 Randomized GIFT-I Study

INTRODUCTION

The all-oral 2 direct-acting antiviral (DAA) regimen of ombitasvir/paritaprevir/ritonavir 25/150/100 mg once a day has been evaluated in hepatitis C virus subgenotype 1b-infected Japanese adults in the GIFT-I study. The aim of this analysis was to evaluate potential relationships between DAA exposures and laboratory abnormalities/adverse events of peripheral edema in patients in GIFT-I.

METHODS

The GIFT-I study consisted of a randomized, double-blind, placebo-controlled substudy in patients without cirrhosis and an open-label substudy in patients with compensated cirrhosis. Patients received ombitasvir/paritaprevir/ritonavir for 12 weeks. Exposure-response relationships between individual components of the ombitasvir/paritaprevir/ritonavir regimen and clinical parameters of interest were explored using pharmacokinetic and clinical data from patients in the study. Graphical analyses were performed. For events that occurred in at least 10 patients (total bilirubin elevation ≥grade 2 and peripheral edema ≥grade 1), multivariate logistic regression analyses were used to identify significant relationships between predictor variables (drug exposures) and response variables (probability of adverse events or laboratory abnormalities), with consideration for the effect of potential covariates and baseline status of response variables.

RESULTS

Data from 321 noncirrhotic and 42 compensated cirrhotic patients were analyzed. There were 14 events of peripheral edema (10 at grade 1 and 4 at grade 2) in patients who received concomitant administration of calcium channel blockers and ombitasvir/paritaprevir/ritonavir. There was no apparent relationship between the incidences of peripheral edema and exposures of paritaprevir, ombitasvir, or ritonavir. There was a shallow relationship between total bilirubin elevation and exposures of paritaprevir which is an inhibitor of bilirubin transporter organic anion-transporting polypeptide 1B. Based on graphical analyses, exposures of paritaprevir, ombitasvir, or ritonavir were weakly associated with hemoglobin decrease, but not associated with post baseline alanine aminotransferase or aspartate aminotransferase elevations.

CONCLUSIONS

In Japanese patients, there were no associations or only shallow relationships between DAA exposures and peripheral edema or laboratory abnormalities. Consequently, therapeutic drug monitoring is not expected to be beneficial in managing patients on the 2-DAA regimen.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT02023099.

FUNDING

AbbVie Inc.

Hepatitis C virus infection in inclusion body myositis: A case-control study

OBJECTIVE

To clarify whether there is any association between inclusion body myositis (IBM) and hepatitis C virus (HCV) infection.

METHODS

We assessed the prevalence of HCV infection in 114 patients with IBM whose muscle biopsies were analyzed pathologically for diagnostic purpose from 2002 to 2012 and in 44 age-matched patients with polymyositis diagnosed in the same period as a control by administering a questionnaire survey to the physicians in charge. We also compared clinicopathologic features including the duration from onset to development of representative symptoms of IBM and the extent of representative pathologic changes between patients with IBM with and without HCV infection.

RESULTS

A significantly higher number of patients with IBM (28%) had anti-HCV antibodies as compared with patients with polymyositis (4.5%; odds ratio 8.2, 95% confidence interval 1.9-36) and the general Japanese population in their 60s (3.4%). Furthermore, between patients with IBM with and without HCV infection, we did not find any significant difference in the clinicopathologic features, indicating that the 2 groups have essentially the same disease regardless of HCV infection.

CONCLUSION

Our results provide the statistical evidence for an association between IBM and HCV infection, suggesting a possible pathomechanistic link between the 2 conditions.

Genetic Diversity and Selective Pressure in Hepatitis C Virus Genotypes 1-6: Significance for Direct-Acting Antiviral Treatment and Drug Resistance

Treatment with pan-genotypic direct-acting antivirals, targeting different viral proteins, is the best option for clearing hepatitis C virus (HCV) infection in chronically infected patients. However, the diversity of the HCV genome is a major obstacle for the development of antiviral drugs, vaccines, and genotyping assays. In this large-scale analysis, genome-wide diversity and selective pressure was mapped, focusing on positions important for treatment, drug resistance, and resistance testing. A dataset of 1415 full-genome sequences, including genotypes 1-6 from the Los Alamos database, was analyzed. In 44% of all full-genome positions, the consensus amino acid was different for at least one genotype. Focusing on positions sharing the same consensus amino acid in all genotypes revealed that only 15% was defined as pan-genotypic highly conserved (≥99% amino acid identity) and an additional 24% as pan-genotypic conserved (≥95%). Despite its large genetic diversity, across all genotypes, codon positions were rarely identified to be positively selected (0.23%-0.46%) and predominantly found to be under negative selective pressure, suggesting mainly neutral evolution. For NS3, NS5A, and NS5B, respectively, 40% (6/15), 33% (3/9), and 14% (2/14) of the resistance-related positions harbored as consensus the amino acid variant related to resistance, potentially impeding treatment. For example, the NS3 variant 80K, conferring resistance to simeprevir used for treatment of HCV1 infected patients, was present in 39.3% of the HCV1a strains and 0.25% of HCV1b strains. Both NS5A variants 28M and 30S, known to be associated with resistance to the pan-genotypic drug daclatasvir, were found in a significant proportion of HCV4 strains (10.7%). NS5B variant 556G, known to confer resistance to non-nucleoside inhibitor dasabuvir, was observed in 8.4% of the HCV1b strains. Given the large HCV genetic diversity, sequencing efforts for resistance testing purposes may need to be genotype-specific or geographically tailored.

Sustained Virological Response after 8-Week Treatment of Simeprevir with Peginterferon α-2a plus Ribavirin in a Japanese Female with Hepatitis C Virus Genotype 1b and IL28B Minor Genotype

Direct-acting antivirals with or without peginterferon α (PEG-IFN α) plus ribavirin are now available for the treatment of hepatitis C virus (HCV) infection. Direct-acting antivirals are potent inhibitors of HCV replication, but some of them occasionally possess serious adverse events. We experienced a 64-year-old female with chronic HCV genotype 1b infection who showed elevated alanine aminotransferase of 528 IU/l at week 9 after the commencement of treatment of simeprevir with PEG-IFN α-2a plus ribavirin. However, she achieved sustained virological response at week 24 after the end of treatment. In Japan, we also have to treat elderly patients infected with HCV and/or advanced hepatic fibrosis. Until an effective interferon-free regimen is established, direct-acting antivirals with PEG-IFN plus ribavirin may still play a role in the treatment for certain patients. To avoid serious results from adverse events, careful attention and follow-up will be needed in the treatment course of simeprevir with PEG-IFN plus ribavirin for chronic HCV infection.

Features of hepatitis C virus infection, current therapies and ongoing clinical trials in ten Asian Pacific countries

Estimated hepatitis C virus (HCV) infection rates in the general populations were 1.3, 0.9, 0.4-1.0, 14.7, 0.1-0.3, 0.9-1.9, 1.0-2.0, 5, 4.4-8.6 and 0.5-1.3 % in Australia, Bangladesh, Mainland China, Egypt, Hong Kong, India, Japan, Pakistan, Taiwan and Turkey, respectively. The main HCV genotypes (Gs) are G1, G3, G1b, G4, G1b, G3, G1b, G3, G1b and G2, and G1 in Australia, Bangladesh, Mainland China, Egypt, Hong Kong, India, Japan, Pakistan, Taiwan and Turkey, respectively. Of IL28B genotypes, favorable alleles are ~50 % in Australia and Turkey, but 60-70 % in most of the other Asian countries. Peginterferon plus ribavirin is available in all ten Asian Pasific countries. In addition, HCV NS3/4A protease inhibitors with peginterferon plus ribavirin are currently available in several countries. Clinical trials of interferon-free regimens for HCV are ongoing in most of the ten Asian Pacific countries.

Randomized trial of interferon- and ribavirin-free ombitasvir/paritaprevir/ritonavir in treatment-experienced hepatitis C virus-infected patients

Approximately 2 million Japanese individuals are infected with hepatitis C virus and are at risk for cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Patients in whom interferon (IFN)/ribavirin (RBV) therapy has failed remain at risk as effective therapeutic options are limited. This phase 2, randomized, open-label study evaluated an IFN- and RBV-free regimen of once-daily ombitasvir (ABT-267), an NS5A inhibitor, plus paritaprevir (ABT-450), an NS3/4A protease inhibitor dosed with ritonavir (paritaprevir/ritonavir), in pegylated IFN/RBV treatment-experienced Japanese patients with hepatitis C virus subtype 1b or genotype 2 infection. Patients without cirrhosis (aged 18-75 years) with subtype 1b infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 or 24 weeks; patients with genotype 2 infection received ombitasvir 25 mg plus paritaprevir/ritonavir 100/100 mg or 150/100 mg for 12 weeks. Sustained virologic response (SVR) at posttreatment week 24 (SVR24 ) was the primary endpoint. Adverse events were collected throughout the study. One hundred ten patients received ≥1 dose of study medication. In the subtype 1b cohort, SVR24 rates were high (88.9%-100%) regardless of paritaprevir dose or treatment duration. In the genotype 2 cohort, SVR24 rates were 57.9% and 72.2% with 100 mg and 150 mg of paritaprevir, respectively. The SVR24 rate was higher in patients with subtype 2a (90%) than 2b (27%). Concordance between SVR12 and SVR24 was 100%. The most common adverse events overall were nasopharyngitis (29%) and headache (14%).

CONCLUSION

In this difficult-to-treat population of patients in whom prior pegylated IFN/RBV had failed, ombitasvir/paritaprevir/ritonavir demonstrated potent antiviral activity with a favorable safety profile among Japanese patients with hepatitis C virus genotype 1b or 2a infection.

Mixed HCV infection and reinfection in people who inject drugs--impact on therapy

The majority of new and existing cases of HCV infection in high-income countries occur among people who inject drugs (PWID). Ongoing high-risk behaviours can lead to HCV re-exposure, resulting in mixed HCV infection and reinfection. Assays used to screen for mixed infection vary widely in sensitivity, particularly with respect to their capacity for detecting minor variants (<20% of the viral population). The prevalence of mixed infection among PWID ranges from 14% to 39% when sensitive assays are used. Mixed infection compromises HCV treatment outcomes with interferon-based regimens. HCV reinfection can also occur after successful interferon-based treatment among PWID, but the rate of reinfection is low (0-5 cases per 100 person-years). A revolution in HCV therapeutic development has occurred in the past few years, with the advent of interferon-free, but still genotype-specific regiments based on direct acting antiviral agents. However, little is known about whether mixed infection and reinfection has an effect on HCV treatment outcomes in the setting of new direct-acting antiviral agents. This Review characterizes the epidemiology and natural history of mixed infection and reinfection among PWID, methodologies for detection, the potential implications for HCV treatment and considerations for the design of future studies.

HCV NS5A resistance-associated variants in a group of real-world Japanese patients chronically infected with HCV genotype 1b

BACKGROUND

Recent advances in interferon-free treatment could lead to the eradication of hepatitis C virus (HCV) from patients infected with HCV. One of the direct-acting anti-viral agents, HCV NS5A inhibitor, is available for these combination therapies. However, naturally occurring resistance-associated variants (RAVs) to HCV NS5A inhibitors in treatment-naïve patients chronically infected with HCV genotype 1b are still unknown.

METHODS

We performed ultra-deep sequencing and analysed previously reported RAVs in a total 132 HCV genotype 1b-infected Japanese patients who had never used HCV NS5A inhibitors. We also performed direct-sequencing by Sanger method in consecutively selected 50 of the total 132 samples, and the differences between the results of the two methods were compared.

RESULTS

In the comparison of the variant frequencies of ultra-deep sequencing with RAVs of direct-sequencing by Sanger method in 50 patients, we identified 32 RAVs by direct-sequencing with the Sanger method; minimum variant frequency was shown by ultra-deep sequencing to be 9%. A total of 110 RAVs were identified only by ultra-deep sequencing. In the samples from all 132 patients, L31W (2.3%), L31V (49.2%), L31F (41.7%), L31M (1.5%), L31I (5.3%), L31S (2.0%), L31P (3.0%) and L31R (0.8%), and Y93N (2.3%), Y93H (25%), Y93C (0.8%), Y93P (2.3%) and Y93D (0.8%) were identified.

CONCLUSIONS

We demonstrated naturally-occurring RAVs of HCV NS5A inhibitors by ultra-deep sequencing and that several mutations including Y93H are common in HCV NS5A inhibitor-treatment-naïve patients with chronic HCV genotype 1b. Careful attention should be paid to these RAVs, and further improvement of treatment options might be needed.

Advanced molecular surveillance of hepatitis C virus

Hepatitis C virus (HCV) infection is an important public health problem worldwide. HCV exploits complex molecular mechanisms, which result in a high degree of intrahost genetic heterogeneity. This high degree of variability represents a challenge for the accurate establishment of genetic relatedness between cases and complicates the identification of sources of infection. Tracking HCV infections is crucial for the elucidation of routes of transmission in a variety of settings. Therefore, implementation of HCV advanced molecular surveillance (AMS) is essential for disease control. Accounting for virulence is also important for HCV AMS and both viral and host factors contribute to the disease outcome. Therefore, HCV AMS requires the incorporation of host factors as an integral component of the algorithms used to monitor disease occurrence. Importantly, implementation of comprehensive global databases and data mining are also needed for the proper study of the mechanisms responsible for HCV transmission. Here, we review molecular aspects associated with HCV transmission, as well as the most recent technological advances used for virus and host characterization. Additionally, the cornerstone discoveries that have defined the pathway for viral characterization are presented and the importance of implementing advanced HCV molecular surveillance is highlighted.

Next generation sequencing of the hepatitis C virus NS5B gene reveals potential novel S282 drug resistance mutations

Identifying HCV drug resistance mutations (DRMs) is increasingly important as new direct acting antiviral therapies (DAA) become available. Tagged pooled pyrosequencing (TPP) was originally developed as cost-effective approach for detecting low abundance HIV DRMs. Using 127 HCV-positive samples from a Canadian injection drug user cohort, we demonstrated the suitability and efficiency of TPP for evaluating DRMs in HCV NS5B gene. At a mutation identification threshold of 1%, no nucleoside inhibitor DRMs were detected among these DAA naïve subjects. Clinical NS5B resistance to non-nucleoside inhibitors and interferon/ribavirin was predicted to be low within this cohort. S282T mutation, the primary mutation selected by sofosbuvir in vitro, was not identified while S282G/C/R variants were detected in 9 subjects. Further characterization on these new S282 variants using in silico molecular modeling implied their potential association with resistance. Combining TPP with in silico analysis detects NS5B polymorphisms that may explain differences in treatment outcomes.

New treatments for genotype 1 chronic hepatitis C - focus on simeprevir

Chronic hepatitis C virus (HCV) infection causes end-stage liver diseases and hepato cellular carcinoma. In the USA, Canada, and Japan, simeprevir – one of the second-generation HCV NS3/4A protease inhibitors – in combination with peginterferon α-2a or 2b plus ribavirin has recently been approved for HCV genotype 1-infected patients and is now used in daily clinical practice. This review summarizes the mechanism of action of simeprevir and the results of clinical trials of simeprevir and peginterferon plus ribavirin for HCV genotype 1 patients. In general, the simeprevir and peginterferon plus ribavirin treatment is highly effective and its adverse events are similar to those of peginterferon plus ribavirin only, the exception being milder, reversible jaundice. In the near future, the development of interferon-free regimens with simeprevir is expected. Careful attention should be paid to new results of clinical trials with simeprevir.

Ultra-deep sequencing analysis of the hepatitis A virus 5'-untranslated region among cases of the same outbreak from a single source

Hepatitis A virus (HAV) is a causative agent of acute viral hepatitis for which an effective vaccine has been developed. Here we describe ultra-deep pyrosequences (UDPSs) of HAV 5'-untranslated region (5'UTR) among cases of the same outbreak, which arose from a single source, associated with a revolving sushi bar. We determined the reference sequence from HAV-derived clone from an attendant by the Sanger method. Sixteen UDPSs from this outbreak and one from another sporadic case were compared with this reference. Nucleotide errors yielded a UDPS error rate of < 1%. This study confirmed that nucleotide substitutions of this region are transition mutations in outbreak cases, that insertion was observed only in non-severe cases, and that these nucleotide substitutions were different from those of the sporadic case. Analysis of UDPSs detected low-prevalence HAV variations in 5'UTR, but no specific mutations associated with severity in these outbreak cases. To our surprise, HAV strains in this outbreak conserved HAV IRES sequence even if we performed analysis of UDPSs. UDPS analysis of HAV 5'UTR gave us no association between the disease severity of hepatitis A and HAV 5'UTR substitutions. It might be more interesting to perform ultra-deep sequencing of full length HAV genome in order to reveal possible unknown genomic determinants associated with disease severity. Further studies will be needed.

Hepatitis C virus protease inhibitor-resistance mutations: Our experience and review

Direct-acting antiviral agents (DAAs) for hepatitis C virus (HCV) infection are one of the major advances in its medical treatment. The HCV protease inhibitors boceprevir and telaprevir were the first approved DAAs in the United States, Europe, and Japan. When combined with peginterferon plus ribavirin, these agents increase sustained virologic response rates to 70%-80% in treatment-naïve patients and previous-treatment relapsers with chronic HCV genotype 1 infection. Without peginterferon plus ribavirin, DAA mono-therapies increased DAA-resistance mutations. Several new DAAs for HCV are now in clinical development and are likely to be approved in the near future. However, it has been reported that the use of these drugs also led to the emergence of DAA-resistance mutations in certain cases. Furthermore, these mutations exhibit cross-resistance to multiple drugs. The prevalence of DAA-resistance mutations in HCV-infected patients who were not treated with DAAs is unknown, and it is as yet uncertain whether such variants are sensitive to DAAs. We performed a population sequence analysis to assess the frequency of such variants in the sera of HCV genotype 1-infected patients not treated with HCV protease inhibitors. Here, we reviewed the literature on resistance variants of HCV protease inhibitors in treatment naïve patients with chronic HCV genotype 1, as well as our experience.

No correlation between PNPLA3 rs738409 genotype and fatty liver and hepatic cirrhosis in Japanese patients with HCV

Background

Hepatitis C virus (HCV) infection is associated with the development of cirrhosis and hepatocellular carcinoma and is also related to fatty change of the liver. Variation in patatin-like phospholipase domain-containing 3 (PNPLA3) gene is associated with disease progression in nonalcoholic fatty liver disease (NAFLD). Recent reports have suggested that PNPLA3, IL28B and TLR4-associated single nucleotide polymorphisms (SNPs) may have an impact on hepatic steatosis or fibrosis in patients with chronic HCV infection.

Methods and Findings

Four SNPs (PNPLA3 rs738409, TLR4 rs4986790, TLR4 rs4986791, IL28B rs8099917) were identified in Japanese patients infected with HCV. We examined the association between the distribution of these SNP alleles and fatty change of the liver or existence of hepatic cirrhosis diagnosed by ultrasonography, one of the widely accessible and easy-to-use methods. PNPLA3 rs738409 G-allele and IL28B rs 8099917 minor allele were found in 70.0% and 31.1%, respectively. These two TLR4 SNPs were uniform in Japanese. Fatty change of the liver developed independent of the abscence of hepatic cirrhosis on sonographic findings and younger age. Hepatic cirrhosis was associated with a higher aspartate aminotransferase/platelet ratio index (APRI), no fatty change of the liver, higher BMI and higher AFP levels. No association between PNPLA3 rs738409/IL28B rs8099917 genotypes and hepatic steatosis or liver fibrosis was observed.

Conclusions

According to ultrasound examinations, no association between PNPLA3 rs738409 genotype and fatty change of the liver or hepatic cirrhosis was found in Japanese patients infected with HCV. Together, our results suggested that the mechanism of hepatic steatosis underlying HCV infection might differ from that of NAFLD and should be explored.

No correlation between PNPLA3 rs738409 genotype and fatty liver and hepatic cirrhosis in Japanese patients with HCV

BACKGROUND

Hepatitis C virus (HCV) infection is associated with the development of cirrhosis and hepatocellular carcinoma and is also related to fatty change of the liver. Variation in patatin-like phospholipase domain-containing 3 (PNPLA3) gene is associated with disease progression in nonalcoholic fatty liver disease (NAFLD). Recent reports have suggested that PNPLA3, IL28B and TLR4-associated single nucleotide polymorphisms (SNPs) may have an impact on hepatic steatosis or fibrosis in patients with chronic HCV infection.

METHODS AND FINDINGS

Four SNPs (PNPLA3 rs738409, TLR4 rs4986790, TLR4 rs4986791, IL28B rs8099917) were identified in Japanese patients infected with HCV. We examined the association between the distribution of these SNP alleles and fatty change of the liver or existence of hepatic cirrhosis diagnosed by ultrasonography, one of the widely accessible and easy-to-use methods. PNPLA3 rs738409 G-allele and IL28B rs 8099917 minor allele were found in 70.0% and 31.1%, respectively. These two TLR4 SNPs were uniform in Japanese. Fatty change of the liver developed independent of the abscence of hepatic cirrhosis on sonographic findings and younger age. Hepatic cirrhosis was associated with a higher aspartate aminotransferase/platelet ratio index (APRI), no fatty change of the liver, higher BMI and higher AFP levels. No association between PNPLA3 rs738409/IL28B rs8099917 genotypes and hepatic steatosis or liver fibrosis was observed.

CONCLUSIONS

According to ultrasound examinations, no association between PNPLA3 rs738409 genotype and fatty change of the liver or hepatic cirrhosis was found in Japanese patients infected with HCV. Together, our results suggested that the mechanism of hepatic steatosis underlying HCV infection might differ from that of NAFLD and should be explored.