Treating hepatitis C: current standard of care and emerging direct-acting antiviral agents

Incidence of Liver and Non-liver Cancers After Hepatitis C Virus Eradication: A Population-Based Cohort Study

BACKGROUND AND OBJECTIVES

Direct-acting antivirals (DAAs) offer a high rate of hepatitis C virus (HCV) eradication. However, concerns on the risk of cancer after HCV eradication remain. Our study aimed at quantifying the incidence of cancer in patients treated with anti-HCV therapies in Catalonia (Spain) and their matched controls.

METHODS

This was a population-based study using real-world data from the public healthcare system of Catalonia between 2012 and 2016. Propensity score matching was performed in patients with HCV infection treated with interferon-based therapy (IFN), sequential IFN and DAA (IFN+DAA), and DAA only (DAA) with concurrent controls. We estimated the annual incidence of overall cancer, hepatocellular carcinoma, and non-liver cancer of HCV-treated patients and their corresponding rate ratios.

RESULTS

The study included 11,656 HCV-treated patients and 49,545 controls. We found statistically significant increases in the rate of overall cancer for IFN+DAA-treated (rate ratio [RR] 1.77, 95% confidence interval [CI] 1.27-2.46) and DAA-treated patients (RR 1.90, 95% CI 1.66-2.19) and in the rate of HCC for IFN-treated (RR 1.50, 95% CI 1.02-2.22), IFN+DAA-treated (RR 3.89, 95% CI 2.26-6.69), and DAA-treated patients (RR 6.45, 95% CI 4.90-8.49) compared with their corresponding controls. Moreover, DAA-treated patients with cirrhosis showed an increased rate of overall cancer versus those without cirrhosis (RR 1.92, 95% CI 1.51-2.44).

CONCLUSIONS

Results showed that overall cancer and hepatocellular carcinoma incidence in Catalonia was significantly higher among HCV-treated patients compared with matched non-HCV-infected controls, and risks were higher in patients with cirrhosis. An increased awareness of the potential occurrence of uncommon malignant events and monitoring after HCV eradication therapy may benefit patients.

Hepatitis C: The Story of a Long Journey through First, Second, and Third Generation NS3/4A Peptidomimetic Inhibitors. What Did We Learn?

Hepatitis C viral (HCV) infection is the leading cause of liver failure and still represents a global health burden. Over the past decade, great advancements made HCV curable, and sustained viral remission significantly improved to more than 98%. Historical treatment with pegylated interferon alpha and ribavirin has been displaced by combinations of direct-acting antivirals. These regimens include drugs targeting different stages of the HCV life cycle. However, the emergence of viral resistance remains a big concern. The design of peptidomimetic inhibitors (PIs) able to fit and fill the conserved substrate envelope region within the active site helped avoid contact with the vulnerable sites of the most common resistance-associated substitutions Arg155, Ala156, and Asp168. Herein, we give an overview of HCV NS3 PIs discovered during the past decade, and we deeply discuss the rationale behind the structural optimization efforts essential to achieve pangenotypic activity.

Construction and characterization of a new hepatitis C virus genotype 6a subgenomic replicon that is prone to render the sofosbuvir resistance

Hepatitis C virus (HCV) infection remains a challenge to human public health despite the development of highly effective direct-acting antivirals (DAAs). Sofosbuvir (SOF), a key component in most DAA-based anti-HCV cocktail regimens, is a potent viral RNA polymerase (NS5B) inhibitor with a high barrier to drug resistance. The serine-to-threonine mutation at NS5B 282 (S282T) confers the SOF resistance, but severely impairs viral replication in most HCV genotypes (GTs) and cannot be stably maintained after the termination of the SOF-based therapies. In this study, we first developed a new HCV GT-6a subgenomic replicon PR58D6. Next, we selected SOF-resistant PR58D6 variants by culturing the replicon cells in the presence of SOF. Interestingly, unlike many other HCV replicons which require additional mutations to compensate for the S282T-inducing fitness loss, S282T alone in PR58D6 is genetically stable and confers the SOF resistance without significantly impairing viral replication. Furthermore, we showed that amino acid residue at NS5B 74 (R74) and 556 (D556) which are conserved in GT 6a HCV contribute to efficient replication of PR58D6 containing S282T. Finally, we showed that the G556D mutation in NS5B could rescue the replication deficiency of the S282T in JFH1, a GT-2a replicon. In conclusion, we showed that a novel GT-6a HCV replicon may easily render SOF resistance, which may call for attention to potential drug resistance during DAA therapies of HCV GT-6a patients.

Interventions for dialysis patients with hepatitis C virus (HCV) infection

BACKGROUND

Hepatitis C virus (HCV) infection is common in chronic kidney disease (CKD) patients on dialysis, causes chronic liver disease, may increase the risk of death, and impacts kidney transplant outcomes. Direct-acting antivirals have replaced interferons because of better efficacy and tolerability. This is an update of a review first published in 2015.

OBJECTIVES

We aimed to look at the benefits and harms of interventions for HCV in CKD patients on dialysis: death, disease relapse, treatment response/discontinuation, time to recovery, quality of life (QoL), cost-effectiveness, and adverse events. We aimed to study comparisons of available interventions, compared with placebo, control, with each other and with newer treatments.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant's Specialised Register to 23 February 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE and EMBASE, handsearching conference proceedings, and searching the International Clinical Trials Register Portal (ICTRP) and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, first period of randomised cross-over studies on interventions for HCV in CKD on dialysis were considered.

DATA COLLECTION AND ANALYSIS

Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI). Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Three studies were included in this update, therefore 13 studies (997 randomised participants) met our inclusion criteria. Overall, the risk of bias was judged low in seven studies, unclear in four, low to unclear in one, and high in one study. Interventions included standard interferon, pegylated (PEG) interferon, standard or PEG interferon plus ribavirin; direct-acting antivirals, and direct-acting antivirals plus PEG interferon plus ribavirin. Compared to placebo or control, standard interferon may make little or no difference to death (5 studies, 134 participants: RR 0.89, 95% CI 0.06 to 13.23) or relapse (low certainty evidence), probably improves end-of-treatment response (ETR) (5 studies, 132 participants: RR 8.62, 95% CI 3.03 to 24.55; I² = 0%) (moderate certainty evidence), and probably makes little or no difference to sustained virological response (SVR) (4 studies, 98 participants: RR 3.25, 95% CI 0.81 to 13.07; I² = 53%), treatment discontinuation (4 studies, 116 participants: RR 4.59, 95% CI 0.49 to 42.69; I² = 63%), and adverse events (5 studies, 143 participants: RR 3.56, 95% CI 0.98 to 13.01; I² = 25%) (moderate certainty evidence). In low certainty evidence, PEG interferon (1 study, 50 participants) may improve ETR (RR 1.53, 95% CI 1.09 to 2.15) but may make little or no difference to death (RR 0.33, 95% CI 0.01 to 7.81), SVR (RR 2.40, 95% CI 0.99 to 5.81), treatment discontinuation (RR 0.11, 95% CI 0.01 to 1.96), adverse events (RR 0.11, 95% CI 0.01 to 1.96) and relapses (21/38 relapsed) (RR 0.72, 95% CI 0.41 to 1.25) compared to standard interferon. In moderate certainty evidence, high-dose PEG interferon (alpha-2a and alpha-2b) may make little or no difference to death (2 studies, 97 participants: RR 4.30, 95% CI 0.76 to 24.33; I² = 0%), ETR (RR 1.42, 95% CI 0.51 to 3.90; I² = 20%), SVR (RR 1.19, 95% CI 0.68 to 2.07; I² = 0%), treatment discontinuation (RR 1.20, 95% CI 0.63 to 2.28; I² = 0%) or adverse events (RR 1.05, 95% CI 0.61 to 1.83; I² = 27%) compared to low-dose PEG interferon. High-dose PEG interferon may make little or no difference to relapses (1 study, 43 participants: RR 1.11, 95% CI 0.45 to 2.77; low certainty evidence). There were no significant subgroup differences. Standard interferon plus ribavirin may lead to higher treatment discontinuation (1 study, 52 participants: RR 2.97, 95% CI 1.19 to 7.36; low certainty evidence) compared to standard interferon alone.  In low certainty evidence, PEG interferon plus ribavirin (1 study, 377 participants) may improve SVR (RR 1.80, 95% CI 1.46 to 2.21), reduce relapses (RR 0.33, 95% CI 0.23 to 0.48), slightly increase the number with adverse events (RR 1.10, 95% CI 1.01 to 1.19), and may make little or no difference to ETR (RR 1.01, 95% CI 0.94 to 1.09) compared to PEG interferon alone. The evidence is very uncertain about the effect of PEG interferon plus ribavirin on treatment discontinuation (RR 1.71, 95% CI 0.69 to 4.24) compared to PEG interferon alone. One study reported grazoprevir plus elbasvir improved ETR (173 participants: RR 174.99, 95% CI 11.03 to 2775.78; low certainty evidence) compared to placebo. It is uncertain whether telaprevir plus ribavirin (high versus low initial dose) plus PEG interferon for 24 versus 48 weeks (1 study, 35 participants) improves ETR (RR 1.02, 95% CI 0.67 to 1.56) or SVR (RR 1.02, 95% CI 0.67 to 1.56) because the certainty of the evidence is very low.  Data on QoL, cost-effectiveness, cardiovascular outcomes and peritoneal dialysis were not available.

AUTHORS' CONCLUSIONS

In dialysis patients with HCV infection grazoprevir plus elbasvir probably improves ETR. There is no difference in ETR or SVR for combinations of telaprevir, ribavirin and PEG interferon given for different durations and doses. Though no longer in use, PEG interferon was more effective than standard interferon for ETR but not SVR. Increasing doses of PEG interferon did not improve responses. The addition of ribavirin to PEG interferon may result in fewer relapses, higher SVR, and higher numbers with adverse events.

Evaluation of interactions between the hepatitis C virus NS3/4A and sulfonamidobenzamide based molecules using molecular docking, molecular dynamics simulations and binding free energy calculations

The Hepatitis C Virus (HCV) NS3/4A is an attractive target for the treatment of Hepatitis C infection. Herein, we present an investigation of HCV NS3/4A inhibitors based on a sulfonamidobenzamide scaffold. Inhibitor interactions with HCV NS3/4A were explored by molecular docking, molecular dynamics simulations, and MM/PBSA binding free energy calculations. All of the inhibitors adopt similar molecular docking poses in the catalytic site of the protease that are stabilized by hydrogen bond interactions with G137 and the catalytic S139, which are known to be important for potency and binding stability. The quantitative assessments of binding free energies from MM/PBSA correlate well with the experimental results, with a high coefficient of determination, R2 of 0.92. Binding free energy decomposition analyses elucidate the different contributions of Q41, F43, H57, R109, K136, G137, S138, S139, A156, M485, and Q526 in binding different inhibitors. The importance of these sidechain contributions was further confirmed by computational alanine scanning mutagenesis. In addition, the sidechains of K136 and S139 show crucial but distinct contributions to inhibitor binding with HCV NS3/4A. The structural basis of the potency has been elucidated, demonstrating the importance of the R155 sidechain conformation. This extensive exploration of binding energies and interactions between these compounds and HCV NS3/4A at the atomic level should benefit future antiviral drug design.

Sofosbuvir-based direct-acting antivirals and changes in cholesterol and low density lipoprotein-cholesterol

Worsened lipid profiles were observed in chronic hepatitis C (CHC) patients during direct-acting antivirals (DAAs) treatment, among which combination drugs confounded the effect of individual ingredient on lipid. Tenofovir alafenamide (TAF) also worsened lipid profiles in HIV patients. Structural similarity between sofosbuvir (SOF) and TAF prompted us to investigate rapid increase in total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in CHC patients treated with SOF-based DAAs. A retrospective study was performed to analyze 487 CHC patients receiving DAAs with SVR12. Relative risks on elevating TC and LDL-C were analyzed by logistic regression to determine SOF-based over non-SOF-based regimens. TC or LDL-C levels at baseline, week-4 and SVR12 were compared by Wilcoxon matched-pairs signed rank test. Week 4 or SVR12 to baseline ratios of serum TC or LDL-C between regimens were compared by Mann–Whitney's test. 487 patients were treated with Harvoni (SOF-based, 206 patients), Epclusa (SOF-based, 124 patients), Maviret (non-SOF-based, 122 patients), or Zepatier (non-SOF-based, 35 patients). At week 4 during drug treatment, Harvoni, Epclusa, and Maviret induced statistically significant elevation of TC and LDL-C, but Zepatier did not. SOF-based regimens had 2.72-fold higher relative risk (RR) causing 10% elevation of TC (95% CI 1.84–4.02, p < 0.001) and 2.04-fold higher RR causing 10% elevation of LDL-C (95% CI 1.39–3.01, p < 0.001) than non-SOF-based DAAs. SOF-based DAAs were associated with significantly larger amplitude of increases in TC and LDL-C than non-SOF-based DAAs during the initial 4 weeks of treatment, but the increases were not sustained to SVR12.

Determination of Risk Factors Associated with the Failure of 12 Weeks of Direct-Acting Antiviral Therapy in Patients with Hepatitis C: A Prospective Study

Introduction

Direct-acting antivirals (DAAs) have significantly improved the efficacy and tolerability of the treatment of hepatitis C virus (HCV). However, studies conducted on actual patients with the aim of predicting the risk associated with treatment failure are lacking.

Methods

Our study enrolled 334 new HCV patients and assessed the effectiveness of treatment and predicted the risk of failure to achieve sustained virological response (SVR) by developing a multiple logistic model. Our study compared the variables between the two groups, those who did (group 0, n = 239) and did not achieve SVR (group 1, n = 95).

Results

The cure rate of HCV at 12^th week in our study was 71.56%. We found that advanced cirrhosis, HCV genotype, HBV coinfection, rapid virological response (RVR), fibrosis index (FIB-4) score, serum levels of AST, ALP, hemoglobin, and viral load before treatment were prognostic factors associated with rate of failure to achieve SVR at week 12 of DAA therapy. In the multiple logistic model, eight significant predictors including advanced cirrhosis status, HCV genotype, RVR, AST/ALP levels, FIB-4 score, and viral load before treatment predicted the risk of failure with excellent model performance (area under the receiver operating characteristic curve (AUC_ROC) [95% CI] =0.986 (0.971-0.999)). RVR and advanced cirrhosis were the two strongest predictors with odd ratios (95% CI) =9.72 (2.8, 39.28) and 51.54 (6.39, 139.82), respectively.

Conclusion

The multiple logistic regression model included significant factors to estimate the probability of failure to achieve SVR, which could improve HCV treatment strategy.

Factors Associated with Significant Platelet Count Improvement in Thrombocytopenic Chronic Hepatitis C Patients Receiving Direct-Acting Antivirals

To clarify the predictive factors of significant platelet count improvement in thrombocytopenic chronic hepatitis C (CHC) patients. CHC patients with baseline platelet counts of <150 × 103/μL receiving direct-acting antiviral (DAA) therapy with at least 12-weeks post-treatment follow-up (PTW12) were enrolled. Significant platelet count improvement was defined as a ≥10% increase in platelet counts at PTW12 from baseline. Platelet count evolution at treatment week 4, end-of-treatment, PTW12, and PTW48 was evaluated. This study included 4922 patients. Sustained virologic response after 12 weeks post-treatment was achieved in 98.7% of patients. Platelet counts from baseline, treatment week 4, and end-of-treatment to PTW12 were 108.8 ± 30.2, 121.9 ± 41.1, 123.1 ± 43.0, and 121.1 ± 40.8 × 103/μL, respectively. Overall, 2230 patients (45.3%) showed significant platelet count improvement. Multivariable analysis revealed that age (odds ratio (OR) = 0.99, 95% confidence interval (CI): 0.99-1.00, p = 0.01), diabetes mellitus (DM) (OR = 1.20, 95% CI: 1.06-1.38, p = 0.007), cirrhosis (OR = 0.66, 95% CI: 0.58-0.75, p < 0.0001), baseline platelet counts (OR = 0.99, 95% CI: 0.98-0.99, p < 0.0001), and baseline total bilirubin level (OR = 0.80, 95% CI: 0.71-0.91, p = 0.0003) were independent predictive factors of significant platelet count improvement. Subgroup analyses showed that patients with significant platelet count improvement and sustained virologic responses, regardless of advanced fibrosis, had a significant increase in platelet counts from baseline to treatment week 4, end-of-treatment, PTW12, and PTW48. Young age, presence of DM, absence of cirrhosis, reduced baseline platelet counts, and reduced baseline total bilirubin levels were associated with significant platelet count improvement after DAA therapy in thrombocytopenic CHC patients.

Hepatitis B Reactivation in Patients Treated with Direct-Acting Antivirals for Hepatitis C

INTRODUCTION

There is limited research about HBV reactivation (HBVr) due to direct-acting antivirals (DAA) for HCV and most are limited by short duration of follow-up, small sample size, and absence of baseline HBV DNA. We aimed to determine the incidence and clinical course of HBVr in HBsAg and/or anti-HBcIgG positive patients treated with DAA for HCV.

METHODS

Seven centers retrospectively analyzed their database on HCV patients treated with DAA between 2015 and 2019. Patients with HBV coinfection or resolved HBV infection were enrolled. Serum transaminases, HBsAg, HBeAg, and HBV DNA were followed every 4 weeks during DAA treatment and every 12 weeks 1 year after treatment. Entecavir or tenofovir disoproxil fumarate was started in case of HBVr. The development of HBVr, HBV flare, liver failure, and mortality were determined.

RESULTS

852 patients received DAA treatment for HCV. Among them, 35 (4.1%) had HBV coinfection and 246 (28.9%) had resolved HBV infection. 257 patients (53.3% male, mean age: 63 ± 9) constituted the study group (29 with coinfection and 228 with resolved infection). Three patients with coinfection were HBV DNA positive. HBVr developed in 10 (34.5%) HBsAg positive patients, either during (n = 3) or 12-48 weeks after finishing DAA treatment. HBV flare and acute liver failure developed in 1 patient (3.4%), each. Two patients with resolved infection developed HBVr (0.87%) and one (0.44%) had HBV flare. Overall, none of the patients died or underwent liver transplantation due to HBVr.

CONCLUSION

Patients with HBV/HCV coinfection have a high risk of HBVr after DAA treatment and should receive antiviral prophylaxis. Patients with resolved infection have a low risk of HBVr and can be monitored by serial ALT measurements.

The Impact of Antiviral Therapy for Hepatitis C Virus on the Survival of Patients after Hepatocellular Carcinoma Treatment

Objective Owing to advances in direct-acting antiviral (DAA) therapy, a considerable number of patients with hepatitis C virus (HCV)-positive hepatocellular carcinoma (HCC) are now able to achieve a sustained viral response (SVR) after curative treatment of HCC. However, the beneficial effect of a DAA-SVR on the survival remains unclear. Methods A total of 205 patients with HCC who were HCV-positive with Child-Pugh A at the onset from 2008 to 2018 were categorized into 2 groups: 140 patients untreated for HCV throughout the entire course after HCC development (untreated group) and 65 patients treated for HCV with DAAs following HCC treatment who achieved an SVR (SVR group). After propensity score matching, 63 patients from each group were selected. Using these patients, the survival and maintenance of Child-Pugh A after HCC treatment were compared between the untreated group and SVR group. Results There was a significant difference in the overall survival (p<0.001) and the rate of maintaining Child-Pugh A (p<0.001) between the groups. The 5-year survival rates were 96% (SVR group) and 60% (untreated group), and the proportions of patients with Child-Pugh A at 5 years after HCC treatment were 96% (SVR group) and 38% (untreated group). Conclusion In patients with HCV-positive HCC, achieving a DAA-SVR after HCC treatment significantly improved the overall survival rate compared with HCV-untreated patients. The contribution of DAA-SVR during the course of HCC treatment to a longer survival is mainly due to the prevention of the progression of Child-Pugh A to B/C. Further research is needed to determine whether aggressive antiviral therapy is also effective for HCC patients with Child-Pugh B/C.

Identification of a novel replication-competent hepatitis C virus variant that confers the sofosbuvir resistance

Despite the excellent antiviral potency of direct-acting antivirals (DAAs) against hepatitis C virus (HCV), emergence of drug-resistant viral mutations remains a potential challenge. Sofobuvir (SOF), a nucleotide analog targeting HCV NS5B - RNA-dependent RNA polymerase (RdRp), constitutes a key component of many anti-HCV cocktail regimens and confers a high barrier for developing drug resistance. The serine to threonine mutation at the amino acid position 282 of NS5B (S282T) is the mostly documented SOF resistance-associated substitution (RAS), but severely hampers the virus fitness. In this study, we first developed new genotype 1b (GT1b) subgenomic replicon cells, denoted PR52D4 and PR52D9, directly from a GT1b clinical isolate. Next, we obtained SOF-resistant and replication-competent PR52D4 replicon by culturing the replicon cells in the presence of SOF. Sequencing analysis showed that the selected replicon harbored two mutations K74R and S282T in NS5B. Reverse genetics analysis showed that while PR52D4 consisting of either single mutation K74R or S282T could not replicate efficiently, the engineering of the both mutations led to a replication-competent and SOF-resistant PR52D4 replicon. Furthermore, we showed that the K74R mutation could also rescue the replication deficiency of the S282T mutation in Con1, another GT1b replicon as well as in JFH1, a GT2a replicon. Structural modeling analysis suggested that K74R might help maintain an active catalytic conformation of S282T by engaging with Y296. In conclusion, we identified the combination of two NS5B mutations S282T and K74R as a novel RAS that confers a substantial resistance to SOF while retains the HCV replication capacity.

Implications of the Conformationally Flexible, Macrocyclic Structure of the First-Generation, Direct-Acting Anti-Viral Paritaprevir on Its Solid Form Complexity and Chameleonic Behavior

Direct-acting antiviral regimens have transformed therapeutic management of hepatitis C across all prevalent genotypes. Most of the chemical matter in these regimens comprises molecules well outside the traditional drug development chemical space and presents significant challenges. Herein, the implications of high conformational flexibility and the presence of a 15-membered macrocyclic ring in paritaprevir are studied through a combination of advanced computational and experimental methods with focus on molecular chameleonicity and crystal form complexity. The ability of the molecule to toggle between high and low 3D polar surface area (PSA) conformations is underpinned by intramolecular hydrogen bonding (IMHB) interactions and intramolecular steric effects. Computational studies consequently show a very significant difference of over 75 Ų in 3D PSA between polar and apolar environments and provide the structural basis for the perplexingly favorable passive permeability of the molecule. Crystal packing and protein binding resulting in strong intermolecular interactions disrupt these intramolecular interactions. Crystalline Form I benefits from strong intermolecular interactions, whereas the weaker intermolecular interactions in Form II are partially compensated by the energetic advantage of an IMHB. Like Form I, no IMHB is observed within the receptor-bound conformation; instead, an intermolecular H-bond contributes to the potency of the molecule. The choice of metastable Form II is derisked through strategies accounting for crystal surface and packing features to manage higher form specific solid-state chemical reactivity and specific processing requirements. Overall, the results show an unambiguous link between structural features and derived properties from crystallization to dissolution, permeation, and docking into the protein pocket.

Effect of sofosbuvir-based DAAs on changes in lower-density lipoprotein in HCV patients: a systematic review and meta-analysis

BACKGROUND

Previous studies reported worsened lipid profiles in patients infected with hepatitis C virus (HCV) during direct-acting antivirals (DAAs) treatment. This study aimed to investigate the effect of sofosbuvir (SOF)-based DAAs on changes in low-density lipoprotein (LDL) in HCV patients.

METHODS

A systematic review of articles published before 31 May 2021 was conducted by searching MEDLINE, Cochrane Library, EMBASE, and CINAHL Plus. Eligible studies were those comparing SOF-based DAAs and non-SOF DAAs for HCV patients and providing numerical data for changes in LDL. Risk of Bias in Non-randomized Studies- of Interventions was used for assessing risk of bias, and meta-analysis was performed for changes in LDL.

RESULTS

Six studies comprising 1248 patients were included, 848 patients treated with SOF-based DAAs and 400 patients with non-SOF DAAs vs. SOF-based DAAs group had significantly greater increases in LDL from baseline to week 4 than non-SOF DAAs group (P = 0.001). However, changes in LDL from baseline to the end of treatment (P = 0.060), to post-treatment week 12 (P = 0.263), and to post-treatment week 24 (P = 0.319) did not significantly differ between the two groups. Further comparison of SOF/ledipasvir with asunaprevir/daclatasvir revealed a similar trend in changes in LDL.

CONCLUSIONS

For HCV patients, SOF-based DAA regimens were associated with rapid and significant increases in LDL during the initial 4 weeks of treatment, and the changes did not sustain after the end of treatment. Potential mechanism might be related to the phosphoramidate side chain of SOF.

Hepatitis C virus infection and anaesthesia practice: A narrative review

This paper reviews the natural and treated history of hepatitis C virus infection, the interactions between current therapies and anaesthesia medications, and the implications of occupational exposure and infection to anaesthetists in light of significant changes in treatment. In the past decade, the introduction of new direct acting antiviral medications has seen high cure rates with a sustained viral response across all virus genotypes. These medications are well tolerated with minimal side-effects. Should a patient on these medications require anaesthesia, there are few clinically significant interactions with commonly used anaesthesia medications, and minimal perioperative investigations are required, although delaying elective surgery until after the completion of treatment regimens should be considered to maximise treatment success. As anaesthetists may practise exposure-prone procedures, regular screening for hepatitis C virus infection remains recommended to enable both patient protection and treatment of the anaesthetist prior to the development of any long-term complications of hepatitis C virus infection. Similarly, early diagnosis and treatment of occupationally acquired hepatitis C virus infection after body fluid exposure is associated with high cure rates with minimal risk of long-term liver damage. Although hepatitis C virus infection remains a significant public health issue in Australia and New Zealand, improvements in outcomes as a result of new treatment regimens have allowed the World Health Organization to target the elimination of hepatitis C virus infection as a public health threat by 2030, and public health strategies are being implemented to achieve this goal.

Cost-Utility of All-Oral Direct-Acting Antiviral Regimens for the Treatment of Genotype 1 Chronic Hepatitis C Virus-Infected Patients in Hong Kong

BACKGROUND

Direct-acting antivirals (DAAs) are entering the hepatitis C virus (HCV) treatment landscape in Hong Kong, prompting the need for cost-effectiveness evaluations of these interventions to enable optimal use of healthcare resources.

AIMS

This study aimed to compare the cost-effectiveness of DAAs to standard-of-care pegylated interferon plus ribavirin (RBV) in treatment-naïve patients without significant liver fibrosis and to compare different DAAs in patients who are treatment-experienced and/or have advanced liver disease.

METHODS

A Markov model was constructed to evaluate cost-effectiveness over a lifetime time horizon from the payer perspective. The target population was treatment-naïve and treatment-experienced HCV genotype 1 patients, stratified by degree of liver fibrosis. The model consists of 16 health states encompassing METAVIR fibrosis score (F0-F4), treatment success or failure, decompensated cirrhosis, hepatocellular carcinoma, liver transplant, and liver-related death. The proportions of patients achieving sustained virologic response were obtained from clinical trials. Other inputs were obtained from published and local data. The primary outcome was incremental cost-utility ratio for each DAA versus pegylated interferon + ribavirin and among different DAAs.

RESULTS

In treatment-naïve F0-2 HCV patients, all DAAs were cost-effective in genotype 1a and daclatasvir + asunaprevir, elbasvir/grazoprevir, ledipasvir/sofosbuvir, and glecaprevir/pibrentasvir were cost-effective compared to pegylated interferon + ribavirin in genotype 1b. In genotypes 1a and 1b, treatment-experienced patients, and F3-4 patients, elbasvir/grazoprevir was the least costly DAA and economically dominant over most other DAAs.

CONCLUSIONS

DAAs can be a cost-effective option for the treatment of genotype 1 HCV patients in Hong Kong, and elbasvir/grazoprevir is cost-effective.

Design and Synthesis of Novel Symmetric Fluorene-2,7-Diamine Derivatives as Potent Hepatitis C Virus Inhibitors

Hepatitis C virus (HCV) is an international challenge. Since the discovery of NS5A direct-acting antivirals, researchers turned their attention to pursue novel NS5A inhibitors with optimized design and structure. Herein we explore highly potent hepatitis C virus (HCV) NS5A inhibitors; the novel analogs share a common symmetrical prolinamide 2,7-diaminofluorene scaffold. Modification of the 2,7-diaminofluorene backbone included the use of (S)-prolinamide or its isostere (S,R)-piperidine-3-caboxamide, both bearing different amino acid residues with terminal carbamate groups. Compound 26 exhibited potent inhibitory activity against HCV genotype (GT) 1b (effective concentration (EC₅₀) = 36 pM and a selectivity index of >2.78 × 10⁶). Compound 26 showed high selectivity on GT 1b versus GT 4a. Interestingly, it showed a significant antiviral effect against GT 3a (EC₅₀ = 1.2 nM). The structure-activity relationship (SAR) analysis revealed that picomolar inhibitory activity was attained with the use of S-prolinamide capped with R- isoleucine or R-phenylglycine residues bearing a terminal alkyl carbamate group.

Metabolism of Direct-acting Antiviral Agents (DAAs) in Hepatitis C Therapy: A Review of the Literature

BACKGROUND

Hepatitis C virus (HCV) infection is still one of the leading causes of chronic liver disease, with chronically infected making up approximately 1% of the global population. Of those infected, 70% (55-85%) will develop chronic HCV infection. Chronic HCV infection causes substantial morbidity and mortality, with complications including cirrhosis, end-stage liver disease, hepatocellular carcinoma, and eventually death.

OBJECTIVE

Therapeutic options for chronic HCV infection have evolved dramatically since 2014, with a translation from pegylated interferon and ribavirin (associated with suboptimal cure and high treatment-related toxicity) to oral direct-acting antiviral treatment. There are four classes of direct-acting antivirals which differ by their mechanism of action and therapeutic target. They are all pointed to proteins that form the cytoplasmic viral replication complex. Multiple studies have demonstrated that direct-acting antiviral therapy is extremely well tolerated, highly efficacious, with few side effects.

METHODS

We performed an indexed MEDLINE search with keywords regarding specific direct-acting antiviral regimes and their pharmacokinetics, drug-drug interactions, and metabolism in specific settings of pregnancy, lactation, liver cirrhosis, liver transplantation and HCC risk, kidney failure and kidney transplantation.

RESULTS

We present a comprehensive overview of specific direct-acting antiviral metabolism and drug-drug interaction issues in different settings.

CONCLUSION

Despite its complex pharmacokinetics and the possibility of drug-drug interactions, direct-acting antivirals are highly efficacious in providing viral clearance, which is an obvious advantage compared to possible interactions or side effects. They should be administered cautiously in patients with other comorbidities, and with tight control of immunosuppressive therapy.

Prevalence of Naturally-Occurring NS5A and NS5B Resistance-Associated Substitutions in Iranian Patients With Chronic Hepatitis C Infection

BACKGROUND

Hepatitis C virus (HCV), non-structural 5A (NS5A), and non-structural 5B (NS5B) resistance-associated substitutions (RASs) are the main causes of failure to direct-acting antiviral agents (DAAs). NS5A and NS5B RASs can occur in patients with HCV infection naturally and before exposure to DAAs.

OBJECTIVES

This study aimed to evaluate naturally-occurring NS5A and NS5B RASs in Iranian patients with HCV genotype 1a (HCV-1a) and -3a infections.

METHODS

In this cross-sectional study, viral RNA was extracted from serum specimens. NS5A and NS5B regions were amplified using RT-PCR followed by DNA sequencing. The results of nucleotide sequences were aligned against reference sequences of HCV-1a and -3a and the amino acid substitutions were analyzed using geno2pheno [hcv] web application.

RESULTS

Among 135 patients with hepatitis C, NS5A amino acid substitutions/RASs were identified in 26.4% and 15.9% of patients with HCV-1a and -3a infections, respectively. The identified amino acid substitutions/RASs in the NS5A region of patients with HCV-1a infection were M28T/V/I 11.1%, Q30R/H 4.2%, L31M 1.4%, and H58Y/P/C/D/Q/S/T 16.7%. Y93H substitution was not found in HCV-1a sequences. In patients with HCV-3a infection, NS5A amino acid substitutions/RASs were A30T/K 9.5%, L31F 1.6%, P58S/T/C 3.2%, Y93H 3.2%, and Y93N 3.2%. No resistance substitutions were identified in NS5B sequences from patients with HCV-1a and -3a infections.

CONCLUSION

In this study, baseline amino acid substitutions/RASs were only identified in the NS5A region in Iranian patients with HCV-1a and -3a infections, and the prevalence of these amino acid substitutions/RASs were in accordance with similar studies. There were no RASs in the HCV-1a and -3a NS5B region.

Prevention of Hepatitis C Virus Infection and Liver Cancer

Hepatocellular carcinoma (HCC) is the fifth most prevalent cancer and the second leading cause of cancer-related death worldwide.

Hepatitis C: clinical management and debated issues

Hepatitis C virus represents an important global health issue with 71 million of infected people in the word. Direct-acting antivirals are quite new molecules that hit specific Hepatitis C virus proteins useful for viral replication and assembly. Notably, Direct-acting antivirals bring to high sustained virological response rates showing also a great safety profile. This treatment revolution had an impact on transplantation world, in fact the number of liver transplants due to Hepatitis C virus-related cirrhosis and hepatocellular carcinoma is quickly decreasing. Even if this therapy has achieved excellent results in terms of morbility and mortality rates' reduction, there are some debated issues to consider. In the present review the main clinical challenges in every-day management of Hepatitis C virus patients treated with Direct-acting antivirals and the debated effects of viral clearance (metabolic, cardiovascular, immunologic and neoplastic) are discussed. The detection of barriers that can preclude the delivery of Hepatitis C virus care, is the most complex challenge for the scientific community. To obtain the Hepatitis C virus global eradication by 2030, as the World Health Organization has set, will be complex and laborious and will need a further multilevel effort.

Hepatitis C Virus: Efficacy of New DAAs Regimens

BACKGROUND

HCV treatment showed dramatical change due to the introduction of potent, strong, direct antiviral drugs. Before the appearance of Direct-acting antivirals, multiple therapeutic interventions were used for hepatitis C, but none of these interventions were effective on patient-centered outcomes. Direct-acting antivirals cause disruption of viral replication because they target specific nonstructural viral proteins.

AIM

To review the advantages of efficient HCV therapy and its long term drawbacks.

METHODS

A search of the literature published in indexed databases (PubMed, Medline In-Process, and Embase) within the last 5 years was conducted. Any duplicated citations were excluded before first-pass screening. Citations (titles and abstracts) were screened for eligibility by a single reviewer. Full texts (including congress abstracts, posters and other congress communications) of citations deemed relevant during title and abstract screening were retrieved for second-pass review.

RESULTS

Studies on the clinical effects of DAAs for hepatitis C show better tolerance, improved survival and fewer complications when compared to previous interferon therapy.

CONCLUSION

HCV treatment has improved dramatically. Since that time, there are multiple approved oral therapies all with high efficacy. The most important factor which should be considered during choosing appropriate therapy is to ensure that it covers the viral genotype of the infected patients.

Levels of tacrolimus after treatment for chronic hepatitis C with direct antiviral agents in solid organ transplant recipients

Background and objective The main objective was to evaluate the impact of Hepatitis C Virus treatment with direct-acting antiviral agents on tacrolimus blood levels in recipients of kidney and heart allografts. Method We analysed Hepatitis C Virus infected adult patients who received tacrolimus as immunosuppressive maintenance therapy and received direct-acting antiviral agents treatment in a tertiary hospital with solid transplant multidisciplinary program in Madrid, Spain. Liver and renal function, tacrolimus dose and blood levels were analysed before and 12 weeks after the end of treatment. Results We identified 7 kidney and 2 heart transplant recipients. All patients achieved sustained virologic response at 24 weeks. At week 12 after treatment, all liver functionality tests improved significantly with no significant changes in renal function. A decrease in the tacrolimus blood level/dose ratio for every patient was observed (370.04 ± 253.93 vs. 186.44 ± 123.74 ng/mL per mg/kg; p < 0.05). The requirements of tacrolimus dose increased after Hepatitis C Virus treatment (0.03 ± 0.04 vs. 0.04 ± 0.03 mg/kg/day, p < 0.05) to reach lower blood levels than before treatment (6 ± 2.25 vs. 4.67 ± 1.51 ng/mL, p < 0.05). Conclusion Caution is advised to clinicians; close monitoring of tacrolimus levels after direct-acting antiviral agents is recommended in order to avoid infradosification that could pose a risk of graft rejection.

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.

Baseline resistance associated substitutions in HCV genotype 1 infected cohort treated with Simeprevir, Daclatasvir and Sofosbuvir in Brazil

BACKGROUND

The World Health Organization estimates that 1% of the world population (71 million) is infected with hepatitis C virus (HCV). In 2015, three direct-acting antivirals (DAAs), simeprevir (SMV), sofosbuvir (SOF) and daclatasvir (DCV) were included in the Brazilian protocol for the treatment of chronic hepatitis C. Despite the fact that the use of these drugs is associated with higher treatment response rates and with lower incidence of side effects, studies have shown the association between the presence of viral resistance mutations and the failure of pharmacological treatment.

AIM

This way, this study aimed to evaluate the safety and effectiveness of treatment for HCV genotypes 1a and 1b infected patients with these DAAs, also analyzing the occurrence and prevalence of baseline resistance associated substitutions (RAS), observing the impact of these mutations into the treatment success.

METHODS

Clinical data were collected from all the 262 HCV infected patients included for comparative analysis, while serum samples collected from 144 of these individuals, before treatment, were submitted to molecular biology approaches for mutation analysis into NS3, NS5A and NS5B regions.

RESULTS

Regarding the treatment regimens, 49.6% of the patients received SOF+DCV±ribavirin and 50.4% used SOF+SMV±ribavirin. The sustained virological response at 12 weeks post-treatment (SVR12) rate was 92.7% (93.9% for SOF plus DCV and 91.7% for SOF plus SMV). No clinical or laboratorial factor was statistically associated with SVR. The most common adverse reactions were haematological events, nausea/vomiting, headache and asthenia. Out of 144 blood samples, 70 (48.6%) had detected RAS, 34.8% treated with SOF+DCV±ribavirin and 61.3% SOF+SMV±ribavirin. The resistance mutations against SMV were detected into NS3: substitutions G122S (28%), I170V (22.7%), Y56F (17.3%) and V132I (14.7%). The mutations against DCV R30Q (9.1%), P58H (6.1%) and Q62E (6.1%) were observed into NS5A, and for SOF the mutations A421V (10.6%), L159F (6.4%) and C316N (6.4%) were present inside NS5B viral protein. Four patients did not reach SVR, three of them presented viruses carrying RAS (1 treated with SOF+DCV and 2 with SOF+SMV). Some of these mutations, like R30Q (present in relapsing samples) and L159F, are well known by their influence on antiviral resistance, while others, like C316N, have a compensatory effect on viral fitness, maintaining these baseline RAS.

CONCLUSION

The use of treatment regimens composed of SOF and DCV or SOF and SMV showed a high SVR rate, despite of a high rate of RAS, and a good tolerability profile in patients with HCV genotype 1. However, the high occurrence of baseline RAS observed in this casuistic is still a concern and studies like this show the necessity to understand how they are maintained in the population and to direct more efficiently the use of DAAs.

Animal Models Used in Hepatitis C Virus Research

The narrow range of species permissive to infection by hepatitis C virus (HCV) presents a unique challenge to the development of useful animal models for studying HCV, as well as host immune responses and development of chronic infection and disease. Following earlier studies in chimpanzees, several unique approaches have been pursued to develop useful animal models for research while avoiding the important ethical concerns and costs inherent in research with chimpanzees. Genetically related hepatotropic viruses that infect animals are being used as surrogates for HCV in research studies; chimeras of these surrogate viruses harboring specific regions of the HCV genome are being developed to improve their utility for vaccine testing. Concurrently, genetically humanized mice are being developed and continually advanced using human factors known to be involved in virus entry and replication. Further, xenotransplantation of human hepatocytes into mice allows for the direct study of HCV infection in human liver tissue in a small animal model. The current advances in each of these approaches are discussed in the present review.

Tumor aggression among hepatitis-C related hepatocellular carcinoma patients: an observational study regarding the impact of anti-HCV therapy

BACKGROUND

Hepatitis C virus (HCV) represents a major risk factor for hepatocellular carcinoma (HCC) development and anti-HCV therapy is a significant measure to reduce the incidence of HCC, however development of HCC in HCV treated patients is an emerging clinical problem which needs to be investigated. In this study we aim to analyze association between anti-HCV therapy and tumor pattern of HCV related HCC patients.

METHODS

Hepatocellular Carcinoma (HCC) patients with seropositivity for hepatitis C virus (HCV) antibodies, registered at three tertiary care hospitals of Rawalpindi and Islamabad, Pakistan during August 2017 to July 2018 were enrolled. Selected patients were then segregated in two groups on the basis of their HCV treatment history i.e., "TN" (HCV Treatment Naïve i.e. having no history/medical record for treatment prior to HCC diagnosis) and "TH" (Treated for HCV infection). Aggressiveness index (AgI) scoring system was applied to determine the tumor pattern. Univariate and multivariate analysis was carried out to analyze the independent effect of anti-HCV therapy on tumor pattern.

RESULTS

Out of 234 consecutive HCC patients, 171 HCV-related HCC patients were enrolled in final analysis and labeled as "TN" (n = 120) and "TH" (n = 51). Tumor pattern was found to be significantly aggressive (P = 0.02) in the treated cohort with an adjusted odds of 2.47 for aggressive and 6.92 for highly aggressive tumor. Neutrophil to lymphocyte ratio (NLR) was strongly associated with highly aggressive tumor pattern (P = 0.012). Patients in TN group were found to be marginally older than those in the TH group (59.5 vs. 55 years) where mean age of the patients treated with direct acting anti-viral agents was found to be visibly lower than mean age of patients who received interferon based treatment (53.5 vs. 57 years) with significant masculine predominance (62.1 vs. 37.9%, P = 0.049).

CONCLUSION

We observed raised neutrophil to lymphocyte ratio and prominence of younger age with aggressive tumor biology in HCV treated HCC patients. These observations highlight the need for a longitudinal prospective study on HCV positive subjects treated with antivirals, irrespective of treatment response.

Direct-Acting Antivirals Improve Overall Survival in Interventional Oncology Patients with Hepatitis C and Hepatocellular Carcinoma

PURPOSE

To investigate the impact of direct-acting antivirals (DAAs) and 12-week sustained virologic response (SVR12) in patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) treated by interventional oncology (IO) therapies.

MATERIALS AND METHODS

Retrospective analysis of patients diagnosed from 2005 to 2016 with HCC and receiving IO therapies. A total of 478 patients met inclusion criteria. Patients were age 29-90 years (mean 63.6 ± 9.4 years) and 78.9% (n =3 77) male. Two hundred and eighty-five (57%) patients had chronic HCV, 93 (33%) received DAAs, and 63 (68%) achieved SVR12. Liver function, tumor characteristics, and IO therapy including ablation, image-guided transcatheter tumor therapies (ITTT) (eg, chemoembolization and radioembolization), and combination locoregional therapy were assessed in analysis.

RESULTS

Median overall survival (OS) of the cohort was 26.7 months (95% confidence interval [CI] 21.9-29.9). OS for ablation, combination locoregional therapy and ITTT, was 37.3 (CI 30.7-49.9), 29.3 (CI 24.2-38.0), and 19.7 months (CI 16.5-22.8), respectively (P < .0001). OS in patients with HCV was 30.7 months (CI 24.2-35.2) versus 22.2 months in non-HCV patients (CI 17.8-27.8, P = .03). Patients with HCV who received DAA had higher survival, 49.2 months (CI 36.5-not reached) versus those not receiving DAA, 18.5 months (CI 14.1-25.3, P < .0001). OS was 71.8 months (CI 42.3-not reached) for patients who achieved SVR12 after DAA versus 26.7 months in the non-SVR12 group (CI 15.9-31.1, P < .0001). Multivariable analysis revealed independent factors for OS including IO treatment type, DAA use and achieving SVR12 (P < .05).

CONCLUSIONS

DAA use and SVR12 is associated with higher OS in patients with HCV-related HCC treated by IO therapies.

Hepatitis C virus infection and tight junction proteins: The ties that bind

The hepatitis C virus (HCV) is a major cause of liver diseases ranging from liver inflammation to advanced liver diseases like cirrhosis and hepatocellular carcinoma (HCC). HCV infection is restricted to the liver, and more specifically to hepatocytes, which represent around 80% of liver cells. The mechanism of HCV entry in human hepatocytes has been extensively investigated since the discovery of the virus 30 years ago. The entry mechanism is a multi-step process relying on several host factors including heparan sulfate proteoglycan (HSPG), low density lipoprotein receptor (LDLR), tetraspanin CD81, Scavenger Receptor class B type I (SR-BI), Epidermal Growth Factor Receptor (EGFR) and Niemann-Pick C1-like 1 (NPC1L1). Moreover, in order to establish a persistent infection, HCV entry is dependent on the presence of tight junction (TJ) proteins Claudin-1 (CLDN1) and Occludin (OCLN). In the liver, tight junction proteins play a role in architecture and homeostasis including sealing the apical pole of adjacent cells to form bile canaliculi and separating the basolateral domain drained by sinusoidal blood flow. In this review, we will highlight the role of liver tight junction proteins in HCV infection, and we will discuss the potential targeted therapeutic approaches to improve virus eradication.

Retreatment of chronic hepatitis C virus genotype-4 patients after non-structural protein 5A inhibitors' failure: efficacy and safety of different regimens

BACKGROUND

Nonstructural protein 5A (NS5A) is an important regimen for the treatment of chronic hepatitis C virus (HCV) genotype-4 infected patients. Retreatments for NS5A virologic failure are limited. The aim of this study is to provide real-life data regarding the effectiveness and safety of retreatment with different regimens after NS5A regimen virologic failure in GT4 patients.

PATIENTS AND METHODS

A total of 524 HCV patients (mean age 48 ± 11 years, 71% males), with virologic failure to sofosbuvir+daclatasvir, n = 450 and sofosbuvir/ledipasvir, n = 74 were included in this study. Patients were retreated with sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin, n = 278 and sofosbuvir + simeprevir + daclatasvir + ribavirin, n = 246. Response was evaluated 12 weeks after the end of treatment (SVR12).

RESULTS

Overall, SVR12 was 95.2% [95% confidence interval (CI) 93.3%-97.1%]. In sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin and sofosbuvir + simeprevir + daclatasvir + ribavirin, SVR12s were 94.9% (95% CI 92.5%-97.4%) and 95.5% (95% CI 92.8%-98%), respectively. In liver cirrhosis patients, SVR12s were 96.4% (95% CI 90.7%-100%) and 98% (95% CI 94.9%-100%), respectively. Relapse in the sofosbuvir + ombitasvir/paritaprevir/ritonavir + ribavirin was n = 14 patients, and n = 11 patients in sofosbuvir + simeprevir + daclatasvir + ribavirin. Three patients developed hepatic encephalopathy, haematemesis, lower limb oedema, and one patient died in the SOF + OBV/PTV/RTV + RIB. In the sofosbuvir + simeprevir + daclatasvir + ribavirin, three patients developed hepatocellular carcinoma and one patient died. No treatment discontinuation due to anaemia.

CONCLUSION

Salvage treatment for NS5A-treatment failure is effective and well tolerated in genotype-4 patients, in both noncirrhotic and compensated cirrhotic groups.

Emerging resistance to directly-acting antiviral therapy in treatment of chronic Hepatitis C infection-A brief review of literature

Hepatitis caused by Hepatitis C virus (HCV) is a major cause of chronic liver disease. HCV is transmitted by injection drug use, blood transfusion, hemodialysis, organ transplantation and less frequently sexual intercourse. It has been recognized as a global health problem because of the progression to cirrhosis and hepatocellular carcinoma. Globally, about 170 million people are infected with HCV. Since the discovery of this virus in 1989, the clinical management of chronic hepatitis C infection has undergone a paradigm shift from alpha interferon to direct-acting antiviral (DAA) therapy. However, resistance to many of these antiviral agents has been reported increasingly from all over the globe. This review article focuses on the emerging HCV resistance to DAAs and the relevance of in vitro DAA resistance testing in clinical practice.

Success of Direct-Acting, Antiviral-Based Therapy for Chronic Hepatitis C Is Not Affected by Type 2 Diabetes

Chronic hepatitis C virus (HCV) is a risk factor for type 2 diabetes. In the era of interferon-based HCV therapy, type 2 diabetes was associated with decreased likelihood of sustained virologic response (SVR). Preliminary studies suggest that type 2 diabetes may not reduce the efficacy of regimens involving direct-acting antiviral (DAA) medications. We aimed to determine whether preexisting type 2 diabetes is associated with a reduced rate of SVR achieved 12 weeks after treatment of HCV with DAA-based regimens.

Clinical impact of normal alanine aminotransferase on direct-acting antiviral outcome in patients with chronic hepatitis C virus infection

Background and Aims

This study aimed to clarify the clinical picture of hepatitis C virus (HCV) carriers with normal alanine aminotransferase (CNALT) and those with ALT elevation (non‐CNALT) under direct‐acting antivirals (DAAs).

Methods

We enrolled 1002 patients with HCV (427 men, median age: 69 years) who had received DAAs for comparisons between CNALT (ALT ≤33 U/L in males and ≤25 U/L in females; n = 374) and non‐CNALT (n = 628) groups.

Results

CNALT patients displayed a higher platelet count (PLT) (170 000 vs 146 000/μL, P < 0.0001) and albumin (4.1 vs 4.1 g/dL, P = 0.0006) but lower AST (25 vs 51 U/L, P < 0.0001), alpha fetoprotein (3.2 vs 5.4 ng/mL, P < 0.0001), and liver fibrosis marker scores (all P < 0.0001). The sustained virologic response rate was comparable between the CNALT and non‐CNALT groups (97.8 vs 95.3%, P = 0.106). The cumulative incidence of hepatocellular carcinoma (HCC) after DAA treatment was comparable between the CNALT and non‐CNALT groups (P = 0.117, log‐rank test). In CNALT patients with HCC history, PLT ≥150 000/μL was an independent risk factor of HCC recurrence (P = 0.019). In non‐CNALT patients without HCC history, male gender (P = 0.021) and albumin <4.0 g/dL (P = 0.007) were independent risk factors, while PLT < 150 000/μL (P = 0.081) was a marginal risk factor of HCC occurrence.

Conclusion

CNALT patients displayed a milder degree of liver fibrosis. Combinations of CNALT and PLT status might be useful as markers for HCC occurrence or recurrence surveillance.

Novel anti-flavivirus drugs targeting the nucleolar distribution of core protein

The risk of infectious diseases caused by Flavivirus is increasing globally. Here, we developed a novel high-throughput screening (HTS) system to evaluate the inhibitory effects of compounds targeting the nuclear localization of the flavivirus core protein. We screened 4000 compounds based on their ability to inhibit the nuclear localization of the core protein, and identified over 20 compounds including inhibitors for cyclin dependent kinase and glycogen synthase kinase. The efficacy of the identified compounds to suppress viral growth was validated in a cell-based infection system. Remarkably, the nucleolus morphology was affected by the treatment with the compounds, suggesting that the nucleolus function is critical for viral propagation. The present HTS system provides a useful strategy for the identification of antivirals against flavivirus by targeting the nucleolar localization of the core protein.

Impact of Direct Acting Antivirals on Survival in Patients with Chronic Hepatitis C and Hepatocellular Carcinoma

With the increasing use of direct-acting antivirals (DAA) for treatment of chronic hepatitis C virus (HCV) infection, we looked at the impact of DAA use and 12-week sustained viral response (SVR12) in patients with hepatocellular carcinoma (HCC) and HCV. This is a retrospective analysis of 969 HCC patients diagnosed from 2005 to 2016 at an urban tertiary-care hospital. Kaplan-Meier curves and multivariable Cox proportional hazards models were used to assess survival. Median overall survival of the cohort was 24.2 months. 470 patients had HCV (56%). 123 patients received DAA therapies for HCV (26.2%), 83 of whom achieved SVR12 (67.4%). HCV-positive and HCV-negative patients had similar survival, 20.7 months vs 17.4 months (p = 0.22). Patients receiving DAA therapy had an overall survival of 71.8 months vs 11.6 months for patients without (p < 0.0001). DAA patients who achieved SVR12 had an overall survival of 75.6 months vs. 26.7 months in the non SVR12 group (p < 0.0001). Multivariable analysis revealed AJCC, Child-Pugh Score, MELD, tumor size, tumor location, cancer treatment type, receiving DAA treatment and achieving SVR12 had independent influence on survival (p < 0.05). This suggests DAA therapy and achieving SVR12 is associated with increased overall survival in HCV patients with HCC.

Asymmetric Synthesis of 2'-C-Methyl-4'-selenonucleosides as Anti-Hepatitis C Virus Agents

In search of a new template for anti-hepatitis C virus (HCV) agents, we designed and synthesized the 2'-C-methyl-4'-selenopyrimidine and -purine nucleosides and their phosphoramidate prodrugs to replace a furanose oxygen of anti-HCV nucleos(t)ides with a selenium atom on the basis that selenium is a chemical isostere of oxygen. These nucleosides are expected to show different physicochemical properties such as better lipophilicity which might enhance the penetration across cell membranes and the conformational constraint induced by a bulky selenium atom in the sugar ring. The 2'-C-methyl-4'-selenopyrimidine and -purine nucleosides 8 and 9 were synthesized from 2-C-methyl-d-ribono-γ-lactone (14) via construction of 2-C-methyl-d-selenosugar 18 through C-4 epimerization and S_N2 cyclization with Se^2- as key steps. The key 4'-selenosugar was converted to the 2'-C-methyl-4'-selenopyrimidine and -purine nucleosides using Pummerer-type rearrangement and Vorbrüggen glycosylation, respectively. In addition, the ProTide strategy has been applied to synthesize the adenine and uracil phosphoramidate derivatives 10a and 10b to overcome the limitations associated with parent nucleosides such as inefficient conversion to their corresponding 5'-monophosphate form and poor cellular uptake. The regio- and stereochemistry of 4'-selenonucleosides were confirmed by 2D NOESY NMR spectroscopy and X-ray crystallography. None of the final pyrimidine and purine nucleosides and their prodrugs exhibited significant anti-HCV activity up to 100 μM.

Accuracy of budget impact estimations and impact on patient access: a hepatitis C case study

BACKGROUND

High budget impact (BI) estimates of new drugs limit access to patients due to concerns regarding affordability and displacement effects. The accuracy and methodological quality of BI analyses are often low, potentially mis-informing reimbursement decision making. Using hepatitis C as a case study, we aim to quantify the accuracy of the BI predictions used in Dutch reimbursement decision-making and to characterize the influence of market-dynamics on actual BI.

METHODS

We selected hepatitis C direct-acting antivirals (DAAs) that were introduced in the Netherlands between January 2014 and March 2018. Dutch National Health Care Institute (ZIN) BI estimates were derived from the reimbursement dossiers. Actual Dutch BI data were provided by FarmInform. BI prediction accuracy was assessed by comparing the ZIN BI estimates with the actual BI data.

RESULTS

Actual BI, from 1 Jan 2014 to 1 March 2018, was €248 million whilst the BI estimates ranged from €388-€510 million. The latter figure represents the estimated BI for the reimbursement scenario that was adopted, implying a €275 million overestimation. Absent incorporation of timing of regulatory decisions and inadequate correction for the introduction of new products were main drivers of BI overestimation, as well as uncertainty regarding the patient population size and the impact of the final reimbursement decision.

DISCUSSION

BI in reimbursement dossiers largely overestimated actual BI of hepatitis C DAAs. When BI analysis is performed according to existing guidelines, the resulting more accurate BI estimates may lead to better informed reimbursement decisions.

Development of latent Interferon alpha 2b as a safe therapeutic for treatment of Hepatitis C virus infection

Interferon therapy for the treatment of hepatitis C virus infection has very limited clinical application due to short serum half-life and side effects of therapy in systemic route of administration. In the present study, we have focused to improve the interferon therapy by overcoming the limitation of side effects. We hypothesized that latent interferon alpha 2b (IFNα2b) produced by fusion of Latency associated protein (LAP) domain of TGFβ and IFNα2b having HCV NS3 protease cleavage site as linker that will be activated only at target site (liver) by viral protease (HCV NS3 protease) present on the surface of infected cells. The fusion proteins were expressed in pichia pastoris as homodimer and cleaved by recombinant HCV NS3 protease in vitro into two fragments corresponding to the IFNα-2b and LAP respectively. The latency of chimeric proteins and biological activity after treatment with HCV NS3 protease was assessed by cytopathic effect inhibition assay in A594 cells infected with encephalomyocarditis virus (EMCV) and reduction in HCV viral load in Huh7 cells. The HCV NS3 protease was present on the surface of HCV replicating Huh7 cells in amount that activated half of the effective concentration (EC₅₀) of latent IFNα2b fusion protein. As free circulating HCV NS3 protease was not detected in sera from chronic HCV patients and in vitro cleavage of intact latent IFNα2b fusion protein was not observed with peripheral blood mononuclear cells (PBMCs) isolated from chronic HCV patients, thus there are less likely chances of activation and off target binding of latent IFNα2b to show side effects during systemic route of administration. Therefore, most of the side effects of interferon can be overwhelmed at the cost of 50% reduced biological activity. Thus, the use of latent IFNα2b can be considered again as an option for treatment of HCV infection in combination with direct acting antivirals rather than alone with improved safety profile.

Profile of sofosbuvir/velpatasvir/voxilaprevir in the treatment of hepatitis C

The treatment of chronic hepatitis C has been revolutionized with the introduction of direct-acting antivirals (DAAs). However, some patients are not cured with first-line treatment. Sofosbuvir/velpatasvir/voxilaprevir is a fixed-dose combination of a polymerase inhibitor, an NS5A inhibitor, and a protease inhibitor with activity against strains of the hepatitis C virus that show resistance to other first-line antiviral regimens. Sofosbuvir/velpatasvir/voxilaprevir has been studied in four Phase III randomized trials: POLARIS-1, −2, −3, and −4, which enrolled both treatment naïve and experienced patients with and without compensated cirrhosis. In these trials, at least 95% of patients treated with sofosbuvir/velpatasvir/voxilaprevir achieved sustained virological response (SVR). This includes favorable treatment outcomes in patients who had previously failed a regimen containing sofosbuvir or an NS5A inhibitor. Patient-reported outcomes also improved during and after treatment with sofosbuvir/velpatasvir/voxilaprevir. Treatment with sofosbuvir/velpatasvir/voxilaprevir is well tolerated, with the most commonly reported adverse events being headache, fatigue, diarrhea, and nausea. The approval of sofosbuvir/velpatasvir/voxilaprevir allows a treatment option for patients who have failed treatment with certain DAA regimens.

Nanomedicine as a future therapeutic approach for Hepatitis C virus

Hepatitis C virus (HCV) is not easily cleared from the human body and in most cases turned into chronic infection. This chronicity is a major cause of liver damage, cirrhosis and hepatocellular carcinoma. Therefore, immediate detection and treatment of HCV guarantees eradication of the virus and prevention of chronicity complications. Since discovery of HCV in 1989, several emerging treatments were developed such as polyethylene glycol(PEG)-ylated interferon/ribavirin, direct acting antivirals and host targeting antivirals. Despite the progress in anti-HCV therapy, there is still a pressing need of new approaches for affordable and effective drug delivery systems using nanomedicine. In this review, the contribution of nanoparticles as a promising delivery system for HCV immunizing, diagnostic and therapeutic agents are discussed.

Treatment of hepatitis C virus infection in patients with mixed cryoglobulinemic syndrome and cryoglobulinemic glomerulonephritis

Cryoglobulinemia is a common extrahepatic manifestation of infection with hepatitis C virus (HCV). When signs and symptoms of systemic vasculitis or glomerulonephritis occur in the presence of circulating cryoglobulins, this syndrome is called "mixed cryoglobulinemia syndrome" (MCS). Historically, interferon-based therapies in HCV have been associated with lower rates of viral cure in patients with MCS than in the general HCV-infected population. The advent of direct-acting antiviral therapies have revolutionized the treatment of HCV, dramatically increasing rates of cure. Early studies of first-generation protease inhibitors (telaprevir and boceprevir) in combination with interferon and ribavirin demonstrated HCV cure rates of 67% and complete clinical response rates of vasculitis symptoms in 60% of patients with MCS; however, regimens were poorly tolerated by patients, 22% discontinued treatment early. More recently, all-oral, interferon-free regimens have become available and combination therapies are now being approved for patients with and without renal impairment. Patients with HCV-MCS achieved sustained virologic response in 297 out of 313 patients (95%) treated with direct-acting antiviral therapy, and 85% had a complete or partial clinical response of MCS symptoms. Current direct-acting antiviral therapies are well tolerated in patients with HCV-MCS and only 1.6% discontinued treatment early. Patients with cryoglobulinemic glomerulonephritis also had an excellent cure rate (94%). The majority improved; 17/52 (33%) experienced full remission and 15/52 (29%) experienced partial remission. There were no reports of worsening kidney function in patients treated with direct-acting antiviral therapies. Less than 5% of patients with HCV-MCS treated with IFN-free direct-acting antiviral therapy required immunosuppression. However, patients with severe vasculitis appear to still require concomitant immunosuppression.

Incidence and risk factors of hepatocellular carcinoma change over time in patients with hepatitis C virus infection who achieved sustained virologic response

AIM

In patients with chronic hepatitis C, hepatocellular carcinoma (HCC) occurs at a certain frequency, even if a sustained virologic response (SVR) is achieved by antiviral treatment. Old age, liver fibrosis, and high post-treatment α-fetoprotein (AFP) level are typical risk factors of post-SVR HCC. We examined whether the frequencies and factors of HCC in patients with an SVR achieved from interferon treatment changed. Methods Among patients prospectively registered for pegylated interferon and ribavirin treatment, 2021 with an SVR without HCC development during the treatment period were followed up. The mean observation period was 49.5 ± 26.2 months.

RESULTS

The multivariable Cox regression analysis showed that older age, diabetes mellitus, advanced liver disease, and higher post-treatment AFP level were the independent risk factors throughout the observation period. The annual occurrence rate of HCC was 0.74% in the third year, 0.54% in the fourth year, and 0.40% in the fifth year; it gradually decreased from the third year. Because the time course hazards for HCC changed at 48 months, we separately analyzed its risk factors before and after this change point. The multivariable Cox regression analysis showed that the four above-mentioned factors were significantly related to HCC development within 4 years. Conversely, the univariable Cox regression analysis only identified diabetes mellitus as a significant factor for HCC development after 4 years.

CONCLUSION

The frequency of HCC in hepatitis C patients who achieved an SVR from interferon treatment decreased during the observation period, and its risk factors changed between the early and late periods.

Resistance outside the substrate envelope: hepatitis C NS3/4A protease inhibitors

Direct acting antivirals have dramatically increased the efficacy and tolerability of hepatitis C treatment, but drug resistance has emerged with some of these inhibitors, including nonstructural protein 3/4 A protease inhibitors (PIs). Although many co-crystal structures of PIs with the NS3/4A protease have been reported, a systematic review of these crystal structures in the context of the rapidly emerging drug resistance especially for early PIs has not been performed. To provide a framework for designing better inhibitors with higher barriers to resistance, we performed a quantitative structural analysis using co-crystal structures and models of HCV NS3/4A protease in complex with natural substrates and inhibitors. By comparing substrate structural motifs and active site interactions with inhibitor recognition, we observed that the selection of drug resistance mutations correlates with how inhibitors deviate from viral substrates in molecular recognition. Based on this observation, we conclude that guiding the design process with native substrate recognition features is likely to lead to more robust small molecule inhibitors with decreased susceptibility to resistance.

Discovery of novel pan-genotypic HCV NS5A inhibitors containing a novel tetracyclic core

A series of novel tetracyclic core-containing HCV NS5A inhibitors has been discovered. Incorporation of tetrahydropyran-substituted amino acid moiety improved their potency and yielded HCV NS5A inhibitors with a minimum potency shift from the GT1a strain compared to other genotypes and mutants. Compounds 53 and 54 showed the best potency profile and had reasonable half-times in rat PK studies. However, further optimization of their oral bioavailability is still needed in order to advance them for further development. [BMCL ABSTRACT] ©2000 Elsevier Science Ltd. All rights reserved.

Fib-4 Predicts Early Hematological Adverse Events Induced by Interferon-Based Triple Therapy in Chronic Hepatitis C Virus Patients

Interferon-alpha (IFN-α)-based therapy is associated with several hematological adverse events in hepatitis C virus (HCV)-infected patients with advanced fibrosis. We performed this study to evaluate the association between Fibrosis-4 (Fib-4) index and hematological adverse events in patients with chronic HCV infection, undergoing IFN-α-based triple therapy. We included 120 HCV-infected patients, receiving triple therapy: weekly PegIFN-α, daily ribavirin (1,000-1,200 mg), and daily sofosbuvir (400 mg) for 12 weeks. We compared Fib-4 scores for patients who developed hematological adverse events at weeks 4 (w4) and w12 of treatment and w12 post-treatment versus those who did not. Treatment with the aforementioned triple regimen was associated with a sustained virological response (SVR)-12 rate of 93.9%. We found no significant associations (P > 0.05) between SVR12 rate and the degree of fibrosis or the risk of hematological adverse events. The Fib-4 score could predict patients who developed hematological adverse events (anemia, leukopenia, and neutropenia) in the first month of treatment, but not in later stages. A Fib-4 cutoff value of 3.59 had high specificity for anemia, leukopenia, and neutropenia (85.1%, 87.2%, and 88.2%, respectively), but had low sensitivity for detecting the 3 events. In conclusion, the Fib-4 score may predict early hematological adverse effects in HCV-infected patients on IFN-based triple therapy.

No difference between direct-acting antivirals for hepatitis C in hepatocellular carcinoma risk

BACKGROUND AND AIMS

It is unclear whether there are differences between direct-acting antivirals (DAAs) for hepatitis C virus in risk of hepatocellular carcinoma (HCC) after antiviral therapy. We aimed to compare different DAA regimens with respect to risk of de novo HCC following antiviral therapy.

PATIENTS AND METHODS

We identified 33 137 patients who initiated hepatitis C virus antiviral treatment in the Veterans Affair healthcare system between 6 December 2013 and 31 December 2015 with one of four DAA-only regimens (± ribavirin): paritaprevir/ritonavir/ombitasvir/dasabuvir (n=6289), sofosbuvir (n=4356), sofosbuvir+simeprevir (n=3210), and ledipasvir/sofosbuvir (n=19 282). We retrospectively followed patients until 15 June 2017 to identify incident (de novo) cases of HCC. We used propensity score-adjusted Cox proportional hazards regression to compare different DAA regimens with respect to HCC risk.

RESULTS

During a mean follow-up of 1.52 years, 741 new cases of HCC were diagnosed after antiviral treatment (annual incidence=1.47%). Patients treated with sofosbuvir+simeprevir had the highest annual HCC incidence (2.47%), followed by sofosbuvir (1.91%), ledipasvir/sofosbuvir (1.26%), and paritaprevir/ritonavir/ombitasvir/dasabuvir (0.95%). However, there were great differences between DAA-treated patients in the prevalence of cirrhosis, markers of advanced fibrosis, thrombocytopenia, and other HCC risk factors. After adjustment for baseline characteristics associated with HCC, there were no significant differences in HCC risk between the four DAA regimens.

CONCLUSION

There are no significant differences between DAA regimens in HCC risk after antiviral treatment. This suggests that DAAs do not have direct carcinogenic effects as it would be unlikely that different DAAs would have identical carcinogenic effects.

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

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