Hepatitis C virus resistance to the new direct-acting antivirals

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Single-Ascending-Dose, Food-Effect, and Multiple-Dose Study of the Safety, Tolerability, and Pharmacokinetics of the Pangenotypic Anti-Hepatitis C Virus Drug Holybuvir in Healthy Chinese Subjects

Holybuvir is a novel pangenotypic hepatitis C virus NS5B inhibitor. This first in-human study aimed to evaluate the pharmacokinetics (PK), safety, and tolerability of holybuvir and its metabolites and the effect of food on the PK of holybuvir and its metabolites in healthy Chinese subjects. A total of 96 subjects were enrolled in this study which included (i) a single-ascending-dose (SAD) study (100 to 1,200 mg), (ii) a food-effect (FE) study (600 mg), and (iii) a multiple-dose (MD) study (400 and 600 mg once daily for 14 days). The results showed that single oral administration of holybuvir at doses up to 1,200 mg was well tolerated. Holybuvir was rapidly absorbed and metabolized in the human body, which was consistent with the characteristics of holybuvir as a prodrug. PK analysis showed that Cmax and area under the curve (AUC) increased with dose in no dose-proportional manner after a single-dose administration (100 to 1,200 mg). Although high-fat meals did change the PK of holybuvir and its metabolites, clinical significance of changes in PK parameters induced by eating a high-fat diet would be further confirmed. Following multiple-dose administration, accumulation of metabolites SH229M4 and SH229M5-sul was observed. The favorable PK and safety results support the further development of holybuvir for patients with HCV. (This study was registered at Chinadrugtrials.org under identifier CTR20170859.).

Protein Abundance of Drug Metabolizing Enzymes in Human Hepatitis C Livers

Hepatic drug metabolizing enzymes (DMEs), whose activity may be affected by liver diseases, are major determinants of drug pharmacokinetics. Hepatitis C liver samples in different functional states, i.e., the Child-Pugh class A (n = 30), B (n = 21) and C (n = 7) were analyzed for protein abundances (LC-MS/MS) and mRNA levels (qRT-PCR) of 9 CYPs and 4 UGTs enzymes. The protein levels of CYP1A1, CYP2B6, CYP2C8, CYP2C9, and CYP2D6 were not affected by the disease. In the Child-Pugh class A livers, a significant up-regulation of UGT1A1 (to 163% of the controls) was observed. The Child-Pugh class B was associated with down-regulation of the protein abundance of CYP2C19 (to 38% of the controls), CYP2E1 (to 54%), CYP3A4 (to 33%), UGT1A3 (to 69%), and UGT2B7 (to 56%). In the Child-Pugh class C livers, CYP1A2 was found to be reduced (to 52%). A significant trend in down-regulation of the protein abundance was documented for CYP1A2, CYP2C9, CYP3A4, CYP2E1, UGT2B7, and UGT2B15. The results of the study demonstrate that DMEs protein abundances in the liver are affected by hepatitis C virus infection and depend on the severity of the disease.

An Insight into Hepatitis C Virus: In Search of Promising Drug Targets

Hepatitis C Virus (HCV) is a global health concern, chronically infecting over 70 million people worldwide. HCV is a bloodborne pathogen that primarily affects the liver, and chronic HCV infection can lead to cirrhosis, liver cancer, and liver failure over time. There is an urgent need for more effective approaches to prevent and treat HCV. This review summarizes current knowledge on the virology, transmission, diagnosis, and management of HCV infection. It also provides an in-depth analysis of HCV proteins as promising targets for antiviral drug and vaccine development. Specific HCV proteins discussed as potential drug targets include the NS5B polymerase, NS3/4A protease, entry receptors like CD81, and core proteins. The implications of HCV proteins as diagnostic and prognostic biomarkers are also explored. Current direct-acting antiviral therapies are effective but have cost, genotype specificity, and resistance limitations. This review aims to synthesize essential information on HCV biology and pathogenesis to inform future research on improved preventive, diagnostic, and therapeutic strategies against this global infectious disease threat.

Identification of NS5B Resistance against SOFOSBUVIR in Hepatitis C Virus Genotype 3a, naive and treated Patients

AIMS

Pakistan has the second highest prevalence of HCV with genotype 3a (GT-3a) being the most frequently circulating genotype. Currently resistance associated substitutions (RASs) are a major challenge in HCV treatment with direct acting antivirals (DAAs). Sofosbuvir (SOF) is an FDA-approved NS5B nucleotide inhibitor. The aim of this study was to identify these RASs in the NS5B gene in naive and treated Pakistani HCV 3a isolates against SOF.

METHODS AND RESULTS

Blood samples were collected from anti-HCV positive patients, followed by HCV RNA isolation and real time PCR quantification. HCV positive patients were processed for HCV RNA genotyping, Patients with genotype 3a were processed for NS5B gene amplification and sequencing. GT-3a was the most prevalent genotype (62.2%). S282T was identified in 2 (8.7%) patients, C316Y/G/R in 3 (13%), V321A, and L320P in 1 (4.3%) each in SOF/RBV resistant patients. Variants of S282 were detected in 3 (13%) of SOF/RBV treated patients. While INF/RBV associated mutations were also analyzed, D244N, A333R, and A334E were identified in 2 (9.5%), 3 (14.2%), and 7 (33.3%) in treatment-naive and 15 (65.2%), 7 (30.4%), and 5 (21.7%) treated patients respectively. Q309R was observed only in one treatment experienced patients. Some substitutions were present at higher frequency in both groups like N307G, K304R, A272D and R345H, considered that they do not have any role in Sofosbuvir resistance.

CONCLUSION

It was concluded that Sofosbuvir RASs are present in Pakistani HCV GT-3a isolates, and they should be monitored carefully, especially in treatment-experienced patients, for further selection of treatment regimens.

SIGNIFICANCE AND IMPACT OF STUDY

HCV RASs have been studied very well across the world but there is scarcity of data regarding this topic in Pakistani population, this study provides data regarding prevalence of these RASs in Pakistani HCV isolates emphasizing the fact that these RASs must be carefully monitored before starting HCV treatment especially in treatment failure patients.

Characterisation of a Hepatitis C Virus Subtype 2a Cluster in Scottish PWID with a Suboptimal Response to Glecaprevir/Pibrentasvir Treatment

Direct-acting antivirals (DAAs) have revolutionised the treatment of Hepatitis C virus (HCV), allowing the World Health Organisation (WHO) to set a target of eliminating HCV by 2030. In this study we aimed to investigate glecaprevir and pibrentasvir (GP) treatment outcomes in a cohort of patients with genotype 2a infection.

METHODS

Clinical data and plasma samples were collected in NHS Greater Glasgow & Clyde. Next generation whole genome sequencing and replicon assays were carried out at the MRC-University of Glasgow Centre for Virus Research.

RESULTS

132 cases infected with genotype 2a HCV were identified. The SVR rate for this group was 91% (112/123) following treatment with GP. An NS5A polymorphism, L31M, was detected in all cases of g2a infection, and L31M+R353K in individuals that failed treatment. The results showed that R353K was present in 90% of individuals in the Glasgow genotype 2a phylogenetic cluster but in less than 5% of all HCV subtype 2a published sequences. In vitro efficacy of pibrentasvir against sub-genomic replicon constructs containing these mutations showed a 2-fold increase in IC₅₀ compared to wildtype.

CONCLUSION

This study describes a cluster of HCV genotype 2a infection associated with a lower-than-expected SVR rate following GP treatment in association with the NS5A mutations L31M+R353K.

Protein Abundance of Drug Transporters in Human Hepatitis C Livers

Transmembrane drug transport in hepatocytes is one of the major determinants of drug pharmacokinetics. In the present study, ABC transporters (P-gp, MRP1, MRP2, MRP3, MRP4, BCRP, and BSEP) and SLC transporters (MCT1, NTCP, OAT2, OATP1B1, OATP1B3, OATP2B1, OCT1, and OCT3) were quantified for protein abundance (LC-MS/MS) and mRNA levels (qRT-PCR) in hepatitis C virus (HCV)-infected liver samples from the Child–Pugh class A (n = 30), B (n = 21), and C (n = 7) patients. Protein levels of BSEP, MRP3, MCT1, OAT2, OATP1B3, and OCT3 were not significantly affected by HCV infection. P-gp, MRP1, BCRP, and OATP1B3 protein abundances were upregulated, whereas those of MRP2, MRP4, NTCP, OATP2B1, and OCT1 were downregulated in all HCV samples. The observed changes started to be seen in the Child–Pugh class A livers, i.e., upregulation of P-gp and MRP1 and downregulation of MRP2, MRP4, BCRP, and OATP1B3. In the case of NTCP, OATP2B1, and OCT1, a decrease in the protein levels was observed in the class B livers. In the class C livers, no other changes were noted than those in the class A and B patients. The results of the study demonstrate that drug transporter protein abundances are affected by the functional state of the liver in hepatitis C patients.

Space and Genotype-Dependent Virus Distribution during Infection Progression

The paper is devoted to a nonlocal reaction-diffusion equation describing the development of viral infection in tissue, taking into account virus distribution in the space of genotypes, the antiviral immune response, and natural genotype-dependent virus death. It is shown that infection propagates as a reaction-diffusion wave. In some particular cases, the 2D problem can be reduced to a 1D problem by separation of variables, allowing for proof of wave existence and stability. In general, this reduction provides an approximation of the 2D problem by a 1D problem. The analysis of the reduced problem allows us to determine how viral load and virulence depend on genotype distribution, the strength of the immune response, and the level of immunity.

An update on direct antiviral agents for the treatment of hepatitis C

Introduction: The development of direct-acting antiviral (DAA) agents for the treatment of hepatitis C virus (HCV) infection has completely transformed the management of this disease. The advantages of using DAA therapies include high efficacy (sustained virological response (SVR) rate >95%) with minimal side effects, good tolerability, easy drug administration (once daily oral dosing), and short duration of treatment (8-12 weeks). This transformative nature of DAA therapy underpins the goal of the World Health Organization to eliminate HCV infection as a public health threat by 2030.Areas covered: This review seeks to address the current status of DAA therapies, including recent developments, current limitations, and future challenges.Expert opinion: The current DAA regimens, with their high effectiveness and safety profiles, have changed patient perception of HCV infection from a disease that requires complex evaluation and long-term monitoring to a disease that can be cured after one visit to the general practitioner. Despite the remarkably high success rate of DAAs, few patients (4-5%) fail to obtain SVR even after treatment. Five years ahead, the landscape of HCV treatment will undoubtedly continue to evolve, and more pan-genotypic treatment options will be available to all patients.

Resistance-associated substitutions (RASs) to HCV direct-acting antivirals (DAAs) at baseline of treatment in thalassemia patients: a referral center study

Patients with thalassemia major are at high risk of hepatitis C through blood transfusion from donors infected by hepatitis C virus (HCV). The use of direct-acting antiviral (DAA) therapy against such HCV infections has increased in different populations. However, resistant viral variants can affect treatment outcomes, and therefore improved surveillance strategies are needed. Accordingly, we aimed to evaluate resistance-associated substitutions (RASs) to HCV DAAs at the baseline of treatment in thalassemia patients in a referral center. Out of 89 thalassemia patients who suffered from HCV infection and were referred to our center between 2016 and 2017, 43 underwent further analysis of the HCV nonstructural proteins NS5A and NS5B using polymerase chain reaction (PCR) sequencing methods. Unique primers were designed using bioinformatics software for separate detection of HCV subtypes 1a, 3a, and 1b. Detection of RASs was performed based on previously published literature. Statistical analysis was carried out using SPSS version 19. The participants, 60.4% (26/43) of whom were male, had a mean age ± standard deviation (SD) of 33.0 ± 5.0 years. HCV subtype 1a was found in 27 cases, 3a in 13, and 1b in three. In HCV subtype 1a there were 163 mutations in NS5A and 212 mutations in NS5B. The frequency of RASs was 20.9% (8 RASs in 9 patients), including M28V and H58P in subtype 1a, L28M, R30Q, C316N, and C316S in subtype 1b, and S24F in subtype 3a. Statistically, the subtype 1b and a higher mutation rate in NS5A were associated with RASs (p-value < 0.05). The emergence of natural RASs to HCV DAAs serves as a warning of the risk of drug resistance in response to the broad usage of antivirals. However, relapses in these DAA-treated HCV-infected thalassemia patients are rarely reported. Our findings indicate that the prevalence of RASs prevalence at baseline was 20.9% in these patients, and this calls for extrapolation to a larger population study, as highlighted in other studies, with larger sample sizes, high-throughput methods, and follow-up in order to fully evaluate treatment outcomes in RASs-detected individuals. Optimized therapeutic strategies, particularly in complex, difficult-to-cure patients, can effectively prevent DAA treatment failure as a result of selection for RASs.

IL28A protein homotetramer structure is required for autolysosomal degradation of HCV-NS5A in vitro

Interferon lambda-2 (IL28A) has a wide antiviral effect with fewer side-effects. Autophagy is a host mechanism to maintain intracellular homeostasis and defends invasion of pathogenic microorganisms. HCV NS5A can disable host defense systems to support HCV replication. Thus, molecular mechanism of interaction among interferon lambda, autophagy, and HCV was concerned and explored in this study. We report that HCV NS5A activated an incomplete autophagy by promoting the autophagic ubiquitylation-like enzymes ATG3, ATG5, ATG7, ATG10, and autophagosome maker LC3B, but blocked autophagy flux; IL28A bound to NS5A at NS5A-ISDR region, and degraded HCV-NS5A by promoting autolysosome formations in HepG2 cells. A software prediction of IL28A protein conformation indicated a potential structure of IL28A homotetramer; the first α-helix of IL28A locates in the interfaces among the four IL28A chains to maintain IL28A homotetrameric conformation. Co-IP and cell immunofluorescence experiments with sequential deletion mutants demonstrate that IL28A preferred a homotetramer conformation to a monomer in the cells; the IL28A homotetramer is positively correlated with autolysosomal degradation of HCV NS5A and the other HCV proteins. Summarily, the first α-helix of IL28A protein is the key domain for maintaining IL28A homotetramer which is required for promoting formation of autolysosomes and degradation of HCV proteins in vitro.

A Prospective Italian Study on Baseline NS3 and NS5A Resistance to Direct-Acting Antivirals in a Real-World Setting of HIV-1/HCV Coinfected Patients and Association with Treatment Outcome

We prospectively evaluated the frequency of natural resistance-associated substitutions (RASs) in the NS3 and NS5A regions according to different HCV genotypes and their possible effect on treatment outcome in HIV-1/HCV patients treated with direct-acting antivirals (DAAs). Baseline RASs in the NS3 and NS5A domains were investigated in 62 HIV-1/HCV patients treated with DAAs: 23 patients harbored HCV-GT1a, 26 harbored GT3a, and 13 harbored GT4d. A higher occurrence of RASs was found in the NS3 domain within GT1a (13/23) than GT3a (0/26) or GT4d (2/13). With regard to treatment outcome, NS3 RASs were detected in 14/56 patients with sustained virological response (SVR) and in 1/6 non-responder (NR) patients. Occurrence of RASs of NS5A domain was lower in SVR (4/56, had RASs) than in NR (3/6, had RASs). Evaluation of RASs at baseline instead of at virological failure, especially in the NS5A domain, could positively influence the choice of new DAA combinations for the treatment of HIV-1/HCV patients.

Deguelin inhibits HCV replication through suppressing cellular autophagy via down regulation of Beclin1 expression in human hepatoma cells

AIMS

Deguelin, a natural compound derived from Mundulea sericea (Leguminosae) and some other plants exhibits an activity to inhibit autophagy, a cellular machinery required for hepatitis C virus (HCV) replication. This study aimed to illuminate the impact of deguelin on HCV replication and mechanism(s) involved.

METHODS

HCV JFH-1-Huh7 infectious system was used for the investigation. Real time RT-PCR, Western blot, fluorescent microscopy assay were used to measure the expression levels of viral or cellular factors. Overexpression and silencing expression techniques were used to determine the role of key cellular factors.

RESULTS

Deguelin treatment of Huh7 cells significantly inhibited HCV JFH-1 replication in a dose- and time-dependent manner. Deguelin treatment suppressed autophagy in Huh7 cells, evidenced by the decrease of LC3B-II levels, the conversion of LC3B-I to LC3B-II, and the formation of GFP-LC3 puncta as well as the increase of p62 level in deguelin-treated cells compared with control cells. HCV infection could induce autophagy which was also suppressed by deguelin treatment. Mechanism research reveals that deguelin inhibited expression of Beclin1, which is a key cellular factor for the initiation of the autophagosome formation in autophagy. Overexpression or silencing expression of Beclin1 in deguelin-treated Huh7 cells could weaken or enhance the inhibitory effect on autophagy by deguelin, respectively, and thus partially recover or further inhibit HCV replication correspondingly.

CONCLUSIONS

Deguelin may serve as a novel anti-HCV compound via its inhibitory effect on autophagy, which warrants further investigation as a potential therapeutic agent for HCV infection.

Viral Hepatitis C Therapy: Pharmacokinetic and Pharmacodynamic Considerations: A 2019 Update

It has been estimated by the World Health Organization (WHO) that over 71 million people were infected with the hepatitis C virus (HCV) in 2015. Since then, a number of highly effective direct-acting antiviral (DAA) regimens have been licensed for the treatment of chronic HCV infection: sofosbuvir/daclatasvir, sofosbuvir/ledipasvir, elbasvir/grazoprevir, sofosbuvir/velpatasvir, glecaprevir/pibrentasvir, and sofosbuvir/velpatasvir/voxilaprevir. With these treatment regimens, almost all chronic HCV-infected patients, even including prior DAA failures, can be treated effectively and safely. It is therefore likely that further development of DAAs will be limited. In this descriptive review we provide an overview of the clinical pharmacokinetic characteristics of currently available DAAs by describing their absorption, distribution, metabolism, and excretion. Potential drug-drug interactions with the DAAs are briefly discussed. Furthermore, we summarize what is known about the pharmacodynamics of the DAAs in terms of efficacy and safety. We briefly discuss the relationship between the pharmacokinetics of the DAAs and efficacy or toxicity in special populations, such as hard to cure patients and patients with liver cirrhosis, liver transplantation, renal impairment, hepatitis B virus or HIV co-infection, bleeding disorders, and children. The aim of this overview is to educate/update prescribers and pharmacists so that they are able to safely and effectively treat HCV-infected patients even in the presence of underlying co-infections or co-morbidities.

A proof-of-concept study in HCV-infected Huh7.5 cells for shortening the duration of DAA-based triple treatment regimens

With the development of more effective direct-acting antivirals (DAAs), dual- or triple-therapy regimens represent the major strategy used to cure chronic hepatitis C virus (HCV) infection. Thus, shorter treatment duration regimens with low burden, few adverse effects and good patient adherence are urgently needed. This study theoretically demonstrates a proof-of-concept approach for shortening therapy duration by examining HCV-infected Huh7.5 cells after treatment with a high or low fixed dose of three DAAs (simeprevir + daclatasvir + sofosbuvir) for 6-15 days. The results demonstrated that HCV-infected Huh7.5 cells achieved an ultrarapid virologic response with undetectable HCV RNA and protein and were cured after treatment with the triple-therapy regimen for 15 days. When the treatment duration was shortened, virologic relapse might occur after treatment with a low fixed dose of the three DAAs for 9 days and did occur after treatment with a low fixed dose for 6 days, although HCV was below detectable levels at the end of treatment. However, virologic relapse could be avoided with treatment of a high fixed dose of the three DAAs for 9 or 6 days. Although a virologic breakthrough occurred after an intermittent treatment regimen at the low fixed dose, the high fixed dose cured HCV-positive Huh7.5 cells with intermittent treatment. In conclusion, HCV is persistently present below detectable levels in HCV-infected Huh7.5 cells for a long time after treatment, and a shortened therapy duration is associated with an increased risk of virologic relapse, but virologic relapse or breakthrough might be avoided by treatment with a combination of more highly effective DAAs.

Farnesoid X receptor agonist GW4064 indirectly inhibits HCV entry into cells via down-regulating scavenger receptor class B type I

Farnesoid X receptor (FXR) agonists play important regulatory roles in bile acid, lipid and glucose metabolism in vitro and in vivo. Thus, FXR agonists exhibit potential therapeutic effects on metabolism-related diseases that are associated with extrahepatic manifestations induced by hepatitis C virus (HCV) infection. This study investigated the effect and mechanism of FXR agonist GW4064 against HCV in vitro to explore the potential application of FXR agonists. Results showed that GW4064 and other FXR agonists have potent antiviral activity against HCV in Huh7.5 cells. GW4064 down-regulated the expression of scavenger receptor class B type I protein via FXR and thereby indirectly inhibited HCV entry into cells, leading to interruption of HCV life cycle. GW4064 also exhibited synergistic anti-HCV effect with known direct-acting antiviral agents (DAAs) used in the clinic and remained sensitive to DAA-resistant HCV mutations. Therefore, FXR agonists are also a kind of antiviral agent, and might be helpful in treatment of HCV-induced hepatic and extrahepatic manifestations.

Efficacy and safety of alisporivir for the treatment of hepatitis C infection

Alisporivir (ALV) (previously known as Debio 025) is a potent, pangenotypic host-targeting antiviral oral agent acting on cyclophilin A, which is necessary for HCV replication. Areas covered: This article reviews the therapeutic efficacy and safety of ALV for the treatment of HCV infection. Expert opinion: Direct-acting antivirals (DAAs) have revolutionized the HCV antiviral treatment paradigm with success rates well above 95% for all HCV genotypes. However, challenges still remain in certain patient populations such as those who have developed resistance and have experienced multi-DAA failure. To cure HCV infection, a treatment regimen must combine antiviral potency and a high barrier to resistance. ALV fulfills this need as shown by the studies evaluating its clinical efficacy. Nevertheless, ALV missed the chance to be included in the HCV treatment armamentarium after the FDA halted clinical studies following reports of serious side effects (three cases of pancreatitis, one lethal). However, it is possible that ALV could still be considered for HCV-infected non-cirrhotic patients that are infected with a multiresistant virus or with HCV genotype 3, although it must be said that the drug industry would be reluctant to invest in new antivirals if the current clinical need is effectively met.

In Vitro Antiviral Profile of Ruzasvir, a Potent and Pangenotype Inhibitor of Hepatitis C Virus NS5A

Inhibition of NS5A has emerged as an attractive strategy to intervene in hepatitis C virus (HCV) replication. Ruzasvir (formerly MK-8408) was developed as a novel NS5A inhibitor to improve upon the potency and barrier to resistance of early compounds. Ruzasvir inhibited HCV RNA replication with 50% effective concentrations (EC50s) of 1 to 4 pM in Huh7 or Huh7.5 cells bearing replicons for HCV genotype 1 (GT1) to GT7. The antiviral activity was modestly (10-fold) reduced in the presence of 40% normal human serum. The picomolar potency in replicon cells extended to sequences of clinical isolates available in public databases that were synthesized and tested as replicons. In GT1a, ruzasvir inhibited common NS5A resistance-associated substitutions (RASs), with the exception of M28G. De novo resistance selection studies identified pathways with certain amino acid substitutions at residues 28, 30, 31, and 93 across genotypes. Substitutions at position 93 were more common in GT1 to -4, while changes at position 31 emerged frequently in GT5 and -6. With the exception of GT4, the reintroduction of selected RASs conferred a ≥100-fold potency reduction in the antiviral activity of ruzasvir. Common RASs from other classes of direct-acting antiviral agents (DAAs) did not confer cross-resistance to ruzasvir. The interaction of ruzasvir with an NS3/4A protease inhibitor (grazoprevir) and an NS5B polymerase prodrug (uprifosbuvir) was additive to synergistic, with no evidence of antagonism or cytotoxicity. The antiviral profile of ruzasvir supported its further evaluation in human trials in combination with grazoprevir and uprifosbuvir.

Pretreatment Hepatitis C Virus NS5A/NS5B Resistance-Associated Substitutions in Genotype 1 Uruguayan Infected Patients

Hepatitis C Virus (HCV) infection treatment has dramatically changed with the advent of direct-acting antiviral agents (DAAs). However, the efficacy of DAAs can be attenuated by the presence of resistance-associated substitutions (RASs) before and after treatment. Indeed, RASs detected in DAA treatment-naïve HCV-infected patients could be useful for clinical management and outcome prediction. Although the frequency of naturally occurring HCV NS5A and NS5B RASs has been addressed in many countries, there are only a few reports on their prevalence in the South American region. The aim of this study was to investigate the presence of RASs to NS5A and NS5B inhibitors in a DAA treatment naïve cohort of Uruguayan patients infected with chronic hepatitis C and compare them with reports from other South American countries. Here, we found that naturally occurring substitutions conferring resistance to NS5A and NS5B inhibitors were present in 8% and 19.2%, respectively, of treatment-naïve HCV genotype 1 infected patients. Importantly, the baseline substitutions in NS5A and NS5B herein identified differ from the studies previously reported in Brazil. Furthermore, Uruguayan strains subtype 1a clustered within all major world clades, showing that HCV variants currently circulating in this country are characterized by a remarkable genetic diversity.

Pharmacokinetic and pharmacodynamic evaluation of daclatasvir, asunaprevir plus beclabuvir as a fixed-dose co-formulation for the treatment of hepatitis C

INTRODUCTION

Many reports have evaluated the clinical efficacy and safety of the fixed-dose all-oral combination of daclatasvir, asunaprevir, and beclabuvir (DCV-TRIO), which was approved in Japan in December 2016 for the treatment of hepatitis C genotype (GT)-1 infection. Areas covered: This article reviews the pharmacodynamic and pharmacokinetic properties of the DCV-TRIO combination. The topics covered include data regarding the drug's absorption, distribution, metabolism, excretion, and antiviral activity strategies. Its therapeutic efficacy and safety in GT-1 infection from phase 2/3 clinical trials are also discussed. Expert opinion: The ideal regimen for the treatment of Hepatitis C virus infection should be potent, pangenotypic, Ribavirin-free, safe, co-formulated, and affordable. Considering these characteristics, DCV-TRIO is neither pangenotypic nor potent enough against GT-1a, regardless of the presence or absence of cirrhosis. Other potential limitations of this regimen are its dosification (twice-daily), and the fact that since it includes a protease inhibitor, it is contraindicated in decompensated cirrhosis. For these reasons, it has only been approved in Japan, where more than 70% of the patients are infected with GT-1b. However, this co-formulation might still have a place in the treatment of non-cirrhotic patients infected with GT-1b provided that massive access to treatment is facilitated.

Deferred treatment with sofosbuvir-velpatasvir-voxilaprevir for patients with chronic hepatitis C virus who were previously treated with an NS5A inhibitor: an open-label substudy of POLARIS-1

BACKGROUND

Direct-acting antiviral regimens containing NS5A inhibitors are highly effective treatments for chronic hepatitis C virus (HCV) infection, but are not always successful. In the POLARIS-1 phase 3 study, sofosbuvir-velpatasvir-voxilaprevir for 12 weeks was highly effective in the treatment of chronic HCV infection in patients previously treated with a direct-acting antiviral regimen containing an NS5A inhibitor. We aimed to assess the efficacy and safety of sofosbuvir-velpatasvir-voxilaprevir in patients from the deferred treatment group of POLARIS-1, who were initially assigned to masked placebo treatment.

METHODS

This open-label, deferred treatment substudy was done at 73 clinical sites (hospitals and clinics) in the USA, France, Canada, the UK, Germany, Australia, and New Zealand. Patients who received placebo in the primary study and who did not have a new clinically significant illness at the post-treatment week 4 assessment were eligible to enter this substudy. Participants received a combination tablet of sofosbuvir (400 mg), velpatasvir (100 mg), and voxilaprevir (100 mg) once daily for 12 weeks. The primary efficacy outcome was achievement of sustained virological response (defined as HCV RNA concentration below the lower limit of quantification) 12 weeks after the end of treatment (SVR12). The primary safety outcome was the proportion of patients who discontinued treatment due to adverse events. This study is registered with ClinicalTrials.gov, number NCT02607735, and the EU Clinical Trials Register, number 2015-003455-21.

FINDINGS

152 patients received placebo in the primary study and were potentially eligible for participation in the open-label substudy, of whom 147 were enrolled from March 30, 2016, to Oct 12, 2016. All 147 patients completed treatment, and 143 (97%; 95% CI 93-99) achieved SVR12. Four (3%) patients had virological relapse; all had HCV genotype 1a infection and one also had compensated cirrhosis. The most common adverse events were fatigue (31 [21%]), headache (29 [20%]), diarrhoea (28 [19%]), and nausea (21 [14%]). No deaths, treatment discontinuations, or treatment-related serious adverse events occurred.

INTERPRETATION

Supporting the results from the blinded portion of the phase 3 primary study, the single-tablet regimen of sofosbuvir-velpatasvir-voxilaprevir for 12 weeks was safe, well tolerated, and highly effective in patients with chronic HCV infection who had previous treatment failure with NS5A inhibitor-containing regimens. A salvage regimen for this population represents an important advance for patients with limited retreatment options.

FUNDING

Gilead Sciences.

Opposite Effects of Two Human ATG10 Isoforms on Replication of a HCV Sub-genomic Replicon Are Mediated via Regulating Autophagy Flux in Zebrafish

Autophagy is a host mechanism for cellular homeostatic control. Intracellular stresses are symptoms of, and responses to, dysregulation of the physiological environment of the cell. Alternative gene transcription splicing is a mechanism potentially used by a host to respond to physiological or pathological challenges. Here, we aimed to confirm opposite effects of two isoforms of the human autophagy-related protein ATG10 on an HCV subgenomic replicon in zebrafish. A liver-specific HCV subreplicon model was established and exhibited several changes in gene expression typically induced by HCV infection, including overexpression of several HCV-dependent genes (argsyn, leugpcr, rasgbd, and scaf-2), as well as overexpression of several ER stress related genes (atf4, chop, atf6, and bip). Autophagy flux was blocked in the HCV model. Our results indicated that the replication of the HCV subreplicon was suppressed via a decrease in autophagosome formation caused by the autophagy inhibitor 3MA, but enhanced via dysfunction in the lysosomal degradation caused by another autophagy inhibitor CQ. Human ATG10, a canonical isoform in autophagy, facilitated the amplification of the HCV-subgenomic replicon via promoting autophagosome formation. ATG10S, a non-canonical short isoform of the ATG10 protein, promoted autophagy flux, leading to lysosomal degradation of the HCV-subgenomic replicon. Human ATG10S may therefore inhibit HCV replication, and may be an appropriate target for future antiviral drug screening.

Host-targeting therapies for hepatitis C virus infection: current developments and future applications

Chronic hepatitis C virus (HCV) infection is a leading cause of chronic liver diseases and hepatocellular carcinoma (HCC) worldwide. In the past few years, anti-HCV therapies have undergone a revolution with the approval of multiple direct-acting antivirals (DAAs), which enable interferon-free treatments with considerable improvement of sustained virologic response in patients. Today, DAAs have become the standard of care for HCV therapy. However, several limitations remain, which include access to therapy, treatment failure in a subset of patients and persistent risk of HCC development following cure in patients with advanced fibrosis. By targeting conserved host proteins involved in the HCV life cycle, host-targeting agents (HTAs) offer opportunities for pan-genotypic antiviral approaches with a high barrier to drug resistance. Moreover, when applied in combination with DAAs, HTAs could improve the management of difficult-to-treat patients by acting through a complementary mechanism of action. In this review, we summarize the different HTAs evaluated in preclinical and clinical development and discuss their potential role for anti-HCV therapies.

Global elimination of hepatitis C virus infection: Progresses and the remaining challenges

Today, with the introduction of interferon-free direct-acting antivirals and outstanding progresses in the prevention, diagnosis and treatment of hepatitis C virus (HCV) infection, the elimination of HCV infection seems more achievable. A further challenge is continued transmission of HCV infection in high-risk population specially injecting drug users (IDUs) as the major reservoir of HCV infection. Considering the fact that most of these infections remain undiagnosed, unidentified HCV-infected IDUs are potential sources for the rapid spread of HCV in the community. The continuous increase in the number of IDUs along with the rising prevalence of HCV infection among young IDUs is harbinger of a forthcoming public health dilemma, presenting a serious challenge to control transmission of HCV infection. Even the changes in HCV genotype distribution attributed to injecting drug use confirm this issue. These circumstances create a strong demand for timely diagnosis and proper treatment of HCV-infected patients through risk-based screening to mitigate the risk of HCV transmission in the IDUs community and, consequently, in the society. Meanwhile, raising general awareness of HCV infection, diagnosis and treatment through public education should be the core activity of any harm reduction intervention, as the root cause of failure in control of HCV infection has been lack of awareness among young drug takers. In addition, effective prevention, comprehensive screening programs with a specific focus on high-risk population, accessibility to the new anti-HCV treatment regimens and public education should be considered as the top priorities of any health policy decision to eliminate HCV infection.

Baseline NS5A resistance associated substitutions may impair DAA response in real-world hepatitis C patients

Oral DAA have demonstrated high efficacy as treatment of hepatitis C. However, the presence of resistance-associated substitutions (RAS) at baseline has occasionally been associated with impaired treatment response. Herein, we examined the impact of baseline RAS at the HCV NS5A gene region on treatment response in a real-life setting. All hepatitis C patients treated with DAA including NS5A inhibitors at our institution were retrospectively examined. The virus NS5A gene was analyzed using population sequencing at baseline and after 24 weeks of completing therapy in all patients that failed. All changes recorded at positions 28, 29, 30, 31, 32, 58, 62, 92, and 93 were considered. A total of 166 patients were analyzed. HCV genotypes were as follows: G1a (31.9%), G1b (48.2%), G3 (10.2%), and G4 (9.6%). Overall, 69 (41.6%) patients were coinfected with HIV and 46.7% had advanced liver fibrosis (Metavir F3-F4). Sixty (36.1%) patients had at least one RAS at baseline, including M28A/G/T (5), Q30X (12), L31I/F/M/V (6), T58P/S (25), Q/E62D (1), A92 K (7), and Y93C/H (15). Overall, 4.8% had two or more RAS, being more frequent in G4 (12.5%) followed by G1b (6.3%) and G1a (1.9%). Of 10 (6%) patients that failed DAA therapy, five had baseline NS5A RAS. No association was found for specific baseline RAS, although changes at position 30 were more frequent in failures than cures (22.2% vs 6.4%, P = 0.074). Moreover, the presence of two or more RAS at baseline was more frequent in failures (HR: 7.2; P = 0.029). Upon failure, six patients showed emerging RAS, including Q30C/H/R (3), L31M (1), and Y93C/H (2). Baseline NS5A RAS are frequently seen in DAA-naïve HCV patients. Two or more baseline NS5A RAS were found in nearly 5% and were significantly associated to DAA failure. Therefore, baseline NS5A testing should be considered when HCV treatment is planned with NS5A inhibitors.

Avasimibe: A novel hepatitis C virus inhibitor that targets the assembly of infectious viral particles

Direct-acting antivirals (DAAs), which target hepatitis C virus (HCV) proteins, have exhibited impressive efficacy in the management of chronic hepatitis C. However, the concerns regarding high costs, drug resistance mutations and subsequent unexpected side effects still call for the development of host-targeting agents (HTAs) that target host factors involved in the viral life cycle and exhibit pan-genotypic antiviral activity. Given the close relationship between lipid metabolism and the HCV life cycle, we investigated the anti-HCV activity of a series of lipid-lowering drugs that have been approved by government administrations or proven safety in clinical trials. Our results showed that avasimibe, an inhibitor of acyl coenzyme A:cholesterol acyltransferase (ACAT), exhibited marked pan-genotypic inhibitory activity and superior inhibition against HCV when combined with DAAs. Moreover, avasimibe significantly impaired the assembly of infectious HCV virions. Mechanistic studies demonstrated that avasimibe induced downregulation of microsomal triglyceride transfer protein expression, resulting in reduced apolipoprotein E and apolipoprotein B secretion. Therefore, the pan-genotypic antiviral activity and clinically proven safety endow avasimibe exceptional potential as a candidate for combination therapy with DAAs. In addition, the discovery of the antiviral properties of ACAT inhibitors also suggests that inhibiting the synthesis of cholesteryl esters might be an additional target for the therapeutic intervention for chronic HCV infection.

Synthesis and biological evaluation of tricyclic matrinic derivatives as a class of novel anti-HCV agents

Background

12N-benzyl matrinic acid analogues had been identified to be a novel scaffold of anti-HCV agents with a specific mechanism, and the representative compound 1 demonstrated a moderate anti-HCV activity. The intensive structure–activity relationship of this kind of compounds is explored so as to obtain anti-HCV candidates with good druglike nature.

Results

Taking compound 1 as the lead, 32 compounds (of which 27 were novel) with diverse structures on the 11-side chain, including methyl matrinate, matrinol, matrinic butane, (Z)-methyl Δ^βγ-matrinic crotonate derivatives were synthesized and evaluated for their anti-HCV activities. Among all the compounds, matrinol 7a demonstrated potential potency with a greatly improved SI value of 136. Pharmacokinetic studies of 7a showed the potential for oral administration that would allow further in vivo safety studies. The free hydroxyl arm in 7a made it possible to prepare pro-drugs for the potential in the treatment of HCV infection.

Conclusions

27 novel 12N-substituted matrinol derivatives were prepared. The SAR study indicated that the introduction of electron-donating substitutions on the benzene ring was helpful for the anti-HCV activity, and the unsaturated 11-side chain might not be favorable for the activity. This study provided powerful information on further strategic optimization and development of this kind of compounds into a novel family of anti-HCV agents. Graphical abstract

Sofosbuvir, velpatasvir and voxilaprevir combination for the treatment of hepatitis C

The advent of direct-acting antiviral (DAA) treatments for chronic hepatitis C virus (HCV) infection has dramatically increased rates of cure. However, there remain difficult-to-treat populations, including patients with genotype 3 infection and cirrhosis, and limited salvage treatment options for those that have failed first-line DAA therapy. Areas covered: This is a review of the preclinical and clinical development of sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX), an interferon-free, oral, once daily, pangenotypic treatment for chronic HCV infection. All relevant literature from 2015 through June of 2017 is included. Expert commentary: Voxilaprevir, a second-generation HCV protease inhibitor, in combination with the already approved combination of sofosbuvir and velpatasvir, was evaluated in the POLARIS trials and found to be a safe and effective regimen. Patients with prior DAA treatment failure, genotype 3, cirrhosis and/or unfavorable resistance profiles all achieved cure rates of 96% or greater. The most distinctive role for this potent regimen may prove to be as a salvage regimen for patients who have failed previous DAA therapy.

Tree shrew, a potential animal model for hepatitis C, supports the infection and replication of HCV in vitro and in vivo

The tree shrew (Tupaia belangeri chinensis), a small animal widely distributed in Southeast Asia and southwest China, has the potential to be developed as an animal model for hepatitis C. To determine the susceptibility of the tree shrew to hepatitis C virus (HCV) infection in vitro and in vivo, a well-established HCV, produced from the J6/JFH1-Huh7.5.1 culture system, was used to infect cultured primary tupaia hepatocytes (PTHs) and tree shrews. The in vitro results showed that HCV genomic RNA and HCV-specific nonstructural protein 5A (NS5A) could be detected in the PTH cell culture from days 3-15 post-infection, although the viral load was lower than that observed in Huh7.5.1 cell culture. The occurrence of five sense mutations [S391A, G397A, L402F and M405T in the hypervariable region 1 (HVR1) of envelope glycoprotein 2 and I2750M in NS5B] suggested that HCV undergoes genetic evolution during culture. Fourteen of the 30 experimental tree shrews (46.7 %) were found to be infected, although the HCV viremia was intermittent in vivo. A positive test for HCV RNA in liver tissue provided stronger evidence for HCV infection and replication in tree shrews. The results of an immunohistochemistry assay also demonstrated the presence of four HCV-specific proteins (Core, E2, NS3/4 and NS5A) in the hepatocytes of infected tree shrews. The pathological changes observed in the liver tissue of infected tree shrews could be considered to be representative symptoms of mild hepatitis. These results revealed that the tree shrew can be used as an animal model supporting the infection and replication of HCV in vitro and in vivo.

Treatment of hepatitis C with new fixed dose combinations

INTRODUCTION

The advent of oral direct-acting antivirals (DAA) has revolutionized the hepatitis C virus (HCV) therapeutic landscape providing cure rates over 90%. However, a subset of patients remains at higher risk for treatment failure, including those infected with: i) genotype 3 and cirrhosis; ii) resistance-associated substitutions (RAS) occurring either as natural polymorphisms or selected after prior DAA failure; and iii) poor drug adherence associated with social disabilities (homeless, psychiatric illnesses, injection drug use, alcoholism, etc.). Whereas discovery of new DAA with increased antiviral activity across all genotypes and over RAS may enhance efficacy, development of fixed dose combinations (FDC) may be the best way to improve drug adherence in difficult-to-treat HCV populations. Areas covered: Three FDC regimens are in the last steps of clinical development for treating hepatitis C. Two distinct nucleotide analogues that inhibit the HCV polymerase, sofosbuvir and uprifosbuvir, are part of the FDC from Gilead and Merck, respectively. The AbbVie dual FDC does not include a polymerase inhibitor. All three new FDC include second-generation NS3 protease inhibitors and NS5A inhibitors active across all HCV genotypes and over common RAS. Expert opinion: Hepatitis C cure rates over 95% are expected with all three next-coming DAA, even in the most difficult-to-treat and/or cure patient populations. These regimens would be particularly needed for the growing number of prior DAA failures. Co-formulations and 8-week shorter treatment lengths will help to overcome drug adherence challenges in certain populations.

Evaluation of sofosbuvir, velpatasvir plus voxilaprevir as fixed-dose co-formulation for treating hepatitis C

INTRODUCTION

The fixed-dose combination of three direct-acting antivirals (DAA), namely sofosbuvir, velpatasvir and voxilaprevir is the first pangenotypic, single tablet regimen developed for the treatment of HCV infection. Areas covered: The pharmacokinetics, pharmacodynamics, efficacy and safety of the co-formulation are reviewed. Information on drug absorption, distribution, metabolism and excretion of each of the three antivirals is evaluated. Finally, antiviral activity, safety and potential for drug interactions in phase II/III clinical trials in distinct patient populations are discussed. Expert opinion: The triple co-formulation of sofosbuvir-velpatasvir-voxilaprevir represents a major step towards HCV eradication. It depicts high efficacy even in patients infected with viruses harboring resistance-associated substitutions (RAS), including those selected after DAA failures. Likewise, very high success rates and good tolerance are seen in special patient populations, including decompensated cirrhotics, HIV coinfection, organ transplantation or renal insufficiency. A pill once daily for 8 weeks gives SVR rates above 95%. In prior DAA failures, extending treatment to 12 weeks maximizes SVR rates.

Hepatitis C virus-apolipoprotein interactions: molecular mechanisms and clinical impact

INTRODUCTION

Chronic hepatitis C virus (HCV) infection is a leading cause of cirrhosis, hepatocellular carcinoma and liver failure. Moreover, chronic HCV infection is associated with liver steatosis and metabolic disorders. With 130-150 million people chronically infected in the world, HCV infection represents a major public health problem. One hallmark on the virus is its close link with hepatic lipid and lipoprotein metabolism. Areas covered: HCV is associated with lipoprotein components such as apolipoproteins. These interactions play a key role in the viral life cycle, viral persistence and pathogenesis of liver disease. This review introduces first the role of apolipoproteins in lipoprotein metabolism, then highlights the molecular mechanisms of HCV-lipoprotein interactions and finally discusses their clinical impact. Expert commentary: While the study of virus-host interactions has resulted in a improvement of the understanding of the viral life cycle and the development of highly efficient therapies, major challenges remain: access to therapy is limited and an urgently needed HCV vaccine remains still elusive. Furthermore, the pathogenesis of disease biology is still only partially understood. The investigation of HCV-lipoproteins interactions offers new perspectives for novel therapeutic approaches, contribute to HCV vaccine design and understand virus-induced liver disease and cancer.

Ombitasvir and paritaprevir boosted with ritonavir and combined with dasabuvir for chronic hepatitis C

Hepatitis C is a leading cause of cirrhosis and hepatocellular carcinoma responsible for almost 700,000 deaths worldwide annually. Until 2014, management of HCV infections was based on interferon alfa containing regimens, with efficacy of 40-70% and a high adverse event rate. Interferon-free therapeutic options improved sustained viral response (SVR) rate to >90% and safety profile to placebo-like levels. Areas covered: This article describes all-oral regimen consisting of three direct acting antivirals (DAA) - ombitasvir (OBV), paritaprevir (PTV) and dasabuvir (DSV), which in clinical practice is boosted with ritonavir (r) and sometimes with ribavirin (RBV). This combination is registered for treatment of patients infected with HCV genotype 1 and 4. We focused on the regimen characteristics, pharmacokinetics, risk of resistance as well as efficacy and safety in clinical trials and real world studies. Expert commentary: Combination of OBV/PTV/r±DSV±RBV provides SVR rate of about 95% and good safety profile even in patients with compensated liver cirrhosis and failure with previous therapy. Currently it should be of particular value in areas with a predominance of genotype 1b infections. Due to the complexity and risk of drug to drug interactions, it will probably be replaced in coming few years with pangenotypic combinations of next generation DAAs.

Sofosbuvir, Velpatasvir, and Voxilaprevir for Previously Treated HCV Infection

BACKGROUND

Patients who are chronically infected with hepatitis C virus (HCV) and who do not have a sustained virologic response after treatment with regimens containing direct-acting antiviral agents (DAAs) have limited retreatment options.

METHODS

We conducted two phase 3 trials involving patients who had been previously treated with a DAA-containing regimen. In POLARIS-1, patients with HCV genotype 1 infection who had previously received a regimen containing an NS5A inhibitor were randomly assigned in a 1:1 ratio to receive either the nucleotide polymerase inhibitor sofosbuvir, the NS5A inhibitor velpatasvir, and the protease inhibitor voxilaprevir (150 patients) or matching placebo (150 patients) once daily for 12 weeks. Patients who were infected with HCV of other genotypes (114 patients) were enrolled in the sofosbuvir-velpatasvir-voxilaprevir group. In POLARIS-4, patients with HCV genotype 1, 2, or 3 infection who had previously received a DAA regimen but not an NS5A inhibitor were randomly assigned in a 1:1 ratio to receive sofosbuvir-velpatasvir-voxilaprevir (163 patients) or sofosbuvir-velpatasvir (151 patients) for 12 weeks. An additional 19 patients with HCV genotype 4 infection were enrolled in the sofosbuvir-velpatasvir-voxilaprevir group.

RESULTS

In the three active-treatment groups, 46% of the patients had compensated cirrhosis. In POLARIS-1, the rate of sustained virologic response was 96% with sofosbuvir-velpatasvir-voxilaprevir, as compared with 0% with placebo. In POLARIS-4, the rate of response was 98% with sofosbuvir-velpatasvir-voxilaprevir and 90% with sofosbuvir-velpatasvir. The most common adverse events were headache, fatigue, diarrhea, and nausea. In the active-treatment groups in both trials, the percentage of patients who discontinued treatment owing to adverse events was 1% or lower.

CONCLUSIONS

Sofosbuvir-velpatasvir-voxilaprevir taken for 12 weeks provided high rates of sustained virologic response among patients across HCV genotypes in whom treatment with a DAA regimen had previously failed. (Funded by Gilead Sciences; POLARIS-1 and POLARIS-4 ClinicalTrials.gov numbers, NCT02607735 and NCT02639247 .).

Evolution of matrinic ethanol derivatives as anti-HCV agents from matrine skeleton

Twenty-two novel 12N-substituted matrinic ethanol derivatives were synthesized and evaluated for their antiviral activities against HCV taking compound 1 as the lead. The SAR study indicated that the shortening of the 11-butyl chain to ethyl chain did not affect the activity significantly. Out of the target compounds, matrinic ethanol 6a demonstrated a potential anti-HCV effect with an EC₅₀ value of 3.2μM and a SI value of 96.6. The free hydroxyl arm in 6a made it possible as a parent structure to prepare pro-drug for the potential application in HCV treatment. This study provided powerful information on further strategic optimization and development of this kind of compounds into a novel family of anti-HCV agents.

Recommendations for the Clinical Management of Hepatitis C in Iran: A Consensus-Based National Guideline

CONTEXT

Hepatitis C virus (HCV) infection is a major public health issue worldwide, including Iran. The new direct-acting antiviral agents (DAAs) with high efficacy have changed the landscape of HCV treatment. This guideline provides updated recommendations for clinical management of HCV infection in Iran.

EVIDENCE ACQUISITION

The recommendations of this guideline are based on international and national scientific evidences and consensus-based expert opinion. Scientific evidences were collected through a systematic review of studies that evaluated efficacy and safety of DAA regimens, using PubMed, Scopus and Web of Science. Expert opinion was based on the consensus of Iran Hepatitis Scientific Board (IHSB) in the 3^rd national consensus on management of Hepatitis C in Iran, held on 22^nd of July 2016.

RESULTS

Pegylated Interferon alpha (PegIFN), Ribavirin (RBV), Sofosbuvir (SOF), Ledipasvir (LDV) and Daclatasvir (DCV) are currently available in Iran. Pre-treatment assessments include HCV RNA level, HCV genotype and resistance testing, assessment of liver fibrosis, and underlying diseases. In HCV genotype 1 and 4, DCV/SOF and LDV/SOF are recommended. In HCV genotype 2, SOF plus RBV and in HCV genotype 3, DCV/SOF is recommended. Additional care for underlying diseases should be considered.

CONCLUSIONS

Affordable new HCV treatment regimens are available in Iran, providing an opportunity for HCV elimination. Recommendations provided in this current national guideline can facilitate evidence-based management of HCV infection.