Oral Combination Therapies for Hepatitis C Virus Infection: Successes, Challenges, and Unmet Needs

Real-world effectiveness of voxilaprevir/velpatasvir/sofosbuvir in patients following DAA failure

Background & Aims

Voxilaprevir/velpatasvir/sofosbuvir (VOX/VEL/SOF) is highly effective for re-treatment of direct-acting antiviral (DAA)-experienced patients with chronic HCV infection. In the present study, predictors of virologic treatment response were analyzed in an integrative analysis of three large real-world cohorts.

Methods

Consecutive patients re-treated with VOX/VEL/SOF after DAA failure were enrolled between 2016 and 2021 in Austria, Belgium, Germany, Italy, Spain and Switzerland.

Results

A total of 746 patients were included: median age was 56 (16-88) years and 77% were male. Most patients were infected with HCV genotype 1 (56%) and 3 (32%). 86% of patients carried resistance-associated substitutions in the NS3, NS5A or NS5B regions. Overall, 95.4% (683/716) of patients achieved a sustained virologic response. Treatment effectiveness was significantly affected by advanced liver disease (p <0.001), hepatocellular carcinoma (p <0.001), higher baseline ALT levels (p = 0.02), HCV genotype 3 (p <0.001), and prior VEL/SOF treatment (p = 0.01). In a multivariate analysis, only HCV genotype 3, hepatocellular carcinoma and cirrhosis turned out to be independent predictors of treatment failure. Resistance-associated substitutions, as well as the presence of rare genotypes, did not impact treatment outcome. The effectiveness of rescue therapy with glecaprevir/pibrentasvir and SOF, with or without ribavirin, for 12 to 24 weeks was found to be high (100%).

Conclusions

Infection with HCV genotype 3, the presence of liver cancer and cirrhosis are independently associated with failure of VOX/VEL/SOF re-treatment. It is unclear whether the addition of ribavirin and/or extension of treatment duration may be effective to avoid virologic relapse on VOX/VEL/SOF. However, rescue treatment with glecaprevir/pibrentasvir+SOF seems to be effective.

Impact and implications

Representative data on the effectiveness of voxilaprevir/velpatasvir/sofosbuvir (VOX/VEL/SOF) in clinical practice are still scarce and the collection of a larger number of patients with difficult-to-treat cofactors including the assessment of resistance-associated substitution profiles is required before more specific recommendations for optimal re-treatment in these patients can be given. Thus, we aimed to analyze treatment effectiveness and predictors of virologic response to VOX/VEL/SOF in an integrative analysis of three large real-word cohorts. The study results, derived from a multicenter cohort consisting of 746 patients, demonstrated that re-treatment with VOX/VEL/SOF is an effective salvage therapy associated with an overall per protocol sustained virologic response rate of 95%. Hepatocellular carcinoma onset, cirrhosis and HCV genotype 3 were identified as independent negative predictors of treatment response, whereas resistance-associated substitutions, as well as rare genotypes and chimera, did not impact sustained virologic response rates following re-treatment with VOX/VEL/SOF.

Donor Viral Hepatitis and Liver Transplantation

Despite increasing numbers of organ transplants completed each year, there continues to be an organ shortage in liver transplantation. This has led to the utilization of previously discarded or "marginal" allografts, such as those from donors with hepatitis C virus (HCV) or hepatitis B virus (HBV). The advent of direct acting antivirals and nucleos(t)ide analogs has allowed these allografts to be safely transplanted regardless of the recipients' hepatitis status with comparable graft and patient survival. Recent advances have even allowed usage of actively viremic donors with similar graft and patient outcomes. This article presents an overview of the use of HCV positive and HBV positive allografts.

Rescue Therapy after Failure of HCV Antiviral Treatment with Interferon-Free Regimens

Direct-acting antivirals (DAA) regimens have provided hope for eliminating hepatitis C virus (HCV) infection. Patients following ineffective therapy with DAA, especially those previously treated with inhibitors of non-structural protein 5A (NS5A), remain a challenge. The study aimed to assess the effectiveness of DAA pangenotypic options in patients after failure of NS5A containing genotype-specific regimens. The analysis included 120 patients selected from the EpiTer-2 database with data on 15675 HCV-infected individuals treated with IFN-free therapies from 1 July 2015 to 30 June 2022 at 22 Polish hepatology centres. The majority of them were infected with genotype (GT) 1b (85.8%) and one-third was diagnosed with fibrosis F4. Among the rescue pangenotypic regimens, the most commonly used was the sofosbuvir/velpatasvir (SOF/VEL) ± ribavirin (RBV) combination. The sustained virologic response, which was a measure of treatment effectiveness, was achieved by 102 patients, resulting in cure rate of 90.3% in the per protocol analysis. All 11 non-responders were infected with GT1b, 7 were diagnosed with cirrhosis, and 9 were treated with SOF/VEL±RBV. We demonstrated the high effectiveness of the pangenotypic rescue options in patients after genotype specific NS5A-containing regimens failures, identifying cirrhosis as a negative prognostic factor of treatment effectiveness.

Decade of optimizing therapy with direct-acting antiviral drugs and the changing profile of patients with chronic hepatitis C

Chronic infection with the hepatitis C virus (HCV) remains a major health problem affecting approximately 58 million people worldwide. In the era of interferon (IFN)-based regimens, patients particularly infected with genotypes 1 and 4 achieved a low response rate. The implementation of direct-acting antivirals changed the landscape of HCV treatment. The increase in effectiveness provided us with the hope of eliminating HCV as a significant public threat by 2030. In the following years, there was an observed improvement in the treatment of HCV with genotype-specific regimens and highly effective pangenotypic options that are the most recent stage of the revolution. The optimization of therapy was accompanied by changes in the patient profile from the beginning of the IFN-free era over time. Patients treated with antiviral therapies were younger in successive periods, less burdened with comorbidities and comedications, more frequently treatment-naïve and had less advanced liver disease. Before the IFN-free era, specific subpopulations such as patients with HCV/HIV coinfection, those with a history of previous treatment, patients with renal impairment or with cirrhosis had lower chances for a virologic response. Currently, these populations should no longer be considered difficult to treat. Despite the high effectiveness of HCV therapy, there is a small percentage of patients with treatment failure. However, they can be effectively retreated with pangenotypic rescue regimens.

Discovery of SARS-CoV-2 antiviral synergy between remdesivir and approved drugs in human lung cells

SARS coronavirus 2 (SARS-CoV-2) has caused an ongoing global pandemic with significant mortality and morbidity. At this time, the only FDA-approved therapeutic for COVID-19 is remdesivir, a broad-spectrum antiviral nucleoside analog. Efficacy is only moderate, and improved treatment strategies are urgently needed. To accomplish this goal, we devised a strategy to identify compounds that act synergistically with remdesivir in preventing SARS-CoV-2 replication. We conducted combinatorial high-throughput screening in the presence of submaximal remdesivir concentrations, using a human lung epithelial cell line infected with a clinical isolate of SARS-CoV-2. This identified 20 approved drugs that act synergistically with remdesivir, many with favorable pharmacokinetic and safety profiles. Strongest effects were observed with established antivirals, Hepatitis C virus nonstructural protein 5A (HCV NS5A) inhibitors velpatasvir and elbasvir. Combination with their partner drugs sofosbuvir and grazoprevir further increased efficacy, increasing remdesivir's apparent potency > 25-fold. We report that HCV NS5A inhibitors act on the SARS-CoV-2 exonuclease proofreader, providing a possible explanation for the synergy observed with nucleoside analog remdesivir. FDA-approved Hepatitis C therapeutics Epclusa® (velpatasvir/sofosbuvir) and Zepatier® (elbasvir/grazoprevir) could be further optimized to achieve potency and pharmacokinetic properties that support clinical evaluation in combination with remdesivir.

Direct antiviral agents (DAAs) and their use in pregnant women with hepatitis C (HCV)

INTRODUCTION

Direct-Acting Antiviral Agents (DAAs) provide safer, efficacious, tolerable, and curative therapy for women with hepatitis C. Their preferred safety and efficacy profile make them potential therapies for the elimination of perinatal transmission of hepatitis C virus (HCV). However, DAAs are not currently recommended for use during pregnancy due to limited pharmacokinetic and safety data.

AREAS COVERED

This review covers the different DAA drug combinations, the available data on their pharmacodynamic and pharmacokinetic properties, how the physiology in pregnancy can potentially affect DAA drug disposition, known drug-drug interactions with DAAs, and available and planned epidemiological and pharmacokinetic studies on DAA use during pregnancy. Although no large randomized clinical trials or prospective cohort studies involving DAAs have been completed in pregnancy, the currently available studies demonstrate no significant changes in pharmacokinetics, and no major safety concerns in women with hepatitis C.

EXPERT OPINION

Initial pharmacokinetic and safety data suggest that DAAs have high efficacy and a low risk of adverse events during pregnancy. As more pharmacokinetic and epidemiologic data become available, DAAs could become a preferred option for treating HCV during pregnancy and elimination of perinatal transmission of hepatitis C virus.

TEMPOL inhibits SARS-CoV-2 replication and development of lung disease in the Syrian hamster model

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a worldwide outbreak, known as coronavirus disease 2019 (COVID-19). Alongside vaccines, antiviral therapeutics is an important part of the healthcare response to COVID-19. We previously reported that TEMPOL, a small molecule stable nitroxide, inactivated the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 by causing the oxidative degradation of its iron-sulfur cofactors. Here, we demonstrate that TEMPOL is effective in vivo in inhibiting viral replication in the Syrian hamster model. The inhibitory effect of TEMPOL on SARS-CoV-2 replication was observed in animals when the drug was administered 2 h before infection in a high-risk exposure model. These data support the potential application of TEMPOL as a highly efficacious antiviral against SARS-CoV-2 infection in humans.

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TEMPOL’s IC₉₀ in human lung epithelial Calu-3 cells is 2.89 μM and CC₅₀ > 10 mM

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TEMPOL has potent antiviral activity against highly pathogenic SARS- and MERS-Co-Vs

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TEMPOL inhibits SARS-CoV-2 replication and lung pathology in the Syrian hamster

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Fe-S cofactor insertion can be targeted to interfere with coronavirus replication

Tackling the emerging threat of antifungal resistance to human health

Invasive fungal infections pose an important threat to public health and are an under-recognized component of antimicrobial resistance, an emerging crisis worldwide. Across a period of profound global environmental change and expanding at-risk populations, human-infecting pathogenic fungi are evolving resistance to all licensed systemic antifungal drugs. In this Review, we highlight the main mechanisms of antifungal resistance and explore the similarities and differences between bacterial and fungal resistance to antimicrobial control. We discuss the research and innovation topics that are needed for risk reduction strategies aimed at minimizing the emergence of resistance in pathogenic fungi. These topics include links between the environment and One Health, surveillance, diagnostics, routes of transmission, novel therapeutics and methods to mitigate hotspots for fungal adaptation. We emphasize the global efforts required to steward our existing antifungal armamentarium, and to direct the research and development of future therapies and interventions.

Hepatitis C: Problems to extinction and residual hepatic and extrahepatic lesions after sustained virological response

Loss of follow-up or reinfections hinder the expectations of hepatitis C eradication despite the existence of highly effective treatments. Moreover, the elimination of the infection does not imply the reversion of those chronic alterations derived from the previous infection by hepatitis C virus (HCV). This review analyzes the risk factors associated with loss to follow-up in diagnosis or treatment, and the possibility of reinfection. Likewise, it assesses the residual alterations induced by chronic HCV infection considering the liver alterations (inflammation, fibrosis, risk of decompensation, hepatocellular carcinoma, liver transplantation) and, on the other hand, the comorbidities and extrahepatic manifestations (cryoglobulinemia, non-Hodgkin lymphoma, peripheral insulin resistance, and lipid, bone and cognitive alterations). Peculiarities present in subjects coinfected with human immunodeficiency virus are analyzed in each section.

Combination Therapy with Fluoxetine and the Nucleoside Analog GS-441524 Exerts Synergistic Antiviral Effects against Different SARS-CoV-2 Variants In Vitro

The ongoing SARS-CoV-2 pandemic requires efficient and safe antiviral treatment strategies. Drug repurposing represents a fast and low-cost approach to the development of new medical treatment options. The direct antiviral agent remdesivir has been reported to exert antiviral activity against SARS-CoV-2. Whereas remdesivir only has a very short half-life time and a bioactivation, which relies on pro-drug activating enzymes, its plasma metabolite GS-441524 can be activated through various kinases including the adenosine kinase (ADK) that is moderately expressed in all tissues. The pharmacokinetics of GS-441524 argue for a suitable antiviral drug that can be given to patients with COVID-19. Here, we analyzed the antiviral property of a combined treatment with the remdesivir metabolite GS-441524 and the antidepressant fluoxetine in a polarized Calu-3 cell culture model against SARS-CoV-2. The combined treatment with GS-441524 and fluoxetine were well-tolerated and displayed synergistic antiviral effects against three circulating SARS-CoV-2 variants in vitro in the commonly used reference models for drug interaction. Thus, combinatory treatment with the virus-targeting GS-441524 and the host-directed drug fluoxetine might offer a suitable therapeutic treatment option for SARS-CoV-2 infections.

Carbon Monoxide Therapy Using Hybrid Carbon Monoxide-Releasing/Nrf2-Inducing Molecules through a Neuroprotective Lens

Carbon monoxide (CO) has long been known for its toxicity. However, in recent decades, new applications for CO as a therapeutic compound have been proposed, and multiple forms of CO therapy have since been developed and studied. Previous research has found that CO has a role as a gasotransmitter and promotes anti-inflammatory and antioxidant effects, making it an avenue of interest for medicine. Such effects are possible because of the Nrf2/HO1 pathway, which has become a target for therapy development because its activation also leads to CO release. Currently, different forms of treatment involving CO include inhaled CO (iCO), carbon monoxide-releasing molecules (CORMs), and hybrid carbon monoxide-releasing molecules (HYCOs). In this article, we review the progression of CO studies to develop possible therapies, the possible mechanisms involved in the effects of CO, and the current forms of therapy using CO.

Salvage Therapy with Sofosbuvir/Velpatasvir/Voxilaprevir in DAA-experienced Patients: Results from a Prospective Canadian Registry

BACKGROUND

Despite the current highly effective therapies with direct-acting antiviral agents (DAAs), some patients with chronic hepatitis C virus (HCV) infection still do not achieve sustained virological response (SVR) and require retreatment. Sofosbuvir/velpatasvir/voxilaprevir (SVV) is recommended as the first-line retreatment option for most patients. The aim of this study was to evaluate the efficacy of SVV as salvage therapy after at least one course of DAA.

METHODS

Data were collected on all HCV-infected patients who failed DAAs and were prescribed SVV from a prospective Canadian registry (CANUHC) including 17 sites across Canada. Factors associated with failure to achieve SVR with SVV therapy and the utility of RAS testing and ribavirin use were evaluated.

RESULTS

A total of 128 patients received SVV after non-SVR with DAA treatment: 80% male, median age 57.5 (31-86), 44% cirrhotic, and 17 patients post liver transplant. First line regimens included: sofosbuvir/velpatasvir (27.3%), sofosbuvir/ledipasvir (26.5%), grazoprevir/elbasvir (12.5%), other (33.5%). Ribavirin was added to SVV in 26 patients due to past sofosbuvir/velpatasvir use (n = 8), complex resistance associated substitution profiles (n = 16) and/or cirrhosis (n = 9). Overall SVR rate was 96% (123/128). Of 35 patients who previously failed sofosbuvir/velpatasvir, 31 (88.5%) achieved SVR compared to 92 of 93 (99%) among those receiving any other regimen (P = .01).

CONCLUSIONS

Similar to reports from phase 3 clinical trials, SVV proved highly effective as salvage therapy for patients who failed a previous DAA therapy. Those who failed SVV had at least 2 of the following factors: genotype 3, presence of cirrhosis, past liver transplantation, past exposure to sofosbuvir/velpatasvir and/or complex resistance profiles.

Orally delivered MK-4482 inhibits SARS-CoV-2 replication in the Syrian hamster model

The COVID-19 pandemic progresses unabated in many regions of the world. An effective antiviral against SARS-CoV-2 that could be administered orally for use following high-risk exposure would be of substantial benefit in controlling the COVID-19 pandemic. Herein, we show that MK-4482, an orally administered nucleoside analog, inhibits SARS-CoV-2 replication in the Syrian hamster model. The inhibitory effect of MK-4482 on SARS-CoV-2 replication is observed in animals when the drug is administered either beginning 12 h before or 12 h following infection in a high-risk exposure model. These data support the potential utility of MK-4482 to control SARS-CoV-2 infection in humans following high-risk exposure as well as for treatment of COVID-19 patients.

Missed linkage to care for patients who screened positive for Hepatitis C in a tertiary care centre: Results of the Telepass project

Italy is one of the countries on track with the WHO's agenda to eliminate hepatitis C virus (HCV) by 2030. Healthcare facilities play a crucial role in seeking patients who are infected but have not yet been treated. We assessed the effectiveness of a recall strategy, named 'Telepass' project, for patients exposed to HCV infection who have not yet been linked to care in a large tertiary care centre. The 'Telepass' project was structured in two phases: (a) a retrospective analysis first identified all anti-HCV-positive subjects among patients who underwent pre-operative assessment in the facility in the course of one year; (b) a following prospective phase, aimed to recall patients in need either of further diagnostic tests (ie HCV-RNA) or treatment. A total of 12246 records of patients tested for HCV antibodies were reviewed. The overall prevalence of anti-HCV-positive subjects was 1.83% (224/12246) with a male/female ratio of 2.07. Out of the 224 anti-HCV-positive patients, 123 (54.91%) did not have documented HCV-RNA tests and were therefore selected for recall. Of these, 123 were reachable and 26 (21.13%) were successfully linked to care. Ten patients (38.46%) tested HCV-RNA positive and initiated treatment with direct-acting antivirals (DAAs). The Telepass study highlights that a recall strategy starting from internal hospital databases can help identify patients with chronic HCV infection who have not yet been linked to care, and provides an epidemiological insight into the prevalence of HCV infection in Italy in the late DAAs era.

Efficacy and Safety of Glecaprevir/Pibrentasvir in HCV Patients With Previous Direct-Acting Antiviral Therapy Failures: A Meta-Analysis

Background: Since a greater number of hepatitis C virus (HCV) patients have access to direct-acting antiviral (DAA) based therapies, the number of patients not properly responding to prior DAA regimens is increasing. The objective of this comprehensive analysis was to assess the efficacy and safety of glecaprevir/pibrentasvir (GLE/PIB) in HCV patients who experienced previous DAA therapy failures.

Methods: Bibliographic databases were systematically searched for relevant articles published by November 2020. The main endpoints were sustained viral response after 12 weeks (SVR12), adverse events (AEs; any grade) and severe adverse events (SAEs). Publication bias assessment was performed using funnel plots and the Egger's test.

Results: Fourteen studies consisting of a total of 1,294 subjects were included in this study and the pooled estimate of SVR12, AEs and SAEs rates were 96.8% (95%CI: 95.1–98.2), 47.1% (95%CI: 26.0–69.3), and 1.8% (95%CI: 0.7–3.4), respectively. Subgroup analysis showed that pooled SVR12 rates were 97.9% (95%CI: 96.7–98.9) for Japan and 91.1% (95%CI: 87.3–94.3) for the United States; 95.8% (95%CI: 93.9–97.4) for genotype (GT)1 and 100.0% (95%CI: 99.6–100.0) for GT2; 95.3% (95%CI: 92.4–97.2) for cirrhosis and 96.3% (95%CI: 94.2–97.7) for non-cirrhosis cases. There was no publication bias included this study.

Conclusion: This comprehensive analysis revealed that GLE/PIB is an effective and secure retreatment option for patients who did not optimally respond to DAA treatment, especially the Asian population with GT1-2.

New Therapeutics for Hepatitis B: The Road to Cure

Chronic hepatitis B virus (HBV) infection impacts an estimated 257-291 million people globally. The current approach to treatment for chronic HBV infection is complex, reflecting a risk:benefit approach driven by the lack of an effective curative regimen. This complexity and the lack of a durable treatment response, necessitating indefinite treatment in the majority of cases, have resulted in low uptake of testing and treatment, particularly in regions where comprehensive primary care is lacking and access to affordable testing and treatment is limited. Multiple targeted therapies are now in early human study with the primary goal to achieve persistent HBV DNA and hepatitis B surface antigen suppression after a finite course of treatment, which is referred to as functional cure. This article summarizes the current therapies for HBV infection and discusses the limitations of these therapies, novel approaches to HBV cure, and therapeutic endpoints of clinical trials aimed to cure hepatitis B.

Preclinical Profile and Characterization of the Hepatitis B Virus Core Protein Inhibitor ABI-H0731

ABI-H0731, a first-generation hepatitis B virus (HBV) core protein inhibitor, has demonstrated effective antiviral activity in chronic hepatitis B (CHB) patients in a phase 1b clinical trial and is currently being further evaluated in phase 2 clinical trials. Here, we report the preclinical profile of ABI-H0731. In in vitro cell culture systems (HepG2-derived cell lines HepAD38 and HepG2-NTCP and primary human hepatocytes [PHHs]), ABI-H0731 exhibited selective inhibition of HBV DNA replication (50% effective concentration [EC₅₀] from 173 nM to 307 nM).

ABI-H0731, a first-generation hepatitis B virus (HBV) core protein inhibitor, has demonstrated effective antiviral activity in chronic hepatitis B (CHB) patients in a phase 1b clinical trial and is currently being further evaluated in phase 2 clinical trials. Here, we report the preclinical profile of ABI-H0731. In in vitro cell culture systems (HepG2-derived cell lines HepAD38 and HepG2-NTCP and primary human hepatocytes [PHHs]), ABI-H0731 exhibited selective inhibition of HBV DNA replication (50% effective concentration [EC₅₀] from 173 nM to 307 nM). Most importantly, ABI-H0731 suppressed covalently closed circular DNA (cccDNA) formation in two de novo infection models with EC₅₀s from 1.84 μM to 7.3 μM. Mechanism-of-action studies indicated that ABI-H0731 is a direct-acting antiviral that targets HBV core protein, preventing HBV pregenomic RNA (pgRNA) encapsidation and subsequent DNA replication. The combination of ABI-H0731 with entecavir appears to decrease viral DNA faster and deeper than nucleoside/nucleotide analogue (NrtI) therapy alone. In addition, ABI-H0731 disrupts incoming nucleocapsids, causing the premature release of relaxed circular DNA (rcDNA) before delivery to the nucleus, and thus prevents new cccDNA formation. ABI-H0731 exhibits pangenotypic activity and is additive to moderately synergistic when combined with an NrtI. In addition to its potency and novel mechanism of action, ABI-H0731 possesses drug-like properties and a preclinical pharmacokinetic profile supportive of once-daily dosing in patients with CHB. Taken together, these data support the ongoing clinical development of ABI-H0731 as a treatment for HBV.

Orally delivered MK-4482 inhibits SARS-CoV-2 replication in the Syrian hamster model

The COVID-19 pandemic progresses unabated in many regions of the world. An effective antiviral against SARS-CoV-2 that could be administered orally for use following high-risk exposure would be of substantial benefit in controlling the COVID-19 pandemic. Herein, we show that MK-4482, an orally administered nucleoside analog, inhibits SARS-CoV-2 replication in the Syrian hamster model. The inhibitory effect of MK-4482 on SARS-CoV-2 replication was observed in animals when the drug was administered either beginning 12 hours before or 12 hours following infection in a high-risk exposure model. These data support the potential utility of MK-4482 to control SARS-CoV-2 infection in humans following high-risk exposure as well as for treatment of COVID-19 patients.

HCV Glycoprotein Structure and Implications for B-Cell Vaccine Development

Despite the approval of highly efficient direct-acting antivirals in the last decade Hepatitis C virus (HCV) remains a global health burden and the development of a vaccine would constitute an important step towards the control of HCV. The high genetic variability of the viral glycoproteins E1 and E2, which carry the main neutralizing determinants, together with their intrinsic structural flexibility, the high level of glycosylation that shields conserved neutralization epitopes and immune evasion using decoy epitopes renders the design of an efficient vaccine challenging. Recent structural and functional analyses have highlighted the role of the CD81 receptor binding site on E2, which overlaps with those neutralization epitopes within E2 that have been structurally characterized to date. This CD81 binding site consists of three distinct segments including “epitope I”, “epitope II” and the “CD81 binding loop”. In this review we summarize the structural features of the HCV glycoproteins that have been derived from X-ray structures of neutralizing and non-neutralizing antibody fragments complexed with either recombinant E2 or epitope-derived linear peptides. We focus on the current understanding how neutralizing antibodies interact with their cognate antigen, the structural features of the respective neutralization epitopes targeted by nAbs and discuss the implications for informed vaccine design.

Efficacy and safety of direct acting antiviral regimens for hepatitis C virus and human immunodeficiency virus co-infection: systematic review and network meta-analysis

BACKGROUND AND AIM

Various all-oral direct-acting antiviral (DAA) regimens are being widely used in the treatment of human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infected patients; however, the comparative efficacy and safety of different types and combinations of DAAs are not completely clear. There is still a lack of integration of evidence for optimized therapies for HIV/HCV co-infection.

METHODS

We conducted a systematic literature search in several databases up to January 1, 2020. All the studies that reported the sustained virologic response (SVR) and adverse events of DAAs in HIV/HCV co-infected patients were included. The Bayesian Markov Chain Monte Carlo method was used for the pooled estimates of network meta-analysis.

RESULTS

We identified 33 eligible articles with 7 combinations of all-oral DAAs for the analyses of efficacy and safety. Grazoprevir-elbasvir ± ribavirin (GZR/EBR ± RBV: 95.6%; 95% CrI, 91.7-98.1%), ombitasvir/paritaprevir/ritonavir and dasabuvir ± ribavirin (3D ± RBV: 95.3%; 95% CrI, 93.4-96.9%), sofosbuvir-ledipasvir ± ribavirin (SOF/LDV ± RBV: 95.2%; 95% CrI, 93.7-96.6%), and sofosbuvir-daclatasvir ± ribavirin (SOF/DCV ± RBV: 94.8%; 95% CrI, 92.5-96.6%) were the most effective combinations for HIV/HCV co-infected patients, with SVR rates of approximately 94% and above while severe adverse events were rare. However, the SVR rates of sofosbuvir-ribavirin (SOF/RBV) and sofosbuvir-simeprevir ± ribavirin (SOF/SMV ± RBV) both failed to reach 90%, and the incidences of adverse events were higher than 5%.

CONCLUSIONS

Efficacy and safety of all-oral DAAs were in prospect for HIV/HCV co-infection patients. GZR/EBR ± RBV was the optimal combination recommended for HIV/HCV co-infected patients based on the excellent treatment effects and insignificant adverse events.

Virological patterns of hepatitis C virus patients with failure to the current-generation direct-acting antivirals

There are few data on the virological characterisation of patients with failure to current-generation direct-acting antivirals (DAAs), namely elbasvir/grazoprevir, sofosbuvir/velpatasvir and glecaprevir/pibrentasvir. This study aimed to characterise virological patterns in patients with failure to current DAA regimens as well as the efficacy of re-treatment. All 61 consecutive hepatitis C virus (HCV) treatment-naïve patients with failure to current DAAs from January 2018 to February 2019 were enrolled. Sanger sequencing of NS3, NS5A and NS5B proteins was performed using homemade protocols. NS5A resistance-associated substitutions (RASs) were more frequent in the 17 patients treated with sofosbuvir/velpatasvir (89.5%) and 33 patients treated with elbasvir/grazoprevir (97%) compared with the 11 patients treated with glecaprevir/pibrentasvir (18.2%) (P = 0.002 and 0.000, respectively). NS3 RASs were more often detected in the 33 patients with failure to elbasvir/grazoprevir (30.3%) than in the 11 patients treated with glecaprevir/pibrentasvir (9.1%). NS3 RASs were also detected in 12% of sofosbuvir/velpatasvir-treated patients. NS5B RASs were infrequently identified. Of the glecaprevir/pibrentasvir-treated patients, 73% did not show RASs in any HCV regions, a prevalence higher than that observed in those treated with elbasvir/grazoprevir (0%; P < 0.05) or sofosbuvir/velpatasvir (12%; P < 0.05). Of the 61 patients, 21 (34.4%) were re-treated with sofosbuvir/velpatasvir and voxilaprevir. All patients achieved sustained virological response at 12 weeks (SVR12). To our knowledge, this is one of the first real-life studies describing patients who failed current-generation DAAs; the prevalence of RASs differed according to the DAA regimen used, and the efficacy of re-treatment was high.

Economic impact of health resource optimisation in the approach to patients with hepatitis C

TThe incorporation of direct-acting antiviral agents to the treatment of chronic hepatitis C infection has simplified diagnosis and follow-up, allowing optimisation of health resources (consultations and tests) dedicated to the management of the disease. The aim of this study was to estimate the economic impact of this simplification. Health resource optimisation was estimated through the Delphi method, based on a panel of 36 experts, consisting of Spanish clinicians, and on clinical practice guidelines. The unit costs (€ in 2017) of the health resources included were obtained from Spanish sources. Simplification of the process, as well as liaison between the medical specialist, nurses and the pharmacy service, would generate savings of €591.17 per patient. Likewise, the mean length of consultations would be shorter with regimens of only 1 tablet daily compared with regimens of more than 1 tablet daily. Supplement information: This article is part of a supplement entitled "The value of simplicity in hepatitis C treatment", which is sponsored by Gilead. © 2019 Elsevier España, S.L.U. All rights reserved.

Effectiveness and safety of sofosbuvir/velpatasvir/voxilaprevir in patients with chronic hepatitis C previously treated with DAAs

BACKGROUND & AIMS

Around 5% of patients with chronic hepatitis C virus (HCV) infection treated with direct-acting antiviral (DAA) agents do not achieve sustained virological response (SVR). The currently approved retreatment regimen for prior DAA failure is a combination of sofosbuvir, velpatasvir, and voxilaprevir (SOF/VEL/VOX), although there is little data on its use in clinical practice. The aim of this study was to analyse the effectiveness and safety of SOF/VEL/VOX in the real-world setting.

METHODS

This was a prospective multicentre study assessing the efficacy of retreatment with SOF/VEL/VOX in patients who had experienced a prior DAA treatment failure. The primary endpoint was SVR 12 weeks after the completion of treatment (SVR12). Data on safety and tolerability were also recorded.

RESULTS

A total of 137 patients were included: 75% men, 35% with liver cirrhosis. Most were infected with HCV genotype (GT) 1 or 3. The most common prior DAA combinations were sofosbuvir plus an NS5A inhibitor or ombitasvir/paritaprevir/r+dasabuvir. A total of 136 (99%) patients achieved undetectable HCV RNA at the end of treatment. Overall SVR12 was 95% in the 135 patients reaching this point. SVR12 was lower in patients with cirrhosis (89%, p = 0.05) and those with GT3 infection (80%, p <0.001). Patients with GT3 infection and cirrhosis had the lowest SVR12 rate (69%). Of the patients who did not achieve SVR12, 1 was reinfected and 7 experienced treatment failure (6 GT3, 1 GT1a). The presence of resistance-associated substitutions did not impact SVR12. Adverse effects were mild and non-specific.

CONCLUSION

Real-world data show that SOF/VEL/VOX is an effective, safe rescue therapy for patients with prior DAA treatment failure despite the presence of resistance-associated substitutions. However, patients with liver cirrhosis infected by GT3 remain the most-difficult-to-treat group.

LAY SUMMARY

Treatment with sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) for 12 weeks is the current recommendation for the 5% of patients infected with HCV who do not achieve eradication of the virus under treatment with direct-acting antivirals. In a Spanish cohort of 137 patients who failed a previous combination of direct-acting antivirals, a cure rate of 95% was achieved with SOF/VEL/VOX. Genotypic characteristics of the virus (genotype 3) and the presence of cirrhosis were factors that decreased the rate of cure. Treatment with SOF/VEL/VOX is an effective and safe rescue therapy due to its high efficacy and very good safety profile.

Content Validity and Reliability of a Self-Report Measure of Medication Nonadherence in Hepatitis C Treatment

BACKGROUND

Nonadherence to direct-acting agents (DAAs) for hepatitis C (HCV) decreases viral response. To measure nonadherence to DAAs, a reliable, valid, and easily implemented method is needed.

AIMS

The goals of this study were to refine a previously validated (in patients with hypertension) self-report measure of extent of nonadherence and reasons for nonadherence in the context of DAAs and to obtain initial evidence of content validity and reliability.

METHODS

Phase I involved two focus groups with patients with HCV (n = 12) and one focus group with prescribers of HCV medications (n = 6) to establish content validity of reasons for nonadherence. Subsequent cognitive interviews with patients (n = 11) were conducted to refine items. Phase II was a prospective cohort study involving weekly administration of the refined measure by telephone to patients (n = 75) who are prescribed DAAs to evaluate reliability and consistency with viral response.

RESULTS

In the cohort study, internal consistency ranged from acceptable (α = .69) to very high (α = 1.00) across time points and was quite high on average (α = .91). Across the 75 participants, there were 895 measurement occasions; of those, nonadherence was reported on only 27 occasions (3%), all of which occurred in the first 12 weeks. These 27 occasions represented 19 (26%) different individuals. At 12 weeks, 1 (1%) of patients had a detectable HCV viral load; at 12-24 weeks posttreatment, 4 (5%) had a sustained viral response. Nonadherent patients reported an average of 1.41 reasons for nonadherence.

CONCLUSIONS

This multi-method study established content validity of reasons for nonadherence and reliability of extent of nonadherence. High rates of adherence and viral response were consistent with previous studies using other nonadherence measurement methods.

Management of HCV patients in cases of direct-acting antiviral failure

Introduction: Over 70 million people are infected with hepatitis C virus (HCV), increasing the risk of cirrhosis and hepatocellular carcinoma. Areas covered: Since the approval of the first interferon-free direct-acting antiviral (DAA) therapy in 2011, a number of DAAs have been approved, and HCV is now considered curable. Until recently, however, there were no clear guidelines on how to re-treat patients who fail DAA therapy. Current protease inhibitors (PIs) are generally unaffected by earlier resistance-associated variants (RAVs), but many NS5A inhibitors continue to have overlapping resistance profiles, and NS5A RAVs can persist even in the absence of DAAs. Expert opinion: Fortunately, RAVs affecting NS5B polymerase inhibitors are rare, making sofosbuvir a safe choice as the backbone of re-treatment therapies. Recent re-treatment guidelines that take into account genotype, fibrosis, treatment history, and RAV suggest that >90% of patients with prior treatment failures can be successfully re-treated with sofosbuvir/velpatasvir, sofosbuvir/velpatasvir/voxilaprevir or glecaprevir/pibrentasvir.

A pilot study of safety and efficacy of HCV retreatment with sofosbuvir/velpatasvir/voxilaprevir in patients with or without HIV (RESOLVE STUDY)

BACKGROUND & AIMS

Cure rates in response to retreatment with sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX) are high, but this regimen has not been studied in patients with a history of poor adherence or treatment interruption, nor in patients with HIV/HCV coinfection. Herein, we aimed to assess the safety and efficacy of this combination in patients with genotype 1 HCV infection who had relapsed following combination direct-acting antiviral (DAA) therapy, regardless of HIV infection or previous treatment course.

METHODS

The RESOLVE study was a multicenter, open-label, phase IIb study investigating the safety, tolerability and efficacy of SOF/VEL/VOX in 77 patients with virologic rebound following combination DAA therapy. Efficacy was defined as HCV RNA below the lower limit of detection 12 weeks after the end of treatment (SVR12), while safety endpoints included the incidence of grade 3 and 4 adverse events (AEs) following treatment, and the proportion of patients who stopped treatment prematurely due to AEs.

RESULTS

In an intent-to-treat analysis, 70/77 (90.9%, 95% CI 82.1-95.8%) patients achieved SVR12, including 14/17 (82.4%) HIV coinfected participants and 18/22 (81.8%) of those with previous non-completion of DAA therapy. In an analysis of all patients who completed 12 weeks of study medication, 70/71 patients (99%) achieved SVR12. One patient experienced a grade 3 AE, and 4 experienced a grade 4 AE, all unrelated to study participation. Reported AEs were similar in HIV-coinfected patients, and patients receiving dolutegravir-based antiretroviral treatment experienced no clinically significant increases in aminotransferases.

CONCLUSION

Retreatment with 12 weeks of SOF/VEL/VOX was safe and effective in patients with relapsed HCV following initial combination DAA-based treatment. Treatment response was not affected by HIV coinfection or previous treatment course.

LAY SUMMARY

Twelve weeks of the combination of direct-acting antivirals (SOF/VEL/VOX) was safe and effective in patients with relapsed hepatitis C virus infection who had previously received combination therapy with direct-acting antivirals. Treatment response was not diminished by HIV coinfection, or non-completion of previous direct-acting antiviral-based therapy.

Implementing a Comprehensive HCV Clinic within an HIV Clinic: A Model of Care for HCV Micro-elimination

BACKGROUND

Among the 1.2 M persons living with HIV in the United States, 25% are co- infected with HCV. The availability of effective direct antiviral agents (DAAs) makes the goal of HCV elimination feasible, but implementation requires improvements to the HCV treatment cascade, especially linkage to and initiation of treatment in underserved populations.

METHODS

In this retrospective review, a cohort of patients receiving care at a hospital-based HIV clinic in New Haven, CT (1/1/2014-3/31/2017) with chronic HCV infection not previously treated with DAAs were followed longitudinally. Patients were referred to a co-located multi-disciplinary team. Standardized referral and treatment algorithms, electronic medical record templates were developed; monthly meetings were held; a registry was created to review progress.

RESULTS

Of 173 patients, 140 (80.9%) were 50-70 years old; 115 (66.5%) male; 99 (57.2%) African-American, 43 (24.9%) White, 23 (13.3%) Hispanic. Comorbidities included: cirrhosis (25.4%); kidney disease (17.3%) mental health issues (60.7%); alcohol abuse (30.6%); active drug use (54.3%). Overall, 161 (93.1%) were referred, 147 (85%) linked, 122 (70.5%) prescribed DAAs, 97 (56.1%) had SVR12. Comparison between those with SVR12 and those unsuccessfully referred, linked or treated, showed that among those not-engaged in HCV care, there was a higher proportion of younger (mean age 54.2 vs 57 years old, p=0.022), female patients (p= 0.001) and a higher frequency of missed appointments.

CONCLUSIONS

Establishing a co-located HCV clinic within an HIV clinic resulted in treatment initiation in 70.5% and SVR12 in 56.1%. This success in a hard-to-treat population is a model for achieving WHO micro-elimination goals.

Genetic mutations in NF-κB pathway genes were associated with the protection from hepatitis C virus infection among Chinese Han population

Host genetic polymorphism is one of major unalterable major factors for HCV infection. NF-κB proteins play multiple roles in immune response and involve in HCV infection and progression. This study was conducted to explore the relationship between single nucleotide polymorphisms (SNPs) in NF-κB pathway and the susceptibility as well as resolution of HCV infection. A total of 1642 Chinese subjects were enrolled in the study, including 963 uninfected control cases, 231 cases with spontaneous viral clearance and 448 cases with persistent HCV infection, and four SNPs (Rel rs842647, NF-κB2 rs12769316, RelA rs7101916, RelB rs28372683) were genotyped by TaqMan assay among them. Potentially functional polymorphisms were analyzed using online bioinformatics tools. The logistic analyses results indicated that RelA rs7101916 T allele (P_Bonferroni = 0.016) and RelB rs28372683 A allele (P_Bonferroni = 4.8e-5) were associated with an decreased risk of the susceptibility to HCV infection among Chinese Han population, which were consistent with the results of cumulative effects and haplotype analysis. The silico analysis of SNPs function suggested that the genetic variation of rs7101916 and rs28372683 could influence gene transcriptional regulation and expression, subsequently affecting NF-κB pathway activation and the susceptibility to HCV infection. This study firstly reported that the carriage of RelA rs7101916 T or RelB rs28372683 A was the potential protective factor against HCV infection among the Chinese population.

Sofosbuvir/velpatasvir/voxilaprevir in the treatment of chronic hepatitis C infection

The landscape of HCV treatment has been entirely transformed due to the development of direct-acting antivirals (DAAs), but there are limited data guiding salvage therapy in patients who previously failed an NS5A inhibitor-containing DAA regimen. We review the preclinical and clinical data for sofosbuvir/velpatasvir/voxilaprevir (SOF/VEL/VOX), an interferon-free, oral, once daily, pan-genotypic treatment for chronic HCV infection. This combination is a highly effective, well-tolerated and safe 12-week treatment regimen for patients with any genotype, including genotype-3 patients with baseline resistance-associated substitutions (RAS). Its most distinctive role is in patients who have previously failed treatment with advanced DAA regimens. Its efficacy is not significantly affected by RASs, and treatment-emergent RASs are uncommon.

Exposure-Response Analysis for Efficacy of Daclatasvir, Asunaprevir, and Beclabuvir Combinations in HCV-Infected Patients

The combination regimen of daclatasvir, asunaprevir, and beclabuvir (3DAA regimen) was developed as a fixed-dose combination for the treatment of hepatitis C virus (HCV) infection in Japan. The objectives of this analysis were to characterize the relationship between drug exposure and sustained virologic response at posttreatment week 12 (SVR12) in HCV-infected subjects and to evaluate the impact of demographic covariates and clinical factors on the exposure-response (E-R) relationship. The E-R efficacy analysis was performed with data from phase 2 and phase 3 studies in HCV-infected subjects treated with the 3DAA regimen. The relationship between the probability of achieving SVR12 and exposure to daclatasvir, asunaprevir, and beclabuvir was described using a logistic regression model and included assessments of the potential covariate effects. The impacts of the covariates on the rate of SVR12 and interactions of covariates with the individual drug effects were tested. The final model for SVR12 included effects of non-genotype-1a status, resistance-associated NS5A-Q30 substitution in genotype-1a subjects, and baseline RNA level on the intercept, and effect of prior peg-interferon failure on the beclabuvir slope. Sex, race, age, weight, fibrosis score, alanine transaminase, and cirrhosis status had no statistically significant impact on the rate of SVR12. The individual E-R relationships with each drug, were relatively flat, and the effects of exposure were not significant. With the exception of the NS5A-Q30 substitution in genotype-1a subjects, statistically significant covariate effects had little impact on SVR12 rates. Overall, the E-R model was developed that captured the high SVR12 rates and the effect of covariates for the 3DAA regimen in HCV-infected patients.

Direct acting antiviral treatment of chronic hepatitis C in Denmark: factors associated with and barriers to treatment initiation

OBJECTIVES

We describe factors associated with and barriers to initiation of Direct Acting Antiviral (DAA) treatment in patients with chronic hepatitis C, who fulfill national fibrosis treatment guidelines in Denmark.

MATERIALS AND METHODS

In this nationwide cohort study, we included patients with chronic hepatitis C from The Danish Database for Hepatitis B and C (DANHEP) who fulfilled fibrosis treatment criteria. Factors associated with treatment initiation and treatment failure were determined by logistic regression analyses. Medical records were reviewed from patients who fulfilled fibrosis treatment criteria, but did not initiate DAA treatment to determine the cause.

RESULTS

In 344 (49%) of 700 patients, who fulfilled treatment criteria, factors associated with DAA treatment initiation were transmission by other routes than injecting drug use odds ratio (OR) 2.13 (CI: 1.38-3.28), previous treatment failure OR 2.58 (CI: 1.84-3.61) and ALT above upper limit of normal OR 1.60 (CI: 1.18-2.17). The most frequent reasons for not starting treatment among 356 (51%) patients were non-adherence to medical appointments (n = 107/30%) and ongoing substance use (n = 61/17%). Treatment failure with viral relapse occurred in 19 (5.5%) patients, who were more likely to have failed previous treatment OR 4.53 (CI: 1.59-12.91).

CONCLUSIONS

In this nationwide cohort study, we found non-adherence to medical appointments and active substance use to be major obstacles for DAA treatment initiation. Our findings highlight the need for interventions that can overcome these barriers and increase the number of patients who can initiate and benefit from curative DAA treatment.

Pathogens and autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe form of hepatitis resulting in the autoimmune-mediated destruction of the liver parenchyma. Whereas many of the immunopathogenic events have been elucidated and some of the drivers of the disease have been identified, little is known about the aetiology of the disease. There are certain risk factors, such as particular human leucocyte antigen (HLA) haplotypes, that enhance the susceptibility for AIH or influence the severity of the disease. However, as for many other autoimmune diseases, the mere presence of such risk factors does not warrant the occurrence of the disease. Not all individuals carrying risk factors develop AIH, and not all patients with AIH are carriers of high-risk alleles. Thus, additional environmental factors need to be considered as triggers for AIH. Environmental factors include diet, sunlight exposure, stress, medication and hygiene, as well as pathogen infections and vaccinations. This review discusses if pathogens should be considered as triggers for the initiation and/or propagation of AIH.

Outcome and adverse events in patients with chronic hepatitis C treated with direct-acting antivirals: a clinical randomized study

OBJECTIVE

New potent direct-acting antiviral (DAA) regimens against hepatitis C virus have been approved in recent years. However, information about the rate of adverse events (AEs) across different DAA regimens is limited. We aimed to evaluate differences in AEs and treatment efficacy in patients with chronic hepatitis C (CHC), genotype (GT) 1 or 3, randomized to two different treatment arms, correspondingly.

PATIENTS AND METHODS

We randomly assigned 96 patients in a 1 : 1 ratio, to treatment for 12 weeks with either paritaprevir/ombitasvir/ritonavir/dasabuvir/ribavirin (RBV) or ledipasvir/sofosbuvir (SOF)/RBV if infected with GT1 (72 patients) or to daclatasvir/SOF/RBV for 12 weeks or SOF/RBV for 24 weeks, if infected with GT3 (24 patients). Data on AEs were collected throughout the entire study period.

RESULTS

A total of 70 (97%) patients with CHC with GT1 and 20 (83%) patients with GT3 achieved cure. The GT3 treatment arm was prematurely terminated, owing to change in national treatment guidelines. Thus, only AEs for GT1 patients are described. AEs occurred in 70 (97%) GT1 patients, and most common AEs were anemia (n=56/78%), fatigue (n=53/74%), and headache (n=33/46%). No difference was observed in relation to treatment group (P=1.0), anemia (P=1.0), or liver cirrhosis (P=0.53). In seven (11%) patients, AEs assessed by the investigator to be possibly related to the DAA regimen were still present 12 weeks after treatment.

CONCLUSIONS

We found no difference in AEs possibly related to the DAA regimen in patients with CHC, but surprisingly, AEs possibly related to the DAA regimen persisted in a significant number of patients after treatment. This finding can be of importance for clinicians in relation to patient information concerning AEs possibly related to DAA treatment.

Ferrocene-based inhibitors of hepatitis C virus replication that target NS5A with low picomolar in vitro antiviral activity

An unprecedented series of organometallic HCV (hepatitis C virus) NS5A (nonstructural 5A protein) replication complex inhibitors that incorporates a 1,1'-ferrocenediyl scaffold was explored. This scaffold introduces the elements of linear flexibility and non-planar topology that are unconventional for this class of inhibitors. Data from 2-D NMR spectroscopic analyses of these complexes in solution support an anti (unstacked) arrangement of the pharmacophoric groups. Several complexes demonstrate single-digit picomolar in vitro activity in an HCV genotype-1b replicon system. One complex to arise from this investigation (10a) exhibits exceptional picomolar activity against HCV genotype 1a and 1b replicons, low hepatocellular cytotoxicity, and good pharmacokinetic properties in rat.

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

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

Exposure-Response (Efficacy) Analysis of Daclatasvir and Asunaprevir in Japanese Patients With Hepatitis C Virus Infection

The treatment of hepatitis C virus (HCV) infection has been revolutionized by the development of all-oral combination regimens of direct-acting antiviral agents. The current analysis characterized the relationship between exposures of daclatasvir (DCV; tablets) and asunaprevir (ASV; capsules) and sustained virologic response (SVR) in Japanese patients who are HCV genotype (GT) 1b nonresponders to pegylated interferon (IFN) α/ribavirin or IFNβ/ribavirin, and IFN-based therapy-ineligible naive/intolerant patients receiving DCV and ASV, and provided insight into patient covariates that were most closely associated with efficacy. The relationship between the probability of achieving SVR at 12 weeks after treatment (SVR12) and average steady-state plasma concentrations estimated from population pharmacokinetic models for DCV and ASV is described using a logistic regression model with data from a phase 2 and a phase 3 study in Japanese patients infected with HCV GT 1b (N=265). The functional form characterization, which describes a relationship between DCV and ASV average steady-state plasma concentrations and SVR12, as well as covariate identification (demographic, laboratory, and prognostic and treatment covariates) were investigated during model development. The presence of the signature nonstructural protein 5A Y93H mutation at baseline was the only significant parameter of SVR12 in the final exposure-response model. Model evaluation plots demonstrate that the final model was able to predict the observed SVR rates. Exposure-response analysis supports the clinical utility of the combination regimen of 60-mg once-daily DCV and 100-mg twice-daily ASV in Japanese patients infected with HCV GT 1b.

Conformational Flexibility in the CD81-Binding Site of the Hepatitis C Virus Glycoprotein E2

Numerous antibodies have been described that potently neutralize a broad range of hepatitis C virus (HCV) isolates and the majority of these antibodies target the binding site for the cellular receptor CD81 within the major HCV glycoprotein E2. A detailed understanding of the major antigenic determinants is crucial for the design of an efficient vaccine that elicits high levels of such antibodies. In the past 6 years, structural studies have shed additional light on the way the host’s humoral immune system recognizes neutralization epitopes within the HCV glycoproteins. One of the most striking findings from these studies is that the same segments of the E2 polypeptide chain induce antibodies targeting distinct antigen conformations. This was demonstrated by several crystal structures of identical polypeptide segments bound to different antibodies, highlighting an unanticipated intrinsic structural flexibility that allows binding of antibodies with distinct paratope shapes following an “induced-fit” mechanism. This unprecedented flexibility extends to the entire binding site for the cellular receptor CD81, underlining the importance of dynamic analyses to understand (1) the interplay between HCV and the humoral immune system and (2) the relevance of this structural flexibility for virus entry. This review summarizes the current understanding how neutralizing antibodies target structurally flexible epitopes. We focus on differences and common features of the reported structures and discuss the implications of the observed structural flexibility for the viral replication cycle, the full scope of the interplay between the virus and the host immune system and—most importantly—informed vaccine design.

The Mexican consensus on the treatment of hepatitis C

The aim of the Mexican Consensus on the Treatment of HepatitisC was to develop clinical practice guidelines applicable to Mexico. The expert opinion of specialists in the following areas was taken into account: gastroenterology, infectious diseases, and hepatology. A search of the medical literature was carried out on the MEDLINE, EMBASE, and CENTRAL databases through keywords related to hepatitisC treatment. The quality of evidence was subsequently evaluated using the GRADE system and the consensus statements were formulated. The statements were then voted upon, using the modified Delphi system, and reviewed and corrected by a panel of 34 voting participants. Finally, the level of agreement was classified for each statement. The present guidelines provide recommendations with an emphasis on the new direct-acting antivirals, to facilitate their use in clinical practice. Each case must be individualized according to the comorbidities involved and patient management must always be multidisciplinary.

Current Cell-Based Therapies in the Chronic Liver Diseases

Liver diseases account for one of the leading causes of deaths in global health care. Furthermore, chronic liver failure such as liver cirrhosis is, namely, responsible for these fatal conditions. However, only liver transplantation is an established treatment for this end-stage condition, although the availability of this salvage treatment option is quite limited. Thus, the novel therapy such as artificial liver devices or cellular administration has been regarded as feasible. Especially cellular therapies have been proposed in decades. The technical advancement and progress of understanding of cellular differentiation have contributed to the development of basis of cellular therapy. This attractive therapeutic option has been advanced from original embryonic stem cells to more effective cellular fractions such as Muse cells. Indeed several cellular therapies including bone marrow-derived stem cells or peripheral blood-derived stem cells were initiated; the recent most organized clinical trials could not demonstrate its efficacy. Thus, truly innovative cellular therapy is needed to meet the scientific demands, and Muse cell administration is the remaining approach to this. In this article, we will discuss the current development and status of cellular therapy toward chronic liver failure.

Liver Cirrhosis as a Risk Factor for Direct-Acting Antiviral Therapy Failure in Real-Life Hepatitis C Virus/Human Immunodeficiency Virus Coinfection

Current hepatitis C virus (HCV) treatment guidelines recommend treating HCV/human immunodeficiency virus (HIV)-coinfected individuals similar to HCV-monoinfected individuals. Recently inferior response rates to direct acting antiviral (DAA) therapy in HCV/HIV coinfection have been reported. Our German hepatitis C cohort (GECCO) cohort data show that coinfected patients with liver cirrhosis are less likely to achieve viral eradication.

Efficacy of 8 Weeks of Sofosbuvir, Velpatasvir, and Voxilaprevir in Patients With Chronic HCV Infection: 2 Phase 3 Randomized Trials

BACKGROUND & AIMS

Patients with chronic hepatitis C virus (HCV) infection have high rates of sustained virologic response (SVR) after 12 weeks of treatment with the nucleotide polymerase inhibitor sofosbuvir combined with the NS5A inhibitor velpatasvir. We assessed the efficacy of 8 weeks of treatment with sofosbuvir and velpatasvir plus the pangenotypic NS3/4A protease inhibitor voxilaprevir (sofosbuvir-velpatasvir-voxilaprevir).

METHODS

In 2 phase 3, open-label trials, patients with HCV infection who had not been treated previously with a direct-acting antiviral agent were assigned randomly to groups given sofosbuvir-velpatasvir-voxilaprevir for 8 weeks or sofosbuvir-velpatasvir for 12 weeks. POLARIS-2, which enrolled patients infected with all HCV genotypes with or without cirrhosis, except patients with genotype 3 and cirrhosis, was designed to test the noninferiority of 8 weeks of sofosbuvir-velpatasvir-voxilaprevir to 12 weeks of sofosbuvir-velpatasvir using a noninferiority margin of 5%. POLARIS-3, which enrolled patients infected with HCV genotype 3 who had cirrhosis, compared rates of SVR in both groups with a performance goal of 83%.

RESULTS

In POLARIS-2, 95% (95% confidence interval [CI], 93%-97%) of patients had an SVR to 8 weeks of sofosbuvir-velpatasvir-voxilaprevir; this did not meet the criterion to establish noninferiority to 12 weeks of sofosbuvir-velpatasvir, which produced an SVR in 98% of patients (95% CI, 96%-99%; difference in the stratum-adjusted Mantel-Haenszel proportions of -3.2%; 95% CI, -6.0% to -0.4%). The difference in the efficacy was owing primarily to a lower rate of SVR (92%) among patients with HCV genotype 1a infection receiving 8 weeks of sofosbuvir-velpatasvir-voxilaprevir. In POLARIS-3, 96% of patients (95% CI, 91%-99%) achieved an SVR in both treatment groups, which was significantly superior to the performance goal. Overall, the most common adverse events were headache, fatigue, diarrhea, and nausea; diarrhea and nausea were reported more frequently by patients receiving voxilaprevir. In both trials, the proportion of patients who discontinued treatment because of adverse events was low (range, 0%-1%).

CONCLUSIONS

In phase 3 trials of patients with HCV infection, we did not establish that sofosbuvir-velpatasvir-voxilaprevir for 8 weeks was noninferior to sofosbuvir-velpatasvir for 12 weeks, but the 2 regimens had similar rates of SVR in patients with HCV genotype 3 and cirrhosis. Mild gastrointestinal adverse events were associated with treatment regimens that included voxilaprevir. ClinicalTrials.gov numbers: POLARIS-2, NCT02607800; and POLARIS-3, NCT02639338.

Sofosbuvir-velpatasvir-voxilaprevir with or without ribavirin in direct-acting antiviral-experienced patients with genotype 1 hepatitis C virus

The optimal retreatment strategy for hepatitis C virus (HCV) genotype 1-infected patients who fail direct-acting antiviral (DAA)-based regimens remains unknown. In this phase 2, open-label study conducted at a single center in the United States, patients with HCV genotype 1 infection who previously failed to achieve sustained virological response (SVR) on a DAA-based regimen were randomized to receive treatment with a fixed-dose combination tablet of sofosbuvir-velpatasvir-voxilaprevir with or without ribavirin (RBV) for 12 weeks. Patients were stratified by their cirrhosis and past nonstructural protein (NS) 5A inhibitor exposure. The primary efficacy endpoint was the proportion of patients with SVR at 12 weeks after treatment (SVR12). SVR12 was achieved by 24 of 24 patients (100%; 95% confidence interval [CI], 86-100) receiving sofosbuvir-velpatasvir-voxilaprevir alone and 24 of 25 (96%; 95% CI, 80-100) receiving the same treatment with RBV. None of the patients discontinued sofosbuvir-velpatasvir-voxilaprevir therapy because of an adverse event (AE). The most commonly reported AEs with sofosbuvir-velpatasvir-voxilaprevir alone were diarrhea and bronchitis; and with sofosbuvir-velpatasvir-voxilaprevir plus RBV were fatigue, anemia, gastroenteritis, and nausea.

CONCLUSION

A fixed-dose combination of sofosbuvir-velpatasvir-voxilaprevir was well tolerated and effective at achieving virological response in patients with HCV genotype 1 infection and past DAA treatment experience. (Hepatology 2017;65:1803-1809).

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 .).