Treatment of hepatitis C virus genotype 4 in the DAA era

Progress, evolving therapeutic/diagnostic approaches, and challenges in the management of hepatitis C virus infections

Hepatitis C virus (HCV) infections are emerging as one of the foremost challenges in healthcare owing to its chronicity and the virus's quasispecies nature. Worldwide, over 170 million people are chronically infected with HCV, with an annual mortality of over 500,000 people across the world. The emerging pathophysiological evidence links HCV infections to a risk of developing liver diseases such as cirrhosis and hepatocellular carcinoma. Despite the great strides that have been made towards understanding the pathophysiology of disease progression, the tailored treatments of HCV infection remain to be established. The present review provides an update of the literature pertaining to evolving therapeutic approaches and prophylactic measures for the effective management of HCV infections. An extensive discussion of established and experimental immune prophylactic measures also sheds light on current developments in the design of vaccination strategies against HCV infection. We have also attempted to address the application of nanotechnology in formulating effective therapeutic interventions against HCV. Pointing out the limitations of the existing diagnostic methods and therapeutic approaches against HCV might inspire the design and development of novel, efficient, reliable, and cost-effective diagnostic technologies as well as novel therapeutic and immune prophylactic interventions for the effective management of HCV.

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

OBJECTIVE

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

DESIGN

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

RESULT

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

CONCLUSION

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

Pangenotypic and Genotype-Specific Antivirals in the Treatment of HCV Genotype 4 Infected Patients with HCV Monoinfection and HIV/HCV Coinfection

The introduction of the direct-acting antivirals (DAA) has substantially improved the effectiveness of the therapy in patients with chronic hepatitis C. We aimed to compare the efficacy of pangenotypic and genotype-specific DAA in the cohort of genotype (GT) four patients with HCV monoinfection and HIV coinfection. A total of 662 GT4-infected patients treated in 2015–2020—of whom 168 (25.3%) were coinfected with HIV, selected from the retrospective EpiTer-2 database—were enrolled in the analysis. Among HIV-coinfected patients, 54% (90) were treated with genotype-specific regimens and 46% (78) with pangenotypic options, while among HCV-monoinfected patients, the rates were 72% and 28%, respectively. Significantly higher rate of males (67.9% vs. 57.7%, p = 0.01), a lower rate of liver cirrhosis (10.2% vs. 18.1%, p = 0.02), and higher of treatment-naïve patients (87.5% vs. 76.7%, p = 0.003) were documented in the HIV coinfected population. The overall sustained virologic response after exclusion of non-virologic failures was achieved in 98% with no significant difference between HIV-positive and HIV-negative patients, 96.2% vs. 98.5%, respectively. While the genotype-specific regimens resulted in a similar cure rate regardless of the HIV status, the pangenotypic options were more efficacious in patients with HCV monoinfection (99.3% vs. 94.4%, p = 0.05). Hereby, we demonstrated the high effectiveness and good safety profile of the DAA therapy in the population of HCV GT4 infected patients with HIV coinfection supporting the current recommendations to treat HCV/HIV coinfected patients with the same options as those with HCV monoinfection.

Genetic Subtypes and Natural Resistance Mutations in HCV Genotype 4 Infected Saudi Arabian Patients

This study aimed to characterize the HCV genetic subtypes variability and the presence of natural occurring resistance-associated substitutions (RASs) in Saudi Arabia patients. A total of 17 GT patients were analyzed. Sequence analysis of NS3, NS5A, and NS5B regions was performed by direct sequencing, and phylogenetic analyses were used to determine genetic subtypes, RAS, and polymorphisms. Nine patients were infected by GT 4a, two with GT 4o and three with GT 4d. Two patients were infected with apparent recombinant virus (4a/4o/4a in NS3/NS5A/NS5B), and one patient was infected with a previously unknown, unclassifiable, virus of GT 4. Natural RASs were found in six patients (35%), including three infected by GT 4a, two by GT 4a/GT 4o/GT 4a, and one patient infected by an unknown, unclassifiable, virus of GT 4. In particular, NS3-RAS V170I was demonstrated in three patients, while NS5A-RASs (L28M, L30R, L28M + M31L) were detected in the remaining three patients. All patients were treated with sofosbuvir plus daclatasvir; three patients were lost to follow-up, whereas 14 patients completed the treatment. A sustained virological response (SVR) was obtained in all but one patient carrying NS3-RAS V170I who later relapsed. GT 4a is the most common subtype in this small cohort of Saudi Arabia patients infected with hepatitis C infection. Natural RASs were observed in about one-third of patients, but only one of them showed a treatment failure.

Hepatitis C virus genotype 4: A poorly characterized endemic genotype

Globally, 13% of all hepatitis C virus (HCV) infections are caused by genotype 4 (GT4), which consists of 17 subtypes with various levels of susceptibility to anti-HCV therapy. This genotype is endemic in the Middle East and Africa and has considerably spread to Europe lately. The molecular features of HCV-GT4 infection, as well as its appropriate therapeutics, are poorly characterized as it has not been the subject of widespread basic research. As such, in this review, we aim to gather the current state of knowledge of this genotype with a particular emphasis on its heterogeneity, sequence signatures, resistance-associated substitutions, and available in vivo and in vitro models used for its study. We urge developing more cell-culture models based on different GT4 subtypes to better understand the virology and therapeutic response of this particular genotype. This review may raise more awareness about this genotype and trigger more basic research work to develop its research tools. This will be critical to design better therapeutics and help to provide adequate guidelines for physicians working with HCV-GT4 patients.

Treatment with Grazoprevir/Elbasvir in Post-kidney Transplant Patients with Hepatitis C Virus Genotype 4 Infection

Background: Kidney transplant (KT) recipients have a high rate of hepatitis C virus (HCV) infection, which can impact long-term graft and patient survival rates. Although direct-acting antivirals (DAAs) are effective for treating HCV, there is limited data on their use in post-KT patients with HCV genotype 4 infection. Objectives: To evaluate the effectiveness and occurrence of adverse events with grazoprevir/elbasvir combination treatment without ribavirin in post-KT patients with HCV genotype 4 infection. Methods: In this case series, nine therapy-naïve adult post-KT patients with HCV genotype 4 infection were recruited. They had stable graft function and received a fixed dose of grazoprevir/elbasvir (50 mg/100 mg) combination without ribavirin daily for 12 weeks. Patients co-infected with hepatitis B virus, HIV, or with evidence of decompensated liver disease were excluded from the study. Patients were monitored for viral load, laboratory values, and adverse events associated with drug treatment. The response was defined by the sustained virologic response at 12 weeks (SVR12) after the end of treatment. Results: All nine patients completed the treatment period and achieved SVR12 with no treatment failure or relapse. Of them, six patients had HCV genotype 4 infection alone, and three had HCV of mixed genotypes 1 and 4. Two (22%) patients showed a rapid HCV clearance at four weeks. No adverse events or serious adverse events were reported. The patients’ renal function was stable during and after the treatment with no deterioration of graft function, and no adjustments to the immunosuppressive therapy were required. Conclusions: Grazoprevir/elbasvir combination without ribavirin is an effective and safe treatment option for post-KT patients with genotype 4 HCV infection.

Management and Treatment of Hepatitis C: Are There Still Unsolved Problems and Unique Populations?

Direct-acting antivirals (DAA) have revolutionized the treatment of patients with chronic hepatitis C virus (HCV) infection, possibly leading to HCV elimination by 2030 as endorsed by the World Health Organization (WHO). However, some patients belonging to the so-called unique or special populations are referred to as difficult-to-treat due to unreached sustained virological response, potential drug side effects or interactions or co-morbidities. Several years after the DAA introduction and on the basis of excellent findings in terms of efficacy and safety, some doubts arise around the exact meaning of the special population designation and whether this group of patients actually exists. The aim of this review is to discuss and analyze current evidence on the management and treatment of the so-called "unique populations". We placed particular emphasis on patients with decompensated cirrhosis, chronic kidney disease (CKD), coinfections, rare genotypes, and previous treatment failure, in order to provide physicians with an updated overview of the actual problems and needs in the current scenario.

HCV Infection and Chronic Renal Disease

Chronic Hepatitis C virus (HCV) infection is defined as persistence of HCV RNA in the blood for more than six months. HCV is a major cause of chronic liver disease and cirrhosis. It’s serious public health problem, affects about 71 million people worldwide. HCV doesn’t destroy hepatocytes directly. It activates the host's innate and acquired immune system and causes liver injury indirectly. Behind hepatic, HCV can cause extra-hepatic manifestations. One of them is renal disease which can lead to end-stage renal disease, ESRD. The prevalence of HCV infection in patients on hemodialysis is high, ranging from 5% to 60%. HCV infection is a significant cause of morbidity and mortality in patients with ESRD on hemodialysis. In this review, we discuss HCV infection and chronic renal disease as comorbidities, their severity and outcome.

HCV Diagnosis and Sequencing Using Dried Blood Spots from Patients in Kinshasa (DRC): A Tool to Achieve WHO 2030 Targets

The World Health Organization has established an elimination plan for hepatitis C virus (HCV) by 2030. In Sub-Saharan Africa (SSA) access to diagnostic tools is limited, and a number of genotype 4 subtypes have been shown to be resistant to some direct-acting antivirals (DAAs). This study aims to analyze diagnostic assays for HCV based on dried blood spots (DBS) specimens collected in Kinshasa and to characterize genetic diversity of the virus within a group of mainly HIV positive patients. HCV antibody detection was performed on 107 DBS samples with Vidas® anti-HCV and Elecsys anti-HCV II, and on 31 samples with INNO-LIA HCV. Twenty-six samples were subjected to molecular detection. NS3, NS5A, and NS5B regions from 11 HCV viremic patients were sequenced. HCV seroprevalence was 12.2% (72% with detectable HCV RNA). Both Elecsys Anti-HCV and INNO-LIA HCV were highly sensitive and specific, whereas Vidas® anti-HCV lacked full sensitivity and specificity when DBS sample was used. NS5B/NS5A/NS3 sequencing revealed exclusively GT4 isolates (50% subtype 4r, 30% 4c and 20% 4k). All 4r strains harbored NS5A resistance-associated substitutions (RAS) at positions 28, 30, and 31, but no NS3 RAS was detected. Elecsys Anti-HCV and INNO-LIA HCV are reliable methods to detect HCV antibodies using DBS. HCV subtype 4r was the most prevalent among our patients. RASs found in subtype 4r in NS5A region confer unknown susceptibility to DAA.

Hepatitis C: How Good Are Real-Life Data and Do Generics Work

Chronic hepatitis C virus infection remains a national and global public health burden and is associated with significant morbidity and mortality. Oral direct-acting antiviral combination regimens have excellent tolerability and efficacy with rates exceeding 90%. Sustained virologic response is associated with significant improvements in clinical outcomes. However, translation of sustained virologic response rates from trials to community settings has been poor with interferon-based regimens. We review and summarize key datasets from major real-world observational cohort studies. We review preliminary data from oral generic direct-acting antiviral formulations. Future real-world studies are needed to further clarify optimal treatment strategies for difficult-to-treat populations.

Establishment of infectious genotype 4 cell culture-derived hepatitis C virus

To establish infectious genotype 4a (GT4a) cell culture-derived hepatitis C virus (HCVcc), we constructed full-length ED43 and 12 mutants possessing single or double mutations that increase ED43 replicon replication, and performed cell culture after RNA transfection. Sequential long-term culture of full-length ED43 RNA-transfected cells showed increased viral production in two ED43 mutants named ED43 QK/SI and TR/SI among the tested clones. These ED43 mutants possessed a common mutation, R1405G, in the NS3 helicase region and another mutation, D2413G or V2414A, in the NS5a-NS5b cleavage site. Furthermore, serial reinfection of naïve Huh7.5.1 cells accelerated peak HCV production at an earlier time point after every infection. After the fourth infection, we found a common mutation, R1405G, and six additional mutations in both ED43 QK/SI and TR/SI mutants. All seven mutations supported continuous viral production for more than 40 days in both ED43 QS-7M (QK/SI with seven mutations) and ED43 TS-7M (TR/SI with seven mutations). In addition, ED43 TS-7M did not require additional mutations for continuous virus culture up to 124 days. Both ED43 QS-7M and TS-7M were sensitive to the neutralizing E2 antibodies HCV1 and AR3A and the direct-acting antivirals, simeprevir, ledipasvir and sofosbuvir. In conclusion, we established an infectious ED43 strain containing adaptive mutations, which is important for the analysis of HCV genotype-specific pathogenesis, development of pan-genotypic agents and analysis of drug resistance.

High rate of acute kidney injury in patients with chronic kidney disease and hepatitis C virus genotype 4 treated with direct-acting antiviral agents

BACKGROUND

Direct-acting antivirals (DAAs) have significantly improved the efficacy and safety of treating chronic hepatitis C (CHC), but their effectiveness and safety among patients with chronic kidney disease (CKD) remains poorly understood. Sofosbuvir/daclatasvir regimen is supposed to be used for patients with creatinine clearance more than 30 mL/min, while ombitasvir/paritaprevir/ritonavir regimen is used for patients with creatinine clearance less than 30 mL/min.

AIM

The aim of the study was to assess the safety and efficacy of DAAs among patients with CKD.

METHODS

Eighteen CKD stage 2-3b patients received sofosbuvir for 3 months. In addition, 42 CKD stage-4 patients received ritonavir-boosted paritaprevir plus ombitasvir for 3 months. Finally, ribavirin was added for 30 of them.

RESULTS

The patients'age was 49.2 ± 12 years. Baseline serum creatinine was 3.76 ± 1.67 mg/dL. Fifty patients were HCV genotype 4. A 3-month sustained viral response was achieved in 56 patients and 49 patients achieved a 6-month viral response. There were 11 relapsers. Acute kidney injury (AKI) upon CKD (AKI/CKD) occurred in 28 patients, of which 20 needed hemodialysis. Fifteen/28 recovered from AKI, whereas 13 were maintained on hemodialysis. In multivariate analysis, there were only two independent risk factors for developing AKI/CKD, i.e., being cirrhotic as defined by baseline abdominal ultrasound findings [odds ratio 4.15 (1.33-12.97); p = 0.013] and having had as DAA therapy OMV/PTV/RTV [odds ratio 7.35 (1.84-29.35); p = 0.001].

CONCLUSION

Treatment of HCV among stage 2, 3a, and 3b patients was achieved safely with a sofosbuvir-based regimen. We recommend that stage-4 patients wait until starting hemodialysis or transplantation.

STAT3 signaling pathway plays importantly genetic and functional roles in HCV infection

Background

Hepatitis C virus (HCV) infection is an extensive health problem, which leads to serious liver diseases. Host genetic polymorphisms were associated with HCV infection, progression, and treatment effect of patients. Signal transducers and activators of transcription 3 (STAT3) signaling pathway was important to HCV infection, but no genetic association was studied between STAT3 signaling pathway and HCV infection.

Methods

To investigate the genetic and functional roles of the STAT3 signaling pathway, we collected 394 HCV patients and 395 normal controls to genotype 25 signal nucleotide polymorphisms (SNPs) of six genes (Interleukin 6 [IL6, OMIM 147620], Interleukin 6 receptor [IL6R, OMIM 147880], Hepatocyte nuclear factor 1 alpha [HNF1A, OMIM 142410], Hepatocyte nuclear factor 4 alpha [HNF4A, OMIM 600281], STAT3 [OMIM 102582], and ATP binding cassette subfamily C member 2 [ABCC2, OMIM 601107]). Then expression level of these genes were analyzed in HCV infected cells with or without IL6 transfection.

Results

Our results identified that the SNPs in STAT3 signaling pathway were associated with HCV infection or biochemical features of Yunnan HCV patients. Genotype AA of rs4075015 (IL6R) and GG of rs3212172 (HNF4A) increased the risk of HCV infection (p = 0.024 and 0.029), but the genotype AA of rs7553796 (IL6R) played a protective role in HCV infection (p = 0.0008). High‐density lipoprotein cholesterol (HDL‐C) and Glutamyl transpeptidase (GGT) level were associated with genotypes of rs4845617 (IL6R, p = 0.045) and rs1053023 (STAT3, p = 0.034), respectively. Cell assays suggested that IL6 transfection could suppress HCV proliferation. RNA and protein levels of the IL6R, HNF1A, STAT3, and ABCC2 genes significantly increased after HCV infection.

Conclusion

We identified STAT3 signaling pathway influenced HCV infection and biochemical characteristics of HCV patients through genetic and functional aspects.

The role of plasma exchange in the management of autoimmune disorders

Therapeutic plasma exchange (TPE) has been mainly used in the treatment of autoimmune diseases. The main mechanisms of action of TPE include the removal of circulating autoantibodies, immune complexes, complement components, cytokines and adhesion molecules, along with sensitization of antibody-producing cells to immunosuppressant agents. TPE is useful in autoimmune haematological, renal, rheumatic and neurological diseases, and is recommended for acute disorders, together with relapsed or worsened chronic diseases that are often unresponsive to conventional treatments. The American Society for Apheresis and the British Society of Haematology have published guidelines on the clinical use of apheresis procedures, indicating the different levels of efficacy of TPE. Based on the evidence from current literature and our personal experience, this review discusses the indications and the suggested regimens for TPE in autoimmune haematological and non-haematological disorders.