Interferon-free therapies for chronic hepatitis C: toward a hepatitis C virus-free world?

Changing epidemiology of patients treated with direct acting antivirals for HCV and persistently high SVR12 in an endemic area for HCV infection in Italy: real-life 'LIver Network Activity' (LINA) cohort update results

BACKGROUND

Second generation direct acting antivirals (DAAs) drastically changed the landscape of chronic HCV (CHCV). Aim of this paper was to assess the effectiveness of DAAs, also looking at the demographic characteristics of subjects enrolled.

RESEARCH DESIGN AND METHODS

Ambispective multi-center real-life study conducted among patients with CHCV treated with DAAs in Campania Region (Southern Italy). Patient were enrolled in two cohorts according to time of enrolment.

RESULTS

1,479 patients were enrolled. Patients aged ≥60 years were 74.7% in the historic cohort (953 patients) and 70.2% in the prospective cohort (526 patients. Patients aged ≥ 60 years showed a higher prevalence of genotype 1b (p<0.001) and 2 (p<0.001), while patients aged < 60 years showed a higher prevalence of genotype 1a (p<0.001), 3 (p<0.001) and 4 (p<0.05). SVR12 was 98.5% in both cohorts. SVR12 was similar among patients of the prospective cohort aged < and ≥ 60 years (99.4% vs 98.1%). SVR12 among patients with and without cirrhosis was 96.0% and 98.9%, respectively.

CONCLUSIONS

DAAs provide high efficacy also in harder to treat patients. The effectiveness of DAAs is leading to a shift in patients characteristics with a greater prevalence of younger subjects and persons with mild liver disease.

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.

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.

The cost of successful antiviral therapy in hepatitis C patients: a comparison of IFN-free versus IFN-based regimens at an individual patient level in Australia

Background

Chronic hepatitis C remains a major global health burden with serious long-term consequences if left untreated. Recently the treatment standard of care has shifted to new interferon (IFN)-free drug regimens, which have been shown to be safe and effective. The aim of our study was to assess and compare medical resource utilization and costs of successfully treating patients with IFN-based and IFN-free therapies in Australia.

Methods

We performed a retrospective chart review of 30 HCV-infected patients successfully treated with IFN-based therapy between 2013 and 2015. We also generated a model for a virtual group of 100 genotype 1 (GT1) and 100 genotype 3 (GT3) patients treated with IFN-free therapy derived from national guidelines and clinical trial data.

Results

In comparison to virtual patients receiving IFN-free therapy, our IFN-treated patients on average had distinctively more liver clinic visits and blood tests. However, mean total cost per patient was $19,164 and $85,300 (AUD) more for GT1 and GT3 patients receiving IFN-free therapy, respectively. This difference was largely accounted for by higher antiviral drug costs. Of our 30 patients treated with IFN, total mean cost per patient during the study period was $33,595.

Conclusion

Resource utilization is lower with IFN-free treatment, which reflects the reduced need for patient monitoring and improved side-effect profile of these new drugs. However, total costs are still largely dominated by antiviral drug costs, representing a huge burden on national budgets. Our insight into resource utilization and costs associated with both types of treatment can serve as a reference for future studies.

Hepatitis B and C

Chronic viral hepatitis is a global health threat and financial burden. Hepatitis B and C viruses (HBV and HCV) are the most common causes of chronic viral hepatitis in the United States. Most cases are asymptomatic before adulthood. Research has resulted in effective therapy for HCV and the promise of effective therapies for HBV. For HCV, therapy is pegylated interferon and ribavirin. Clinical trials with effective direct-acting antiviral agents are underway in pediatrics. For HBV, approved agents are alpha-interferon, lamivudine, adefovir, tenofovir, and entecavir. However, treatment seldom results in functional cure and more effective therapies are urgently needed.

Limiting the access to direct-acting antivirals against HCV: an ethical dilemma

Hepatitis C virus (HCV) infection affects about 200 million people worldwide and represents a leading cause of liver-related mortality. Eradication of HCV infection, achieved mainly through direct-acting antivirals (DAA), results in a decrease of mortality and an improvement of quality of life. These drugs have a maximal efficacy and an optimal tolerability. However, their high cost precludes a universal access even in wealthy countries. Areas covered: This article deals with the policies adopted for the use of the new anti-HCV drugs, especially in Europe and most of all in Italy, supposedly the developed country with the highest HCV prevalence. The literature search was performed using Pubmed and Web of Science. Moreover, national regulatory institutional websites were consulted. Expert commentary: The current policy of limitation to the access of the DAA presents a series of ethical issues that makes it non-applicable. A 'treat-all' strategy should resolve all ethical dilemmas, by virtue of the wide benefits of anti-HCV treatment not only for the advanced stage of infection, but also for the initial stages. A reduction in price of the drugs is the actual condition to achieve such a change.

Drug-Induced Lung Injury in a Liver Transplant Patient Treated With Sofosbuvir

New direct-acting antivirals (DAAs) have dramatically improved sustained virologic response (SVR) rates in patients treated for chronic hepatitis C. Although the safety of these agents has been very good in registration trials, unexpected side effects have been reported after much broader use of DAAs on marketing. We retrospectively examined all liver transplant recipients with chronic hepatitis C that received sofosbuvir-based regimens at our clinic. A total of 24 liver transplant recipients with recurrent chronic hepatitis C had received sofosbuvir up to April 2015. Regimens were as follows: sofosbuvir+simeprevir (8), SOF+ledipasvir (6), sofosbuvir+daclatasvir (5) and sofosbuvir+ribavirin (5). Overall, treatment was very well tolerated with only mild adverse events in 42% of patients. However, a 52-year-old woman developed severe respiratory failure within 10 days after beginning sofosbuvir+daclatasvir. High-resolution computerized tomography showed areas of diffused ground-glass opacities in both lungs, suggesting drug-induced lung injury. The bronchoalveolar lavage showed marked signs of acute inflammation without recovering any infectious agent. The patient was treated with high-dose corticosteroids and steadily recovered. DAA therapy was not discontinued, but sofosbuvir was replaced by simeprevir. She reached sustained virologic response after completing 24 weeks of DAA therapy. Given the close temporal association, radiologic and bronchoalveolar lavage findings, and negative work-up for infectious agents, we postulated that sofosbuvir was the most likely explanation for drug-induced lung injury in our patient.

The therapeutic potential of new investigational hepatitis C virus translation inhibitors

INTRODUCTION

Hepatitis C virus (HCV) infection is a leading cause of liver cirrhosis, hepatocellular carcinoma and liver-related death worldwide. Currently, the anti-HCV armamentarium encompasses several direct-acting antivirals (DAA) that achieve very high response rates and have an excellent tolerability profile. However, they do not represent a final solution for HCV global eradication for at least these two reasons: i) some patients harbour resistant strains to DAAs and cannot benefit from currently available treatments; ii) the cost of these drugs remains very high.

AREAS COVERED

This review summarizes pre-clinical and clinical data regarding HCV translation inhibitors, a new class of drugs currently in the pipeline with novel mechanisms of action.

EXPERT OPINION

The availability of DAAs resolved most issues related to HCV treatment compared with the previous interferon-based therapies. However, there are some patients that cannot achieve a viral clearance with currently available treatments. Therefore, there is still room for new drugs in this setting, providing that they demonstrate an advantage in terms of efficacy, safety, cost or or simplicity of use. Based on preliminary results, at least for some promising molecules (e.g. miravirsen and RG-101), studies on safety and efficacy on this intriguing class of drugs are needed.

Prevention and management of treatment failure to new oral hepatitis C drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. Sustained virologic response rates above 90% have been achieved with recommended direct-acting antiviral (DAA) combinations in most registration trials. However, outcomes in real-world patients are lower. In patients experiencing DAA failure, resistance-associated variants (RAVs) are almost universally selected. At this time it is unclear when and how to re-treat hepatitis C in patients with prior DAA failure.

AREAS COVERED

The rate of DAA failure and predictors of lack of treatment response using distinct DAA combinations are analyzed. We discuss the management of HCV treatment failure and the impact of RAVs on re-treatment strategies.

EXPERT OPINION

Failure to DAA combinations occurs more often in chronic hepatitis C patients with baseline predictors of poor response, such as those with RAVs, genotypes 3 or 1a, advanced liver cirrhosis, elevated serum HCV-RNA and perhaps HIV coinfection. Impaired antiviral efficacy is more frequent when multiple factors are present. On-treatment predictors of DAA failure are poor drug adherence and development of side effects. Extending the length of therapy, adding ribavirin and/or using DAA from other drug families may allow successful re-treatment of most prior DAA failures.

Polymorphisms at IL28B gene as predictors of viral relapse in genotype 4 Egyptian hepatitis C patients

Chronic HCV is one of the commonest causes of chronic liver disease worldwide with about 15% of population infected in Egypt. Certain single nucleotide polymorphisms (SNPs) lying near the IL28B gene were found to affect the spontaneous clearance as well as treatment outcome of HCV. To examine the association between different IL28B variants and the relapse of HCV infection after combined therapy with ribavirin and pegylated interferon (pegIFN). Hundered HCV genotype four patients received 1.5 mg/kg/week peginterferon alfa-2b plus 800-1400 mg/d ribavirin (weight-adjusted) for 48 weeks. IL28B polymorphisms (rs12980275, rs12979860, and 1 rs8099917) were studied in responders and relapsers at week 72. Out of 69 patients receiving treatment, 13 (18.8%) were relapsers. By stratifying patients on the basis of the IL-28/60 genotype (CC vs. CT/TT), CC patients showed lower relapse rates (2.3%) compared with CT/TT patients (46.2%) (P < 0.001). On the basis of the IL-28/75 genotype (GG vs. GA/AA), the GG patients achieved higher relapse rates (62.5%) compared with GA/AA patients (13.1%) (P = 0.004). Moreover, no statistical significant difference was observed between the TT patients compared with GG/GT patients on the basis of the IL-28/17 genotype. SNPs at IL-28/60 and IL-28/75 are possible predictors of relapse in patients receiving dual treatment.

Occult HCV Infection: The Current State of Knowledge

Context

Occult HCV infection (OCI) is defined as the presence of HCV-RNA in hepatocytes and the absence of HCV in the serum according to usual tests. We aimed to define OCI and provide information about the currently available diagnostic methods. Then we focus on specific groups that are at high risk of OCI and finally investigate immune responses to OCI and the available treatment approaches.

Evidence Acquisition

PubMed, Scopus and Google Scholar were comprehensively searched with combination of following keywords: “occult”, “hepatitis C virus” and “occult HCV infection”. The definition of OCI, diagnostic methods, specific groups that are at high risk and available treatment approaches were extract from literature. An analysis of available articles on OCI also was done based on Scopus search results.

Results

OCI has been reported in several high-risk groups, especially in hemodialysis patients and subjects with cryptogenic liver disease. Furthermore, some studies have proposed a specific immune response for OCI in comparison with chronic hepatitis C (CHC).

Conclusions

With a clinical history of approximately 11 years, occult HCV infection can be considered an occult type of CHC. Evidences suggest that considering OCI in these high-risk groups seems to be necessary. We suggest that alternative diagnostic tests should be applied and that there is a need for the participation of all countries to determine the epidemiology of this type of HCV infection. Additionally, evaluating OCI in blood transfusion centers and in patients who receive large amounts of blood and clotting factors, such as patients with hemophilia, should be performed in future projects.

New hepatitis C therapies for special patient populations

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has become a curable disease. More than 90% sustained virologic response rates have been obtained with 8-24 weeks of treatment with distinct combinations of direct-acting antivirals (DAA) in most registration trials. However, outcomes in real-world patients tend to be lower and treatment of special patient populations is often challenging.

AREAS COVERED

We address the treatment of chronic hepatitis C with DAA in major special patient populations, such as HIV-positive persons, transplant recipients, patients with advanced cirrhosis, renal insufficiency, hepatitis B or D coinfection, injection drug users (IDUs) and prior DAA failures.

EXPERT OPINION

Drug interactions between DAA and medications given to persons with HIV infection or transplant recipients can result in treatment failure and adverse events. Severe organ dysfunction as in kidney insufficiency or decompensated cirrhosis may lead to DAA overexposure and toxicities. Dysfunctional social circumstances and behavior are associated to poor drug adherence and increased risk for HCV re-infection in active IDUs. Finally, DAA response might be impaired by viral interference in patients with hepatitis B or D coinfection or drug resistance in HCV either at baseline or after prior DAA failures.

The discovery of sofosbuvir: a revolution for therapy of chronic hepatitis C

INTRODUCTION

Hepatitis C virus (HCV) infection is a worldwide health problem, whose management has been revolutionized after the availability of sofosbuvir, a direct-acting antiviral (DAAs). Sofosbuvir is a HCV NS5B polymerase inhibitor. Antiviral regimens including sofosbuvir are associated with success rates >90%, even in the case of "difficult-to-treat" patients such as subjects with liver cirrhosis as well as prior null response to IFN and ribavirin.

AREAS COVERED

This drug discovery case history focuses on the pre-clinical and clinical development of sofosbuvir. The authors analyze all of the main steps leading to the global approval of sofosbuvir. The paper also highlights the encouraging data from the subsequent trials wherein sofosbuvir was tested in combination with other DAAs (IFN- and often ribavirin-free regimens) and from first real life studies.

EXPERT OPINION

Sofosbuvir is a very powerful weapon in the new armamentarium against HCV. Thanks to its valuable features including its pangenotypic activity, once-daily oral administration, its excellent tolerability, and safety profile, it represents the backbone of several effective regimens, in combination with IFN or with other DAAs (IFN-free therapies). Regimens including sofosbuvir have quickly become the touchstone for all the novel anti-HCV treatments.

Increased expression and dysregulated association of restriction factors and type I interferon in HIV, HCV mono- and co-infected patients

Host restriction factors and type I interferon are important in limiting HIV and HCV infections, yet the role of HIV, HCV mono- and co-infection in regulating these antiviral genes expression is not clear. In this study, we measured the levels of TRIM5α, TRIM22, APOBEC3G, and IFN-α, -β mRNA expression in peripheral blood mononuclear cells of 43 HIV mono-infected, 70 HCV mono-infected and 64 HIV/HCV co-infected patients along with 98 healthy controls. We also quantified HIV and HCV viral loads in mono- and co-infected patients. The results showed that HCV, HIV mono- and co-infection differentially increased TRIM22, APOBEC3G, and IFN-α, -β mRNA expression while the mRNA expression of TRIMα was upregulated only by HCV-mono infection. HIV/HCV co-infection was associated with higher viral load, compared to either HIV or HCV mono-infection. Additionally, we showed TRIMα and TRIM22 positively correlated with IFN-α, -β, which could be dysregulated by HIV, HCV mono- and co-infection. Furthermore, we found TRIM22 negatively correlated with HCV viral load in mono-infected patients and APOBEC3G positively correlated with HCV viral load in co-infected patients. Collectively, our findings suggest the potential role of restriction factors in restricting HIV, HCV mono- and co-infection in vivo, which appears to be a therapeutic target for potential drug discovery.

Daclatasvir-containing all-oral regimens for the treatment of hepatitis C virus infection

The treatment of chronic hepatitis C is revolutionizing rapidly. The aim of this study is to review the efficacy and safety of daclatasvir (DCV)-containing all-oral regimens in clinical studies for chronic hepatitis C treatment. Using PubMed and search terms of 'DCV,' 'hepatitis C virus (HCV) treatment,' and 'HCV NS5A inhibitors,' literature on the clinical development of DCV, as well as abstracts presented at the April 2015 annual meeting of the European Association for the Study of the Liver (EASL) and November 2014 annual meeting of the American Association for the Study of Liver Diseases were reviewed. The final search was undertaken on 14 July 2015. With its potent antiviral activity to all HCV genotypes (GT) demonstrated in preclinical, phases 1-3 studies, DCV has been acting as a very competent team player in clinical trials of all-oral regimens. It is generally safe and well tolerated with a low genetic barrier to resistance and low potential for drug-drug interaction. Administered with a non-structural protein 3 (NS3) protease inhibitor (asunaprevir, ASV) with or without a non-nucleoside NS5B polymerase inhibitor (beclabuvir, BCV), or a nucleotide NS5B polymerase inhibitor (sofosbuvir, SOF), DCV is able to achieve greater than a 90-% HCV eradication rate in both treatment-naïve and treatment-experienced patients with GT 1. A triple combination regimen with DCV/ASV/BCV results in 100% sustained virologic response (SVR) rates in HCV GT 4 treatment-naïve subjects. DCV/SOF combination also had demonstrated up to 90-% SVR rates in GT 3-infected non-cirrhotic patients. The efficacy and safety of DCV-containing all-oral regimens highlight a new era of interferon-free therapy for chronic hepatitis C.

Asunaprevir for hepatitis C: a safety evaluation

INTRODUCTION

The introduction of direct-acting antiviral (DAA) agents has revolutionized the treatment of hepatitis C virus (HCV) chronic infection. Non-structural 3 protease inhibitors are currently the most numerous class of DAAs on the market.

AREAS COVERED

This review mainly focuses on the tolerability and safety profile of asunaprevir (ASV)-containing DAA regimens. ASV is a second-wave protease inhibitor currently in Phase III clinical development in most countries and already available in Japan.

EXPERT OPINION

ASV shows potent antiviral effect and clinical efficacy on HCV genotypes 1 and 4. The all-oral combination daclatasvir/ASV reached high eradication rates in HCV genotype 1b and 4 infection, and a lower efficacy in genotype 1a infection. ASV presents a low potential for drug-drug interaction and a good tolerability as part of multiple, including all-oral, regimens. ASV is associated with a transient and usually mild increase in aminotransferase levels in a low percentage of cases. Due to the impaired pharmacokinetic profile observed in advanced liver disease, ASV use in patients with moderate or severe hepatic impairment is not allowed. In conclusion, ASV represents a powerful weapon against HCV infection and has to be considered an optimal option as a component of genotype tailored interferon-free combinations.

ABT-450/ ritonavir and ABT-267 in combination with ABT-333 for the treatment of hepatitis C virus

INTRODUCTION

The global prevalence of chronic hepatitis C virus (HCV) is estimated to be 80 - 115 million and currently viremic infections account for 350,000 deaths annually. As the knowledge about HCV evolves, new anti-viral treatments have been developed. The primary goal of antiviral therapies has been to eradicate HCV virus from serum and achieve sustained virologic response (SVR). Historically, interferon has been a staple of nearly all HCV treatment regimens, despite significant toxic effects.

AREAS COVERED

In recent years, HCV treatment has changed rapidly and significantly. All-oral treatment regimens show promise for treatment with shorter duration and more manageable side effects. New antivirals aimed at improving SVR may provide a cure to nearly all HCV-infected patients. The unique combination of ABT-450 (paritaprevir) and ABT-267 (ombitasvir) provides highly effective treatment for patients with genotype 1 HCV. This review will examine the antiviral properties, pharmacokinetics, pharmacodynamics, and side effects of these agents.

EXPERT OPINION

The combination of ABT-450/r and ABT-267 has improved potency, favorable side effect profile, and low risk of resistance compared to the first-generation protease inhibitors. This combination is likely to be a major part of novel upcoming HCV treatment regimens and is likely to be widely used by clinicians. Additional data is awaited in additional patient populations, and with possible shorter treatment durations.

Dual antiviral therapy for HIV and hepatitis C - drug interactions and side effects

INTRODUCTION

Roughly 20% of HIV-positive persons worldwide are coinfected with hepatitis C virus (HCV). The recent advent of direct-acting antivirals (DAA) that cure most hepatitis C patients has attracted much attention. Knowledge on drug interactions between DAA and antiretrovirals (ARV) may allow maximizing antiviral efficacy while minimizing drug-related toxicities.

AREAS COVERED

We review the most frequent side effects and clinically significant drug interactions between DAA and ARV. We further discuss how they can be prevented and managed in HIV/HCV-coinfected patients.

EXPERT OPINION

The safety profile of current DAA and the most recently approved ARV is quite favorable. Interactions between DAA and ARV could be frequent in clinical practice. The most common drug interactions affect drug metabolism by inducing or inhibiting the cytochrome P450 system, leading to abnormal drug exposures. Throughout this mechanism HCV and HIV protease inhibitors interact, especially when co-formulated with ritonavir as a pharmacoenhancer, and non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide polymerase inhibitors, and most HCV NS5A inhibitors (i.e., ledipasvir) and HIV integrase inhibitors (i.e., dolutegravir), do not or only marginally affect CYP450, and therefore are free of significant drug interactions. Exposure to HIV and HCV nucleos(t)ide analogues (i.e., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (i.e., P-glycoprotein).

Beclabuvir for the treatment of hepatitis C

INTRODUCTION

About 185,000,000 people worldwide are chronically infected with hepatitis C virus (HCV). Currently, the most successful HCV infection antiviral therapies reduce the chance of progression towards the advanced phases of the hepatopathy (liver cirrhosis, hepatocellular carcinoma and death). Recently, however, several new direct-acting antivirals against HCV are available or are in an advanced phase of clinical development.

AREAS COVERED

This review focuses on beclabuvir , an allosteric non-nucleotide inhibitor of HCV polymerase. The article covers its pharmacokinetics, mechanism of action, in addition to its tolerability and safety profile as well as its resistance pattern.

EXPERT OPINION

The pharmacokinetic, efficacy and tolerability profile of beclabuvir, as well as its barrier to resistance, are very favorable. In particular, the combination of beclabuvir with asunaprevir and daclatasvir achieves very high rates of viral eradication (about 90%) in patients infected with HCV genotype 1, which is the most common genotype worldwide. Therefore, beclabuvir represents a powerful weapon against HCV infection and has to be considered an optimal option in tailored IFN-free combinations.

Achieving sustained virological response: what's the impact on further hepatitis C virus-related disease?

Continuous hepatic inflammation as a result of chronic infection with the hepatitis C virus may lead to the development of fibrosis and eventually cirrhosis. At the stage of cirrhosis, patients are at elevated risk of liver failure and hepatocellular carcinoma, two complications that shorten their life expectancy. Survival may be further impaired by the extra-hepatic manifestations of chronic hepatitis C virus infection, such as diabetes mellitus and lymphoma. Sustained virological response (SVR) following antiviral therapy has been associated with regression of hepatic fibrosis as well as with a reduction in portal pressure, both important markers of liver disease severity. Long-term follow-up studies indicated that SVR was related not only to a reduced occurrence of solid clinical end points, including liver failure and hepatocellular carcinoma, but also cardiovascular events and malignant lymphomas. Together, these findings may explain the recently observed improved overall survival among patients who attained SVR, even in the case of advanced liver disease.

First-generation protease inhibitor-triple therapy: SVR 24, safety, and predictors of response in a large single center cohort

BACKGROUND/AIMS

Aim of this retrospective study was to analyze the efficacy, safety, and predictors of treatment success for first-generation-PI triple therapies, including either boceprevir or telaprevir, in a mono-centric "real-life" setting with respect to SVR 24.

PATIENTS

131 patients (102 patients telaprevir, 29 patients boceprevir) were treated. Of these, 33/131 patients were treatment naïve, 72/131 patients had been pretreated with PEG-IFN/RBV (PR) (thereof: 36 with non-response, 30 with relapse, 6 unknown), and 26/131 patients previously had received non-pegylated interferon. 96/131 patients were infected with HCV genotype 1b. 41/131 patients had liver cirrhosis.

RESULTS

95/131 (73%) patients achieved SVR 24. SVR rates for subgroups were: 26/33 (79%) for treatment naïve, 25/30 (83%) for PR-relapse, 20/36 (56%) for PR-non-response, 21/26 (81%) for non-PR pretreated patients, (26/41) 63% for patients with liver cirrhosis, 23/35 (66%) genotype 1a, 72/96 (75%) genotype 1b. Predictors of SVR 24 were eRVR and a negative viral load at PI-treatment week 4 (p < 0.0001), negative predictors were quantifiable HCV viral load at PI-treatment week 4 (p < 0.0001), baseline platelet count < 100/nl (p < 0.0001), and previous PR-non-response (p = 0.006). 33/131 (25%) patients discontinued treatment prematurely, of those 14/131 (11%) patients due to virological failure. Side effects were frequent (anemia 59/131 [45%], severe infections 6/131 [5%]).

CONCLUSIONS

According to our SVR 24 results, efficacy of PI-based triple therapy in our "real-life" cohort is comparable to the large multi-centric clinical trials. Pronounced side effects are frequent during therapy and often need complex therapeutic interventions. Since new DAA are available, it is open to discussion, if first-generation PI-triple therapy is no longer indicated at all.

Drug interactions with new hepatitis C oral drugs

INTRODUCTION

Chronic hepatitis C virus (HCV) infection has recently become a curable disease with antiviral therapy. The knowledge of drug interactions using direct-acting antivirals (DAA) may permit maximizing antiviral efficacy and avoiding drug-related toxicities. Ageing in the chronic hepatitis C population, along with added co-morbidities that require other medications, has increased the attention on drug interactions using DAA.

AREAS COVERED

This review provides an update of the most clinically significant pharmacokinetic and pharmacodynamic drug interactions occurring between currently available DAA and other medications. The review also revisits how drug interactions with DAA can be prevented and managed.

EXPERT OPINION

Interactions between DAA and other drugs are frequent in clinical practice. The most frequent drug interactions modify drug metabolism by inducing or inhibiting the cytochrome P450, leading to abnormal drug exposures. Through this mechanism HCV protease inhibitors, especially when co-formulated with ritonavir as pharmacoenhancer, and non-nucleoside HCV polymerase inhibitors interact with other medications. In contrast, NS5B nucleos(t)ide analog inhibitors (i.e., sofosbuvir) and some HCV NS5A inhibitors (i.e., ledipasvir), which do not or only marginally affect CYP450, are relatively free of significant pharmacokinetic interactions. However, exposure to HCV nucleos(t)ide analogs may be influenced by induction/inhibition of drug transporters (i.e., P-glycoprotein) as well as by pharmacodynamic interference with other nucleos(t)ide analogs used as antivirals or cancer drugs. Drug interactions for some NS5A inhibitors (i.e., daclatasvir) are generally moderate and can be managed with dose adjustments.

Asunaprevir-containing regimens for the treatment of hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection has been a tremendous health burden worldwide with an annual mortality of 300,000 people due to decompensated cirrhosis or hepatocellular carcinoma. A combination of interferon (IFN), ribavirin (RBV), and/or direct-acting antivirals (DAAs) can eradicate HCV in a various proportion of infected patients. Unfortunately, IFN-based therapy is associated with significant adverse effects, contraindications, and limited tolerability, leading to lower adherence or even treatment discontinuation. With the rapid evolution of newer DAAs or host-targeting agents, emerging HCV therapy is moving towards an IFN- and RBV-free strategy. To this end, a recently developed NS3 protease inhibitor, asunaprevir (ASV), in combination with other DAAs as IFN/RBV-containing or -free regimen, has shown promising results with fewer adverse effects. In this review, preclinical profiles and clinical proof-of-concept studies of ASV, including viral resistance, host polymorphism, and role of ASV in future HCV therapy are reviewed and discussed.

Clinical value and safety of liver biopsies in patients transplanted for hepatitis C virus-related end-stage liver disease

BACKGROUND

Hepatitis C is the leading indication for liver transplantation. Differentiation between recurrent graft hepatitis C (RGH-C) and graft rejection (GR) is challenging. Liver biopsy is standard to diagnose both conditions; however, little information is available regarding this procedure in hepatitis C virus (HCV)-infected liver transplant recipients.

METHODS

Liver biopsies (n = 211) from all consecutive patients (n = 138) transplanted for hepatitis C at Hannover Medical School between January 2000 and October 2011 were screened, and a final cohort of 96 patients with 196 biopsies was included. Indications, histopathological findings, and biopsy-related complications were documented. Modifications in the treatment based on the biopsy result and the biochemical outcome were analyzed.

RESULTS

Most biopsies (196/211, 93%) were representative. Five patients (2.5%) developed non-fatal biopsy-related complications. Biopsy results were GR (35%), RGH-C (31%), and other diagnoses (34%). GR was independently associated with lower albumin (P = 0.025) and higher bilirubin levels (P = 0.011). Treatment was modified based on the biopsy result in 25% of cases. Alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT), and bilirubin levels improved in 41%, 25%, and 31% of cases 4 weeks post biopsy respectively. ALT improvements were more significant in patients with GR than in those with RGH-C.

CONCLUSION

Liver biopsy in HCV-infected liver transplant recipients is safe and representative in >90% of cases. GR is independently associated with lower albumin and higher bilirubin levels.

A review on recent developments of indole-containing antiviral agents

Indole represents one of the most important privileged scaffolds in drug discovery. Indole derivatives have the unique property of mimicking the structure of peptides and to bind reversibly to enzymes, which provide tremendous opportunities to discover novel drugs with different modes of action. There are seven indole-containing commercial drugs in the Top-200 Best Selling Drugs by US Retail Sales in 2012. There are also an amazing number of approved indole-containing drugs in the market as well as compounds currently going through different clinical phases or registration statuses. This review focused on the recent development of indole derivatives as antiviral agents with the following objectives: 1) To present one of the most comprehensive listings of indole antiviral agents, drugs on market or compounds in clinical trials; 2) To focus on recent developments of indole compounds (including natural products) and their antiviral activities, summarize the structure property, hoping to inspire new and even more creative approaches; 3) To offer perspectives on how indole scaffolds as a privileged structure might be exploited in the future.

GS-9669: a novel non-nucleoside inhibitor of viral polymerase for the treatment of hepatitis C virus infection

Hepatitis C virus (HCV) is an RNA virus that chronically infects 2-3% of the world's population. About 25% of these chronic carriers evolve towards liver cirrhosis, a disease that is significantly associated with reduced survival and quality of life. Antiviral therapy can eradicate the infection - a process that is associated with a reduced disease progression rate. Several oral direct agents have been developed and tested for the treatment of HCV infection. This review focuses on the mechanism of action, pharmacokinetics, efficacy, safety and resistance of GS-9669, a non-nucleoside inhibitor of viral polymerase, active against HCV genotype 1. In combination with other oral antivirals, GS-9669 results: in very high rates of viral eradication (90-100%) in patients with HCV genotype 1 infection, with a good tolerability and safety profile. In conclusion, GS-9669 is a good candidate to be used in interferon-free combinations for the treatment of chronic HCV infection.

Ombitasvir: a potent pan-genotypic inhibitor of NS5A for the treatment of hepatitis C virus infection

Hepatitis C virus (HCV) chronically infects about 150,000,000 people worldwide and is a relevant cause of liver cirrhosis, hepatocellular carcinoma and death. Antiviral treatment is rapidly moving from interferon (IFN)-based therapy to IFN-free approaches. This review focuses on the mechanism of action, pharmacokinetics, efficacy, tolerability, safety and resistance of ombitasvir, which is an inhibitor of the HCV nonstructural protein 5A. The pharmacokinetics of ombitasvir enables its once daily administration. In vivo, in combinations with other oral direct acting antivirals, ombitasvir achieves very high rates of sustained virological response (about 95%) in patients with HCV genotype 1 infection with a good tolerability. Resistance profiling revealed a low barrier to resistance when given as monotherapy. However, coadministration of ombitasvir and other antivirals enhances its barrier to resistance. In conclusion, ombitasvir is a good drug to be used in IFN-free combinations for the treatment of chronic hepatitis C.

Asunaprevir, a protease inhibitor for the treatment of hepatitis C infection

According to the World Health Organization, approximately 150 million people worldwide are chronic carriers of hepatitis C virus (HCV). HCV infection can evolve into cirrhosis of the liver and its complications, which are ultimately responsible for more than 350,000 deaths every year. Antiviral therapy, when successful, is able to decrease the rate of progression and increase survival. Two types of therapies are currently available, ie, interferon-based therapies and interferon-free ones. The latter have several advantages in terms of safety and tolerability, and could be used even in the most advanced stages of the disease. However, their use is restricted to some viral genotypes (genotype 2 and 3) and they are expensive. Several molecules are in an advanced phase of development. This review deals with the pharmacokinetics, pharmacodynamics, tolerability, and safety of asunaprevir, an inhibitor of HCV nonstructural 3 protease. Asunaprevir exerts optimal in vitro activity particularly against HCV genotypes 1 and 4, and its pharmacokinetic profile enables twice daily administration. The drawback of asunaprevir, and of all protease inhibitors, is its low barrier to resistance. Consequently, it is used in association with other drugs to prevent resistance. Specifically, when combined with daclatasvir, an NS5A inhibitor, asunaprevir results in a very high rate of viral eradication in both treatment-naïve and treatment-experienced patients, with a sustained virological response rate of 80%-90%. Tolerability is fair; in fact, asunaprevir is associated with a transient increase in aminotransferase levels, which is mild in most cases. In conclusion, asunaprevir is a good candidate component of interferon-free combinations and may revolutionize the treatment of chronic HCV infection in the near future.