Retreatment of HCV with ABT-450/r-ombitasvir and dasabuvir with ribavirin

Ombitasvir/Paritaprevir/Ritonavir Plus Dasabuvir: A Review in Chronic HCV Genotype 1 Infection

A fixed-dose tablet comprising ombitasvir (an NS5A replication complex inhibitor), paritaprevir (an NS3/4A protease inhibitor) and ritonavir (a cytochrome P450 inhibitor) taken in combination with dasabuvir (an NS5B polymerase inhibitor) is indicated for the treatment of chronic hepatitis C virus (HCV) genotype 1 infection in several countries, including the USA (copackaged as Viekira Pak(™)) and those of the EU (Viekirax(®) and Exviera(®)). In phase II and III trials, this interferon-free regimen, taken ± ribavirin, provided high rates of sustained virological response 12 weeks post-treatment in adults with chronic HCV genotype 1a or 1b infection, including those with compensated cirrhosis, liver transplants or HIV-1 co-infection. The regimen was generally well tolerated, with nausea, insomnia, asthenia, pruritus, other skin reactions and fatigue being among the most common tolerability issues. Thus, ombitasvir/paritaprevir/ritonavir plus dasabuvir is an effective interferon-free, direct-acting antiviral regimen for use ± ribavirin in a broad range of adults chronically infected with HCV genotype 1.

Disconnected by design: analytic approach in treatment networks having no common comparator

In a network meta-analysis, comparators of interest are ideally connected either directly or via one or more common comparators. However, in some therapeutic areas, the evidence base can produce networks that are disconnected, in which there is neither direct evidence nor an indirect route for comparing certain treatments within the network. Disconnected networks may occur when there is no accepted standard of care, when there has been a major paradigm shift in treatment, when use of a standard of care or placebo is debated, when a product receives orphan drug designation, or when there is a large number of available treatments and many accepted standards of care. These networks pose a challenge to decision makers and clinicians who want to estimate the relative efficacy and safety of newly available agents against alternatives. A currently recommended approach is to insert a distribution for the unknown treatment effect(s) into a network meta-analysis model of treatment effect. In this paper, we describe this approach along with two alternative Bayesian models that can accommodate disconnected networks. Additionally, we present a theoretical framework to guide the choice between modeling approaches. This paper presents researchers with the tools and framework for selecting appropriate models for indirect comparison of treatment efficacies when challenged with a disconnected framework. Copyright © 2016 John Wiley & Sons, Ltd.

HCV Council--critical appraisal of data: recommendations for clinical practice in a rapidly evolving therapeutic landscape

BACKGROUND & AIMS

HCV Council 2014, like its predecessor HCV Council 2011, assembled leading clinicians and researchers in the field of hepatitis C to critically evaluate current data regarding best practices for managing patients with chronic hepatitis C virus (HCV).

METHODS

Clinical practice statements were developed that reflect the areas of potential controversy with high clinical impact. Faculty members were responsible for reviewing the literature to support or reject these statements. After a review and comprehensive discussion of the data, the HCV Council faculty voted on the nature of the evidence and the level of support for each statement.

RESULTS

The results of the detailed analysis with expert opinion are summarized in this article.

CONCLUSION

Numerous questions regarding optimal management of certain populations and clinical scenarios remain unanswered. The discussion in the article provides a summary of evidenced-based expert opinion that may help guide clinicians as additional information is developed.

Hepatitis C treatment as prevention of viral transmission and liver-related morbidity in persons who inject drugs

Hepatitis C virus (HCV) seroprevalence remains high in people who inject drug (PWID) populations, often above 60%. Highly effective direct-acting antiviral (DAA) regimens (90% efficacy) are becoming available for HCV treatment. This therapeutic revolution raises the possibility of eliminating HCV from this population. However, for this, an effective cascade of care is required. In the context of the available DAA therapies, we used a dynamic individual-based model including a model of the PWID social network to simulate the impact of improved testing, linkage to care, and adherence to treatment, and of modified treatment recommendation on the transmission and on the morbidity of HCV in PWID in France. Under the current incidence and cascade of care, with treatment initiated at fibrosis stage ≥F2, HCV prevalence decreased from 42.8% to 24.9% (95% confidence interval: 24.8-24.9) after 10 years. Changing treatment initiation criteria to treat from F0 was the only intervention leading to a substantial additional decrease in prevalence, which fell to 11.6% (95% CI: 11.6-11.7) at 10 years. Combining this change with improved testing, linkage to care, and adherence to treatment decreased HCV prevalence to 7.0% (95% CI: 7.0-7.1) at 10 years and avoided 15% (95% CI: 14-17) and 29% (95% CI: 28-30) of cirrhosis complications over 10 and 40 years, respectively.

CONCLUSIONS

Major decreases in prevalent HCV infections occur only when treatment is initiated at early stages of fibrosis, suggesting that systematic treatment in PWID, where incidence remains high, would be beneficial. However, elimination within the 10 next years will be difficult to achieve using treatment alone, even with a highly improved cascade of care.

Management of HCV-Associated Liver Cirrhosis

BACKGROUND

Treatment of chronic hepatitis C infection is most urgent in patients with severe liver fibrosis and cirrhosis because of the high risk of decompensation, hepatocellular carcinoma, and consecutively death. The development and approval of several direct-acting antiviral drugs (DAA) in the past years has revolutionized antiviral therapy especially for patients with liver cirrhosis.

METHODS

This review will focus on recent data from clinical trials and recommendations for the therapy of hepatitis C-infected patients with compensated cirrhosis.

RESULTS

Clinical data for cirrhotic patients mainly exist for a combination of the nucleotide analog sofosbuvir with either a protease inhibitor (simeprevir) or an NS5A inhibitor (daclatasvir, ledipasvir) or a three-DAA combination consisting of an NS3 protease inhibitor, an NS5A inhibitor, and a non-nucleoside NS5B inhibitor (paritaprevir/ritonavir, ombitasvir, and dasabuvir). Rates of sustained virologic response in patients with compensated cirrhosis are comparable to patients without cirrhosis; however, the addition of ribavirin and/or longer treatment durations are especially recommended when other negative predictors are present, such as prior treatment failure, features of advanced cirrhosis, or the presence of baseline resistance.

CONCLUSION

Nowadays, a highly active, short, and safe interferon-free treatment regimen is available for almost all patients.

[Hepatitis C infection: Therapeutic strategies]

The development of new direct acting antivirals has significantly modified strategies to treat chronic hepatitis C. Treatments were previously made of an interferon-based combination. This article aims to review the direct acting antivirals clinical data and to discuss the new regimens for the management of chronic hepatitis C. Direct acting antivirals combinations - with or without ribavirin - are the new chronic hepatitis C standard treatment regimen. These combinations often result in sustained viral response rate (>90%, including in patients with uncomplicated cirrhosis) after a 12-week treatment for most patients. The innovation could represent a new era for patients with unmet medical need (especially ineligible or non-responders to interferon and/or ribavirin patients). Further investigations are required to confirm the efficacy in specific population (complicated cirrhosis, pre- or post-transplantation, chronic renal failure, comorbidities, etc.) where clinical data are still limited. Other treatments are currently being developed and might lead to new perspectives, especially in terms of treatment duration or therapeutic simplification.

[Topical problems of antiviral therapy for chronic hepatitis C]

Antiviral therapy using interferon-free regimens for chronic hepatitis C (CHC) is being more frequently practiced by hepatologists due to the high efficiency of a short treatment cycle and the lowest rate of adverse events. The review discusses the most topical problems that will present themselves in practicing hematologists when treating patients with CHC under the present-day conditions. The use of direct-acting antiviral drugs requires knowledge and skills for physicians to orient themselves in the list of these drugs to create their based regimens, the efficiency and safety of which are proven in the context of evidence-based medicine. The review gives data on the efficiency and safety of 3D therapy for CHC according to the baseline characteristics of patients.

Dosing Recommendations for Concomitant Medications During 3D Anti-HCV Therapy

The development of direct-acting antiviral (DAA) agents has reinvigorated the treatment of hepatitis C virus infection. The availability of multiple DAA agents and drug combinations has enabled the transition to interferon-free therapy that is applicable to a broad range of patients. However, these DAA combinations are not without drug-drug interactions (DDIs). As every possible DDI permutation cannot be evaluated in a clinical study, guidance is needed for healthcare providers to avoid or minimize drug interaction risk. In this review, we evaluated the DDI potential of the novel three-DAA combination of ombitasvir, paritaprevir, ritonavir, and dasabuvir (the 3D regimen) with more than 200 drugs representing 19 therapeutic drug classes. Outcomes of these DDI studies were compared with the metabolism and elimination routes of prospective concomitant medications to develop mechanism-based and drug-specific guidance on interaction potential. This analysis revealed that the 3D regimen is compatible with many of the drugs that are commonly prescribed to patients with hepatitis C virus infection. Where interaction is possible, risk can be mitigated by paying careful attention to concomitant medications, adjusting drug dosage as needed, and monitoring patient response and/or clinical parameters.

Open-label study of faldaprevir plus peginterferon and ribavirin in hepatitis C virus genotype 1-infected patients who failed placebo plus peginterferon and ribavirin

Faldaprevir, a hepatitis C virus (HCV) NS3/4A protease inhibitor, was evaluated in HCV genotype 1-infected patients who failed peginterferon and ribavirin (PegIFN/RBV) treatment during one of three prior faldaprevir trials. Patients who received placebo plus PegIFN/RBV and had virological failure during a prior trial were enrolled and treated in two cohorts: prior relapsers (n = 43) and prior nonresponders (null responders, partial responders and patients with breakthrough; n = 75). Both cohorts received faldaprevir 240 mg once daily plus PegIFN/RBV for 24 weeks. Prior relapsers with early treatment success (ETS; HCV RNA <25 IU/mL detectable or undetectable at week 4 and <25 IU/mL undetectable at week 8) stopped treatment at week 24. Others received PegIFN/RBV through week 48. The primary efficacy endpoint was sustained virological response (HCV RNA <25 IU/mL undetectable) 12 weeks post treatment (SVR12). More prior nonresponders than prior relapsers had baseline HCV RNA ≥ 800,000 IU/mL (80% vs 58%) and a non-CC IL28B genotype (91% vs 70%). Rates of SVR12 (95% CI) were 95.3% (89.1, 100.0) among prior relapsers and 54.7% (43.4, 65.9) among prior nonresponders; corresponding ETS rates were 97.7% and 65.3%. Adverse events led to faldaprevir discontinuations in 3% of patients. The most common Division of AIDS Grade ≥ 2 adverse events were anaemia (13%), nausea (10%) and hyperbilirubinaemia (9%). In conclusion, faldaprevir plus PegIFN/RBV achieved clinically meaningful SVR12 rates in patients who failed PegIFN/RBV in a prior trial, with response rates higher among prior relapsers than among prior nonresponders. The adverse event profile was consistent with the known safety profile of faldaprevir.

Review article: safety and tolerability of direct-acting anti-viral agents in the new era of hepatitis C therapy

BACKGROUND

Direct-acting anti-virals (DAAs) licensed to treat chronic HCV infection have revolutionised treatment algorithms by drastically mitigating side effects while enhancing efficacy relative to interferon-based therapy.

AIM

To review adverse events (AEs) uniquely associated with DAA therapy across a broad spectrum of patient populations.

METHODS

Searches of PubMed and FDA surveillance studies were undertaken to complete an exhaustive review. Search terms included 'DAAs', 'safety', and 'tolerability'.

RESULTS

While DAAs are remarkably well tolerated, they are accompanied by unique AEs. Simeprevir, an NS3/4A protease inhibitor, has been known, albeit infrequently, to cause mild hyperbilirubinemia and photosensitivity reactions; and paritaprevir boosted with ritonavir causes bilirubin and ALT elevations. Asunaprevir, another protease inhibitor, infrequently causes elevated transaminase levels. NS5A and NS5B inhibitors are well tolerated, although sofosbuvir is contraindicated in patients with severe renal impairment. Ribavirin co-administered in certain treatment regimens has been associated with cough, rash and haemolytic anaemia.

CONCLUSIONS

With the impending reality of a more tolerable interferon-sparing regimen, the future of DAA therapy offers shorter treatment duration, simplified disease management, and a patient-centred regimen. With advantages come drawbacks, including development of resistance to therapy and accessibility to this expensive treatment. DAA therapy continues to advance at a brisk pace with a promising trend for higher tolerability, even in difficult-to-treat subgroups such as those with cirrhosis, nonresponders to prior therapy, and transplant recipients. Subgroup-specific contraindications and safety-related limitations are active areas of research. Concerted research efforts and continuing advances lend hope to the goal of rendering HCV a routinely curable disease.

Examining Hepatitis C Virus Treatment Preference Heterogeneity Using Segmentation Analysis: Treat Now or Defer?

OBJECTIVE

To improve our understanding of patients' treatment preferences for chronic hepatitis C (HCV).

METHODS

Subjects with HCV were recruited from 2 VA medical centers. Preferences were ascertained using conjoint analysis. We used segmentation analysis to examine whether there were groups of respondents with similar preferences that were systematically different from the preferences of others. We then measured the associations between treatment preference with subjects' characteristics and their gist principles related to living with HCV and the burden of therapy.

RESULTS

A total of 199 subjects participated in this study. The segmentation analysis demonstrated that subjects could be classified into 2 distinct groups. The larger group [group 1, n=118 (59%)] opted for current treatment and the other [group 2, n=81 (41%)] preferred to defer. Patients with cirrhosis were less likely to belong to group 2 (prefer to defer) compared with those without cirrhosis (40.5% vs. 21.3%), whereas subjects self-identifying as African American were more likely to belong to group 2 than white subjects (51.3% vs. 30.5%). Members of group 1 had a more positive overall gist principles related to HCV compared with members of group 2 [mean (SD) score=28.63 (3.06) vs. 26.46 (2.79), P<0.0001]. These gist principles mediated the relationship between race and treatment preference (Sobel test statistic=-2.68, 2-tailed P=0.007).

CONCLUSIONS

Our findings indicate that there are groups of HCV patients with similar preferences that are distinct from other groups' preferences. Patients' gist principles related to the significance of having a chronic viral infection and the burdens of therapy are strongly related to their current treatment decisions. These findings help inform how best to initiate and deliver treatment for patients with HCV.

Recent advances in management of the HIV/HCV coinfected patient

Chronic hepatitis C virus (HCV) is a global epidemic, affecting approximately 150 million individuals throughout the world. The implications of HCV infection have been magnified in those who are infected with both HCV and the HIV as liver disease progression, liver failure and liver-related death are increased, particularly in those without well-controlled HIV disease. The development of direct-acting antiviral agents for HCV that allow shorter treatment periods with increased efficacy and decreased adverse events have greatly changed the outlook for HCV-infected individuals. With these advancements, growing treatment options for the coinfected population have also come. This review will address pharmacotherapy issues in the HIV/HCV coinfected population.

Applicability of Hepatitis C Virus RNA Viral Load Thresholds for 8-Week Treatments in Patients With Chronic Hepatitis C Virus Genotype 1 Infection

BACKGROUND

Interferon-free treatment of chronic hepatitis C virus (HCV) genotype 1 infection may be shortened to 8 weeks in treatment-naive, noncirrhotic patients with baseline HCV RNA levels of <4 or <6 million (M) IU/mL based on post-hoc analyses of phase 3 trial data. The applicability of these viral load thresholds in clinical practice is unknown.

METHODS

Pretreatment and on-treatment serum samples (n = 740) from patients with HCV genotype 1 infection were included for HCV RNA analysis with 2 widely used assays, Cobas AmpliPrep/CobasTaqMan (CAP/CTM) and Abbott RealTime HCV (ART) assays.

RESULTS

HCV RNA levels were significantly higher with CAP/CTM than with ART (overall difference, +0.11 log10 IU/mL; P < .001). In treatment-naive, noncirrhotic patients, discordance rates around the clinical cutoffs at 4M and 6M IU/mL were 23% and 18%, respectively. The mean differences between assays in discordant samples were 0.38 (4M) and 0.41 (6M) log10 IU/mL, respectively. Overall, 87% and 95% of treatment-naive, noncirrhotic patients, respectively, had baseline HCV RNA levels below 4M and 6M IU/mL with ART. These rates were significantly higher than those measured with CAP/CTM (64% and 78%, respectively; P < .001). Finally, discordance rates around the proposed thresholds in 2 consecutive samples of the same patient were in the range of 1%-2% for ART and 13%-17% for CAP/CTM.

CONCLUSIONS

Selection of patients for 8-week regimens on the basis of a single HCV RNA determination may not be reliable because viral load levels around the proposed clinical thresholds show significant interassay and intrapatient variability.

Therapeutic Advances in HCV Genotype 1 Infection: Insights from the Society of Infectious Diseases Pharmacists

Hepatitis C virus (HCV) is the most common blood-borne infection in the United States. The high morbidity and mortality due to untreated infection have prompted updated screening recommendations that now include one-time HCV screening for all patients born between 1945 and 1965, in addition to risk factor-based screening. Current guidelines recommend treatment for all patients with chronic HCV. Treatment for HCV genotype 1 has evolved dramatically since the approval of the direct-acting antivirals. The approval of ledipasvir-sofosbuvir, ombitasvir-paritaprevir-ritonavir and dasabuvir, and simeprevir with sofosbuvir has dramatically altered the treatment landscape. High sustained virologic response (SVR) rates favor treatment, yet access to care poses a challenge for patients and providers. Current and emerging data with new therapies indicate high SVR rates in treatment-naïve and treatment-experienced patients, including patients with cirrhosis and in other special populations. Additional data suggest the addition of ribavirin can decrease treatment duration without compromising SVR rates. Resistance is an increasing area of interest in HCV, with baseline mutations identified and the potential for the development of resistance-associate variants in patients undergoing treatment. Due to the rapid evolution of HCV treatment, pharmacists should address challenges and play an integral role in agent selection, dosing, drug interaction screening, adverse effect monitoring, and the coordination of treatment. Clinical application of the latest information will reduce patient risk and improve outcomes.

Thumb Site 2 Inhibitors of Hepatitis C Viral RNA-dependent RNA Polymerase Allosterically Block the Transition from Initiation to Elongation

Replication of the hepatitis C viral genome is catalyzed by the NS5B (nonstructural protein 5B) RNA-dependent RNA polymerase, which is a major target of antiviral drugs currently in the clinic. Prior studies established that initiation of RNA replication could be facilitated by starting with a dinucleotide (pGG). Here we establish conditions for efficient initiation from GTP to form the dinucleotide and subsequent intermediates leading to highly processive elongation, and we examined the effects of four classes of nonnucleoside inhibitors on each step of the reaction. We show that palm site inhibitors block initiation starting from GTP but not when starting from pGG. In addition we show that nonnucleoside inhibitors binding to thumb site-2 (NNI2) lead to the accumulation of abortive intermediates three-five nucleotides in length. Our kinetic analysis shows that NNI2 do not significantly block initiation or elongation of RNA synthesis; rather, they block the transition from initiation to elongation, which is thought to proceed with significant structural rearrangement of the enzyme-RNA complex including displacement of the β-loop from the active site. Direct measurement in single turnover kinetic studies show that pyrophosphate release is faster than the chemistry step, which appears to be rate-limiting during processive synthesis. These results reveal important new details to define the steps involved in initiation and elongation during viral RNA replication, establish the allosteric mechanisms by which NNI2 inhibitors act, and point the way to the design of more effective allosteric inhibitors that exploit this new information.

Modeling Ribavirin-Induced Anemia in Patients with Chronic Hepatitis C Virus

Ribavirin remains an important component of hepatitis C treatment in certain clinical scenarios, but it causes hemolytic anemia. A quantitative understanding of the ribavirin exposure-anemia relationship is important in dose individualization/optimization. We developed a model relating ribavirin triphosphate (RTP) exposure in red blood cells (RBCs), RBC lifespan, feedback regulation of RBC production when anemia occurs, and the resulting hemoglobin decline. Inosine triphosphatase (ITPA) and interleukin 28B (IL28B) genetics were found to be significant covariates. Clinical trial simulations predicted that anemia is least severe in IL28B non-CC (rs12979860, CT or TT), ITPA variant subjects, followed by IL28B non-CC, ITPA wild-type, IL28B CC, ITPA variant, and IL28B CC, ITPA wild-type subjects (most severe). Reducing the ribavirin dose from 1,200/1,000 mg to 800/600 mg could reduce the proportions of grade 2 anemia by about half. The resulting model framework will aid the development of dosing strategies that minimize the incidence of anemia in treatment regimens that include ribavirin.

Advances in hepatitis C therapy: What is the current state - what come's next?

Chronic hepatitis C virus (HCV) infection affects 80-160 million people worldwide and is one of the leading causes of chronic liver disease. It is only a few years ago that standard treatment regimes were based on pegylated interferon alpha and ribavirin. However, treatment of HCV has undergone a revolutionary change in recent years. The admission of the nucleotide polymerase inhibitor Sofosbuvir enabled an interferon-free regimen with direct antiviral agents (DAA). Meanwhile seven DAAs are available and can be applied in several combinations for 8 to 24 wk depending on HCV genotype and patient characteristics such as cirrhosis and chronic renal failure. High rates of sustained virological response (SVR) rates can be achieved with these novel drugs. Even in difficult to treat populations such as patients with liver cirrhosis, HCV-human immunodeficiency virus co-infections, after liver transplantion, or with chronic kidney disease comparable high rates of SVR can be achieved. The anticipated 2(nd) generation DAAs are strikingly effective in patients so far classified as difficult to treat including decompensated liver cirrhosis or post-transplant patients. These 2(nd) generations DAAs will have higher resistance barriers, higher antiviral effects and a pan-genotypic spectrum. This review highlights the current state of the art of antiviral treatment in hepatitis C and gives an outlook for upcoming therapies.

Drug-Drug Interaction of Omeprazole With the HCV Direct-Acting Antiviral Agents Paritaprevir/Ritonavir and Ombitasvir With and Without Dasabuvir

Paritaprevir (administered with low-dose ritonavir), ombitasvir, and dasabuvir are direct-acting antiviral agents administered as combination regimens for the treatment of chronic hepatitis C virus infection. Drug-drug interactions between 2D (ombitasvir/paritaprevir/ritonavir) or 3D (ombitasvir/paritaprevir/ritonavir and dasabuvir) regimens and omeprazole, a CYP2C19 substrate and acid-reducing agent, were evaluated in 24 healthy volunteers. Subjects received omeprazole (40 mg once daily) on day 1 and days 20-24 and the 2D or 3D regimen (ombitasvir/paritaprevir/ritonavir 25/150/100 mg once daily ± dasabuvir 250 mg twice daily) on days 6-24. Compared with omeprazole alone, coadministration with the 2D or 3D regimen decreased omeprazole geometric mean Cmax and AUCt values by 40% to 50%. Ombitasvir, dasabuvir, and ritonavir mean exposures showed <10% change, and paritaprevir mean exposures showed <20% change when the 2D or 3D regimen was administered with omeprazole compared with administration without omeprazole. Although no a priori dose adjustment is needed, a higher omeprazole dose should be considered if clinically indicated when coadministered with the 2D or 3D regimen. No dose adjustment is required for the 2D or 3D regimen when administered with omeprazole, other acid-reducing agents, or CYP2C19 inhibitors.

Hepatitis C virus infection and thyroid autoimmune disorders: A model of interactions between the host and the environment

The hepatitis C virus (HCV) infection is an important public health problem and it is associated with hepatic and extrahepatic manifestations. Autoimmune thyroid diseases are common in HCV infected patients and the standard interferon-based treatment is associated with an increase of the immune-mediated thyroid damage. Recent evidence in the literature analyzed critical points of the mechanisms of thyroid damage, focusing on the balance between the two sides of the interaction: The environment (virus infection with potential cross-reaction) and the host (susceptibility genes with consistent immune response). The spectrum of antiviral treatment for chronic HCV infection is rapidly expanding for the development of dual o triple therapy. The availability of interferon-free combined treatment with direct antiviral agents for HCV is very promising, in order to ameliorate the patient compliance and to reduce the development of thyroid autoimmunity.

Ribavirin: Past, present and future

Before the advent of direct acting antiviral agents (DAAs) ribavirin, associated to pegylated-interferon played a crucial role in the treatment of chronic hepatitis C, preventing relapses and breakthroughs. In the present era of new potent DAAs, a place is still devoted to the drug. Ribavirin associated with sofosbuvir alone is efficient in the treatment of most cases of G2 infected patients. All options currently available for the last difficult-to-treat cirrhotic G3 patients contain ribavirin. Reducing treatment duration to 12 wk in G1 or G4 cirrhotic compensated patients is feasible thanks to ribavirin. Retreating patients with acquired anti NS5A resistance-associated variants using ribavirin-based strategies could be useful. The addition of ribavirin with DAAs combinations however, leads to more frequent but mild adverse events especially in cirrhotic patients. Preliminary data with interferon-free second generation DAAs combinations without ribavirin suggest that future of the drug is jeopardized even in difficult-to-treat patients: The optimization of ribavirin dosage according to an early monitoring of blood levels has been suggested to be relevant in double therapy with peginterferon or sofosbuvir but not with very potent combinations of more than two DAAs.

Chronic hepatitis C: This and the new era of treatment

Over the last years it has started a real revolution in the treatment of chronic hepatitis C. This occurred for the availability of direct-acting antiviral agents that allow to reach sustained virologic response in approximately 90% of cases. In the near future further progress will be achieved with the use of pan-genotypic drugs with high efficacy but without side effects.

Why I do not treat patients for mild disease

The short-term prognosis of patients with chronic hepatitis C and mild disease is excellent. Monitoring of the progression of fibrosis is easy to perform with non-invasive tests. Current all-oral interferon (IFN)- and ribavirin (RBV)-free regimens offer sustained viral response (SVR) rates of more than 90% as well as 12-weeks of treatment for most patients with mild disease. Several DAA combinations can be selected to optimize efficacy and safety outcomes. A short treatment duration of 8 weeks could be indicated in most patients with mild disease. However, additional data from clinical trials and real-life experience are needed to confirm this option. Moreover, current regimens are not cost-effective for patients with mild disease. In practice, deferral of HCV treatment for a few years and monitoring the progression of fibrosis is a safe option until cheaper, shorter, more effective and more convenient HCV regimens become available.

Ideal oral combinations to eradicate HCV: The role of ribavirin

Current all-oral interferon-free regimens offer sustained virological response (SVR) rates above 90% as well as 12-week treatment durations for the majority of patients with chronic hepatitis C virus (HCV), including treatment-naïve and -experienced patients with or without cirrhosis. There are multiple direct-acting antiviral (DAA) combinations that can be selected to optimize efficacy and safety outcomes. Each of them can be tailored according to different parameters including the use of ribarivin (RBV). For sofosbuvir (SOF)-based combinations, RBV is useful in the following situations: HCV genotype 1, treatment-experienced, cirrhotic patients, or patients with decompensated cirrhosis, and HCV genotype 3, cirrhotic patients. In these situations the addition of RBV allows to shorten the treatment to 12weeks in the majority of cases and therefore decreases the cost of the treatment. The need of RBV remains to be determined in cirrhotic patients with a SOF plus simeprevir regimen. RBV-containing regimens are recommended in all HCV genotype 1a patients who receive the 3-DAA combination: paritaprevir/r, ombitasvir, dasabuvir. Globally, the addition of RBV to the different combinations of DAA increases slightly the risk of anaemia. However severe anaemia was rare and easily manageable with RBV dose reduction without any impact on SVR. In practice, because RBV is cheap and well tolerated when combined with interferon-free regimen, it remains a useful tool to fine tune anti-HCV treatment regimens and optimize their results.

Efficacy and safety of ombitasvir/paritaprevir/r and dasabuvir compared to IFN-containing regimens in genotype 1 HCV patients: The MALACHITE-I/II trials

BACKGROUND & AIMS

Telaprevir plus pegylated interferon/ribavirin (TPV+PegIFN/RBV) remains a therapeutic option for chronic hepatitis C virus (HCV) genotype (GT) 1 infection in many regions. We conducted two open-label, phase IIIb trials comparing safety and efficacy of all-oral ombitasvir/paritaprevir/ritonavir and dasabuvir±ribavirin (OBV/PTV/r+DSV±RBV) and TPV+PegIFN/RBV.

METHODS

Treatment-naïve (MALACHITE-I) or PegIFN/RBV-experienced (MALACHITE-II) non-cirrhotic, chronic HCV GT1-infected patients were randomized to OBV/PTV/r+DSV+weight-based RBV, OBV/PTV/r+DSV (treatment-naïve, GT1b-infected patients only), or 12weeks of TPV+PegIFN+weight-based RBV and 12-36 additional weeks of PegIFN/RBV. The primary endpoint was sustained virologic response 12weeks post-treatment (SVR12). Patient-reported outcome questionnaires evaluated mental and physical health during the studies.

RESULTS

Three hundred eleven treatment-naïve and 148 treatment-experienced patients were randomized and dosed. Among treatment-naïve patients, SVR12 rates were 97% (67/69) and 82% (28/34), respectively, in OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV-treated GT1a-infected patients; SVR12 rates were 99% (83/84), 98% (81/83), and 78% (32/41) in OBV/PTV/r+DSV+RBV, OBV/PTV/r+DSV, and TPV+PegIFN/RBV-treated GT1b-infected patients. Among treatment-experienced patients, SVR12 rates were 99% (100/101) and 66% (31/47) with OBV/PTV/r+DSV+RBV and TPV+PegIFN/RBV. Mental and physical health were generally better with OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV. Rates of discontinuation due to adverse events (0-1% and 8-11%, respectively, p<0.05) and rates of hemoglobin decline to <10g/dl (0-4% and 34-47%, respectively, p<0.05) were lower for OBV/PTV/r+DSV±RBV than TPV+PegIFN/RBV.

CONCLUSIONS

Among non-cirrhotic, HCV GT1-infected patients, SVR12 rates were 97-99% with 12week, multi-targeted OBV/PTV/r+DSV±RBV regimens and 66-82% with 24-48 total weeks of TPV+PegIFN/RBV. OBV/PTV/r+DSV±RBV was associated with a generally better mental and physical health, more favorable tolerability, and lower rates of treatment discontinuation due to adverse events.

Population Pharmacokinetics of Paritaprevir, Ombitasvir, Dasabuvir, Ritonavir, and Ribavirin in Patients with Hepatitis C Virus Genotype 1 Infection: Combined Analysis from 9 Phase 1b/2 Studies

Direct-acting antiviral agents (DAAs) are established as the standard of care for chronic hepatitis C virus (HCV) infection. One of the newest additions to the HCV arsenal is an oral three-DAA combination therapy (i.e., the 3D regimen) that does not require concomitant use of pegylated interferon. The clinical development program for the 3D regimen has yielded a robust dataset that is inclusive of various dosing schemes and a diverse patient population. Using data from nine phase 1b/2a/2b studies that enrolled patients with HCV genotype 1 infection, population pharmacokinetic models were developed for each component of the 3D regimen (ombitasvir, paritaprevir, ritonavir, and dasabuvir) and for ribavirin, an adjunctive therapy used to enhance therapeutic efficacy in some populations. Formulation effects, accumulation, relative bioavailability, and interactions between DAAs were assessed during model development, and demographic and clinical covariates were identified and evaluated for their effects on drug exposures. Proposed models were assessed via goodness-of-fit plots, visual predictive checks, and bootstrap evaluations. Population pharmacokinetic models adequately described their respective plasma concentration-time data with precise and reliable model parameter estimates and with good predictive performance. Covariates, including age, sex, body weight, cytochrome P450 2C8 inhibitor use, non-Hispanic ethnicity, and creatinine clearance, were associated with apparent clearance and/or apparent volume parameters; however, the magnitude of effect on drug exposure was modest and not considered to be clinically significant. No patient-related or clinical parameters were identified that would necessitate dose adjustment of the 3D regimen in patients with HCV genotype 1 infection.

Direct-acting antivirals for the treatment of hepatitis C virus infection: optimizing current IFN-free treatment and future perspectives

There has been a revolution in the treatment of chronic hepatitis C. Several oral regimens combining direct-acting antivirals (DAAs) from different families [NS5B nucleotide inhibitors, NS5B non-nucleoside inhibitors, NS5A replication complex inhibitors and NS3/4A protease inhibitors (PI)] have been developed. These regimens result in an increase in sustained virological response (SVR) rates to above 90% and reduce the duration of treatment to 12 weeks or less. As of 2016 several regimens will be approved with additive potencies, without cross-resistance and with a good safety profile. Remaining issues will include increasing screening and access to care so that HCV may become the first chronic viral infection eradicated worldwide. This review summarizes results obtained with oral DAA combinations that have been approved and/or have completed phase 3 clinical trials for HCV infection and discusses future perspectives.

[Treatment of hepatitis C]

Chronic hepatitis C virus (HCV) infection is the major cause of liver cirrhosis, hepatocellular carcinoma and liver transplantation in the western world. The development and approval of nine directly acting antiviral drugs in recent years has led to a dramatic improvement in therapeutic efficacy accompanied by fewer side effects. With current treatment options sustained virologic response in more than 90 % of patients can be achieved depending on HCV genotype, liver cirrhosis and prior therapies. Modern HCV treatment regimens are interferon-free and should be administered for 12-24 weeks. Shorter courses are possible in selected patients. For the treatment of HCV genotype 1 infection combinations of either the nucleotide polymerase inhibitor sofosbuvir with the protease inhibitor simeprevir or with one of the two NS5A inhibitors daclatasvir or ledipasvir on the one hand or triple DAA therapy of paritaprevir, ombitasvir and dasabuvir on the other hand are applicable. Ribavirin has still a role as an add-on in difficult to treat patients.

Mechanisms of Hepatitis C Viral Resistance to Direct Acting Antivirals

There has been a remarkable transformation in the treatment of chronic hepatitis C in recent years with the development of direct acting antiviral agents targeting virus encoded proteins important for viral replication including NS3/4A, NS5A and NS5B. These agents have shown high sustained viral response (SVR) rates of more than 90% in phase 2 and phase 3 clinical trials; however, this is slightly lower in real-life cohorts. Hepatitis C virus resistant variants are seen in most patients who do not achieve SVR due to selection and outgrowth of resistant hepatitis C virus variants within a given host. These resistance associated mutations depend on the class of direct-acting antiviral drugs used and also vary between hepatitis C virus genotypes and subtypes. The understanding of these mutations has a clear clinical implication in terms of choice and combination of drugs used. In this review, we describe mechanism of action of currently available drugs and summarize clinically relevant resistance data.

Dasabuvir (ABT333) for the treatment of chronic HCV genotype I: a new face of cure, an expert review

Hepatitis C virus (HCV) affects nearly 1.3% of US population and around 2% of people worldwide. It is associated with serious complication of Cirrhosis and Hepatocellular carcinoma leading to significant morbidity and mortality. Until now the only treatment option for this serious disease was interferon based therapy which had poor tolerance and at best SVR (Sustained virological response) in only 50% of cases. With the introduction of other direct - acting antiviral agents the treatment of HCV has been revolutionized with significantly high rates of cure. Among novel Direct acting antivirals are non-nucleoside inhibitor NS5B which is highly effective in treatment of HCV genotype 1 a and 1b including those with compensated cirrhosis achieving high cure rates with SVR more than 97 % in pooled analysis from six different phase 3 trials. This review will discuss the DAA - Dasabuvir, a non - nucleoside NS5B inhibitor, its mechanism of action, efficacy, safety & tolerance, and drug resistance. Dasabuvir is approved by FDA in combination with other DAA agents called as the 3D(Viekira Pak) in various interferon free regimens achieving high cure rates (SVR >95%) with low adverse effects. In Europe, it is approved by European medicines agency for use in combination with Ombitasvir, Paritaprevir, and ritonavir with or without ribavirin. The drug is used in treatment naive as well as previously treated patient with high success rates. It is also approved in patients with compensated cirrhosis, patients with HIV co-infection and liver transplant recipients which were in the past were excluded from treatment with interferon based therapy. Dasabuvir is extensively evaluated in large clinical trials and shown excellent SVR among HCV genotype1 patient population in combination with other oral DAAs, with good safety profile and tolerance. Its drawback is its genotype restriction, need for ribavirin (RBV) for 1a genotype, low resistance barrier and high cost. It is well tolerated with less than 1 % of patients permanently discontinuing treatment and 2% of patient experiencing a serious adverse reaction. It is contraindicated in patients with known hypersensitivity to ritonavir (e.g. Steven - Johnson syndrome) and strong inducers of CYP3A and CYP2CB.

Impact of IL28B, APOH and ITPA Polymorphisms on Efficacy and Safety of TVR- or BOC-Based Triple Therapy in Treatment-Experienced HCV-1 Patients with Compensated Cirrhosis from the ANRS CO20-CUPIC Study

BACKGROUND

Human genetic factors influence the outcome of pegylated interferon and ribavirin hepatitis C therapy. We explored the role of IL28B, APOH and ITPA SNPs on the outcomes of triple therapy including telaprevir or boceprevir in patients with compensated cirrhosis chronically infected with HCV-1.

PATIENTS AND METHODS

A total of 256 HCV-1 Caucasian treatment-experienced patients with compensated cirrhosis from the ANRS CO20-CUPIC cohort were genotyped for a total of 10 candidate SNPs in IL28B (rs12979860 and rs368234815), APOH (rs8178822, rs12944940, rs10048158, rs52797880, rs1801689 and rs1801690) and ITPA (rs1127354 and rs7270101). We tested the association of IL28B and APOH SNPs with sustained virological response and of ITPA SNPs with anemia related phenotypes by means of logistic regression assuming an additive genetic model.

RESULTS

None of the six APOH SNPs were associated with sustained virological response. The favorable alleles of the IL28B SNPs rs12979860 and rs368234815 were associated with sustained virological response (rs12979860: OR = 2.35[1.50-3.70], P = 2x10(-4)). Refined analysis showed that the effect of IL28B SNPs on sustained virological response was restricted to prior PegIFN/RBV relapse (OR = 3.80[1.82-8.92], P = 8x10(-4)). We also confirmed the association between ITPA low activity alleles and protection against early hemoglobin decline in triple therapy (P = 2x10(-5)).

CONCLUSION

Our results suggest that the screening of rs12979860 may remain interesting for decision making in prior relapse HCV-1 Caucasian patients with compensated cirrhosis eligible for a telaprevir- or boceprevir-based therapy.

On computer-intensive simulation and estimation methods for rare-event analysis in epidemic models

This article focuses, in the context of epidemic models, on rare events that may possibly correspond to crisis situations from the perspective of public health. In general, no close analytic form for their occurrence probabilities is available, and crude Monte Carlo procedures fail. We show how recent intensive computer simulation techniques, such as interacting branching particle methods, can be used for estimation purposes, as well as for generating model paths that correspond to realizations of such events. Applications of these simulation-based methods to several epidemic models fitted from real datasets are also considered and discussed thoroughly.

Update on hepatitis C: Direct-acting antivirals

Hepatitis C virus (HCV) was discovered 26 years ago. For decades, interferon-based therapy has been the mainstay of treatment for HCV. Recently, several direct-acting antivirals (DAAs) have been approved for treatment of HCV-infected patients and to help combat the virus. These drugs have revolutionized the management of HCV as all-oral regimens with favorable side effect profiles and superior rates of sustained virological response. Emerging real-world data are demonstrating results comparable to registration trials for DAA agents. Suddenly, the potential for eradicating HCV is on the horizon.

Analysis of Hepatitis C Virus Genotype 1b Resistance Variants in Japanese Patients Treated with Paritaprevir-Ritonavir and Ombitasvir

Treatment of HCV genotype 1b (GT1b)-infected Japanese patients with paritaprevir (NS3/4A inhibitor boosted with ritonavir) and ombitasvir (NS5A inhibitor) in studies M12-536 and GIFT-I demonstrated high sustained virologic response (SVR) rates. The virologic failure rate was 3% (13/436) across the two studies. Analyses were conducted to evaluate the impact of baseline resistance-associated variants (RAVs) on treatment outcome and the emergence and persistence of RAVs in patients experiencing virologic failure. Baseline paritaprevir resistance-conferring variants in NS3 were infrequent, while Y93H in NS5A was the most prevalent ombitasvir resistance-conferring variant at baseline. A comparison of baseline prevalence of polymorphisms in Japanese and western patients showed that Q80L and S122G in NS3 and L28M, R30Q, and Y93H in NS5A were significantly more prevalent in Japanese patients. In the GIFT-I study, the prevalence of Y93H in NS5A varied between 13% and 21% depending on the deep-sequencing detection threshold. Among patients with Y93H comprising <1%, 1 to 40%, or >40% of their preexisting viral population, the 24-week SVR (SVR₂₄) rates were >99% (276/277), 93% (38/41), and 76% (25/33), respectively, indicating that the prevalence of Y93H within a patient's viral population is a good predictor of treatment response. The predominant RAVs at the time of virologic failure were D168A/V in NS3 and Y93H alone or in combination with other variants in NS5A. While levels of NS3 RAVs declined over time, NS5A RAVs persisted through posttreatment week 48. Results from these analyses are informative in understanding the resistance profile of an ombitasvir- plus paritaprevir/ritonavir-based regimen in Japanese GT1b-infected patients.

Hepatitis C Virus: A European Perspective

Chronic hepatitis C virus (HCV) infection is a major public health burden in Europe, being one of the leading causes of chronic liver disease, liver cirrhosis, and hepatocellular carcinoma. Properties of the HCV disease burden are heterogeneous across the European continent, with differences in incidence, prevalence, diagnosis and treatment rates, transmission routes, and genotype distribution. Recent estimates expect an increase in HCV-related morbidity and mortality in most European countries until 2030 even when current treatment options are taken into account. The European perspective on hepatitis C virus infection is summarized herein.

Hepatitis C: pay now or pay later?

Hepatitis C is a leading cause of liver disease and resulting complications are predicted to increase in the coming decades. However, recent availability of interferon-free treatment has put the spotlight on this epidemic and its health and economic impacts. Yet the cost of therapy is frequently prohibitive. When available, treatment provides an opportunity to abort disease progression, thus forgoing expensive downstream healthcare expenditures. Cost savings from therapy seem both probable and measurable in select patients with advanced disease and low risk of reinfection. The economic argument for early treatment is not as clear in those with less advanced liver disease and higher risk of reinfection. The optimal alignment of the relevant clinical and epidemiologic variables has yet to be clearly defined.

Current and Evolving Treatments of Genotype 1 Hepatitis C Virus

Development of antiviral agents that target the hepatitis C virus (HCV) has improved the success and tolerability of treatment, especially for patients with HCV genotype 1 infection. The new treatment options mean that clinicians are better able to prevent complications from chronic HCV infection. The field of direct-acting antiviral therapies for HCV infection continues to advance at a rapid pace, and many more potential treatment regimens are being investigated. This article presents a summary of the current treatments available for patients infected with HCV genotype 1 and looks ahead to those that may play a role in the future.

Treatment of hepatitis C in coinfected patients

HCV and liver disease have emerged as major causes of morbidity and mortality in HIV-positive patients. Treating HCV in patients with HIV has been challenging up until a few years ago due to poorer outcomes with interferon-based therapies in this population. The direct-acting antiviral (DAA) agents offer a new era in the treatment of HCV for all patients regardless of HIV status. This article reviews multiple aspects of the care of the coinfected patient with a focus on the modern DAA agents. HCV clinical treatment trials involving HIV-positive patients and antiretroviral therapy/DAA drug–drug interactions are reviewed in detail.

Chronic Hepatitis C: An Overview of Evidence on Epidemiology and Management from a Brazilian Perspective

Chronic hepatitis C remains one of the main causes of chronic liver disease worldwide and presents a variable natural history ranging from minimal changes to advanced fibrosis and cirrhosis and its complications, such as development of hepatocellular carcinoma. Approximately, 1.45 million people are estimated to be infected by HCV in Brazil representing a major public health issue. The aim of this paper was to review the epidemiology and management of chronic hepatitis C from a Brazilian perspective. The management of chronic hepatitis C has been challenged by the use of noninvasive methods to stage liver fibrosis as an alternative to liver biopsy and the high cost of new interferon-free antiviral treatments. Moreover, the need of cost-effectiveness analysis in hepatitis C and the recent changes in treatment protocols were discussed.

Profile of paritaprevir/ritonavir/ombitasvir plus dasabuvir in the treatment of chronic hepatitis C virus genotype 1 infection

Over the last several years, many advances have been made in the treatment of chronic hepatitis C virus (HCV) infection with the development of direct-acting antivirals. Paritaprevir/ritonavir/ombitasvir with dasabuvir (PrOD) is a novel combination of a nonstructural (NS) 3/4A protein inhibitor boosted by ritonavir, an NS5A protein inhibitor, and an NS5B nonnucleoside polymerase inhibitor. This review aims to discuss the pharmacology, efficacy, safety, drug interactions, and viral drug resistance of PrOD in the treatment of HCV genotype 1 infections. Phase I, II, and III human and animal studies that describe the pharmacology, pharmacokinetics, efficacy, and safety of PrOD for HCV were identified and included. Studies that evaluated patients without cirrhosis (n=2,249) and with cirrhosis (n=422) demonstrated that PrOD for 12 or 24 weeks was effective at achieving sustained virologic response rates (>90%) in patients with genotype 1a or 1b HCV infection. Although indicated for the treatment of HCV genotype 1 infection, PrOD is also recommended for the treatment of HCV in patients coinfected with HIV. Additionally, promising data exist for the use of PrOD in liver-transplant recipients. The most common adverse drug events associated with PrOD included nausea, pruritus, insomnia, diarrhea, asthenia, dry skin, vomiting, and anemia. The high efficacy rates seen coupled with a favorable side effect profile seen with PrOD with or without ribavirin have led to its addition as a recommended treatment regimen for HCV genotype 1 infection.

Interferon-free combination therapies for the treatment of hepatitis C: current insights

The hepatitis C virus (HCV) treatment landscape has rapidly changed over the past 5 years. The development of direct-acting antiviral (DAA) agents that specifically target various steps in the HCV lifecycle has revolutionized therapeutic options for patients with HCV, with the development of highly effective and well-tolerated oral interferon-free regimens. There are many DAAs that are currently in development or have recently been approved, which target different nonstructural HCV proteins and host targets that are essential for HCV replication. This review will focus on the different classes of DAAs and the various combinations that are in advanced development for the treatment of chronic HCV infection and will focus on the different regimens in specific patient populations.