Challenges and opportunities for hepatitis C drug development in HIV-hepatitis C virus-co-infected patients

Consequence of HIV and HCV co-infection on host immune response, persistence and current treatment options

Hepatitis C virus (HCV) is a common opportunistic pathogen especially among Human immunodeficiency virus (HIV) infected patients. Due to incongruous studies, the pathological effect of HCV on HIV induced disease are still not fully understood. While some studies have showed no effect of HCV on HIV infection, others reported a defined role of HCV in aggravating the rates of AIDS-related illnesses and mortality. The explanation of such variances may be due to the host immune response, viral genotypes, sub-type and quasi-species distribution. The factors that complicate the management of HIV/HCV patients are: (1) reduced HCV antibody production, (2) drug interactions, (3) liver disease and (4) different epidemiologic characteristics. However, it is abundantly clear that the morbidity and mortality caused by HCV have increased since the introduction of highly active antiretroviral therapy (HAART) against HIV. In this review, the consequence of HIV/HCV co-infection on host immune response, viral replication, disease progression, mortality and morbidity, viral load, persistence and current treatment options have been discussed. Based on the clinical studies, it is necessary to evaluate the effect of HCV therapy on HIV progression and to provide a fully active HCV treatment for patients receiving HIV treatment. In conclusion, it is recommended to provide fully active HAART therapy in combination with a known HCV therapy.

Clinical use of cobicistat as a pharmacoenhancer of human immunodeficiency virus therapy

The pharmacoenhancement of plasma concentrations of protease inhibitors by coadministration of so-called boosters has been an integral part of antiretroviral therapy for human immunodeficiency virus (HIV) for 1.5 decades. Nearly all HIV protease inhibitors are combined with low-dose ritonavir or cobicistat, which are able to effectively inhibit the cytochrome-mediated metabolism of HIV protease inhibitors in the liver and thus enhance the plasma concentration and prolong the dosing interval of the antiretrovirally active combination partners. Therapies created in this way are clinically effective regimens, being convenient for patients and showing a high genetic barrier to viral resistance. In addition to ritonavir, which has been in use since 1996, cobicistat, a new pharmacoenhancer, has been approved and is widely used now. The outstanding property of cobicistat is its cytochrome P450 3A-selective inhibition of hepatic metabolism of antiretroviral drugs, in contrast with ritonavir, which not only inhibits but also induces a number of cytochrome P450 enzymes, UDP-glucuronosyltransferase, P-glycoprotein, and other cellular transporters. This article reviews the current literature, and compares the pharmacokinetics, pharmacodynamics, and safety of both pharmacoenhancers and discusses the clinical utility of cobicistat in up-to-date and future HIV therapy.

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.

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).

TLR3 polymorphisms are associated with virologic response to hepatitis C virus (HCV) treatment in HIV/HCV coinfected patients

BACKGROUND

Toll-like receptor-3 (TLR3) is a cellular receptor that may recognize double-stranded RNA (dsRNA) from viruses, resulting in production of proinflammatory cytokines and interferons, which are important for the adaptive immune response.

OBJECTIVES

To analyze the association between Toll-like receptor-3 (TLR3) polymorphisms (rs3775291 and rs13126816) and virologic response to pegylated interferon-alpha plus ribavirin (pegIFNα/RBV) therapy in HIV/HCV coinfected patients.

STUDY DESIGN

We performed a retrospective study in 321 naïve patients treated with pegIFNα/RBV. Genotyping was performed by using the GoldenGate(®) assay with VeraCode(®). The outcome variables were early virologic response (EVR) and sustained virologic response (SVR).

RESULTS

In a multivariate analysis, rs3775291 A allele decreased the likelihood of achieving EVR (aOR = 0.20; p = 0.018) and SVR (aOR = 0.38; p = 0.024). Regarding rs13126816, the percentage of EVR decreased with each minor A allele (p = 0.034) in HCV-GT2/3 patients, although no significant association was obtained in the multivariate analysis (p = 0.076). Regarding TLR3 haplotypes (comprised of rs3775291 and rs13126816), GT2/3 patients with AA haplotype had decreased odds of achieving EVR (p = 0.030), whereas GG haplotype increased the likelihood (p = 0.018). Regarding SVR, GG haplotype carriers had increased odds of achieving SVR (p = 0.019, p = 0.043 and p = 0.070 for all, GT2/3 and GT1/4 patients, respectively). Besides, GT1/4 patients with GA haplotype had lower odds of achieving SVR (p = 0.039).

CONCLUSIONS

Our study shows the first evidence that two TLR3 polymorphisms (rs3775291 and rs13126816) seem to be related to the HCV therapy response in HCV/HIV coinfected patients.

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.

The clinical effectiveness of pegylated interferon and ribavirin for the treatment of chronic hepatitis C in HIV-infected patients in Brazil: a multicentric study

Introduction

in Brazil, chronic hepatitis C in patients coinfected with the human immunodeficiency virus (HIV) is treated with pegylated interferon (Peg-IFN) and ribavirin (RBV). However, few studies have evaluated the effectiveness of this treatment in this particular population. The identification of the factors that predict sustained virological response (SVR) under current clinical practice would enable clinicians to more accurately estimate the probability of achieving an SVR and therefore utilize the appropriate therapeutics, especially in the era of direct-acting antiviral (DAA) agents.

Aims

the primary aim of our study was to determine the SVR rate under current clinical practice. The secondary aims were as follows: (1) to determine the factors before and during treatment that predict SVR; and (2) to identify the causes of treatment interruption.

Methods

within a cohort of HIV/hepatitis C virus (HCV)-coinfected patients in Brazil, we performed a retrospective analysis of those individuals treated with Peg-IFN and RBV.

Results

among the 382 analyzed patients, SVR was observed in 118 [30.9% (95% confidence interval (CI): 26.3–35.8)], which included 25.9% (75/289) of the patients with genotypes 1 and 4 and 48.2% (41/85) of those with genotypes 2 and 3. After multivariate analyses the independent positive predictors for SVR after treatment for chronic hepatitis C with Peg-IFN and RBV were: absence of an AIDS-defining illness (p = 0.001), HCV viral load lower than 600,000 IU/mL at the onset of treatment (p = 0.003), higher liver enzyme levels (p = 0.039) at baseline, infection with genotypes 2 or 3 (p = 0.003), and no transient treatment interruption (p = 0.001).

The treatment was interrupted in 25.6% (98/382) of the patients because of adverse events (11.3%, 43/382), virologic failure (7.8%, 30/382), and dropout (6.5%, 43/382). The main adverse events were cytopenia and psychiatric disorders.

Conclusions

in our Brazilian case series, the SVR rate under current clinical practice conditions was similar to that reported in other studies. There was a correlation between an SVR and being infected by genotypes 2 and 3, low viral load, high ALT levels at the onset of treatment, and absence of an AIDS-defining illness. Cytopenia and psychiatric disorders were the major causes of treatment interruption. Efforts should be focused on optimizing management of side effects and counseling to improve adherence and to keep patients on treatment.

Towards hepatitis C eradication from the HIV-infected population

Around 10-15% of the 35 million people living with HIV worldwide have chronic hepatitis C virus (HCV) infection and are prone to develop liver-related complications. Exposure to HCV is almost universal among injecting drug users and is on the rise among homosexual men. Response to peginterferon-ribavirin therapy is generally lower in coinfection compared to HCV monoinfection. For this reason, the advent of direct-acting antivirals (DAA) is eagerly awaited for this population. The results of trials using DAA in coinfection show that treatment response rates are similar to those obtained in HCV monoinfection. Thus, HIV should no longer be considered as a "special" population, as long as antiretroviral therapy is given and drug interactions are taken into account. Envisioning HCV eradication from the HIV population faces major challenges ahead, including identification of the large number of undiagnosed individuals, and ensuring wide access to the best but often expensive HCV medications. This article forms part of a symposium in Antiviral Research on "Hepatitis C: next steps toward global eradication".

Human immunodeficiency virus and liver disease forum 2012

In the United States, more than 1.1 million individuals are infected with the human immunodeficiency virus (HIV). These patients exhibit a high frequency of coinfections with other hepatotropic viruses and ongoing fibrosis, leading to cirrhosis and liver-related mortality. Etiologies of liver disease include viral hepatitis coinfections, drug-related hepatotoxicity, fatty liver disease, and direct and indirect effects from HIV infection, including increased bacterial translocation, immune activation, and presence of soluble proteins, that modulate the hepatic cytokine environment. New treatments for hepatitis C virus (HCV) using direct-acting agents appear viable, though issues related to intrinsic toxicities and drug-drug interactions remain. Recent research suggests that acute HCV infection, unrecognized hepatitis D infection, and hepatitis E may all represent emergent areas of concern. Antiretroviral agents, including those used in recent years, may represent risk factors for hepatic injury and portal hypertension. Key issues in the future include systematic implementation of liver disease management and new treatment in HIV-infected populations with concomitant injection drug use, alcohol use, and low socioeconomic status.

Impact of HCV treatment and depressive symptoms on adherence to HAART among HIV-HCV-coinfected patients: results from the ANRS-CO13-HEPAVIH cohort

BACKGROUND

The additional burden of HCV infection in HIV-HCV-coinfected individuals may have some consequences on adherence to HAART. Few studies have explored the pattern of correlates of non-adherence to HAART while simultaneously considering the impact of HCV treatment and depressive symptoms on adherence to HAART. We used longitudinal data to assess factors associated with non-adherence to HAART.

METHODS

The French national prospective cohort ANRS-CO13-HEPAVIH is a multicentrer cohort, which recruited 1,175 HIV-HCV-coinfected patients in 17 hospital outpatient units delivering HIV and HCV care in France between October 2006 and June 2008. For this analysis, we selected participants on HAART with self-reported data for adherence to HAART (n=727 patients, 1,190 visits). Data were collected using self-administered questionnaires and medical records. A mixed logistic regression model based on an exchangeable correlation matrix was used to identify factors associated with non-adherence to HAART.

RESULTS

Patients reported non-adherence to HAART in 808 (68%) of the 1,190 visits. Four variables remained associated with non-adherence to HAART after multivariate analysis: hazardous alcohol consumption, cocaine use and depressive symptoms, regardless of whether treatment for depression was being received. Finally, patients being treated for HCV infection were less likely to be non-adherent to HAART.

CONCLUSIONS

Besides the problem of polydrug use, two other dimensions deserve special attention when considering adherence to HAART in HIV-HCV-coinfected patients. Access to HCV treatment should be encouraged as well adequate treatment for depression in this population to improve adherence and response to HAART.

Update on HIV/HCV coinfection

Liver disease is currently one of the leading causes of hospitalization and death in HIV-positive individuals. Coinfection with the hepatitis C virus (HCV) is a major contributor to this trend. Besides hepatic damage, which is enhanced in the presence of HIV-associated immunosuppression, HCV may contribute to disease in coinfected individuals by potentiating immune activation and chronic inflammation, which ultimately account for an increased risk of cardiovascular events, kidney disease, and cancers in this population. Fortunately, hepatitis C therapeutics has entered a revolutionary era in which we hope that most patients treated with the new oral direct-acting antivirals (DAA) will be cured. However, many challenges preclude envisioning a prompt elimination of HCV from the coinfected population. Issues that should be addressed include the following: (1) rising incidence of acute hepatitis C in men who have sex with men, and expansion/recrudescence of injection drug use in some settings/regions; (2) adverse drug interactions between antiretrovirals and DAA; and (3) high cost of DAA, which may lead many to defer or fail to access appropriate therapy.

Viral hepatitis: Treating hepatitis C in injection drug users

A large proportion of hepatitis C in the developed world occurs in injection drug users. Treatment uptake in this population is low, despite the rising burden of HCV-related liver disease. Multiple barriers preclude the optimal care of hepatitis C in injection drug users, including low medication adherence and HCV re-infection.

Boceprevir: a review of its use in the management of chronic hepatitis C genotype 1 infection

Boceprevir (Victrelis®) is an inhibitor of the hepatitis C virus (HCV) non-structural protein NS3-4A serine protease and is used in combination with pegylated interferon (peginterferon)-alpha and ribavirin in the treatment of adults with chronic HCV (chronic hepatitis C) genotype 1 infection. Of the various genotypes of HCV, genotype 1 is one of the least responsive to interferon and ribavirin-based therapy, and thus most in need of novel treatments. This article reviews the available pharmacological properties of boceprevir and its clinical efficacy and tolerability in the treatment of chronic hepatitis C genotype 1 infection in adult patients who are either treatment-naive or have failed previous standard therapy. Boceprevir, when co-administered with peginterferon-alpha and ribavirin in patients with chronic hepatitis C genotype 1 infection who were treatment-naive or had previously not fully responded to or had relapsed following treatment, was associated with a significantly higher sustained virological response rate (defined as the proportion of patients with an undetectable plasma HCV RNA level at week 24 of the follow-up period [week 72 overall]) [primary endpoint] than peginterferon-alpha-2b and ribavirin alone, regardless of the boceprevir administration regimen, in the phase III SPRINT-2 (treatment-naive patients) and RESPOND-2 (previously treated patients) trials. There was no significant difference between full-duration (44 weeks) and response-guided (24 or 32 weeks followed by follow-up or peginterferon-alpha-2b plus ribavirin alone) boceprevir regimen recipients with regard to sustained virological response rate. All patients received an initial 4-week lead-in treatment period before the comparative treatment period began. Overall, boceprevir is generally well tolerated when administered concomitantly with peginterferon-alpha plus ribavirin in patients with chronic hepatitis C genotype 1 infection. The most common adverse events in any treatment group were flu-like symptoms, which are typically reported in patients receiving peginterferon-ribavirin therapy. The addition of boceprevir to peginterferon-alpha and ribavirin is associated with an increased risk of anaemia and neutropenia. In conclusion, boceprevir in combination with peginterferon-alpha and ribavirin is an effective and generally well tolerated treatment for treatment-naive or previously treated adult patients with chronic hepatitis C genotype 1 infection. The drug is associated with higher sustained virological response rates in these patients, in whom treatment with interferon and ribavirin alone may not be successful. Thus, boceprevir in combination with peginterferon-alpha and ribavirin is a valuable new treatment option for use in patients with chronic hepatitis C genotype 1 infection.

Triple combination therapy for hepatitis C with telaprevir exhibits greater early antiviral activity than with boceprevir

BACKGROUND

Achievement of early viral suppression is important in patients with chronic HCV infection treated with telaprevir (TLV) or boceprevir (BOC) to avoid selection of drug resistance and attain cure. No head-to-head studies comparing TLV and BOC have been performed so far.

METHODS

All consecutive individuals who initiated triple HCV therapy with TLV or BOC outside clinical trials at three European clinics were evaluated. Rapid virological response (RVR) was defined as unquantifiable HCV RNA (<25 IU/ml) at week 4 for TLV and at week 8 for BOC (4 weeks after lead-in).

RESULTS

A total of 106 patients were evaluated, 33 treated with BOC and 73 with TLV. Median age, gender, body mass index, baseline HCV RNA, HCV subtype 1a (45% versus 42%) and IL28B-CC alleles (29% versus 23%) did not differ significantly in BOC and TLV groups, respectively. HIV coinfection was more prevalent in patients on TLV than BOC (24% versus 44%). Conversely, more patients on BOC than TLV had previously failed pegylated interferon plus ribavirin (82% versus 64%). RVR was achieved by 82% of patients on TLV versus 59% on BOC (P=0.001). Multivariate logistic regression analysis confirmed that TLV use was the strongest predictor of RVR (OR 3.54 [95% CI 1.23, 10.24]; P=0.02), others being HCV subtype 1b versus 1a (OR 3.26 [95% CI 1.17, 9.09]; P=0.02) and low baseline HCV RNA (OR 0.41 [95% CI 0.16, 1.03]; P=0.06). Prior interferon exposure, HIV coinfection or absence of advanced liver fibrosis did not influence the likelihood of RVR.

CONCLUSIONS

Compared to BOC, triple therapy with TLV produces greater RVR rates. TLV might be a better option in more difficult-to-cure patients, such as those with high baseline HCV RNA and/or HCV 1a subtype. HIV coinfection does not influence early HCV RNA responses.

Liver stiffness predicts liver-related complications and mortality in HIV patients with chronic hepatitis C on antiretroviral therapy

BACKGROUND

Liver disease is currently one of the leading causes of death in HIV individuals. Hepatic fibrosis largely mediates this effect and infection with hepatitis C virus (HCV) is the most common cause. Few studies have examined so far the predictive value of liver fibrosis staging on mortality and liver decompensation in HIV/HCV-coinfected patients.

METHODS

A prospective programme of liver fibrosis assessment using transient elastometry has been ongoing at our institution since 2004. Data from all HIV/HCV-coinfected patients who underwent a transient elastometry examination and have at least 18 months of follow-up were selected for the current analysis.

RESULTS

A total of 545 HIV/HCV-coinfected patients were examined (mean age 41 years, 71% men, 81% IDUs, mean BMI 23.3 kg/m2, HBsAg+ 4.2%, alcohol abuse 8.4%, mean CD4 cell count 519 cells/μl). The mean follow-up was 70.9 ± 15.7 months. During follow-up, 12 patients (2.2%) died, four of them due to hepatic complications. Liver-related events (ascites, encephalopathy, oesophageal varices or hepatocellular carcinoma) appeared in 53 patients (10%). In the multivariate analysis, baseline liver stiffness was the strongest predictor of liver-related complications [odds ratio (OR) 1.12, 95% confidence interval (CI) 1.08-1.16, P < 0.0001] and of all-cause mortality (OR 1.09, 95% CI 1.01-1.19, P = 0.02). The achievement of sustained virological response following peginterferon/ribavirin therapy during the study period was protective against the development of liver-related events (OR 0.02, 95% CI 0-0.23, P = 0.01).

CONCLUSION

Liver fibrosis staging, as measured by transient elastometry, predicts liver-related complications and all-cause mortality in HIV/HCV-coinfected patients on antiretroviral therapy.

Effect of HCV infection on cause-specific mortality after HIV seroconversion, before and after 1997

BACKGROUND & AIMS

Individuals with human immunodeficiency virus (HIV) infection frequently also are infected with hepatitis C virus (HCV) (co-infection), but little is known about its effects on the progression of HIV-associated disease. We aimed to determine the effects of co-infection on mortality from HIV and/or acquired immune deficiency syndrome (AIDS), and hepatitis or liver disease, adjusting for the duration of HIV infection.

METHODS

We analyzed data from the 16 cohorts of the Concerted Action on Seroconversion to AIDS and Death in Europe (CASCADE) collaboration, which included information on HCV infection and cause of death. A competing-risks proportional subdistribution hazards model was used to evaluate the effect of HCV infection on the following causes of death: HIV- and/or AIDS-related, hepatitis- or liver-related, natural, and non-natural.

RESULTS

Of 9164 individuals with HIV infection and a known date of seroconversion, 2015 (22.0%) also were infected with HCV. Of 718 deaths, 395 (55.0%) were caused by HIV infection and/or AIDS, and 39 (5.4%) were caused by hepatitis or liver-related disease. Among individuals infected with only HIV or with co-infection, the mortality from HIV infection and/or AIDS-related causes and hepatitis or liver disease decreased significantly after 1997, when combination antiretroviral therapy became widely available. However, after 1997, HIV and/or AIDS-related mortality was higher among co-infected individuals than those with only HIV infection in each risk group: injection drug use (adjusted hazard ratio [aHR], 2.43; 95% confidence interval [CI], 1.14-5.20), sex between men and women or hemophilia (aHR, 3.43; 95% CI, 1.70-6.93), and sex between men (aHR, 3.11; 95% CI, 1.49-6.48). Compared with individuals infected with only HIV, co-infected individuals had a higher risk of death from hepatitis or liver disease.

CONCLUSIONS

Based on analysis of data from the CASCADE collaboration, since 1997, when combination antiretroviral therapy became widely available, individuals co-infected with HIV and HCV have had a higher risk of death from HIV and/or AIDS, and from hepatitis or liver disease, than patients infected with only HIV. It is necessary to evaluate the effects of HCV therapy on HIV progression.

Hepatitis C therapy: highlights from the 2012 annual meeting of the European Association for the Study of the Liver

The results from clinical trials testing new direct-acting antivirals (DAAs) for chronic hepatitis C were the major focus of interest at the 2012 annual meeting of the European Association for the Study of the Liver. Besides triple combinations, in which any one of the new DAAs is given along with peginterferon-α/ribavirin, clinical trials exploring interferon-free oral regimens combining several DAAs attracted major attention. The good tolerance, broad hepatitis C virus (HCV) genotype activity, and high resistance barrier of sofosbuvir make this nucleotide analogue one of the most promising DAAs. Among HCV protease inhibitors, the safety, potency, and convenient dosing of simeprevir, asunaprevir, faldaprevir, and ABT-450/r were particularly highlighted. Among NS5A inhibitors, the good performance of daclatasvir encourages further clinical development. Finally, intriguing results were released about the role of interleukin 28B (IL-28B) polymorphisms using interferon-free regimens, indirectly supporting the role of innate immunity for clearing HCV definitively.

The changing face of hepatitis C in the new era of direct-acting antivirals

The approval of the first protease inhibitors as treatment for hepatitis C virus (HCV) infection is rapidly transforming the way patients with chronic hepatitis C are managed. Treatment regimens are moving to combinations given for shortened periods, excluding poorly tolerated subcutaneous interferon, and providing rates of cure exceeding 75%. The recognition of HCV infection as a systemic disease, not limited to producing liver damage, in which extrahepatic complications play a major role as the cause of morbidity and mortality, is prompting the treatment of a growing number of HCV-infected individuals. However, new challenges are emerging, including the need to diagnose a substantial proportion of asymptomatic carriers, the risk of potentially harmful drug-drug interactions and the high cost of medications. The future will probably see a progressive marginalization of residual HCV populations, with increasing over-representation of illegal immigrants, alcohol abusers, intravenous drug users and the mentally disabled.

Pharmacokinetics of new oral hepatitis C antiviral drugs

INTRODUCTION

Approximately 175 million people worldwide are chronically infected with the hepatitis C virus (HCV), representing 3% of the total world population. Until recently, the only available therapeutic option for these patients was the combination of pegylated IFN-α plus ribavirin that overall resulted in HCV eradication in less than a half of cases. The development of new therapies with greater efficacy has been eagerly awaited but new challenges have emerged, with drug interactions being among the most challenging.

AREAS COVERED

This review updates the main pharmacokinetic and pharmacodynamic characteristics of the most promising new oral direct-acting antivirals (DAA) for hepatitis C. Given that a large proportion of chronic hepatitis C patients receive other medications, drug interactions are further discussed.

EXPERT OPINION

The recent approval of the first HCV genotype 1 protease inhibitors is a landmark step in the fight against the HCV pandemic. The benefit of higher rates of response along with shorter duration of treatment is counterbalanced by significant drug interactions and unprecedented complexities in the use of these drugs and management of their side effects. The knowledge of key pharmacologic parameters of distinct DAA is important for care providers in charge of chronic hepatitis C patients as it will avoid the danger of unexpected drug interactions. This concern must be particularly emphasized in special group populations, such as in HIV-HCV coinfected individuals and transplant patients, in whom interactions between DAA and antiretrovirals or immunosuppressants, respectively, are frequent.

New approaches to the management of hepatitis C in haemophilia in 2012

Hepatitis C virus (HCV) infection is common in patients with Haemophilia. As in other patients, its natural history is characterized by disease progression towards cirrhosis and hepatocellular carcinoma. Many patients with hereditary bleeding disorders infected with HCV are also infected with HIV which is a factor of faster liver disease progression. In the past years, major progress has been made in the management of hepatitis C with the development of non invasive tools to assess liver fibrosis stage, i.e. fibroscan and biomarkers. With these tools, it is now possible to predict with good accuracy the liver disease stage and to take treatment decision. The landscape of antiviral therapy has evolved rapidly, especially for patients infected with HCV genotype 1. Triple therapy with interferon, ribavirin and protease inhibitors has been approved recently, the results of clinical trials showing a clear added benefit in terms of sustained virologic response in naive patients compared to interferon - ribavirin combination therapy. However, results are less promising in cirrhotic patients who failed a previous line of therapy, with a higher rate of side effects and a lower rate of virologic response in patients who qualified as null responders to IFN based therapy. Clinical trials with triple therapy are ongoing in HCV-HIV coinfected patients. Furthermore, new IFN free regimen relying on the combination of direct acting antivirals are currently being evaluated in HCV genotype 1 and non-1 infected patients. These advances provide new hope in the management of chronic hepatitis C, including patients with hereditary bleeding disorders.

Management of hepatitis C in HIV and/or HBV co-infected patients

Co-infection with either HIV or HBV in chronic hepatitis C patients is common, since all these viruses share transmission routes and geographical distribution. Interaction between these viruses generally amplifies liver damage, increasing the risk of developing end-stage liver disease and hepatocellular carcinoma. HIV-HCV co-infection is associated with poorer response to antiviral therapy. New antivirals against HCV are eagerly awaited for this population. HBV-HCV dual infections are less common. The principles guiding indication of therapy in monoinfected patients should be followed considering which virus replicates in persons with serological markers of dual HBV-HCV infection. Although there is growing evidence supporting the use of direct acting antivirals (DAA) in dually infected patients with active HCV replication, prospective trials should be conducted to demonstrate their benefit, assessing carefully the rate and clinical consequences of HBV rebounds.

Challenges for HCV vaccine development in HIV-HCV coinfection

It is estimated that 4-5 million HIV-infected patients are coinfected with HCV. The impact of HIV on the natural course of HCV infection is deleterious. This includes a higher rate of HCV persistence and a faster rate of fibrosis progression. Coinfected patients show poor treatment outcome following standard HCV therapy. Although direct antiviral agents offer new therapeutic options, their use is hindered by potential drug interactions and toxicity in HIV-infected patients under HAART. Overtime, a large reservoir of HCV genotype 1 patients will accumulate in resource poor countries where the hepatitis C treatment is not easily affordable and HIV therapy remains the primary health issue for coinfected individuals. HCV vaccines represent a promising strategy as an adjunct or alternative to current HCV therapy. Here, the authors review the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discuss the challenges for vaccine development in HIV-HCV coinfection.

Chronic hepatitis C and antiviral treatment regimens: where can psychology contribute?

OBJECTIVE

Our goal was to evaluate the existing literature on psychological, social, and behavioral aspects of chronic hepatitis C viral (HCV) infection and antiviral treatment; provide the state of the behavioral science in areas that presently hinder HCV-related health outcomes; and make recommendations for areas in which clinical psychology can make significant contributions.

METHOD

The extant literature on HCV and antiviral therapy was reviewed as related to biopsychosocial factors such as mental health, substance/alcohol use, quality of life, coping, stigma, racial disparities, side effects, treatment adherence, integrated care, and psychological interventions.

RESULTS

For reasons that have not been well elucidated, individuals infected with HCV experience psychological and somatic problems and report poor health-related quality of life. Preexisting conditions, including poor mental health and alcohol/substance use, can interfere with access to and successful completion of HCV treatment. Perceived stigma is highly prevalent and associated with psychological distress. Racial disparities exist for HCV prevalence, treatment uptake, and treatment success. During HCV treatment, patients experience exacerbation of symptoms, treatment side effects, and poorer quality of life, making it difficult to complete treatment. Despite pharmacological advances in HCV treatment, improvements in clinical and public health outcomes have not been realized. The reasons for this lack of impact are multifactorial, but include suboptimal referral and access to care for many patients, treatment-related side effects, treatment nonadherence, and lack of empirically based approaches.

CONCLUSIONS

Biomedical advances in HCV and antiviral treatment have created a fertile field in which psychologists are uniquely positioned to make important contributions to HCV management and treatment.

Telaprevir: a review of its use in the management of genotype 1 chronic hepatitis C

Telaprevir (Incivo®, Incivek®), an orally administered inhibitor of the hepatitis C virus non-structural protein NS3-4A serine protease, is used in combination with pegylated interferon (peginterferon)-alpha and ribavirin in the treatment of adults with genotype 1 chronic hepatitis C virus (HCV) infection (chronic hepatitis C). This article reviews data on the clinical efficacy and tolerability of telaprevir in adults with genotype 1 chronic hepatitis C and provides a summary of its pharmacological properties. In in vitro studies, telaprevir shows good activity against genotype 1 HCV, including viral isolates from patients with chronic hepatitis C. Numerous resistant variants of HCV have been identified in clinical isolates from patients receiving treatment with telaprevir-based therapy. However, the clinical relevance of viral variants emerging during treatment requires further study. Telaprevir administered for 12 weeks in combination with peginterferon-alpha-2a and ribavirin for up to 48 weeks was effective in the treatment of previously untreated or previously treated adults with genotype 1 chronic hepatitis C in three major randomized phase III trials. Sustained virological response rates (i.e. percentages of patients with undetectable HCV RNA levels 24 weeks after the last planned dose of study medication: the primary endpoint) achieved with the telaprevir-based regimens were significantly higher than those produced with peginterferon-alpha-2a and ribavirin alone (the 'current standard of care'). In the largest trial (the ADVANCE trial) in previously untreated patients, 24 weeks after the last planned dose of study drug, recipients of 12 weeks' treatment with telaprevir in combination with peginterferon-alpha-2a and ribavirin followed by treatment with peginterferon-alpha-2a and ribavirin for a further 12 or 36 weeks experienced significantly (p < 0.001) higher sustained virological response rates than patients who received peginterferon-alpha-2a and ribavirin dual therapy for 48 weeks (75% vs 44%). Adverse events were reported more frequently with telaprevir-based regimens than with peginterferon-alpha-2a and ribavirin dual therapy in the major trials. The most common adverse events included fatigue, rash, pruritus, anaemia and nausea. In conclusion, telaprevir in combination with peginterferon-alpha and ribavirin is an effective treatment for treatment-naive and previously treated adults with genotype 1 chronic hepatitis C - patient groups in whom peginterferon-alpha and ribavirin dual therapy may not be successful. Thus, telaprevir is a valuable new treatment option for use in combination with peginterferon-alpha and ribavirin in treatment-naive or previously treated adults with genotype 1 chronic hepatitis C.

Management of patients coinfected with HCV and HIV: a close look at the role for direct-acting antivirals

With the development of effective therapies against human immunodeficiency virus (HIV), hepatitis C virus (HCV) infection has become a major cause of morbidity and mortality among patients with both infections (coinfection). In addition to the high prevalence of chronic HCV, particularly among HIV-infected injection drug users, the rate of incident HIV infections is increasing among HIV-infected men who have sex with men, leading to recommendations for education and screening for HCV in this population. Liver disease is the second leading and, in some cases, a preventable cause of death among coinfected patients. Those at risk for liver disease progression are usually treated with a combination of interferon (IFN) and ribavirin (RBV), which is not highly effective; it has low rates of sustained virologic response (SVR), especially for coinfected patients with HCV genotype 1 and those of African descent. Direct-acting antivirals might overcome factors such as immunodeficiency that can reduce the efficacy of IFN. However, for now it remains challenging to treat coinfected patients due to interactions among drugs, additive drug toxicities, and the continued need for combination therapies that include pegylated IFN. Recently developed HCV protease inhibitors such as telaprevir and boceprevir, given in combination with pegylated IFN and RBV, could increase the rate of SVR with manageable toxicity and drug interactions. We review the latest developments and obstacles to treating coinfected patients.