New horizons in hepatitis C antiviral therapy with direct-acting antivirals

Adaptation of single molecule real time (SMRT) sequence technology for hepatitis C virus genome sequencing and identification of resistance-associated substitutions

BACKGROUND AND OBJECTIVE

Hepatitis C virus (HCV) resistance-associated substitutions (RASs) impact HCV treatment with direct-acting antivirals (DAAs). Therefore, a sensitive sequencing assay for detecting HCV RASs is crucial. PacBio sequencing, a Single molecule real time (SMRT) platform, is capable of long-fragment sequencing. This study aims to assess the prospects of PacBio sequencing by comparing its accuracy with Sanger sequencing at distinct thresholds and its cost-effectiveness with next-generation sequencing (NGS).

METHODS

A total of 28 specimens were selected from the HCV RNA-positive individuals in Linzhou, China. Of these specimens, the NS3 to NS5B regions were amplified and sent for PacBio sequencing. Sequence processing was accomplished by lima, pbmm2 and quasitools software, with threshold setting at 1%, 5%, 10% and 15%.

RESULTS

High-frequency RASs (S122G in NS3, R30Q in NS5A, and C316N in NS5B), rare RASs (V55A, R155P, and S174AT in NS3; Y448H in NS5B), and low-threshold RASs (L31Q and L31QFHY in NS5A; L159F in NS5B) were identified. It was found that the results of HCV RASs at the 10% threshold of PacBio sequencing are comparable to those of Sanger sequencing. In terms of high-throughput sequencing, the price of PacBio sequencing (571 CNY per specimen) is significantly lower than that of NGS (1000 CNY per specimen).

CONCLUSIONS

In summary, these findings suggest that the adoption of the 10% threshold in PacBio sequencing for the analysis of HCV RASs is advisable. Moreover, given its relatively lower cost, PacBio sequencing holds great promise as a valuable tool for large-scale population sequencing.

Hepatocellular Carcinoma Developing in a Patient 29 Years After Achieving Sustained Virologic Response for Hepatitis C With Interferon Therapy: A Case Report

We report a case of an 87-year-old female with a ruptured hepatocellular carcinoma (HCC). She presented with sudden epigastric and right upper abdominal pain. The physical examination revealed mild tenderness in the right upper abdomen, a positive Murphy's sign, and no jaundice. Laboratory tests showed mild anemia and elevated PIVKA-II (prothrombin induced by vitamin K absence II) levels. Abdominal ultrasound and CT revealed a large hypervascular mass in the liver, along with ascites and portal vein thrombosis. The patient had received interferon therapy for hepatitis C virus (HCV) 29 years before her presentation and blood tests and imaging examinations had confirmed sustained undetectability for HCV ribonucleic acid (RNA) and the absence of HCC for five years following treatment. HCV RNA remained undetectable at the time of her admission, and it was presumed that it had been negative for 29 years post-treatment, with no evidence of re-exposure. The patient had not attended any follow-up appointments. While there have been no reported cases of a patient developing HCC 29 years after achieving sustained virologic response (SVR), our case suggests that the absence of HCC risk is not guaranteed, even after a prolonged period post-SVR. Therefore, periodic imaging tests such as abdominal ultrasound or CT may be beneficial in detecting potential HCC, even long after achieving SVR.

Update on Hepatitis C Vaccine: Results and Challenges

Therapy against the Hepatitis C virus (HCV) has significantly improved with the introduction of direct-acting antiviral drugs (DAAs), achieving over 95% sustained virological response (SVR). Despite this, the development of an effective anti-HCV vaccine remains a critical challenge due to the low number of patients treated with DAAs and the occurrence of HCV reinfections in high-risk groups. Current vaccine strategies aim to stimulate either B-cell or T-cell responses. Vaccines based on E1 and E2 proteins can elicit broad cross-neutralizing antibodies against all major HCV genotypes, though with varying efficiencies and without full protection against infection. In humans, the neutralizing antibodies induced by such vaccines mainly target the AR3 region, but their levels are generally insufficient for broad neutralization. Various HCV proteins expressed through different viral vectors have been utilized to elicit T cell immune responses, showing sustained expansion of HCV-specific effector memory T cells and improved proliferation and polyfunctionality of memory T cells over time. However, despite these advancements, the frequency and effectiveness of T-cell responses remain limited.

Distribution of hepatitis С virus drug resistance mutations among patients with recurrence of the disease during therapy with direct antiviral drugs

The aim of the study was to identify the prevalence of drug resistance mutations in the hepatitis C virus among patients with relapse of the disease on therapy with direct antiviral drugs.

Materials and methods. The study material included 31 blood plasma samples from patients with chronic hepatitis C with relapse of the disease on therapy with direct antiviral drugs. Samples were screened for the presence of HCV RNA. In case of detection of HCV RNA, amplification was carried out using a set of primers jointly flanking the NS3, NS5A, NS5B genes. After sequencing the nucleotide sequences of these genes, the subtype of the virus was determined and drug resistance mutations were identified.

Results and discussion. The age of the patients ranged from 33 to 62 and averaged 45.8±8.38 years. The number of men in the group prevailed compared to women — 21 (67%) and 10 (33%), respectively. Viral load determination results ranged from 3.1×103 to 4.2×107 IU/ml. The distribution of genotypes was as follows: 1a — 26% (n=8), 1b — 29% (n=9), 3a — 45% (n=14). The nucleotide sequence of the NS3, NS5A, NS5B regions was determined in all samples. Mutations associated with drug resistance were detected in 87% (n=27). In all identified cases, the mutations resulted in viral resistance to at least one drug included in the patient’s current treatment regimen. In one patient, amino acid substitutions were found in three regions at once, which led to the emergence of resistance to two drugs in the regimen.

Conclusion. Conducting a preliminary examination of patients to identify mutations of drug resistance to direct antiviral drugs can affect the effectiveness of the planned treatment and the choice of the optimal regimen.

Barriers and Facilitators to Hepatitis C Virus (HCV) Treatment for Aboriginal and Torres Strait Islander Peoples in Rural South Australia: A Service Providers' Perspective

This study explored the barriers and facilitators to hepatitis C virus (HCV) treatment for Aboriginal and Torres Strait Islander peoples in rural South Australia as viewed from a healthcare provider perspective in the era of direct acting antivirals (DAAs). Phase 1 was a qualitative systematic review examining the barriers and enablers to diagnosis and treatment amongst Indigenous peoples living with HCV worldwide. Phase 2 was a qualitative descriptive study with healthcare workers from six de-identified rural and regional Aboriginal Community-Controlled Health Services in South Australia. The results from both methods were integrated at the analysis phase to understand how HCV treatment could be improved for rural Aboriginal and Torres Strait Islander peoples. Five main themes emerged: the importance of HCV education, recognizing competing social and cultural demands, the impact of holistic care delivery and client experience, the effect of internal barriers, and overlapping stigma, discrimination, and shame determine how Indigenous peoples navigate the healthcare system and their decision to engage in HCV care. Continued efforts to facilitate the uptake of DAA medications by Aboriginal and Torres Strait peoples in rural areas should utilize a multifaceted approach incorporating education to community and cultural awareness to reduce stigma and discrimination.

The relation between SNPs in the NME1 gene and response to sofosbuvir in Egyptian patients with chronic HCV

Background

Hepatitis C virus (HCV) infection is considered one of the most urgent health problems in the world, with an incidence of approximately 71 million patients and 399,000 deaths per year from related liver diseases. In this study, we examined the association between 2 single nucleotide polymorphisms (SNPs) in the nucleoside diphosphate kinase 1 (NME1) gene (encoding one of the sofosbuvir metabolizing enzymes) and the response to the sofosbuvir plus daclatasvir regimen in Egyptian HCV-infected patients.

Results

Our data showed a similarity in the distribution of the CC, CT, and TT genotypes of NME1 rs2302254 C/T (p  =  0.847) and the CC, TC, and TT genotypes of NME1 rs16949649 T/C (p  =  0.937) among patients who were either treatment responders or relapsers. Based on the univariate and multivariate logistic regression analyses of the significant predictors for sustained virological response (SVR), five factors showed a robust predictive potency for the treatment outcome: age, fasting blood glucose level, platelets, albumin, and alpha-fetoprotein. Strikingly, there was a significant correlation between the rs16949649T/C polymorphism and serum creatinine (p  =  0.023). Higher creatinine levels were observed among the CC carriers than the TC or TT carriers.

Conclusions

The 2 studied SNPs of NME1 had no significant association with SVR in Egyptian HCV-infected patients; however, the noticeable relation between rs16949649T/C and creatinine level might represent a foundation for future studies on the renal extra-hepatic manifestation of HCV and SNPs of NME1 gene.

Total Joint Arthroplasty Should Not Be Delayed in Hepatitis C Patients After Successful Treatment Achieving a Sustained Viral Load

Background

Preoperative treatment recommendations and optimal time to perform total joint arthroplasty (TJA) in patients with hepatitis C virus after treatment completion for achieving best outcomes have not been elucidated. We aim to determine (1) if undetectable viral load (UVL) prior to TJA leads to decreased postoperative complication rates, specifically periprosthetic joint infection (PJI), and (2) if delaying TJA after treatment completion has benefit in decreasing PJI.

Methods

A retrospective review of all hepatitis C virus patients undergoing TJA at 3 academic tertiary care centers was conducted. A total of 270 TJAs performed from 2005 to 2019 were included, 125 with positive viral load at the time of surgery. The duration from completion of treatment regimen to TJA was recorded for the UVL cohort. The primary study outcome was PJI at 1-year follow-up. Secondary outcomes included in-hospital complications, mechanical revision TJA rates, and optimal time to TJA upon completion of treatment.

Results

Patients with positive viral load at the time of TJA had longer length of stay (3.9 vs 2.9 days, P < .0001) and a higher PJI rate at 1 year postoperatively (9% vs 2%, P = .02) than UVL patients. There was no difference of in-hospital complications or revision rates for mechanical etiologies. Delaying TJA after achieving a sustained virologic response did not impact PJI rates.

Conclusions

Sustained UVL prior to TJA is critical to minimize PJI irrespective of the treatment regimen utilized. Surgery can be performed with lower complication rates any time after achieving sustained virologic response.

Level of Evidence

Level III, prognostic retrospective cohort study.

Sofosbuvir/ledipasvir in combination or nitazoxanide alone are safe and efficient treatments for COVID-19 infection: A randomized controlled trial for repurposing antivirals

BACKGROUND AND STUDY AIMS

Currently, there is no therapy approved for COVID-19. We evaluated the efficacy and safety of sofosbuvir/ledipasvir and nitazoxanide for the treatment of patients with COVID-19 infection.

PATIENTS AND METHODS

A multicenter, open-label randomized controlled trial included one hundred and ninety patients with non-severe COVID-19 infection. Patients were randomized into three groups. All groups received standard care treatment (SCT). In addition, group 1 received sofosbuvir/ledipasvir, and group 2 received nitazoxanide. Follow-up by reverse-transcriptase polymerase chain reaction (RT-PCR) was done at intervals of 5, 8, 11, and 14 days. The primary endpoint was viral clearance.

RESULTS

Viral clearance was significantly higher in the sofosbuvir/ledipasvir and nitazoxanide groups compared to the SCT group in all follow-up intervals (p < 0.001). In the sofosbuvir/ledipasvir arm, 36.9% showed early viral clearance by day 5. By day 14, 83.1% of the sofosbuvir/ledipasvir group, 39.7% of the nitazoxanide group, and 19.4% of the SCT group tested negative for SARS-CoV-2. Sofosbuvir/ledipasvir and nitazoxanide treatment were the only significant factors in Cox regression of negative RT-PCR with the highest OR (17.88, 95% CI: 6.66-47.98 and 2.59, 95% CI: 1.11-6.07, respectively). No mortality or serious adverse events were recorded.

CONCLUSION

The addition of sofosbuvir/ledipasvir or nitazoxanide to the SCT results in an early and high viral clearance rate in mild and moderate patients with COVID-19. These drugs represent a safe and affordable treatment for COVID-19.

Biomarkers for the Detection and Management of Hepatocellular Carcinoma in Patients Treated with Direct-Acting Antivirals

Simple Summary

Chronic Hepatitis C virus (HCV) represents the main etiological factor for hepatocellular carcinoma (HCC) in developed countries. The introduction of direct-acting antivirals (DAAs) improved the eradication of the hepatitis C virus (HCV) but not the reduction in the incidence of HCV-associated HCC. Some patients still develop HCC, even after reaching a sustained virological response (SVR). This review is a summary of pre-clinical studies that investigated predictive biomarkers for HCC occurrence and recurrence in HCV-infected patients treated with DAAs. The presented biomarkers are found dysregulated in serum or tissue at specific time points (before, during, after DAA treatment or post SVR) and correlated with HCC-predisposing conditions. Thus, this review aims to improve the management of patients developing HCV-induced HCC.

Abstract

Hepatocellular carcinoma (HCC) is the sixth-most common type of cancer worldwide and chronic Hepatitis C virus (HCV) represents the main etiological factor in developed countries. HCV promotes hepatocarcinogenesis through persistent liver inflammation and dysregulation of cell signaling pathways. The introduction of direct-acting antivirals (DAAs) resulted in a significant improvement in the eradication of the virus, with an expected reduction of HCC incidence. However, the risk of HCC development can persist after DAA treatment. Recent studies have investigated the potential use of molecular biomarkers that predict HCC occurrence or recurrence helping the stratification of patients under surveillance. This review aimed to summarize all pre-clinical exploration of predictive biomarkers to identify DAA-treated patients at risk for HCC development. Dysregulated microRNAs, lncRNAs, histone modifications, cytokines, proteins, and sphingolipids represent various classes of HCC risk predictors identified in two different biological sources (tissue and serum). The non-invasive serum markers can provide a more accessible means to perform clinical monitoring and predict the risk of HCC. In addition, conditions like cirrhosis, predisposing to HCC, strongly correlate with most of the molecular predictors identified, supporting the value of these molecules as possible biomarkers of HCC in DAA-treated patients.

Distribution of Primary Resistance Mutations in Saint Petersburg in Patients with Chronic Hepatitis C

The advent of direct-acting antiviral drugs (DAAs) was a breakthrough in the treatment of patients with chronic hepatitis C, yet high viral replication errors can lead to the development of resistance associated variants (RAVs). Thus, assessment of RAV in infected patients is necessary to monitor treatment effectiveness. The aim of our study was to investigate the presence of primary resistance mutations in the NS3 and NS5 regions of HCV in treatment-naive patients. Samples were taken from 42 patients with HCV who had not previously received DAA treatment. In the present study, we used the method for determining drug resistance mutations based on direct sequencing of the NS3, NS5A, and NS5B genes developed by the Saint Petersburg Pasteur Institute. Primary mutations associated with resistance were detected in 5 patients (12%). According to the Geno2pheno [hcv] 0.92 database, nucleotide substitutions were identified in various viral genes conferring resistance or decreased sensitivity to the respective inhibitors. This study has shown different mutations in the analyzed genes in patients with HCV who had not previously received DAA treatment. These mutations may increase the likelihood of treatment failure in the future.

Resource Management through Artificial Intelligence in Screening Programs-Key for the Successful Elimination of Hepatitis C

BACKGROUND

The elimination of the Hepatitis C virus (HCV) will only be possible if rapid and efficient actions are taken. Artificial neural networks (ANNs) are computing systems based on the topology of the biological brain, containing connected artificial neurons that can be tasked with solving medical problems.

AIM

We expanded the previously presented HCV micro-elimination project started in September 2020 that aimed to identify HCV infection through coordinated screening in asymptomatic populations and developed two ANN models able to identify at-risk subjects selected through a targeted questionnaire.

MATERIAL AND METHOD

Our study included 14,042 screened participants from a southwestern region of Oltenia, Romania. Each participant completed a 12-item questionnaire along with anti-HCV antibody rapid testing. Hepatitis-C-positive subjects were linked to care and ultimately could receive antiviral treatment if they had detectable viremia. We built two ANNs, trained and tested on the dataset derived from the questionnaires and then used to identify patients in a similar, already existing dataset.

RESULTS

We found 114 HCV-positive patients (81 females), resulting in an overall prevalence of 0.81%. We identified sharing personal hygiene items, receiving blood transfusions, having dental work or surgery and re-using hypodermic needles as significant risk factors. When used on an existing dataset of 15,140 persons (119 HCV cases), the first ANN models correctly identified 97 (81.51%) HCV-positive subjects through 13,401 tests, while the second ANN model identified 81 (68.06%) patients through only 5192 tests.

CONCLUSIONS

The use of ANNs in selecting screening candidates may improve resource allocation and prioritize cases more prone to severe disease.

The impact of genetic variations in sofosbuvir metabolizing enzymes and innate immunity mediators on treatment outcome in HCV-infected patients

Hepatitis C virus (HCV) is the leading cause of liver diseases worldwide. At present, combinations of different classes of direct-acting antiviral agents (DAAs) are used as treatment options for HCV, in which sofosbuvir (SOF) is the common DAA among different therapeutic regimes. In Egypt, SOF plus daclatasvir (DCV) is the widely used anti-HCV treatment protocol. Herein, we aimed to assess the association between 3 single-nucleotide polymorphisms (SNPs) at the genes coding for 2 SOF metabolizing enzymes: histidine triad nucleotide-binding protein 1 (HINT1) rs4696/rs7728773 and nucleoside diphosphate kinase 1 (NME1) rs3760468, together with the most potent anti-HCV innate molecule, i.e., interferon lambda 3 (IFNL3) rs12979860 and the response to SOF/DCV in Egyptian patients chronically infected with genotype 4 (GT4). SNPs were genotyped using real-time PCR in DNA from patients who achieved sustained virological response (SVR) at 12 weeks post-SOF/DCV treatment (i.e., responders; n = 188), patients who failed to achieve SVR12 (i.e., non-responders; n = 109), and healthy controls (n = 62). Our results demonstrated that patients bearing HINT1 rs7728773 CT/TT (odds ratio 2.119, 95% CI 1.263-3.559, p = 0.005) and IFNL3 rs12979860 CC (odds ratio 3.995, 95% CI 2.126-7.740, p = 0.0001) were more likely to achieve SVR12. However, neither HINT1 rs4696 nor NME1 rs3760468 seems to contribute to the responsiveness to SOF/DCV. Binary regression analysis defined 5 predictor factors independently associated with SVR12: age, bilirubin, hemoglobin, early stages of fibrosis, and combined HINT1 rs7728773 and IFNL3 rs12979860 favorable and mixed genotypes (odds ratio 3.134, 95% CI 1.518-6.47, p = 0.002), and that was confirmed by the combined ROC curve for the 5 predictor factors (AUC = 0.91, 95% CI 0.869-0.95, P = 0.0001). In conclusion, these data suggest that the two SNPs have the potential in predicting the response rate to SOF/DCV treatment in patients infected with HCV GT4. This study is the first to investigate the pharmacogenetics of SOF metabolizing enzyme and introduce HINT1 rs7728773 as a novel SNP that predicts the treatment efficacy.

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.

Micro-Elimination: Updated Pathway to Global Elimination of Hepatitis C in Small Communities and Industrial Settings during the COVID 19 Pandemic

BACKGROUND

In response to the goal of the World Health Organisation to eliminate hepatitis C virus infections by 2030, Romania is striving for national elimination. An already successful micro-elimination project was expanded to test-and-treat specific populations and at-risk groups. The aim of this project was to identify the individuals with HCV infection in disadvantaged regions who do not have proper medical care access.

MATERIALS AND METHODS

Our two-arm interventional cross-sectional study used rapid anti-HCV antibody testing on two population groups from the Romanian southwestern region of Oltenia, approached between September 2020 and May 2021. The first group consisted of predominantly over 40 years old individuals, recruited through five family doctors from two medium-sized towns (community lot-CL). We approached a second group, aged 18-65, through 11 medical offices of five large factories in the same region (industry lot, IL). A 12-items questionnaire was given to each participant, to determine risk factors and record demographic data. Eligible patients initiated antiviral therapy using direct-acting antivirals (DAAs).

RESULTS

We enrolled 15,383 individuals between all 16 locations. The overall prevalence by antibody testing was 0.77% (119 cases). Of these, 57 subsequently received treatment with DAAs. We identified blood transfusions as a risk factor within the CL. Participants in the IL reported a relatively high risk for the following situations: sharing of personal hygiene belongings with another person, performing previous blood transfusions, dental interventions and previous surgery.

CONCLUSIONS

In this global context, the use of micro-elimination allows interventions to be faster and more efficient. This is possible by targeting smaller and specific HCV risk groups.

Progress and Challenges in the Use of a Liver-on-a-Chip for Hepatotropic Infectious Diseases

The liver is a target organ of life-threatening pathogens and prominently contributes to the variation in drug responses and drug-induced liver injury among patients. Currently available drugs significantly decrease the morbidity and mortality of liver-dwelling pathogens worldwide; however, emerging clinical evidence reveals the importance of host factors in the design of safe and effective therapies for individuals, known as personalized medicine. Given the primary adherence of cells in conventional two-dimensional culture, the use of these one-size-fit-to-all models in preclinical drug development can lead to substantial failures in assessing therapeutic safety and efficacy. Advances in stem cell biology, bioengineering and material sciences allow us to develop a more physiologically relevant model that is capable of recapitulating the human liver. This report reviews the current use of liver-on-a-chip models of hepatotropic infectious diseases in the context of precision medicine including hepatitis virus and malaria parasites, assesses patient-specific responses to antiviral drugs, and designs personalized therapeutic treatments to address the need for a personalized liver-like model. Second, most organs-on-chips lack a monitoring system for cell functions in real time; thus, the review discusses recent advances and challenges in combining liver-on-a-chip technology with biosensors for assessing hepatocyte viability and functions. Prospectively, the biosensor-integrated liver-on-a-chip device would provide novel biological insights that could accelerate the development of novel therapeutic compounds.

Hepatitis C Antiviral Treatment Decreases All-Cause Complications After Total Joint Arthroplasty Regardless of the Presence of Fibrosis

BACKGROUND

Patients with hepatitis C virus (HCV) have an increased risk of complications after total joint arthroplasty (TJA). There is a limited but growing body of evidence on the benefit of preoperative antiviral treatment to reduce complications after TJA. What has not been well established is the effect of preoperative antiviral treatment among those with advanced disease as indicated by hepatic fibrosis.

METHODS

In total, 270 patients at 2 urban medical centers were reviewed for patient demographics, comorbidities, HCV treatment, hepatic fibrosis status, surgical information, and postoperative complications. Patients were divided into 2 groups based on their antiviral treatment status prior to TJA: Treated (n = 129) and Untreated (n = 141). Pearson's chi-squared test, Student's t-test, and multivariate logistic regressions were used to analyze complications between groups.

RESULTS

Patients in the Treated group had significantly fewer all-type complications (4.7% vs 14.9%, P = .007), infections (2.3% vs 12.1%, P = .002), and reoperations (0.8% vs 9.9%, P = .001) compared to the Untreated group. After controlling for hepatic fibrosis, we found that Treated patients still had significantly lower odds of experiencing all-type complications (odds ratio [OR] 0.30, 95% confidence interval [CI] 0.10-0.88; P = .028), infection (OR 0.19, 95% CI 0.04-0.87; P = .033), and reoperation (OR 0.11, 95% CI 0.01-0.90; P = .039) following TJA.

CONCLUSION

HCV antiviral treatment reduces postoperative complications after primary TJA, even among those who have progressed to hepatic fibrosis. Surgeons can use this information in shared decision making prior to TJA to counsel patients about the benefits of preoperative antiviral treatment even in the presence of hepatic fibrosis.

Inhibitor Development against p7 Channel in Hepatitis C Virus

Hepatitis C Virus (HCV) is the key cause of chronic and severe liver diseases. The recent direct-acting antiviral agents have shown the clinical success on HCV-related diseases, but the rapid HCV mutations of the virus highlight the sustaining necessity to develop new drugs. p7, the viroporin protein from HCV, has been sought after as a potential anti-HCV drug target. Several classes of compounds, such as amantadine and rimantadine have been testified for p7 inhibition. However, the efficacies of these compounds are not high. Here, we screened some novel p7 inhibitors with amantadine scaffold for the inhibitor development. The dissociation constant (Kd) of 42 ARD-series compounds were determined by nuclear magnetic resonance (NMR) titrations. The efficacies of the two best inhibitors, ARD87 and ARD112, were further confirmed using viral production assay. The binding mode analysis and binding stability for the strongest inhibitor were deciphered by molecular dynamics (MD) simulation. These ARD-series compounds together with 49 previously published compounds were further analyzed by molecular docking. Key pharmacophores were identified among the structure-similar compounds. Our studies suggest that different functional groups are highly correlated with the efficacy for inhibiting p7 of HCV, in which hydrophobic interactions are the dominant forces for the inhibition potency. Our findings provide guiding principles for designing higher affinity inhibitors of p7 as potential anti-HCV drug candidates.

Detection of drug resistance mutations of hepatitis C virus in patients with failure of the treatment with direct acting antivirals

Background. The development of direct acting antivirals (DAAs) has spurred a revolution in treatment of patients with chronic hepatitis C. However, there are cases showing no response to treatment. In 5% of cases, the viral breakthrough is most likely caused by DAA resistance mutations in the hepatitis C virus genome.The purpose of the study is to detect drug resistance mutations of hepatitis C virus in patients with DAA treatment failure.Materials and methods. The study was performed on plasma samples from 3 patients diagnosed with chronic hepatitis C virus infection and demonstrating DAA virological treatment failure. All isolates had genotype 1b. Drug resistance mutations were detected by using direct sequencing of NS3, NS5A, and NS5B genome regions. The detection technique was developed at the Pasteur Research Institute of Epidemiology and Microbiology.Results. Drug resistance mutations were detected in all cases. By using the Geno2pheno [hcv] 0.92 tool, nucleotide substitutions were detected in different viral genome regions and presumably caused resistance or decreased sensitivity to antivirals both present and absent in the sofosbuvir + daclatasvir combination therapy. Antiviral treatment failure in patients with chronic hepatitis C is caused by drug resistance mutations.Conclusions. The developed technique is efficient for detection of drug resistance mutations in NS3, NS5A, and NS5B regions in cases of virological failure of DAA treatment.

The incidence of resistance-associated variants to NS5A in HCV subtypes 1a and 1b in Taiwan

Background

Resistance-associated variants (RAVs) to direct-antiviral agents (DAAs) may hamper treatment. There was a lack of data on the natural prevalence of RAVs in Taiwanese HCV-infected patients. We investigated the real-life presence of RAVs in the nonstructural 5A (NS5A) region in HCV genotype 1a and 1b in chronically infected individuals in Taiwan.

Methods

In this single-center cohort study, nested polymerase chain reaction and direct sequencing analysis was used to determine the frequency of RAVs in the HCV NS5A region in patients with HCV genotype 1a (n = 55) and 1b (n = 525).

Results

In genotype 1a strains, the incidence of RAVs was 16.4% (9/55) in the NS5A region (M28V/T, n = 6, 10.9%; Q30L, n = 1, 1.8%; Y93N/H, n = 3, 5.5%). In genotype 1b, the incidence of RAVs was 17.5% (92/525) in the NS5A region (L31I/M/V, n = 7, 1.3%; Y93 H/S, n = 87, 16.5%). Patients with RAVs had significantly higher HCV RNA levels (6.1 ± 0.7 vs 5.9 ± 0.8 log IU/mL, p = 0.001) and lower rGT levels (28.9 ± 18.9 vs. 42.9 ± 57.0 U/L, p = 0.001) compared to those without RAVs. Multivariate analysis identified HCV RNA levels (odds ratio = 1.145, 95% CI: 1.060–1.237, p = 0.001) and rGT (OR = 0.989, 95% CI: 0.978–0.999, p = 0.035) as risk factors that are associated with the presence of RAVs. Importantly, there is no association between the presence of RAVs and no SVR (3.8% in patients with RAVs, 15.9% in patients without RAVs, p = 0.32).

Conclusion

RAVs, especially M28V and Y93H in the NS5A region, were highly prevalent in patients with genotype 1a and 1b HCV, respectively, in Taiwan, and they were linked to high HCV RNA levels and low rGT levels. Before using the NS5A inhibitors, the presence of mutated HCV variants should be taken into consideration.

Hepatitis C genotype 4: A report on resistance-associated substitutions in NS3, NS5A, and NS5B genes

AUTHOR CONTRIBUTION

FN performed the literature review and wrote the manuscript; STZ coauthored, edited, and reviewed the manuscript.

ABSTRACT

Treatment response in Hepatitis C virus (HCV) has generated varied effects in patients. Recently, nonresponsive and relapse patients related to host and genotype variabilities have been reported in clinical trials. However, these trials included minimal sample sizes of patients with genotype 4, the most prevalent genotype in Egypt and the Middle East, compared with genotypes 1 and 2. The genetic variabilities that have been detected within the HCV genes, especially the ones associated with genotype 4, and are linked to treatment response, will be the focus of this review with emphasis on direct acting antiviral agents. In addition, the major studies and clinical trials performed globally and their inclusivity of genotype 4 are reported. This review also delineates future study areas and missing data that need further investigation when it comes to genotype 4.

Molecular design, synthesis, and biological evaluation of bisamide derivatives as cyclophilin A inhibitors for HCV treatment

Hepatitis C virus (HCV) is a major cause of end-stage liver diseases. Direct-acting antivirals (DAAs), including inhibitors of nonstructural proteins (NS3/4A protease, NS5A, and NS5B polymerase), represent key components of anti-HCV treatment. However, some DAAs are associated with increased drug resistance and undesired side effects. Previous reports have shown that bisamides could be a novel class of cyclophilin A (CypA) inhibitors for treating HCV as a member of combinational therapies. To fully elucidate structure-activity relationships of bisamide derivatives and find a better hit compound with diverse binding modes, 16 biamides were designed with the help of docking program. They were then synthesized using one-pot four-component Ugi reaction. 7e with selectivity index of more than 18.9 (50% effective concentration of 5.3 μM, but no cytotoxicity at 100 μM) and unique binding mode that could be dived into gatekeeper pocket was selected as a new hit compound. Surface plasmon resonance experiments revealed that 7e is able to bind to CypA with a K_D of 3.66 μM. Taken together, these results suggest that 7e as a CypA inhibitor could be used as an alternative anti-HCV agent in combinational therapy in the future.

What do clinicians need to watch for with direct-acting antiviral therapy?

Introduction

The introduction of drugs targeting the virus replication cycle has revolutionized treatment of chronic hepatitis C virus. These drugs, called direct‐acting antivirals, have brought about extremely high rates of virological cure and have increased the number of patients who can receive treatment due to the lack of absolute contraindications. A combination of different classes of direct‐acting antivirals is the current standard of care. Although treatment administration and monitoring has been simplified in recent years, it is still relatively complex and mostly in the hands of specialists. Several factors must be assessed before starting treatment to maximize efficacy and minimize side effects of treatment. In this review, we describe the factors that impact on the efficacy and safety of antiviral treatment for hepatitis C and provide clear recommendations for clinicians prescribing direct‐acting antivirals.

Methods

We reviewed literature to define best practice, based on factors associated with treatment efficacy and safety data to recommend treatment options, baseline and on‐treatment assessments. The review included searches in PubMed, and the abstracts presented at the International Liver Congress TM and The Liver Meeting TM between January 2013 and September 2017.

Results

Clinical features that must be assessed before starting treatment include virological factors, such as hepatitis C virus genotype, HIV and hepatitis B coinfection and host factors, such as concomitant medications, liver disease stage and renal function.

Conclusions

Patients who start antiviral treatment for chronic hepatitis C require a thorough clinical evaluation. There is a need for assessing factors that impact on the treatment schedule and duration or affect the pharmacokinetics of direct‐acting antivirals.

Upcoming direct acting antivirals for hepatitis C patients with a prior treatment failure

Despite the high efficacy of direct acting antivirals (DAAs) not all patients successfully clear hepatitis C virus infection, in fact, approximately 1-3% fail to reach a sustained virological response 12 weeks after end of treatment. DAA failures are characterized by advanced liver disease, specific genotypes/subtypes and resistance associated substitutions to the DAA class they have been treated with. Current European Association for the Study of the Liver guidelines recommend three therapeutic options for such patients. The first is a 12 week course of sofosbuvir (SOF), velpatasvir (VEL) and voxilaprevir (VOX), which has shown to be effective in 90-99% of patients and was granted A1 level recommendation. The second option, reserved for patients who have predictors of failure consists in 12 weeks regimen with glecaprevir (GLE) and pibrentasvir (PIB), effective in 90-97%. Finally, although not supported by published data, for especially difficult to treat patients there should theoretically be a benefit in prolonged combinations of SOF+GLE/PIB or SOF/VEL/VOX±ribavirin. This review presents the latest evidence from both clinical trials and real-life on such therapeutic strategies.

Hepatitis C and kidney transplant: The eradication time of the virus has arrived

Hepatitis C virus (HCV) infection is a factor that reduces the survival of the patient and the graft in renal transplant (RT). The availability of directly acting antivirals agents (DAAs), very effective and with an excellent safety profile, it allows eradicate HCV from patients with kidney disease, and this is a revolutionary radical change in the natural evolution of this infection, until now without effective and safe treatment for the contraindication use of interferon in kidney transplant patients. The efficiency of some DAAs for all genotypes, even in patients with renal insufficiency constitutes a huge contribution to eradicate HCV in the RT population independently the genotype, severity of kidney failure, progression of liver disease and previous anti HCV therapy. All this is raising, although with controversies, the possibility of use kidneys from infected HCV+ donors for transplant in uninfected receptors and can be treated successfully in the early post-TR, thus increasing the total "pool" of kidneys for RT.

Hepatic IFN-Induced Protein with Tetratricopeptide Repeats Regulation of HCV Infection

Interferons (IFNs) suppress viral infection through the induction of >400 interferon-stimulated genes (ISGs). Among ISGs, IFN-induced protein with tetratricopeptide repeats (IFITs) is one of the most potent and well-characterized ISGs. IFIT family consists of 4 cluster genes. It has been suggested that the antiviral action of each IFIT employs distinct mechanisms. In addition, it has been shown that each IFIT exhibits its antiviral properties partially in a pathogen-specific manner. To date, the expression profile of IFITs in the liver, as well as the antiviral potency of the individual IFITs in the regulation of hepatitis C virus (HCV) infection, is not yet fully defined. Our previous study found that the expression of hepatic IFITs is well correlated with the outcome of IFN-based antiviral therapy. This study explored the significance of each IFIT in the suppression of HCV. Our in vitro and in vivo studies with humanized liver chimeric mouse system revealed that IFIT1, 2, and 3/4 play an important role in the suppression of HCV. In addition, our in vitro experiment found that all IFITs possess a comparable anti-HCV potency. Follow-up studies collectively indicated that IFITs suppress HCV likely through 2 distinct mechanisms: (1) inhibition of internal ribosome entry site-dependent viral protein translation initiation complex according to experiments with bicistronic reporter assay as well as confocal microscopic analyses and (2) sequestration of viral genome based on an experiment using replication defective viral genome. In conclusion, our study defined the importance of IFITs in the regulation of HCV and also suggested the multifaceted antiviral actions.

Hepatitis C - New drugs and treatment prospects

Hepatitis C virus (HCV) affects approx. 3% of the world's population and accounts for ca 300 000 deaths per year. 80% of individuals with HCV develop chronic symptoms which, when untreated, may cause cirrhosis (27%) or hepatocellular carcinoma (25%). The hepatitis C virus is a (+)ssRNA enveloped virus of the family Flaviviridae. Seven major HCV genotypes and their subtypes (a, b) have been identified. In the 1990s, interferons alpha-2 were used in the treatment of HCV and in the next decade HCV therapy was based on pegylated interferon alpha-2 in combination with ribavirin. Since 2011, interferons alpha, DNA and RNA polymerase inhibitors, NS3/4A RNA protease inhibitors, NS5 RNA serine protease inhibitors, NS5B RNA polymerase inhibitors have been approved for clinical use. Monotherapy is avoided in medication due to rapidly developing viral resistance. A total of 113 papers were included comprising original publications and reviews. The paper reviews the molecular targets and chemical structures of drugs used in HCV treatment. Indications and contraindications for anti-HCV drugs are also discussed together with application regimens.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Hepatitis C Continuum of Care in a Treatment Center in Sub-Saharan Africa

BACKGROUND

Hepatitis C virus (HCV) infection is a major public health challenge in Cameroon with over three million people infected. Government efforts to improve care and treatment are unsatisfactory and need to be assessed. We aimed at studying the several steps along the HCV continuum of care in one of two hepatitis treatment centers in Cameroon.

METHODS

We undertook a retrospective chart review of anti-HCV positive individuals, who attended the Douala general hospital between 2008 and 2015. We defined the HCV treatment cascade as follows: step 1-HCV RNA testing, step 2-complete pre-therapeutic evaluation (genotyping and liver fibrosis markers), step 3-initiation of treatment, step 4-treatment completion, and step 5-sustained virological response (SRV). Each successive step in the HCV care continuum was dependent on passing through the previous step.

RESULTS

The mean age of the 669 anti-HCV antibody positive individuals was 57 (sd: ±13) years. Females were 52.8% of the study population. 410 (61.3%) were tested for HCV RNA. Three hundred and sixty-six (54.7%) were confirmed to have viral replication (HCV RNA positive). One hundred and eighty (26.9%) did a complete pre-therapeutic evaluation (both HCV genotyping and liver fibrosis assessment included). Eighty-one (12.1%) initiated treatment with pegylated interferon/ribavirin. Seventy-two (10.8%) completed treatment and 44 (6.6%) had SVR. Sociodemographic characteristics including age, gender, marital status, having medical insurance, and profession were associated with attaining later steps in the care cascade.

CONCLUSION

This study shows that HCV continuum of care and treatment is less optimal at the Douala general hospital and is highly impacted by socio-economic factors. Continued efforts are needed to improve HCV care.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Management of hepatitis C virus infection in patients with chronic kidney disease: position statement of the joint committee of Italian association for the study of the liver (AISF), Italian society of internal medicine (SIMI), Italian society of infectious and tropical disease (SIMIT) and Italian society of nephrology (SIN)

Hepatitis C virus (HCV) infection is now considered a systemic disease due to the occurrence of extra-hepatic manifestations. Among these, the renal involvement is frequent. HCV infection, in fact, is strongly associated with proteinuria and chronic kidney disease (CKD) and negatively affects the prognosis of renal patients. In the last few years, availability of more specific and effective drugs against HCV has dramatically changed the clinical course of this disease. These drugs may provide further advantages in the CKD population as a whole by reducing progression of renal disease, mortality rate and by increasing the survival of graft in renal transplant recipients. The strict pathogenetic and prognostic link between HCV infection and CKD requires an ongoing relationship among the healthcare professionals involved in the treatment of both HCV infection and CKD. Therefore, Scientific Societies involved in the care of this high-risk population in Italy have organized a joint expert panel. The aim of the panel is to produce a position statement that can be used in daily clinical practice for the management of HCV infected patients across the whole spectrum of renal disease, from the conservative phase to renal replacement treatments (dialysis and transplantation). Sharing specific evidence-based expertise of different professional healthcare is the first step to obtain a common ground of knowledge on which to instate a model for multidisciplinary management of this high-risk population. Statements cover seven areas including epidemiology of CKD, HCV-induced glomerular damage, HCV-related renal risk, staging of liver disease in patients with CKD, prevention of transmission of HCV in hemodialysis units, treatment of HCV infection and management of HCV in kidney transplantation.

Sulfur(vi) fluoride exchange as a key reaction for synthesizing biaryl sulfate core derivatives as potent hepatitis C virus NS5A inhibitors and their structure-activity relationship studies

Extremely potent, new hepatitis C virus (HCV) nonstructural 5A (NS5A) featuring substituted biaryl sulfate core structures was designed and synthesized. Based on the previously reported novel HCV NS5A inhibitors featuring biaryl sulfate core structures which exhibit two-digit picomolar half-maximal effective concentration (EC50) values against HCV genotype 1b and 2a, the new inhibitors equipped with the sulfate core structures containing diversely substituted aryl groups were explored. In this study, highly efficient, chemoselective coupling reactions between an arylsulfonyl fluoride and an aryl silyl ether, known as the sulfur(vi) fluoride exchange (SuFEx) reaction, were utilized. Among the inhibitors prepared based on the SuFEx chemistry, compounds 14, 15 and 29 exhibited two-digit picomolar EC50 values against GT-1b and single digit or sub nanomolar activities against the HCV GT-2a strain. Nonsymmetrical inhibitors containing an imidazole and amide moieties on each side of the sulfate core structures were also synthesized. In addition, a biotinylated probe targeting NS5A protein was prepared for labeling using the same synthetic methodology.

Hepatitis C virus genotype 3: clinical features, current and emerging viral inhibitors, future challenges

Hepatitis C virus (HCV) represents a global burden on healthcare that affects over 150 million people worldwide. In the past, HCV genotype 3 was considered difficult to treat relative to other genotypes. Genotype 3 has been associated with a higher rate of complications, including fatty liver disease, fibrosis, hepatocellular carcinoma and mortality. However, with the advent of first- and second-generation direct-acting antivirals, genotype 3 can be treated effectively. Additionally, these new drugs are well tolerated by patients and have significantly fewer side effects compared to ribavirin and interferon-based regimens. However, while great strides have been made in overcoming biological barriers, our next challenge lies in overcoming economic and financial obstacles if we are to eradicate HCV genotype 3. Herein, we review the clinical features associated with HCV genotype 3, current and emerging treatment regimens, and challenges associated with treatment.

Prevalence and mapping of hepatitis C infections among men who have sex with men in New York City

Emerging sexually transmitted hepatitis C virus (HCV) epidemics among men who have sex with men (MSM) have been reported worldwide, with higher HCV infection rates among those who are HIV-infected. This study aims to determine prevalence of recent and chronic HCV infections among community-recruited MSM in New York City (NYC), map HCV infections by home, social, and sexual neighborhoods, and identify clusters of genetically linked HCV variants using phylogenetic analysis. The NYC M2M study recruited MSM via modified time-space, venue-based sampling and internet/mobile app-based recruitment during 2010–13. Participants completed a Google Earth map on neighborhoods of where they lived, socialized, and had sex in the last 3 months, an ACASI questionnaire, and a sexual network inventory about their sex partners. The men received HIV testing and provided serum samples. Testing on stored serum samples included HCV antibody and RNA viral load, HCV antibody avidity assay (avidity index <30% with positive viral load is considered recently infected), and HCV RNA extraction and amplification to generate a 432 base-pair region of Core/E1 for sequencing and phylogenetic analysis. Historic local controls were included in the phylogenetic analysis. Of 1,028 MSM, 79.7% were HIV-negative and 20.3% HIV-positive. Twenty nine MSM (2.8%) were HCV antibody-positive. MSM who were HCV antibody-positive reported a median of 2 male sex partners in last 3 months, with 6.9% aged 18–24, 17.2% 25–29, 13.8% 30–39, and 62.1% 40 and over. 8.1% of HIV-positive MSM were HCV antibody-positive vs. 1.5% of HIV-negative men (p<0.0001). Of 29 HCV-antibody positive MSM, 12 (41%) were HCV RNA-positive (11 subtype 1a and 1 subtype 1b). Two of 12 HCV RNA-positive participants had low antibody avidity values, suggesting recent HCV infection. HCV antibody seropositivity was significantly associated with older age >40 years, adjusted odds ratio (aOR) 3.56 (95% CI 1.57, 8.08), HIV-positive serostatus, aOR 3.18 (95% CI 1.40, 7.22), any sexually transmitted infection (STI) in the last 3 months, aOR 2.81 (95% CI 1.11, 7.13), and injection drug use (IDU) ever, aOR 4.34 (95% CI 1.69, 11.17). Mapping of HCV infections differed slightly by home, social, and sexual neighborhoods. Based on phylogenetic analysis from 12 HCV RNA-positive samples, no evidence of a clustered HCV epidemic was found. Overall HCV seroprevalence was 2.8% among community-recruited MSM in NYC, with higher prevalence among HIV-positive MSM compared to HIV-negative MSM. Only two participants were found to have recent HCV infection, with no evidence of a clustered HCV epidemic based on phylogenetic analysis. Our results support testing of HCV infection among HIV-negative MSM if they report having a recent STI and IDU in the past rather than universal HCV testing in all HIV-negative MSM.

Intrinsic structural versatility of the highly conserved 412-423 epitope of the Hepatitis C Virus E2 protein

HCV infection is a major threaten for human health as it affects hundreds of million people worldwide. Here we investigated the conformational properties of the 412-423 fragment of the envelope E2 protein, one of the most immunogenic regions of the virus proteome whose characterization may provide interesting insights for anti-HCV vaccine development. The spectroscopic characterization of the polypeptide unravels its unexpected tendency to form amyloid-like aggregates. When kept in monomeric state, it shows a limited tendency to adopt regular secondary structure. Enhanced molecular dynamics simulations, starting from four distinct conformational states, highlight its structural versatility. Interestingly, all multiform conformational states of the polypeptide detected in crystallographic complexes with antibodies are present in the structural ensemble of all simulations. This observation corroborates the idea that known antibodies recognize this region through a conformational selection mechanism. Accordingly, the design of effective anti-HCV vaccines should consider the intrinsic flexibility of this region. The structural versatility of the 412-423 region is particularly puzzling if its remarkable sequence conservation is considered. It is likely that flexibility and sequence conservation are important features that endow this epitope with the ability to accomplish distinct functions such as immunity escape and interaction with host receptors.

Fibrosing Cholestatic Hepatitis C After Liver Transplantation: Therapeutic Options Before and After Introduction of Direct-Acting Antivirals: Our Experience and Literature Review

BACKGROUND

Cirrhosis caused by hepatitis C is the most common indication for liver transplantation. The most aggressive form of hepatitis C virus (HCV) relapse after liver transplantation is fibrosing cholestatic hepatitis C, which can be observed in 2% to 15% of recipients.

METHODS

Double therapy with peg-interferon and ribavirin was characterized by low antiviral response, rapid fibrosis, and frequent graft failure within 1 year after surgery.

RESULTS

Introduction of direct-acting antivirals for HCV treatment allows for more efficient therapy with less adverse reactions, including patients with fibrosing cholestatic hepatitis C.

CONCLUSIONS

We present 4 (2.5%) cases of cholestatic viral hepatitis C recurrence in patients undergoing transplantation between 2006 and 2015 at the Transplantation Institute of Warsaw; during this period, 158 liver transplants were performed in patients with cirrhosis caused by HCV infection.

Frequency of, and factors associated with, hepatitis B virus reactivation in hepatitis C patients treated with all-oral direct-acting antivirals: Analysis of a Japanese prospective cohort

AIM

Several case reports have shown that hepatitis B virus (HBV) reactivation developed in hepatitis C patients with a current or previous HBV infection during direct-acting antiviral (DAA) treatment, which led to severe hepatitis or death in some cases. However, its precise frequency and risk factors are not entirely clear. We analyzed a prospective cohort.

METHODS

We analyzed HBV reactivation in 461 consecutive hepatitis C patients who received 12 weeks of ledipasvir/sofosbuvir for genotype 1 or sofosbuvir plus ribavirin for genotype 2 at multiple centers.

RESULTS

By the examination of the preserved sera at baseline, 159 patients (34%) were identified as seropositive for HBV core antibody (anti-HBc) and were included in the subsequent analysis; 4 patients were positive for HBV surface antigen (HBsAg), and the others were negative. Serum HBV DNA was undetectable or was detectable but <20 IU/mL at baseline for all patients. Serial measurement of HBV DNA at 4 weeks and 12 weeks in the preserved serum samples was available in 147 patients and identified HBV reactivation (defined as the appearance of serum HBV DNA ≥20 IU/mL) in 2 HBsAg-positive and 3 HBsAg-negative patients. No patient developed HBV-associated hepatitis. Patients who developed HBV reactivation had significantly lower anti-HBs titers and higher serum alanine transferase levels before treatment.

CONCLUSION

Hepatitis B virus reactivation during direct-acting antiviral therapies occurs in 3.4% (5/147) of patients who are positive for anti-HBc. A low titer of anti-HBs and a high serum alanine transferase level prior to treatment are associated with reactivation in this patient group.

The effect of the TM6SF2 E167K variant on liver steatosis and fibrosis in patients with chronic hepatitis C: a meta-analysis

The impact of Transmembrane 6 superfamily member 2 (TM6SF2) E167K variant, which causes hepatocellular fat retention by altering lipoprotein secretion, on liver damage and metabolic traits in chronic hepatitis C patients is still debated. We performed a systematic review and meta-analysis to clarify this relationship. Four studies with a total of 4325 patients were included. The risk of histologically-determined advanced steatosis, fibrosis, and cirrhosis (but not of severe inflammation) were increased in carriers of the TM6SF2 variant (P < 0.05). Unlike the inconsistent association with steatosis severity, due to the confounding effect of infection by the genotype-3 hepatitis C virus, the TM6SF2 variant was robustly associated with advanced fibrosis (OR = 1.07; 95% confidence interval [CI] = 1.01–1.14) and in particular with cirrhosis (OR = 2.05; 95% CI = 1.39–3.02). Regarding metabolic features, individuals positive for the TM6SF2 variant exhibited 5.8–12.0% lower levels of circulating triglycerides and non-HDL cholesterol (P < 0.05). Carriers of the variant were leaner, but there was high heterogeneity across studies (I² = 97.2%). No significant association was observed between the TM6SF2 variant and insulin resistance or hepatitis C viral load (both P > 0.05). In conclusion, the TM6SF2 E167K variant promotes the development of steatosis, fibrosis and cirrhosis in patients with chronic hepatitis C. Conversely, this variant reduces circulating atherogenic lipid fractions.

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

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

Ribavirin suppresses hepatic lipogenesis through inosine monophosphate dehydrogenase inhibition: Involvement of adenosine monophosphate-activated protein kinase-related kinases and retinoid X receptor α

Ribavirin (RBV) has been widely used as an antiviral reagent, specifically for patients with chronic hepatitis C. We previously demonstrated that adenosine kinase, which monophosphorylates RBV into the metabolically active form, is a key determinant for RBV sensitivity against hepatitis C virus RNA replication. However, the precise mechanism of RBV action and whether RBV affects cellular metabolism remain unclear. Analysis of liver gene expression profiles obtained from patients with advanced chronic hepatitis C treated with the combination of pegylated interferon and RBV showed that the adenosine kinase expression level tends to be lower in patients who are overweight and significantly decreases with progression to advanced fibrosis stages. In our effort to investigate whether RBV affects cellular metabolism, we found that RBV treatment under clinically achievable concentrations suppressed lipogenesis in hepatic cells. In this process, guanosine triphosphate depletion through inosine monophosphate dehydrogenase inhibition by RBV and adenosine monophosphate-activated protein kinase-related kinases, especially microtubule affinity regulating kinase 4, were required. In addition, RBV treatment led to the down-regulation of retinoid X receptor α (RXRα), a key nuclear receptor in various metabolic processes, including lipogenesis. Moreover, we found that guanosine triphosphate depletion in cells induced the down-regulation of RXRα, which was mediated by microtubule affinity regulating kinase 4. Overexpression of RXRα attenuated the RBV action for suppression of lipogenic genes and intracellular neutral lipids, suggesting that down-regulation of RXRα was required for the suppression of lipogenesis in RBV action. Conclusion: We provide novel insights about RBV action in lipogenesis and its mechanisms involving inosine monophosphate dehydrogenase inhibition, adenosine monophosphate-activated protein kinase-related kinases, and down-regulation of RXRα. RBV may be a potential reagent for anticancer therapy against the active lipogenesis involved in hepatocarcinogenesis. (Hepatology Communications 2017;1:550-563).

Discovery of Novel Nucleotide Prodrugs with Improved Potency Against HCV Variants Carrying NS5B S282T Mutation

Resistant HCV variants carrying NS5B S282T mutation confer reduced sensitivity to sofosbuvir, the sole marketed NS5B polymerase inhibitor. On the basis of the finding that 2'-α-F-2'-β-C-methylcytidine 5'-triphosphate (8) was more potent than sofosbuvir's active metabolite on inhibition of both wild-type and S282T mutant polymerase, a dual-prodrug approach has been established. Twenty-nine phosphoramidates with N⁴-modified cytosine were designed, synthesized, and evaluated for anti-HCV activity. The results showed that compounds 4c-4e and 4m (EC₅₀ = 0.19-0.25 μM) exhibited comparable potency to that of sofosbuvir (EC₅₀ = 0.15 μM) on inhibition of wild-type replicons. Notably, 4c (EC₅₀ = 0.366 μM) was 1.5-fold more potent than sofosbuvir (EC₅₀ = 0.589 μM) on inhibition of S282T mutant replicons. In vitro metabolic studies disclosed the possible metabolic pathways of 4c. The toxicity study results indicated a good safety profile of 4c. Together, 4c-4e and 4m hold promise for drug development for the treatment of HCV infection, especially the resistant variants with NS5B S282T mutation.

Sofosbuvir-Based Antiviral Therapy Is Highly Effective In Recurrent Hepatitis C in Liver Transplant Recipients: Canadian Multicenter "Real-Life" Experience

BACKGROUND

This study evaluates the efficacy, safety, and tolerability of regimens containing sofosbuvir (SOF) in the treatment of hepatitis C virus (HCV) recurrence in all genotypes in patients outside of clinical trials in all Canadian transplant centers.

METHODS

One hundred twenty liver transplantation recipients from across Canada with HCV recurrence were started on SOF-based regimens (SOF + simeprevir ± ribavirin (RBV), n = 53; SOF + pegylated interferon + RBV, n = 25; SOF + RBV, n = 36; and SOF + ledipasvir, n = 6) between January and November 2014. Mean age 58 ± 6.85 years, majority (83%) were genotype 1, male (81%), and treatment experienced (82%). Twenty-seven percent had fibrosing cholestatic hepatitis/early aggressive HCV in the graft, and 48% had F3/4 fibrosis. The primary outcomes included patient and graft survival, on- and end-of-treatment response and sustained virological response at 12 weeks after treatment end (SVR12), and adverse events.

RESULTS

One hundred thirteen of 120 (94%) patients were HCV RNA undetectable at end of treatment, and SVR12 was achieved in 102/120 (85%) patients, with 7 relapses, 1 nonresponder, and 10 deaths (liver-related complications). Sixty-three percent had HCV RNA levels below the lower limit of quantification at week 4. Serum creatinine levels remained stable throughout the treatment. Severe anemia occurred in 13% of patients, primarily in RBV-based regimens.

CONCLUSIONS

Sofosbuvir-based antiviral therapy for HCV recurrence after liver transplantation was well tolerated, with an overall high SVR12 rate (85%) including patients with severe disease recurrence and F3-4 cirrhosis. The response rate was higher (91%) in mild HCV recurrence, suggesting earlier treatment might be beneficial.

Viral and host factors associated with outcomes of hepatitis C virus infection (Review)

Hepatitis C virus (HCV) infection is a major health issue globally. Owing to the progress made in host genetics and HCV molecular virology, emerging data have suggested that the natural course and treatment response in patients with HCV infection are largely determined by complex host‑viral interactions. HCV genotype is the most important viral factor predicting the response to pegylated interferon‑α plus ribavirin therapy. The subtype of HCV genotype 1 is the key viral factor that predicts the efficacy of direct‑acting antiviral therapy. HCV genome heterogeneity and baseline viral load are additionally associated with the treatment response. Multiple host genetic variants localized in genes associated with the immune response have been identified as predictors of spontaneous disease course and therapy outcome in chronic HCV. However, most findings from candidate gene association studies have not been proven universal for all investigated populations and independent studies. Previous findings in independent large genome wide association studies confirmed that interferon‑λ3 gene polymorphisms are associated with spontaneous clearance and treatment responsiveness. A polymorphism of the inosine triphosphatase gene has been identified as a protective factor against ribavirin‑induced anemia and dose reductions. Another genetic variant in the patatin‑like phospholipase domain containing 3 genes is associated with hepatic steatosis and fibrosis in patients with HCV. The present review focused on the identified viral and host factors associated with outcomes of patients with HCV, and assessed the involvement of viral and host genetics in the natural history and treatment outcomes of HCV infection. This will provide novel ideas concerning personalized prevention and individualized clinical management.