Current and emerging antiviral treatments for hepatitis C infection

A Novel Small Molecule Inhibits Hepatitis C Virus Propagation in Cell Culture

Hepatitis C virus (HCV) can cause acute and chronic infection that is associated with considerable liver-related morbidity and mortality. In recent years, there has been a shift in the treatment paradigm with the discovery and approval of agents that target specific proteins vital for viral replication. We employed a cell culture-adapted strain of HCV and human hepatoma-derived cells lines to test the effects of our novel small-molecule compound (AO13) on HCV. Virus inhibition was tested by analyzing RNA replication, protein expression, and virus production in virus-infected cells treated with AO13. Treatment with AO13 inhibited virus spread in cell culture and showed a 100-fold reduction in the levels of infectious virus production. AO13 significantly reduced the level of viral RNA contained within cell culture fluids and reduced the cellular levels of HCV core protein, suggesting that the compound might act on a late step in the viral life cycle. Finally, we observed that AO13 did not affect the release of infectious virus from infected cells. Docking studies and molecular dynamics analyses suggested that AO13 might target the NS5B RNA polymerase, however, real-time RT-PCR analyses of cellular levels of HCV RNA showed only an ∼2-fold reduction in viral RNA levels in the presence of AO13. Taken together, this study revealed that AO13 showed consistent, but low-level antiviral effect against HCV, although the mechanism of action remains unclear.

IMPORTANCE The discovery of curative antiviral drugs for a chronic disease such as HCV infection has encouraged drug discovery in the context of other viruses for which no curative drugs currently exist. Since we currently face a novel virus that has caused a pandemic, the need for new antiviral agents is more apparent than ever. We describe here a novel compound that shows a modest antiviral effect against HCV that could serve as a lead compound for future drug development against other important viruses such as SARS-CoV-2.

Effectiveness of direct-acting antiviral drugs against hepatitis C virus: predictive factors of response to the treatment

Background/Aims. Despite the high efficacy and safety of direct-acting antivirals against hepatitis C virus shown in clinical trials, treatment failures continue to occur. Our aim was to establish the effectiveness of these drugs in routine clinical practice, as well as to determine factors that could influence the response to the treatment.Matherials/methods. Single-center, observational, retrospective study. Clinical, virological and pharmacotherapeutic variables were registered at baseline. Adverse drug reactions that occurred were recorded until week 24 of follow-up. Achievement of sustained virologic response was also recorded. Univariate and multivariate analysis were done to determine factors of response.Results. A total of 333 treatment regimens corresponding to 330 different patients were evaluated. Sustained virologic response rate was 94.6% [95%CI: 91.6–96.6%]. 67.9% of the patients experienced adverse drugs reactions (92.2% were grade 1). The univariate analysis identified a higher baseline of platelets, albumin and total cholesterol as predictive factors of sustained virologic response (p < 0.05). Presence of diabetes and complications related to liver disease (splenomegaly, portal hypertension, portal hypertensive gastropathy), body mass index ≥30, greater liver fibrosis, receiving simeprevir and higher baseline levels of glucose, aspartate-aminotransferase, alanine-aminotransferase and alkaline-phosphatase, have been identified as predictive factors of non-response (p < 0.05). The multivariate analysis detected the following independent factors of non-response: body mass index ≥30 and presence of complications related to liver disease.Conclusion. The effectiveness and safety of direct-acting antivirals against hepatitis C virus have been maintained in routine clinical practice. Further research on predictive factors of response is required in order to develop more reliable and reproducible predictive models.

HCV infection status and care seeking among people living with HIV who use drugs in Vietnam

HCV co-infection is widespread among people living with HIV who use drugs (PLHWUD). However, HCV testing was inconsistently implemented among PLHWUD. The low infection awareness and mental health challenges together impede PLHWUD's treatment-seeking. The study used baseline data of a randomized controlled trial conducted in Vietnam. HCV infection status was collected through self-report and medical record review. A linear mixed-effects regression model was used to examine the relationships between PLHWUD's perceived barriers to seeking healthcare, their depressive symptoms, and the consistencies in HCV status reports. Among the 181 PLHWUD in the study, one-third (64; 35.4%) had inconsistent self-reports and medical records of HIV infection status. The agreement between the two records was fair (Kappa statistics = 0.43). PLHWUD with consistent HCV infection confirmed by both medical records and self-reports perceived lower levels of healthcare-seeking barriers than those with discrepant HCV reports (estimated difference = -1.59, SE = 0.71, P = 0.027). Depressive symptoms were significantly correlated with healthcare-seeking barriers among those with discrepant HCV results (estimate = 0.17, SE = 0.06, P = 0.007). There is an urgent need to extend HCV screening efforts and increase HCV awareness among PLHWUD. Explicit HCV result notification and integrated mental health support are recommended to facilitate patients' access to needed care.

The Elimination of Hepatitis C as a Public Health Threat

Hepatitis C virus is a global public health threat, affecting 71 million people worldwide. Increasing recognition of the impact of this epidemic and recent advances in biomedical and technical approaches to hepatitis C prevention and cure have provided impetus for the World Health Organization (WHO) to call for global elimination of hepatitis C as a public health threat by 2030. This work reviews the feasibility of hepatitis C elimination and pathways to overcome existing and potential future barriers to elimination. Drawing on cost-effectiveness modeling and providing examples of successful implementation efforts across the globe, we highlight the resources and strategies needed to achieve hepatitis C elimination. A timely, multipronged response is required if the 2030 WHO elimination targets are to be achieved. Importantly, achieving hepatitis C elimination will also benefit the community well beyond 2030.

A novel HCV electrochemical biosensor based on a polyaniline@Ni-MOF nanocomposite

A novel label-free electrochemical biosensor constructed using a polyaniline@nickel metal–organic framework (Ni-MOF) nanocomposite for direct detection of HCV-RNA.

Linkage and retention in HCV care for HIV-infected populations: early data from the DAA era

Introduction

There is currently no published data on the effectiveness of DAA treatment for elimination of HCV infection in HIV‐infected populations at a population level. However, a number of relevant studies and initiatives are emerging. This research aims to report cascade of care data for emerging HCV elimination initiatives and studies that are currently being evaluated in HIV/HCV co‐infected populations in the context of implementation science theory.

Methods

HCV elimination initiatives and studies in HIV co‐infected populations that are currently underway were identified. Context, intervention characteristics and cascade of care data were synthesized in the context of implementation science frameworks.

Results

Seven HCV elimination initiatives and studies were identified in HIV co‐infected populations, mainly operating in high‐income countries. Four were focused mainly on HCV elimination in HIV‐infected gay and bisexual men (GBM), and three included a combination of people who inject drugs (PWID), GBM and other HIV‐infected populations. None were evaluating treatment delivery in incarcerated populations. Overall, HCV RNA was detected in 4894 HIV‐infected participants (range within studies: 297 to 994): 48% of these initiated HCV treatment (range: 21% to 85%; within studies from a period where DAAs were broadly available the total is 57%, range: 36% to 74%). Among studies with treatment completion data, 96% of 1109 initiating treatment completed treatment (range: 94% to 99%). Among those who could be assessed for sustained virological response at 12 weeks (SVR12), 1631 of 1757 attained SVR12 (93%, range: 86% to 98%).

Conclusions

Early results from emerging research on HCV elimination in HIV‐infected populations suggest that HCV treatment uptake is higher than reported levels prior to DAA treatment availability, but approximately half of patients remain untreated. These results are among diagnosed populations and additional effort is required to increase diagnosis rates. Among those who have initiated treatment, completion and SVR rates are promising. More data are required in order to evaluate the effectiveness of these elimination programmes in the long term, assess which intervention components are effective, and whether they need to be tailored to particular population groups.

Analysis of factors related to needle-stick and sharps injuries at a dental specialty university hospital and possible prevention methods

Needle-stick and sharps injuries (NSIs) can happen even when dental health care workers (DHCWs) act in compliance with standard precautions to prevent transmitting blood-borne infections. The objective of this study was to investigate causes of NSIs that had occurred at a dental specialty university hospital during the past 12 academic years. A total of 215 NSIs were reported during the investigation period, and NSIs ascribed to female DHCWs (n = 148; 68.8%) were significantly (P < 0.05) more common than those ascribed to male DHCWs (n = 67; 31.2%). One hundred twenty-six NSIs (58.6%) were caused by DHCWs with little experience (P < 0.05), and 37 of those (17.2% of the total) were ascribed to undergraduate students during clinical training (P < 0.05). The NSIs occurred both during treatment (n = 119; 55.3%) and during cleaning up used devices (n = 89; 41.4%). The NSIs at the dental hospital occurred with a probability of 0.004% of total therapeutic opportunities. Prevention of NSIs should be the responsibility of dental students and DHCWs, and should be a part of education about infection control to prevent the nosocomial transmission of blood-borne pathogens.

In vitro antiviral activity of spirotetronate compounds against dengue virus serotype 2

Spirotetronate compounds are polyketide secondary metabolites with diverse biological functions, such as antibacterial, antitumor and antiviral activities. Three pure spirotetronate compounds (2EPS-A, -B, -C) isolated from Actinomadura strain 2EPS showed inhibitory activity against dengue virus serotype 2 (DENV-2). 2EPS-A, -B and -C demonstrated the LC₅₀ values of 11.6, 27.5 and 12.0 μg/ml, respectively, in a test of cytotoxicity to Vero cells. The least cytotoxic, 2EPS-B, was further analyzed for its impact on viral propagation in a cell-based replication assay. At a concentration of 6.25 μg/ml, it could reduce the DENV-2 infection in Vero cells by about 94% when cells infected with DENV-2 were exposed to 2EPS-B, whereas direct treatment of DENV-2 with 2EPS-B at the same concentration prior to subsequent infection to Vero cell yielded no inhibition. 2EPS-A, -B an -C showed strong DENV-2 NS2B-NS3 protease inhibition in an in vitro assay, with IC₅₀ values of 1.94 ± 0.18, 1.47 ± 0.15 and 2.51 ± 0.21 μg/ml, respectively. Therefore, the spirotetronate compounds appear to prevent viral replication and viral assembly by inhibition of the viral protease.

Accelerating the elimination of viral hepatitis: a Lancet Gastroenterology & Hepatology Commission

Viral hepatitis is a major public health threat and a leading cause of death worldwide. Annual mortality from viral hepatitis is similar to that of other major infectious diseases such as HIV and tuberculosis. Highly effective prevention measures and treatments have made the global elimination of viral hepatitis a realistic goal, endorsed by all WHO member states. Ambitious targets call for a global reduction in hepatitis-related mortality of 65% and a 90% reduction in new infections by 2030. This Commission draws together a wide range of expertise to appraise the current global situation and to identify priorities globally, regionally, and nationally needed to accelerate progress. We identify 20 heavily burdened countries that account for over 75% of the global burden of viral hepatitis. Key recommendations include a greater focus on national progress towards elimination with support given, if necessary, through innovative financing measures to ensure elimination programmes are fully funded by 2020. In addition to further measures to improve access to vaccination and treatment, greater attention needs to be paid to access to affordable, high-quality diagnostics if testing is to reach the levels needed to achieve elimination goals. Simplified, decentralised models of care removing requirements for specialised prescribing will be required to reach those in need, together with sustained efforts to tackle stigma and discrimination. We identify key examples of the progress that has already been made in many countries throughout the world, demonstrating that sustained and coordinated efforts can be successful in achieving the WHO elimination goals.

Clinical detection of Hepatitis C viral infection by yeast-secreted HCV-core:Gold-binding-peptide

Access to affordable and field deployable diagnostics are key barriers to the control and eradication of many endemic and emerging infectious diseases. While cost, accuracy, and usability have all improved in recent years, there remains a pressing need for even less expensive and more scalable technologies. To that end, we explored new methods to inexpensively produce and couple protein-based biosensing molecules (affinity reagents) with scalable electrochemical sensors. Previous whole-cell constructs resulted in confounding measurements in clinical testing due to significant cross-reactivity when probing for host-immune (antibody) response to infection. To address this, we developed two complimentary strategies based on either the release of surface displayed or secretion of fusion proteins. These dual affinity biosensing elements couple antibody recognition (using antigen) and sensor surface adhesion (using gold-binding peptide-GBP) to allow single-step reagent production, purification, and biosensor assembly. As a proof-of-concept, we developed Hepatitis C virus (HCV)-core antigen-GBP fusion proteins. These constructs were first tested and optimized for consistent surface adhesion then the assembled immunosensors were tested for cross-reactivity and evaluated for performance in vitro. We observed loss of function of the released reagents while secreted constructs performed well in in vitro testing with 2 orders of dynamic range, and a limit of detection of 32 nM. Finally, we validated the secreted platform with clinical isolates (n = 3) with statistically significant differentiation of positive vs. non-infected serum (p < 0.0001) demonstrating the ability to clearly distinguish HCV positive and negative clinical samples.

Eliminating HIV/HCV co-infection in gay and bisexual men: is it achievable through scaling up treatment?

INTRODUCTION

Broad availability of direct-acting antiviral therapy for hepatitis C virus (HCV) raises the possibility that HCV prevalence and incidence can be reduced through scaling-up treatment, leading to the elimination of HCV. High rates of linkage to HIV care among HIV-infected gay and bisexual men may facilitate high uptake of HCV treatment, possibly making HCV elimination more achievable in this group. Areas covered: This review covers HCV elimination in HIV-infected gay and bisexual men, including epidemiology, spontaneous clearance and long term sequelae in the absence of direct-acting antiviral therapy; direct-acting antiviral therapy uptake and effectiveness in this group; HCV reinfection following successful treatment; and areas for further research. Expert commentary: Early data from the direct-acting antiviral era suggest that treatment uptake is increasing among HIV infected GBM, and SVR rates are very promising. However, in order to sustain current treatment rates, additional interventions at the behavioral, physician, and structural levels may be required to increase HCV diagnosis, including prompt detection of HCV reinfection. Timely consideration of these issues is required to maximize the population-level impact of HCV direct-acting antiviral therapy. Potential HCV transmissions from HIV-uninfected GBM, across international borders, and from those who are not GBM also warrant consideration.

A dirty little secret: stigma, shame and hepatitis C in the health setting

While recent medical innovation shows great promise in treating hepatitis C (HCV), it remains a condition associated with profound stigma. HCV is a bloodborne virus (BBV) most commonly transmitted in high-income countries by injecting drug use, and it is the stigmatising association between the two which is deeply problematic for those with HCV. A qualitative study undertaken in 2002 found that disclosure in health settings places those with HCV in positions of pronounced vulnerability. Disclosure is a primal scene, an interface, where the stigma of HCV, replete with connotations of disease and deviance, potentially transforms those affected into shamed subjects. Standard precautions protect health workers and minimise the transmission of contagion, measures which, in theory, also mitigate the requirement of those with BBVs to unnecessarily disclose their blood status. However, questions on pre-employment health checks, concerns that health treatments might adversely affect the liver and an ethical need to pre-emptively inform healthcare professionals undertaking exposure prone procedures are occasions when those with HCV confront the decision to disclose their blood status. This paper employs Goffman's model of actual and virtual social identities, along with Douglas' notion of dirt and pollution, to examine the dilemmas around disclosure those with HCV negotiate within the health setting. Discriminatory responses by healthcare professionals elucidate the stigmatising potential HCV carries. The subsequent reticence by those with HCV to disclose their blood status risks less than optimum healthcare. Recent studies indicate that stigma occurring in health settings remains a perennial concern for those with HCV.

Albumin nanostructures as advanced drug delivery systems

INTRODUCTION

One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin. Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare nanoparticle and microparticle-based structures to bind drugs. Various methods have been used to modify the albumin structure. A range of targeting ligands can be attached to the albumin that can be recognized by specific cell receptors that are expressed on target cells or tissues. Expert opinion: The particular advantages of albumin used in DDSs include ready availability, ease of chemical modification, good biocompatibility, and low immunogenicity. The regulatory approvals that have been received for several albumin-based therapeutic agents suggest that this approach will continue to be successfully explored.

Prevalence and burden of HCV co-infection in people living with HIV: a global systematic review and meta-analysis

BACKGROUND

At global level, there are 37 million people infected with HIV and 115 million people with antibodies to hepatitis C virus (HCV). Little is known about the extent of HIV-HCV co-infection. We sought to characterise the epidemiology and burden of HCV co-infection in people living with HIV.

METHODS

In this systematic review and meta-analysis we searched MEDLINE, Embase, CINAHL+, POPLINE, Africa-wide Information, Global Health, Web of Science, and the Cochrane Library and WHO databases for studies measuring prevalence of HCV and HIV, published between Jan 1, 2002, and Jan 28, 2015. We included studies in HIV population samples of more than 50 individuals and recruited patients based on HIV infection status or other behavioural characteristics. We excluded editorials or reviews containing no primary data, samples of HCV or HIV-HCV co-infected individuals, or samples relying on self-reported infection status. We also excluded samples drawn from populations with other comorbidities or undergoing interventions that put them at increased risk of co-infection. Populations were categorised according to HIV exposure, with the regional burden of co-infection being derived by applying co-infection prevalence estimates to published numbers of HIV-infected individuals. We did a meta-analysis to estimate the odds of HCV in HIV-infected individuals compared with their HIV-negative counterparts.

FINDINGS

From 31 767 citations identified, 783 studies met the inclusion criteria, resulting in 902 estimates of the prevalence of HIV-HCV co-infection. In HIV-infected individuals, HIV-HCV co-infection was 2·4% (IQR 0·8-5·8) within general population samples, 4·0% (1·2-8·4) within pregnant or heterosexually exposed samples, 6·4% (3·2-10·0) in men who have sex with men (MSM), and 82·4% (55·2-88·5) in people who inject drugs (PWID). Odds of HCV infection were six times higher in people living with HIV (5·8, 95% CI 4·5-7·4) than their HIV-negative counterparts. Worldwide, there are approximately 2 278 400 HIV-HCV co-infections (IQR 1 271 300-4 417 000) of which 1 362 700 (847 700-1 381 800) are in PWID, equalling an overall co-infection prevalence in HIV-infected individuals of 6·2% (3·4-11·9).

INTERPRETATION

We noted a consistently higher HCV prevalence in HIV-infected individuals than HIV-negative individuals  across all risk groups and regions, but especially in PWID. This study highlights the importance of routine HCV testing in all HIV-infected individuals, but especially in PWID. There is also a need to improve country-level surveillance of HCV prevalence across different population groups in all regions.

FUNDING

WHO.

Kushenin induces the apoptosis of HCV-infected cells by blocking the PI3K-Akt-mTOR pathway via inhibiting NS5A

With the increased burden induced by HCV, there is an urgent need to develop better-tolerated agents with good safety. In this study, we evaluated the anti-HCV capability of kushenin, as well as the possible mechanism to Huh7.5-HCV cells. The results demonstrated that kushenin significantly inhibited the HCV-RNA level. Similarly, the expression of HCV-specific protein NS5A was also decreased. Molecular docking results displayed that kushenin bonded well to the active pockets of HCV NS5A, further confirming the effects of kushenin on HCV replication. Coimmunoprecipitation assay determined that kushenin suppressed the interaction between PI3K and NS5A in HCV-replicon cells. Furthermore, kushenin exerted an obviously induced function on HCV-replicon cells apoptosis by inhibiting PI3K-Akt-mTOR pathway, which could be ameliorated by the specific activator IGF-1 addition. Taken together, kushenin possesses the ability to inhibit HCV replication, and contributes to the increased apoptosis of HCV-infected cells by blocking the PI3K-Akt-mTOR pathway via inhibiting NS5A. Our results provide important evidence for a better understanding of the pathogenesis of HCV infection, and suggest that kushenin has the potential to treat HCV disease.

Response to treatment following recently acquired hepatitis C virus infection in a multicentre collaborative cohort

Pegylated interferon therapy is highly effective in recently acquired HCV. The optimal timing of treatment, regimen and influence of host factors remains unclear. We aimed to measure sustained virological response (SVR) during recent HCV infection and identify predictors of response. Data were from five prospective cohorts of high-risk individuals in Australia, Canada, Germany and the United States. Individuals with acute or early chronic HCV who commenced pegylated interferon therapy were included. The main outcome was SVR, and predictors were assessed using logistic regression. Among 516 with documented recent HCV infection, 237 were treated (pegylated interferon n = 161; pegylated interferon/ribavirin n = 76) (30% female, median age 35 years, 56% ever injected drugs, median duration of infection 6.2 months). Sixteen per cent (n = 38) were HIV/HCV co-infected. SVR among those with HCV mono-infection was 64% by intention to treat; SVR was 68% among HCV/HIV co-infection. Independent predictors of SVR in HCV mono-infection were duration of HCV infection (the odds of SVR declined by 8% per month of infection, aOR 0.92, 95% CI 0.85-0.99, P = 0.033), IFNL4 genotype (adjusted OR 2.27, 95% CI 1.13-4.56, P = 0.021), baseline HCV RNA <400 000 IU/mL (aOR 2.06, 95% CI 1.03-4.12, P = 0.041) and age ≥40 years (vs <30: aOR 2.92, 95% CI 1.31-6.49, P = 0.009), with no difference by drug regimen, HCV genotype, symptomatic infection or gender. The effect of infection duration on odds of SVR was greater among genotype-1 infection. Interferon-based HCV treatment is highly effective in recent HCV infection. Duration of infection, IFNL4 genotype and baseline HCV RNA levels can predict virological response and may inform clinical decision-making.

Many hepatitis C reinfections that spontaneously clear may be undetected: Markov-chain Monte Carlo analysis of observational study data

Hepatitis C virus (HCV) reinfection rates are probably underestimated due to reinfection episodes occurring between study visits. A Markov model of HCV reinfection and spontaneous clearance was fitted to empirical data. Bayesian post-estimation was used to project reinfection rates, reinfection spontaneous clearance probability and duration of reinfection. Uniform prior probability distributions were assumed for reinfection rate (more than 0), spontaneous clearance probability (0-1) and duration (0.25-6.00 months). Model estimates were 104 per 100 person-years (95% CrI: 21-344), 0.84 (95% CrI: 0.59-0.98) and 1.3 months (95% CrI: 0.3-4.1) for reinfection rate, spontaneous clearance probability and duration, respectively. Simulation studies were used to assess model validity, demonstrating that the Bayesian model estimates provided useful information about the possible sources and magnitude of bias in epidemiological estimates of reinfection rates, probability of reinfection clearance and duration or reinfection. The quality of the Bayesian estimates improved for larger samples and shorter test intervals. Uncertainty in model estimates notwithstanding, findings suggest that HCV reinfections frequently and quickly result in spontaneous clearance, with many reinfection events going unobserved.

Effect of Treatment for CHC on Liver Disease Progression and Hepatocellular Carcinoma Development in African Americans

BACKGROUND AND AIMS

African Americans (AA) historically have a low response rate to hepatitis C therapies, and there is limited information available for this patient population regarding the development and treatment of chronic hepatitis C (CHC). The aim of this study was to evaluate liver disease progression and hepatocellular carcinoma (HCC) development in AA with CHC.

METHODS

Between 1995 and 2008, 246 AA patients with CHC were identified from a database of patients and followed until 2012-2013 (average 8 years) or the development of HCC after 2008.

RESULTS

Viral clearance (intent to treat; sustained virus response (SVR)) was achieved in 15% of patients with interferon based therapies with or without ribavirin. AA patients who achieved an SVR (n=22) did not develop HCC or new onset cirrhosis, whereas the HCC incidence in untreated AA patients was 23% (51/203). Patients who achieved an SVR also had improved fibrosis, as defined by the AST Platelet Ratio Index (APRI) and Fibrosis-4 (FIB-4) score, relative to nonresponders and untreated patients.

CONCLUSIONS

The severity of liver disease at the first visit (except for cirrhosis) correlated with the development of HCC, but because of the overlap in values between patients, these measurements were not useful for predicting individual risk. Since cirrhosis at the first visit was not a predictive factor, treatment with newer antiviral therapies is the best option for reducing the incidence of advanced liver disease and its harmful outcomes in the AA population.

Novel benzidine and diaminofluorene prolinamide derivatives as potent hepatitis C virus NS5A inhibitors

Our study describes the discovery of a series of highly potent hepatitis C virus (HCV) NS5A inhibitors based on symmetrical prolinamide derivatives of benzidine and diaminofluorene. Through modification of benzidine, l-proline, and diaminofluorene derivatives, we developed novel inhibitor structures, which allowed us to establish a library of potent HCV NS5A inhibitors. After optimizing the benzidine prolinamide backbone, we identified inhibitors embedding meta-substituted benzidine core structures that exhibited the most potent anti-HCV activities. Furthermore, through a battery of studies including hERG ligand binding assay, CYP450 binding assay, rat plasma stability test, human liver microsomal stability test, and pharmacokinetic studies, the identified compounds 24, 26, 27, 42, and 43 are found to be nontoxic, and are expected to be effective therapeutic anti-HCV agents.

Effect of zinc supplementation on viral response in patients with chronic hepatitis C and Beta thalassemia major, a pilot study

INTRODUCTION

Zinc deficiency has been reported in patients with both hepatitis C and beta thalassemia major. Zinc supplementation in addition to antiviral therapy of chronic hepatitis C has been accompanied by some success in patients with chronic hepatitis C.

OBJECTIVE

The aim of the present pilot study is to determine the effect of 30 mg elemental zinc on biochemical and virological response in a population of patients with chronic hepatitis C with beta thalassemia major.

MATERIALS AND METHODS

A prospective, double blind,placebo controlled trial included 40 patients being treated with Pegylated interferon Alfa (Peg IFN-α) and ribavirin. Biochemical and virological parameters and plasma zinc levels were determined before starting treatment. Patients were randomly selected to receive either zinc or a placebo in addition to Peg IFN-α and ribavirin for a period of one year. AST, ALT, sustained viral response (SVR), and zinc levels were measured after treatment.Of the original 40 eligible patients, eight withdrawn from the study and 32 patients completed the study; 16 in the zinc group and 16 in the placebo group. Analysis of the data shows that there is no difference between the two groups in AST, ALT, SVR or zinc level following one year of treatment (p=0.224, p=0.616, p=0.670, p=0.999, respectively).

CONCLUSION

The results of this study indicate that using 30 mg/day elemental zinc did not significantly improve the outcome of treatment in thalassemia patients with chronic hepatitis C. In future studies, we recommend trying higher doses zinc in patients with hepatitis C who had beta thalassemia major.

Targeting cellular squalene synthase, an enzyme essential for cholesterol biosynthesis, is a potential antiviral strategy against hepatitis C virus

Hepatitis C virus (HCV) exploits host membrane cholesterol and its metabolism for progeny virus production. Here, we examined the impact of targeting cellular squalene synthase (SQS), the first committed enzyme for cholesterol biosynthesis, on HCV production. By using the HCV JFH-1 strain and human hepatoma Huh-7.5.1-derived cells, we found that the SQS inhibitors YM-53601 and zaragozic acid A decreased viral RNA, protein, and progeny production in HCV-infected cells without affecting cell viability. Similarly, small interfering RNA (siRNA)-mediated knockdown of SQS led to significantly reduced HCV production, confirming the enzyme as an antiviral target. A metabolic labeling study demonstrated that YM-53601 suppressed the biosynthesis of cholesterol and cholesteryl esters at antiviral concentrations. Unlike YM-53601, the cholesterol esterification inhibitor Sandoz 58-035 did not exhibit an antiviral effect, suggesting that biosynthesis of cholesterol is more important than that of cholesteryl esters for HCV production. YM-53601 inhibited transient replication of a JFH-1 subgenomic replicon and entry of JFH-1 pseudoparticles, suggesting that at least suppression of viral RNA replication and entry contributes to the antiviral effect of the drug. Collectively, our findings highlight the importance of the cholesterol biosynthetic pathway in HCV production and implicate SQS as a potential target for antiviral strategies against HCV.

IMPORTANCE

Hepatitis C virus (HCV) is known to be closely associated with host cholesterol and its metabolism throughout the viral life cycle. However, the impact of targeting cholesterol biosynthetic enzymes on HCV production is not fully understood. We found that squalene synthase, the first committed enzyme for cholesterol biosynthesis, is important for HCV production, and we propose this enzyme as a potential anti-HCV target. We provide evidence that synthesis of free cholesterol is more important than that of esterified cholesterol for HCV production, highlighting a marked free cholesterol dependency of HCV production. Our findings also offer a new insight into a role of the intracellular cholesterol pool that is coupled to its biosynthesis in the HCV life cycle.

The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs

With the development of new highly efficacious direct-acting antiviral (DAA) treatments for hepatitis C virus (HCV), the concept of treatment as prevention is gaining credence. To date, the majority of mathematical models assume perfect mixing, with injectors having equal contact with all other injectors. This article explores how using a networks-based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Using observational data, we parameterized an exponential random graph model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were (1) treat randomly selected nodes and (2) "treat your friends," where an individual is chosen at random for treatment and all their infected neighbors are treated. As treatment coverage increases, HCV prevalence at 10 years reduces for both the high- and low-efficacy treatment. Within each set of parameters, the treat your friends strategy performed better than the random strategy being most marked for higher-efficacy treatment. For example, over 10 years of treating 25 per 1,000 PWID, the prevalence drops from 50% to 40% for the random strategy and to 33% for the treat your friends strategy (6.5% difference; 95% confidence interval: 5.1-8.1).

CONCLUSION

Treat your friends is a feasible means of utilizing network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment, such an approach will benefit not just the individual, but also the community more broadly by reducing the prevalence of HCV among PWID.

A comparison of risk factors for hepatitis C among young and older adult prisoners

Internationally, the prevalence of hepatitis C infection is higher among prisoners when compared to the general population, particularly among people who inject drugs. This study estimates the prevalence of, and compares the risk factors for, hepatitis C in young (< 25 years) and older (≥ 25 years) prisoners with a history of injection drug use. Participants were 677 sentenced prisoners in Queensland, Australia, with a lifetime history of injection drug use, recruited in the 6 weeks prior to release from custody. The prevalence of hepatitis C exposure was significantly lower in young prisoners than in older prisoners (20.7% vs. 29.4%, p = .03). Risk factors for hepatitis C varied between young and older prisoners. Young people who inject drugs and who have had shorter time at risk of hepatitis C exposure are an important target group for hepatitis C prevention efforts.

The changing burden of hepatitis C virus infection in the United States: model-based predictions

BACKGROUND

Chronic hepatitis C virus (HCV) infection causes a substantial health and economic burden in the United States. With the availability of direct-acting antiviral agents, recently approved therapies and those under development, and 1-time birth-cohort screening, the burden of this disease is expected to decrease.

OBJECTIVE

To predict the effect of new therapies and screening on chronic HCV infection and associated disease outcomes.

DESIGN

Individual-level state-transition model.

SETTING

Existing and anticipated therapies and screening for HCV infection in the United States.

PATIENTS

Total HCV-infected population in the United States.

MEASUREMENTS

The number of cases of chronic HCV infection and outcomes of advanced-stage HCV infection.

RESULTS

The number of cases of chronic HCV infection decreased from 3.2 million in 2001 to 2.3 million in 2013. One-time birth-cohort screening beginning in 2013 is expected to identify 487,000 cases of HCV infection in the next 10 years. In contrast, 1-time universal screening could identify 933,700 cases. With the availability of highly effective therapies, HCV infection could become a rare disease in the next 22 years. Recently approved therapies for HCV infection and 1-time birth-cohort screening could prevent approximately 124,200 cases of decompensated cirrhosis, 78,800 cases of hepatocellular carcinoma, 126,500 liver-related deaths, and 9900 liver transplantations by 2050. Increasing the treatment capacity would further reduce the burden of HCV disease.

LIMITATION

Institutionalized patients with HCV infection were excluded, and empirical data on the effectiveness of future therapies and on the future annual incidence and treatment capacity of HCV infection are lacking.

CONCLUSION

New therapies for HCV infection and widespread implementation of screening and treatment will play an important role in reducing the burden of HCV disease. More aggressive screening recommendations are needed to identify a large pool of infected patients.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Albumin-drug conjugates in the treatment of hepatic disorders

INTRODUCTION

This review deals with the use of serum albumin (SA) as a carrier for the selective delivery of drugs to liver cells.

AREAS COVERED

The synthesis and properties of the SA conjugates prepared to enhance the performance of the drugs used in the treatment of viral hepatitis, hepatocellular carcinoma (HCC), liver micrometastases and hepatic fibrosis are reported.

EXPERT OPINION

Studies in humans and laboratory animals demonstrated the capacity of SA conjugates to accomplish a liver targeting of the drugs, but at the same time underscored their limits and drawbacks, which can explain why to date these complexes did not reach a practical application. The major drawback is the need of administration by intravenous route, which prevents long-term daily treatments as required by some liver pathologies, such as chronic virus hepatitis and fibrosis. At present, only a conjugate carrying doxorubicin and addressed to the treatment of HCC showed in laboratory animals a solid potentiality to improve the value of the coupled drug. In the future, conjugation to SA could remain a successful strategy to permit the administration of drugs with rapid resolutive effects inside liver cells without causing severe extrahepatic adverse reactions.

Discovery and development of hepatitis C virus NS5A replication complex inhibitors

Lead inhibitors that target the function of the hepatitis C virus (HCV) nonstructural 5A (NS5A) protein have been identified by phenotypic screening campaigns using HCV subgenomic replicons. The demonstration of antiviral activity in HCV-infected subjects by the HCV NS5A replication complex inhibitor (RCI) daclatasvir (1) spawned considerable interest in this mechanistic approach. In this Perspective, we summarize the medicinal chemistry studies that led to the discovery of 1 and other chemotypes for which resistance maps to the NS5A protein and provide synopses of the profiles of many of the compounds currently in clinical trials. We also summarize what is currently known about the NS5A protein and the studies using NS5A RCIs and labeled analogues that are helping to illuminate aspects of both protein function and inhibitor interaction. We conclude with a synopsis of the results of notable clinical trials with HCV NS5A RCIs.

High rates of hepatitis C virus reinfection and spontaneous clearance of reinfection in people who inject drugs: a prospective cohort study

Hepatitis C virus reinfection and spontaneous clearance of reinfection were examined in a highly characterised cohort of 188 people who inject drugs over a five-year period. Nine confirmed reinfections and 17 possible reinfections were identified (confirmed reinfections were those genetically distinct from the previous infection and possible reinfections were used to define instances where genetic differences between infections could not be assessed due to lack of availability of hepatitis C virus sequence data). The incidence of confirmed reinfection was 28.8 per 100 person-years (PY), 95%CI: 15.0-55.4; the combined incidence of confirmed and possible reinfection was 24.6 per 100 PY (95%CI: 16.8-36.1). The hazard of hepatitis C reinfection was approximately double that of primary hepatitis C infection; it did not reach statistical significance in confirmed reinfections alone (hazard ratio [HR]: 2.45, 95%CI: 0.87-6.86, p=0.089), but did in confirmed and possible hepatitis C reinfections combined (HR: 1.93, 95%CI: 1.01-3.69, p=0.047) and after adjustment for the number of recent injecting partners and duration of injecting. In multivariable analysis, shorter duration of injection (HR: 0.91; 95%CI: 0.83-0.98; p=0.019) and multiple recent injecting partners (HR: 3.12; 95%CI: 1.08-9.00, p=0.035) were independent predictors of possible and confirmed reinfection. Time to spontaneous clearance was shorter in confirmed reinfection (HR: 5.34, 95%CI: 1.67-17.03, p=0.005) and confirmed and possible reinfection (HR: 3.10, 95%CI: 1.10-8.76, p-value=0.033) than primary infection. Nonetheless, 50% of confirmed reinfections and 41% of confirmed or possible reinfections did not spontaneously clear.

Conclusions: Hepatitis C reinfection and spontaneous clearance of hepatitis C reinfection were observed at high rates, suggesting partial acquired natural immunity to hepatitis C virus. Public health campaigns about the risks of hepatitis C reinfection are required.

Hepatitis C transmission and treatment in contact networks of people who inject drugs

Hepatitis C virus (HCV) chronically infects over 180 million people worldwide, with over 350,000 estimated deaths attributed yearly to HCV-related liver diseases. It disproportionally affects people who inject drugs (PWID). Currently there is no preventative vaccine and interventions feature long treatment durations with severe side-effects. Upcoming treatments will improve this situation, making possible large-scale treatment interventions. How these strategies should target HCV-infected PWID remains an important unanswered question. Previous models of HCV have lacked empirically grounded contact models of PWID. Here we report results on HCV transmission and treatment using simulated contact networks generated from an empirically grounded network model using recently developed statistical approaches in social network analysis. Our HCV transmission model is a detailed, stochastic, individual-based model including spontaneously clearing nodes. On transmission we investigate the role of number of contacts and injecting frequency on time to primary infection and the role of spontaneously clearing nodes on incidence rates. On treatment we investigate the effect of nine network-based treatment strategies on chronic prevalence and incidence rates of primary infection and re-infection. Both numbers of contacts and injecting frequency play key roles in reducing time to primary infection. The change from "less-" to "more-frequent" injector is roughly similar to having one additional network contact. Nodes that spontaneously clear their HCV infection have a local effect on infection risk and the total number of such nodes (but not their locations) has a network wide effect on the incidence of both primary and re-infection with HCV. Re-infection plays a large role in the effectiveness of treatment interventions. Strategies that choose PWID and treat all their contacts (analogous to ring vaccination) are most effective in reducing the incidence rates of re-infection and combined infection. A strategy targeting infected PWID with the most contacts (analogous to targeted vaccination) is the least effective.

Sequencing assays for failed genotyping with the versant hepatitis C virus genotype assay (LiPA), version 2.0

For optimal antiviral therapy, the hepatitis C virus (HCV) genotype needs to be determined, as it remains a strong predictor of sustained viral response. In this study, we assessed the number of HCV genotyping results that could not be determined using the commercially available line probe assay (LiPA) (Versant hepatitis C virus genotype 2.0 assay) in a large international panel of samples from 9,874 HCV-positive patients. In-house sequencing assays targeting the 5' untranslated region (UTR), core region, NS3 region, and NS5B region of the HCV genome and phylogenetic analyses were used to resolve these LiPA failures. Among all cases, the genotypes of 51 samples (0.52%) could not be determined with the LiPA. These undetermined results were observed more frequently among samples from non-European regions (mainly the Arabian Peninsula). The use of sequencing assays coupled with phylogenetic analysis provided reliable genotype results for 86% of the LiPA failures, which exhibited higher rates of genotypes 4, 5, and 6 than did LiPA-resolved genotypes. As expected, the 5' UTR was not sufficiently variable for clear discrimination between genotypes 1 and 6, but it also resulted in errors in classification of some genotype 3 and 4 cases using well-known Web-based BLAST programs. This study demonstrates the low frequency of genotyping failures with the Versant hepatitis C virus genotype 2.0 assay (LiPA) and also underlines the need for a complex combination of sequences and phylogenetic analyses in order to genotype these particular HCV strains correctly.

Experimental therapies for yellow fever

A number of viruses in the family Flaviviridae are the focus of efforts to develop effective antiviral therapies. Success has been achieved with inhibitors for the treatment of hepatitis C, and there is interest in clinical trials of drugs against dengue fever. Antiviral therapies have also been evaluated in patients with Japanese encephalitis and West Nile encephalitis. However, no treatment has been developed against the prototype flavivirus, yellow fever virus (YFV). Despite the availability of the live, attenuated 17D vaccine, thousands of cases of YF continue to occur each year in Africa and South America, with a significant mortality rate. In addition, a small number of vaccinees develop severe systemic infections with the 17D virus. This paper reviews current efforts to develop antiviral therapies, either directly targeting the virus or blocking detrimental host responses to infection.

Knowledge and attitudes towards hepatitis C and injecting drug use among mental-health support workers of a community managed organisation

Objectives People with mental illness are at significantly higher risk of acquiring hepatitis C virus (HCV) compared with the general population. This study assessed knowledge of and attitudes towards people with HCV and people who inject drugs (PWID) among support workers of clients with mental illness. Methods Support workers from a community managed organisation (CMO) in Australia were recruited to complete an online cross-sectional survey. The survey collected data about their knowledge of HCV and attitudes towards PWID and people with HCV. Results Valid responses were received from 117 support workers. Although HCV knowledge was moderate, there were significant knowledge gaps around transmission and treatment of HCV. Higher HCV knowledge was significantly associated with more positive attitudes towards PWID, but not with attitudes towards people with HCV. Participants had more positive attitudes towards people with HCV than towards PWID. Additionally, those with more positive attitudes towards HCV tended to also have more positive attitudes towards PWID. Conclusions Given that people with mental illness are at higher risk of acquiring HCV, these results point to the need for education targeted at support workers of clients with mental illness to increase HCV knowledge and promote positive attitudes towards PWID and people with HCV. What is known about this topic? The limited research available suggests that there are gaps in HCV knowledge among mental-health-service providers, although such research has generally targeted physicians. What does this paper add? This paper is the first to assess HCV knowledge, attitudes towards PWID and HCV among mental-health support workers. The findings suggest that although HCV knowledge is moderate, significant gaps exist, which are related to negative attitudes towards PWID. What are the implications for practitioners? Supportive and non-judgemental care is essential for people with mental illness and HCV, due to the potential for a double stigma arising from negative attitudes towards both mental illness and injecting drug use. This paper highlights the importance of targeted education for workers in the mental-health sector, to increase HCV knowledge and promote positive attitudes towards people with co-occurring mental-health, substance use problems and HCV.