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

Clinical impact of the hepatitis C virus mutations in the era of directly acting antivirals

Introduced in 2013-2014, the second- and third-wave directly acting antivirals (DAAs) have strongly enhanced the efficacy and tolerability of anti-HCV treatment, with a sustained virological response (SVR) in 90-95% of cases treated. The majority of patients who did not achieve an SVR were found to be infected with HCV strains with a reduced susceptibility to these drugs. Indeed, the high error rate of the viral polymerase and a fast virion production (100-fold higher than the human immunodeficiency virus) result in a mixture of viral genetic populations (quasi-species) pre-existing treatment initiation. These mutants occur frequently in the NS5A region, with a moderate frequency in the NS3/4A region and rarely in the NS5B region. Treatment-induced resistant mutants to NS5A DAAs persist for years after treatment discontinuation, whereas those resistant to the NS3 DAAs have a shorter duration. This review focuses on the type and prevalence of viral strains with a reduced sensitivity to DAAs, their clinical impact and influence on the response to treatment and, consequently, on treatment choice for DAA-experienced patients. J. Med. Virol. 88:1659-1671, 2016. © 2016 Wiley Periodicals, Inc.

Restrictions for reimbursement of direct-acting antiviral treatment for hepatitis C virus infection in Canada: a descriptive study

BACKGROUND

In Canada, interferon-free, direct-acting antiviral hepatitis C virus (HCV) regimens are costly. This presents challenges for universal drug coverage of the estimated 220 000 people with chronic HCV infection nationwide. The study objective was to appraise criteria for reimbursement of 4 HCV direct-acting antivirals in Canada.

METHODS

We reviewed the reimbursement criteria for simeprevir, sofosbuvir, ledipasvir-sofosbuvir and paritaprevir-ritonavir-ombitasvir plus dasabuvir in the 10 provinces and 3 territories. Data were extracted from April 2015 to June 2016. The primary outcomes extracted from health ministerial websites were: 1) minimum fibrosis stage required, 2) drug and alcohol use restrictions, 3) HIV coinfection restrictions and 4) prescriber type restrictions.

RESULTS

Overall, 85%-92% of provinces/territories limited access to patients with moderate fibrosis (Meta-Analysis of Histologic Data in Viral Hepatitis stage F2 or greater, or equivalent). There were no drug and alcohol use restrictions; however, several criteria (e.g., active injection drug use) were left to the discretion of the physician. Quebec did not reimburse simeprevir and sofosbuvir for people coinfected with HIV; no restrictions were found in the remaining jurisdictions. Prescriber type was restricted to specialists in up to 42% of provinces/territories.

INTERPRETATION

This review of criteria of reimbursement of HCV direct-acting antivirals in Canada showed substantial interjurisdictional heterogeneity. The findings could inform health policy and support the development and adoption of a national HCV strategy.

Drug-Drug Interaction between the Direct-Acting Antiviral Regimen of Ombitasvir-Paritaprevir-Ritonavir plus Dasabuvir and the HIV Antiretroviral Agent Dolutegravir or Abacavir plus Lamivudine

The direct-acting antiviral regimen of 25 mg ombitasvir-150 mg paritaprevir-100 mg ritonavir once daily (QD) plus 250 mg dasabuvir twice daily (BID) is approved for the treatment of hepatitis C virus genotype 1 infection, including patients coinfected with human immunodeficiency virus. This study was performed to evaluate the pharmacokinetic, safety, and tolerability effects of coadministering the regimen of 3 direct-acting antivirals with two antiretroviral therapies (dolutegravir or abacavir plus lamivudine). Healthy volunteers (n = 24) enrolled in this phase I, single-center, open-label, multiple-dose study received 50 mg dolutegravir QD for 7 days or 300 mg abacavir plus 300 mg lamivudine QD for 4 days, the 3-direct-acting-antiviral regimen for 14 days, followed by the 3-direct-acting-antiviral regimen with dolutegravir or abacavir plus lamivudine for 10 days. Pharmacokinetic parameters were calculated to compare combination therapy with 3-direct-acting-antiviral or antiretroviral therapy alone, and safety/tolerability were assessed throughout the study. Coadministration of the 3-direct-acting-antiviral regimen increased the geometric mean maximum plasma concentration (Cmax) and the area under the curve (AUC) of dolutegravir by 22% (central value ratio [90% confidence intervals], 1.219 [1.153, 1.288]) and 38% (1.380 [1.295, 1.469]), respectively. Abacavir geometric mean Cmax and AUC values decreased by 13% (0.873 [0.777, 0.979]) and 6% (0.943 [0.901, 0.986]), while those for lamivudine decreased by 22% (0.778 [0.719, 0.842]) and 12% (0.876 [0.821, 0.934]). For the 3-direct-acting-antiviral regimen, geometric mean Cmax and AUC during coadministration were within 18% of measurements made during administration of the 3-direct-acting-antiviral regimen alone, although trough concentrations for paritaprevir were 34% (0.664 [0.585, 0.754]) and 27% (0.729 [0.627, 0.847]) lower with dolutegravir and abacavir-lamivudine, respectively. All study treatments were generally well tolerated, with no evidence of increased rates of adverse events during combination administration. These data indicate that the 3-direct-acting-antiviral regimen can be administered with dolutegravir or abacavir plus lamivudine without dose adjustment.

Sofosbuvir plus ledipasvir in combination for the treatment of hepatitis C infection

Sofsobuvir is the first-in-class NS5B nucleotide inhibitor to be launched as a treatment for the hepatitis C virus (HCV). Its viral potency, pan genotypic activity and high barrier to resistance make it the ideal candidate to become a backbone for several IFN-free regimens. Ledipasvir is a NS5A inhibitor with multi genotypic activity but modest barrier to resistance. The once-daily fixed-dose combination of sofosbuvir plus ledipasvir is the first-in-market single-tablet regimen for the treatment of hepatitis C infection. Recent data demonstrated that this FDC alone, or in combination with ribavirin, is able to achieve HCV cure of at least 90% or more among genotype 1,4, 5 and 6 patients. This combination appears to be suboptimal in genotype 3 patients and other direct acting antiviral combinations with sofosbuvir will help to fulfill this gap in the near future. The safety profile of the fixed dose combination is good. Resistance is not an issue with sofosbuvir but may be a significant issue with regards to ledipasvir for those rare individuals who harbor baseline HCV NS5A resistance-associated variants that conferred a high resistance level. The rational for using FDCs and the available clinical data are reviewed.

Limited Generalizability of Registration Trials in Hepatitis C: A Nationwide Cohort Study

Background

Approval of drugs in chronic hepatitis C is supported by registration trials. These trials might have limited generalizability through use of strict eligibility criteria. We compared effectiveness and safety of real world hepatitis C patients eligible and ineligible for registration trials.

Methods

We performed a nationwide, multicenter, retrospective cohort study of chronic hepatitis C patients treated in the real world. We applied a combined set of inclusion and exclusion criteria of registration trials to our cohort to determine eligibility. We compared effectiveness and safety in eligible vs. ineligible patients, and performed sensitivity analyses with strict criteria. Further, we used log binomial regression to assess relative risks of criteria on outcomes.

Results

In this cohort (n = 467) 47% of patients would have been ineligible for registration trials. Main exclusion criteria were related to hepatic decompensation and co-morbidity (cardiac disease, anemia, malignancy and neutropenia), and were associated with an increased risk for serious adverse events (RR 1.45–2.31). Ineligible patients developed significantly more serious adverse events than eligible patients (27% vs. 11%, p< 0.001). Effectiveness was decreased if strict criteria were used.

Conclusions

Nearly half of real world hepatitis C patients would have been excluded from registration trials, and these patients are at increased risk to develop serious adverse events. Hepatic decompensation and co-morbidity were important exclusion criteria, and were related to toxicity. Therefore, new drugs should also be studied in these patients, to genuinely assess benefits and risk of therapy in the real world population.

Effect of co-medications on paritaprevir, ritonavir, ombitasvir, dasabuvir and ribavirin pharmacokinetics: analysis of data from seven Phase II/III trials

BACKGROUND

The three drug direct-acting antiviral regimen (3D regimen) of ombitasvir, paritaprevir/ritonavir and dasabuvir, with and without ribavirin, was evaluated in one Phase II trial and six Phase III trials in over 2,300 HCV genotype-1-infected patients. Patients continued taking their protocol-permitted co-medications while receiving the 3D ± ribavirin regimen. The effects of the co-medications on exposures of the 3D regimen and ribavirin were examined.

METHODS

Population pharmacokinetic model-predicted steady-state area under the curve (AUC_24,ss) values were evaluated in the presence/absence of the co-medications. Interactions resulting in a greater than 50% reduction or 100% increase in an AUC_24,ss value were examined as covariates for an effect on apparent clearance (CL/F).

RESULTS

More than 1,200 co-medications belonging to 15 drug classes and/or 19 enzyme and transporter inhibitor and/or inducer categories were used concomitantly with the 3D regimen in the trials. Approximately 1,500 patients (65%) in Phase III trials received two or more co-medications from multiple drug classes or categories. No co-medication class/category decreased or increased ombitasvir, dasabuvir, ritonavir or ribavirin AUC_24,ss by more than half or twofold, respectively. Opioids, antipsychotics, anti-epileptics, antidiabetics and non-ethinyl estradiol-containing hormone replacement therapies appeared to have an effect (AUC_24,ss ratio ≤0.5 or ≥2.0) on paritaprevir exposures. However, when these classes were included in the paritaprevir population pharmacokinetic model, only opioids and antidiabetics had a statistically significant effect on CL/F, but with no clinically meaningful increase in exposures (≤55%).

CONCLUSIONS

No dose adjustment is necessary for the 3D ± ribavirin regimen when used with the co-medications included in this analysis as there were no clinically meaningful effects on exposures of the DAAs.

APASL consensus statements and recommendation on treatment of hepatitis C

The Asian-Pacific Association for the Study of the Liver (APASL) convened an international working party on the "APASL consensus statements and recommendation on management of hepatitis C" in March, 2015, in order to revise "APASL consensus statements and management algorithms for hepatitis C virus infection (Hepatol Int 6:409-435, 2012)". The working party consisted of expert hepatologists from the Asian-Pacific region gathered at Istanbul Congress Center, Istanbul, Turkey on 13 March 2015. New data were presented, discussed and debated to draft a revision. Participants of the consensus meeting assessed the quality of cited studies. Finalized recommendations on treatment of hepatitis C are presented in this review.

Iatrogenic Cushing Syndrome from Interaction Between Ritonavir and Oral Budesonide During Direct Acting Antiviral Hepatitis C Therapy

Direct acting antiviral (DAA) regimens containing ritonavir have been developed to treat hepatitis C, with fewer side effects than that by interferon-based regimens. However prescribers must be aware of drug-drug interactions. There are multiple reports of iatrogenic Cushing syndrome (CS) caused by ritonavir, when used to treat human immunodeficiency virus, increasing the bioavailability of exogenous steroids by inhibiting cytochrome p450 enzymes in the liver and gut wall and thus reducing steroid metabolism. We herein report a novel scenario of CS due to interaction between ritonavir for hepatitis C treatment and oral budesonide for autoimmune hepatitis.

First and Foremost Battle the Virus: Eliciting Patient Preferences in Antiviral Therapy for Hepatitis C Using a Discrete Choice Experiment

BACKGROUND

There has been tremendous progress regarding treatment options for hepatitis C virus (HCV) infection. Several interferon-free regimens are awaiting regulatory approval. These innovations promise substantial reductions in the burden of disease and side effects as well as a decrease in treatment duration.

OBJECTIVES

The aim of this quantitaitive study was to elicit patient preferences for attributes of innovative antiviral therapies for hepatitis C.

METHODS

A systematic literature search and 14 semi-structured interviews were performed, resulting in eight patient-relevant characteristics. For the discrete choice experiment, an experimental design (3×3 + 5×6) was generated using Ngene software. The survey was conducted in August 2014 through computer-assisted personal interviews. The data were effects-coded in a random parameter logit estimation.

RESULTS

Participants were patients with HCV (N = 561; 58.1% men) in different treatment states. The analysis revealed a predominance of the attribute "reaching sustained virological response." When considering confidence intervals, the results showed three different preference ranks. At first place was "sustained virological response" (level difference [LD] 3.98), second was "anemia" (LD 1.10), followed by "number of interferon injections" (LD 0.92), "rash" (LD 0.82), "nausea and/or diarrhea" (LD 0.79), and "duration of antiviral therapy" (LD 0.78). The last position was occupied by both "tiredness/fatigue" (LD 0.31) and "headache" (LD 0.34).

CONCLUSIONS

From the patients' point of view, sustained virological response is the most essential criterion for choosing an HCV therapy. It was ranked at the highest, dominating all side effects and modes of administration. Furthermore, this study proved that patients consider both the probability of occurrence and the severity of treatment-induced side effects. Results clearly point to valuation of probabilities that is separate from that of severity.

Effectiveness of Sofosbuvir, Ledipasvir/Sofosbuvir, or Paritaprevir/Ritonavir/Ombitasvir and Dasabuvir Regimens for Treatment of Patients With Hepatitis C in the Veterans Affairs National Health Care System

BACKGROUND & AIMS

We investigated the real-world effectiveness of sofosbuvir, ledipasvir/sofosbuvir, and paritaprevir/ritonavir/ombitasvir and dasabuvir (PrOD) in treatment of different subgroups of patients infected with hepatitis C virus (HCV) genotypes 1, 2, 3, or 4.

METHODS

We performed a retrospective analysis of data from 17,487 patients with HCV infection (13,974 with HCV genotype 1; 2131 with genotype 2; 1237 with genotype 3; and 135 with genotype 4) who began treatment with sofosbuvir (n = 2986), ledipasvir/sofosbuvir (n = 11,327), or PrOD (n = 3174), with or without ribavirin, from January 1, 2014 through June 20, 2015 in the Veterans Affairs health care system. Data through April 15, 2016 were analyzed to assess completion of treatments and sustained virologic response 12 weeks after treatment (SVR12). Mean age of patients was 61 ± 7 years, 97% were male, 52% were non-Hispanic white, 29% were non-Hispanic black, 32% had a diagnosis of cirrhosis (9.9% with decompensated cirrhosis), 36% had a Fibrosis-4 index score >3.25 (indicator of cirrhosis), and 29% had received prior antiviral treatment.

RESULTS

An SVR12 was achieved by 92.8% (95% confidence interval [CI], 92.3%-93.2%) of subjects with HCV genotype 1 infection (no significant difference between ledipasvir/sofosbuvir and PrOD regimens), 86.2% (95% CI, 84.6%-87.7%) of those with genotype 2 infection (treated with sofosbuvir and ribavirin), 74.8% (95% CI, 72.2%-77.3%) of those with genotype 3 infection (77.9% in patients given ledipasvir/sofosbuvir plus ribavirin, 87.0% in patients given sofosbuvir and pegylated-interferon plus ribavirin, and 70.6% of patients given sofosbuvir plus ribavirin), and 89.6% (95% CI 82.8%-93.9%) of those with genotype 4 infection. Among patients with cirrhosis, 90.6% of patients with HCV genotype 1, 77.3% with HCV genotype 2, 65.7% with HCV genotype 3, and 83.9% with HCV genotype 4 achieved an SVR12. Among previously treated patients, 92.6% with genotype 1; 80.2% with genotype 2; 69.2% with genotype 3; and 93.5% with genotype 4 achieved SVR12. Among treatment-naive patients, 92.8% with genotype 1; 88.0% with genotype 2; 77.5% with genotype 3; and 88.3% with genotype 4 achieved SVR12. Eight-week regimens of ledipasvir/sofosbuvir produced an SVR12 in 94.3% of eligible patients with HCV genotype 1 infection; this regimen was underused.

CONCLUSIONS

High proportions of patients with HCV infections genotypes 1-4 (ranging from 75% to 93%) in the Veterans Affairs national health care system achieved SVR12, approaching the results reported in clinical trials, especially in patients with genotype 1 infection. An 8-week regimen of ledipasvir/sofosbuvir is effective for eligible patients with HCV genotype 1 infection and could reduce costs. There is substantial room for improvement in SVRs among persons with cirrhosis and genotype 2 or 3 infections.

A real-world intention-to-treat analysis of a decade's experience of treatment of hepatitis C with interferon-based therapies

Objectives: To assess the uptake of pegylated interferon (PegIFN) plus ribavirin (RBV)-based regimens in patients with hepatitis C virus (HCV) in a large, single-centre, real-world setting over 10 years.

Methods: This was a single centre, retrospective analysis of data from patients who attended their first appointment for treatment of HCV genotype 1–3 between 2003 and 2013. Patients were stratified by HCV genotype. The total number of patients who attended their first appointment, incidence of patients who did not proceed to treatment and associated reasons, and incidence of patients treated were analysed. Sustained virological response (SVR) rates were also reported for all patient populations.

Results: Overall, 1,132 patients attended their first appointment; 47.8% were included in the genotype 1 group (genotype 1a: 22.2%, genotype 1b: 13.3%, genotype 1 other: 12.3%), 7.7% in the genotype 2 group and 44.5% in the genotype 3 group. A greater proportion of patients received treatment versus those who did not receive treatment (84.4% vs 15.6%, respectively). Reasons for declining treatment included: patient declined treatment with PegIFN plus RBV: 35.0%, medical contraindications: 20.3% and mental health-related contraindications: 13.6%. An SVR was achieved in 52.6% of patients who attended their first appointment and 62.3% of patients who received treatment.

Conclusions: Approximately half of the patients included in this study achieved an SVR. A noteworthy proportion of patients did not receive treatment due to a reluctance to receive PegIFN plus RBV or contraindications to therapy. Results suggest an ongoing need for improvement in the treatment uptake and overall outcomes – particularly for genotype 2 and 3 patients for whom availability of interferon-free regimens is limited. The introduction of more tolerable direct-acting antiviral regimes may help overcome barriers to uptake demonstrated within this cohort.

2015 Philip S. Portoghese Medicinal Chemistry Lectureship. Curing Hepatitis C Virus Infection with Direct-Acting Antiviral Agents: The Arc of a Medicinal Chemistry Triumph

The development of direct-acting antiviral agents that can cure a chronic hepatitis C virus (HCV) infection after 8-12 weeks of daily, well-tolerated therapy has revolutionized the treatment of this insidious disease. In this article, three of Bristol-Myers Squibb's HCV programs are summarized, each of which produced a clinical candidate: the NS3 protease inhibitor asunaprevir (64), marketed as Sunvepra, the NS5A replication complex inhibitor daclatasvir (117), marketed as Daklinza, and the allosteric NS5B polymerase inhibitor beclabuvir (142), which is in late stage clinical studies. A clinical study with 64 and 117 established for the first time that a chronic HCV infection could be cured by treatment with direct-acting antiviral agents alone in the absence of interferon. The development of small molecule HCV therapeutics, designed by medicinal chemists, has been hailed as "the arc of a medical triumph" but may equally well be described as "the arc of a medicinal chemistry triumph".

Impact of Donor and Recipient Single Nucleotide Polymorphisms in Living Liver Donor Transplantation for Hepatitis C

INTRODUCTION

Recently, several studies have shown that specific single nucleotide polymorphisms (SNPs) affect liver fibrosis progression in patients with hepatitis C virus (HCV) infection. In this study, we examined the impact of donor and recipient SNPs on the progression of fibrosis after liver transplantation for HCV infection.

METHODS

This cohort study enrolled 43 patients with HCV infection who underwent liver transplantation at our hospital. We evaluated 5 genotypes (rs4374383, rs2629751, rs9380516, rs8099917, and rs738409) that have been reported to be significant predictors of fibrosis in HCV infection using a Taqman assay.

RESULTS

Liver fibrosis (stage ≥ F1, New Inuyama classification) was detected at 1 year after liver transplantation in 30 cases (70%). The rs2629751 non-AA-genotype was found to be significantly associated with fibrosis progression at 1 year after liver transplantation (AA:GG or GA = 46%:88%, P < .05). The primary outcome was stage ≥F2 (portoportal septa) or liver-related mortality in 22 patients. The time to stage ≥F2 fibrosis or liver-related mortality was significantly different only in terms of the donor rs2629751 genotype (AA:GG or GA = 5.5 ± 0.6 years:3.6 ± 0.7 years, P = .025).

CONCLUSIONS

The rs2629751 genotype may be an important predictor of posttransplant outcome in HCV-infected patients. This result might be useful in donor selection for liver transplantation in HCV-infected patients and may guide therapeutic decisions regarding early antiviral treatment.

Metabolism and Disposition of Hepatitis C Polymerase Inhibitor Dasabuvir in Humans

Dasabuvir [also known as ABT-333 or N-(6-(3-(tert-butyl)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide] is a potent non-nucleoside NS protein 5B polymerase inhibitor of the hepatitis C virus (HCV) and is being developed in combination with paritaprevir/ritonavir and ombitasvir in an oral regimen with three direct-acting antivirals for the treatment of patients infected with HCV genotype 1. This article describes the mass balance, metabolism, and disposition of dasabuvir in humans. After administration of a single oral dose of 400-mg [(14)C]dasabuvir (without coadministration of paritaprevir/ritonavir and ombitasvir) to four healthy male volunteers, the mean total percentage of the administered radioactive dose recovered was 96.6%. The recovery from the individual subjects ranged from 90.8% to 103%. Dasabuvir and corresponding metabolites were predominantly eliminated in feces (94.4% of the dose) and minimally through renal excretion (2.2% of the dose). The biotransformation of dasabuvir primarily involves hydroxylation of the tert-butyl group to form active metabolite M1 [N-(6-(5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-3-(1-hydroxy-2-methylpropan-2-yl)-2-methoxyphenyl)naphthalen-2-yl)methanesulfonamide], followed by glucuronidation and sulfation of M1 and subsequent secondary oxidation. Dasabuvir was the major circulating component (58% of total radioactivity) in plasma, followed by metabolite M1 (21%). Other minor metabolites represented < 10% each of total circulating radioactivity. Dasabuvir was cleared mainly through cytochrome P450-mediated oxidation metabolism to M1. M1 and its glucuronide and sulfate conjugates were primarily eliminated in feces. Subsequent oxidation of M1 to the tert-butyl acid, followed by formation of the corresponding glucuronide conjugate, plays a secondary role in elimination. Cytochrome P450 profiling indicated that dasabuvir was mainly metabolized by CYP2C8, followed by CYP3A4. In summary, the biotransformation pathway and clearance routes of dasabuvir were characterized, and the structures of metabolites in circulation and excreta were elucidated.

Antiviral response and resistance analysis of treatment-naïve HCV-infected patients receiving single and multiple doses of GS-9190

GS-9190 is a NS5B non-nucleoside analogue with demonstrated effectiveness in a Phase 1 monotherapy study and in combination with other DAAs for treatment of chronic HCV infection. Here, the resistance profile of GS-9190 monotherapy in a Phase 1b study was investigated. Resistance analysis was performed by population sequencing and allele-specific PCR (AS-PCR) for Y448H with an assay cut-off of 0.5%. Phenotypic susceptibility analyses were performed on patient isolates as well as site-directed mutagenesis of mutations selected during monotherapy. No resistance-associated variants were observed in patients before or after receiving single doses of GS-9190 by population sequencing. In contrast, in patients who received GS-9190 for 8 days, mutations Y448H and Y452H in NS5B were observed by population sequencing in 21/36 (58%) and 2/36 (5.6%) patients, respectively, at Day 8 or Day 14. Among the remaining 15 patients who had no detectable Y448H at Day 8 or Day 14 by population sequencing, low frequencies of Y448H ranging from 1.3 to 9.7% were detected in 14 of 15 patients by AS-PCR. By AS-PCR, Y448H remained detectable at reduced frequency in the majority of patients analysed through 4-6 months of follow-up. Chimeric HCV replicons constructed with the NS5B sequence from patients with Y448H and Y448H + Y452H/Y demonstrated 27-fold and 78.5-fold reduced susceptibility to GS-9190. In conclusion, Y448H was rapidly selected in the majority of patients receiving multiple doses of GS-9190 as monotherapy, despite undetectable levels in pretreatment samples. Y448H confers reduced susceptibility to GS-9190 and other NNIs and persisted in most patients for months post-treatment.

Metabolism and Disposition of the Hepatitis C Protease Inhibitor Paritaprevir in Humans

Paritaprevir (also known as ABT-450), a potent NS3-4A serine protease inhibitor [identified by AbbVie (North Chicago, IL) and Enanta Pharmaceuticals (Watertown, MA)] of the hepatitis C virus (HCV), has been developed in combination with ombitasvir and dasabuvir in a three-direct-acting antiviral agent (DAA) oral regimen for the treatment of patients infected with HCV genotype 1. This article describes the mass balance, metabolism, and disposition of paritaprevir in humans. After the administration of a single 200-mg oral dose of [(14)C]paritaprevir coadministered with 100 mg of ritonavir to four male healthy volunteers, the mean total percentage of the administered radioactive dose recovered was 96.5%, with recovery in individual subjects ranging from 96.0% to 96.9%. Radioactivity derived from [(14)C]paritaprevir was primarily eliminated in feces (87.8% of the dose). Radioactivity recovered in urine accounted for 8.8% of the dose. The biotransformation of paritaprevir in humans involves: 1) P450-mediated oxidation on the olefinic linker, the phenanthridine group, the methylpyrazinyl group, or combinations thereof; and 2) amide hydrolysis at the acyl cyclopropane-sulfonamide moiety and the pyrazine-2-carboxamide moiety. Paritaprevir was the major component in plasma [90.1% of total radioactivity in plasma, AUC from time 0 to 12 hours (AUC0-12hours) pool]. Five minor metabolites were identified in plasma, including the metabolites M2, M29, M3, M13, and M6; none of the metabolites accounted for greater than 10% of the total radioactivity. Paritaprevir was primarily eliminated through the biliary-fecal route followed by microflora-mediated sulfonamide hydrolysis to M29 as a major component in feces (approximately 60% of dose). In summary, the biotransformation and clearance pathways of paritaprevir were characterized, and the structures of metabolites in circulation and excreta were elucidated.

Quality of life of Japanese patients with chronic hepatitis C treated with ledipasvir and sofosbuvir

The interferon (IFN)-free regimens for chronic hepatitis C (CHC) have high efficacy and superior health-related quality of life (HRQOL) in European/North American patients. The impact of these regimens on HRQOL of the Japanese CHC patients is not known.The Short Form-36 was administered before, during, and after treatment to CHC patients with genotype 1 treated with ledipasvir/sofosbuvir ± ribavirin (LDV/SOF ± RBV) for 12 weeks and genotype 2 treated with SOF + RBV for 12 weeks in clinical trials. The HRQOL data were analyzed with reference to treatment regimens and clinical factors.A total of 494 CHC patients were included (19% cirrhotic, 69% genotype 1, 52% treatment-naive; 153 received SOF + RBV, 170 received LDV/SOF + RBV, 171 received LDV/SOF). The sustained virologic response-12 rates for these regimens were 97%, 98%, and 100%, respectively. CHC patients treated with LDV/SOF, SOF + RBV, or LDV/SOF + RBV regimens had similar HRQOL scores at baseline. During treatment, more adverse events were experienced by those treated with RBV-containing regimens (46% vs 22%, P < 0.0001). The decrements in HRQOL were also significant in RBV groups: up to -3.8 points (treatment week-4), -5.2 (treatment week-12), and -3.2 (posttreatment week-12) (all P < 0.001). In contrast, RBV-free regimen (LDV/SOF) was associated with an improvement in HRQOL up to +4.1 points throughout the treatment (P < 0.01). In multivariate analysis, the use of RBV was independently associated with lower HRQOL during and after treatment (beta up to -6.4 points, P = 0.0001).Japanese CHC patients treated with RBV-containing regimens show mild HRQOL impairment. In contrast, patients treated with LDV/SOF not only showed high efficacy but also improvement of HRQOL.

Comparative effectiveness of ledipasvir/sofosbuvir ± ribavirin vs. ombitasvir/paritaprevir/ritonavir + dasabuvir ± ribavirin in 6961 genotype 1 patients treated in routine medical practice

BACKGROUND

Real-world data are needed to inform hepatitis C virus (HCV) treatment decisions.

AIM

To assess the comparative effectiveness of ledipasvir/sofosbuvir ± ribavirin (LDV/SOF ± RBV) vs. ombitasvir/paritaprevir/ritonavir + dasabuvir (OPrD) ± RBV in genotype 1 HCV patients treated in routine medical practice.

METHODS

Observational intent-to-treat cohort of genotype 1 patients initiating 8 or 12 weeks of LDV/SOF ± RBV or 12 weeks of OPrD ± RBV. Sustained virological response (SVR) required RNA below the limit of quantification at least 10 weeks after end of treatment.

RESULTS

6961 patients initiated LDV/SOF (N = 4478), LDV/SOF + RBV (N = 1269), OPrD (N = 297), and OPrD + RBV (N = 917) at 126 facilities. Intention-to-treat SVR rates were 91.4% (3813/4170) for LDV/SOF, 90.0% (1098/1220) for LDV/SOF + RBV, 95.1% (269/283) for OPrD and 85.8% (746/869) for OPrD + RBV. SVR rates in those completing 8 weeks of LDV/SOF were 91.7% (1223/1333) and 12 weeks of LDV/SOF 94.6% (2475/2615), LDV/SOF + RBV 92.2% (1033/1120), OPrD 98.0% (248/253) and OPrD + RBV 95.5% (705/738). Significant predictors of SVR were African American race (OR 0.71, 95%CI 0.59-0.86, P < 0.001), body mass index (BMI) > 30 kg/m(2) (OR 0.73, 95% CI 0.60-0.89, P = 0.002), FIB4 > 3.25 (OR 0.60, 95% CI 0.49-0.72, P < 0.001), OPrD + RBV compared to LDV/SOF (OR 0.60, 95% CI 0.48-0.76, P < 0.001) and subtype 1b (OR 1.38, 95% CI 1.11-1.71, P = 0.003). For those completing 12 weeks, FIB-4 > 3.25 and high BMI remained significant predictors.

CONCLUSIONS

In this robust real-world cohort, SVR rates were similar to clinical trials. FIB-4 > 3.25 and high BMI were significant negative predictors of SVR. Reduced odds of SVR in African Americans and with OPrD + RBV likely arose from excess early discontinuation as these factors were no longer significant, when limited to patients completing a 12-week course.

Simeprevir plus sofosbuvir (12 and 8 weeks) in hepatitis C virus genotype 1-infected patients without cirrhosis: OPTIMIST-1, a phase 3, randomized study

Effective antiviral therapy is essential for achieving sustained virological response (SVR) in hepatitis C virus (HCV)-infected patients. The phase 2 COSMOS study reported high SVR rates in treatment-naive and prior null-responder HCV genotype (GT) 1-infected patients receiving simeprevir+sofosbuvir±ribavirin for 12 or 24 weeks. OPTIMIST-1 (NCT02114177) was a multicenter, randomized, open-label study assessing the efficacy and safety of 12 and 8 weeks of simeprevir+sofosbuvir in HCV GT1-infected treatment-naive and treatment-experienced patients without cirrhosis. Patients were randomly assigned (1:1; stratified by HCV GT/subtype and presence or absence of NS3 Q80K polymorphism [GT1b, GT1a with Q80K, GT1a without Q80K]), prior HCV treatment history, and IL28B GT [CC, non-CC]) to simeprevir 150 mg once daily+sofosbuvir 400 mg once daily for 12 or 8 weeks. The primary efficacy endpoint was SVR rate 12 weeks after end of treatment (SVR12). Superiority in SVR12 was assessed for simeprevir+sofosbuvir at 12 and 8 weeks versus a composite historical control SVR rate. Enrolled were 310 patients, who were randomized and received treatment (n = 155 in each arm). SVR12 with simeprevir+sofosbuvir for 12 weeks (97% [150/155; 95% confidence interval 94%-100%]) was superior to the historical control (87%). SVR12 with simeprevir+sofosbuvir for 8 weeks (83% [128/155; 95% confidence interval 76-89%]) was not superior to the historical control (83%). The most frequent adverse events were nausea, headache, and fatigue (12-week arm: 15% [23/155], 14% [22/155], and 12% [19/155]; 8-week arm: 9% [14/155], 17% [26/155], and 15% [23/155], respectively). No patients discontinued treatment due to an adverse event. One (1%, 12-week arm) and three (2%, 8-week arm) patients experienced a serious adverse event (all unrelated to study treatment).

CONCLUSION

Simeprevir+sofosbuvir for 12 weeks is highly effective in the treatment of HCV GT1-infected patients without cirrhosis, including those with Q80K. (Hepatology 2016;64:370-380).

Cost-effectiveness of currently recommended direct-acting antiviral treatments in patients infected with genotypes 1 or 4 hepatitis C virus in the US

OBJECTIVE

This study compared the cost-effectiveness of direct-acting antiviral therapies currently recommended for treating genotypes (GT) 1 and 4 chronic hepatitis C (CHC) patients in the US.

METHODS

A cost-effectiveness analysis of treatments for CHC from a US payer's perspective over a lifelong time horizon was performed. A Markov model based on the natural history of CHC was used for a population that included treatment-naïve and -experienced patients. Treatment alternatives considered for GT1 included ombitasvir/paritaprevir/ritonavir + dasabuvir ± ribavirin (3D ± R), sofosbuvir + ledipasvir (SOF/LDV), sofosbuvir + simeprevir (SOF + SMV), simeprevir + pegylated interferon/ribavirin (SMV + PR) and no treatment (NT). For GT4 treatments, ombitasvir/paritaprevir/ritonavir + ribavirin (2D + R), SOF/LDV and NT were compared. Transition probabilities, utilities and costs were obtained from published literature. Outcomes included rates of compensated cirrhosis (CC), decompensated cirrhosis (DCC), hepatocellular carcinoma (HCC) and liver-related death (LrD), total costs, life-years and quality-adjusted life-years (QALYs). Costs and QALYs were used to calculate incremental cost-effectiveness ratios.

RESULTS

In GT1 patients, 3D ± R and SOF-containing regimens have similar long-term outcomes; 3D ± R had the lowest lifetime risks of all liver disease outcomes: CC = 30.2%, DCC = 5.0 %, HCC = 6.8%, LT = 1.9% and LrD = 9.2%. In GT1 patients, 3D ± R had the lowest cost and the highest QALYs. As a result, 3D ± R dominated these treatment options. In GT4 patients, 2D + R had lower rates of liver morbidity and mortality, lower cost and more QALYs than SOF/LDV and NT.

LIMITATIONS

While the results are based on input values, which were obtained from a variety of heterogeneous sources-including clinical trials, the findings were robust across a plausible range of input values, as demonstrated in probabilistic sensitivity analyses.

CONCLUSIONS

Among currently recommended treatments for GT1 and GT4 in the US, 3D ± R (for GT1) and 2D + R (for GT4) have a favorable cost-effectiveness profile.

Hepatitis C virus: Promising discoveries and new treatments

Despite advances in therapy, hepatitis C virus (HCV) infection remains an important global health issue. It is estimated that a significant part of the world population is chronically infected with the virus, and many of those affected may develop cirrhosis or liver cancer. The virus shows considerable variability, a characteristic that directly interferes with disease treatment. The response to treatment varies according to HCV genotype and subtype. The continuous generation of variants (quasispecies) allows the virus to escape control by antivirals. Historically, the combination of ribavirin and interferon therapy has represented the only treatment option for the disease. Currently, several new treatment options are emerging and are available to a large part of the affected population. In addition, the search for new substances with antiviral activity against HCV continues, promising future improvements in treatment. Researchers should consider the mutation capacity of the virus and the other variables that affect treatment success.

Safety of interferon-free therapies for chronic hepatitis C: a network meta-analysis

WHAT IS KNOWN AND OBJECTIVE

Interferon-free (IFN-free) therapies for hepatitis C virus (HCV) have been developed to provide more effective, tolerable and safer therapeutic strategies. To date, no network meta-analysis (NMA) evaluating the safety profile of these regimens has been performed. This systematic review and NMA aimed to evaluate safety outcomes of IFN-free treatment options for chronic hepatitis C.

METHODS

A systematic review was performed according to PRISMA and Cochrane recommendations. A literature search was conducted in PubMed/Medline, Scopus, Cochrane Library, International Pharmaceutical Abstracts and Web of Science electronic databases and included only randomized clinical trials that provided safety outcomes of interest of evaluated second-generation direct-acting antivirals: incidence of any adverse events (AEs) and serious AE. NMA allowed estimating probability for the relative safety of the interventions. A consistency model was used to draw conclusions about relative safety of treatments, presented as odds ratio (OR) and corresponding 95% credible interval (CrI).

RESULTS

Fifty-one clinical trials were included (13 089 participants). Most participants had hepatitis C genotype 1 virus (76%) and were treated for 12 weeks. Two NMAs were built to investigate the incidence of AEs and serious AEs, comparing 13 and 10 IFN-free treatment options, respectively. For the outcome incidence of AEs, few significant differences were observed, which were explained by the presence of RBV. Elbasvir with grazoprevir and placebo were both safer than ombitasvir in combination with paritaprevir, ritonavir, daclatasvir plus RBV [ORs with 95% Crl of 4·09 (1·17-14·09) and 2·40 (1·19-4·77), respectively] and sofosbuvir with RBV [ORs with 95% Crl of 0·22 (0·07-0·72) and 2·69 (1·53-4·80), respectively]. Furthermore, elbasvir with grazoprevir was safer than sofosbuvir used with velpatasvir and RBV [OR 0·19 (95% CrI 0·03-0·98)]; ombitasvir in combination with paritaprevir, ritonavir, daclatasvir was safer than the same therapy but combined with RBV [OR 2·14 (95% CrI 1·09-4·44)]; and sofosbuvir used with velpatasvir was safer than sofosbuvir with RBV [OR 2·07 (95% CrI 1·13-3·79)]. Elbasvir with grazoprevir (50%) followed by placebo (28%) had the highest probabilities of less AEs. No significant differences were observed for serious AE outcomes.

WHAT IS NEW AND CONCLUSION

This meta-analysis included a large number of therapies. Small differences were observed in any AEs, but not in serious AEs.

Effectiveness and Safety of Ombitasvir-Paritaprevir/Ritonavir and Dasabuvir With or Without Ribavirin for HCV Genotype 1 Infection for 12 Weeks Under Routine Clinical Practice

Background: No previous studies exist examining the effectiveness and safety in real clinical practice of the combination of ombitasvir/paritaprevir/ritonavir and dasabuvir (OBV/PTV/r+DSV). Objective: To evaluate the effectiveness and safety in real clinical practice of the combination of OBV/PTV/r+DSV with or without ribavirin for 12 weeks in treatment-naïve and previously treated adult patients with chronic hepatitis C virus (HCV) genotype 1 infection. Methods: This was an observational study of a prospective cohort of treatment-naïve and pretreated adult patients who received 12 weeks of OBV/PTV/r (25/150/100 mg once daily) and DSV (250 mg twice daily) with or without ribavirin. The primary effectiveness outcome was sustained virological response 12 weeks after the end of treatment (SVR12). Safety outcomes were presented by the incidence of adverse events. Results: A total of 116 of 121 patients achieved a SVR12 (95.9%, 95% CI = 90.6-98.6). The SVR12 rate was 93.8% (95% CI = 86.0-97.9) in cirrhotic patients and 100% (95% CI = 91.4-100.0) in noncirrhotic patients. Adverse events occurred in 91.7% of patients, of which 81.8% were grade 1/2, and none led to premature discontinuation. Grade 3 adverse events were reported in 9.9% of patients. The most frequent adverse event was anemia (52.1%), although only 1.6% had a hemoglobin level below 8 g/dL. The incidence of any adverse event was higher in the group of patients who received ribavirin (96.5% vs 80.0%, P = 0.002). Conclusions: The combination of OBV/PTV/r+DSV with or without ribavirin for 12-week settings achieved a high rate of SVR12, with an acceptable safety profile in routine clinical care.

Ribavirin-Free Regimen With Sofosbuvir and Velpatasvir Is Associated With High Efficacy and Improvement of Patient-Reported Outcomes in Patients With Genotypes 2 and 3 Chronic Hepatitis C: Results From Astral-2 and -3 Clinical Trials

BACKGROUND

Until recently, the approved treatment regimens for patients with hepatitis C virus (HCV) genotypes (GTs) 2 and 3 contain sofosbuvir (SOF) and ribavirin (RBV) for 12 or 24 weeks. The impact of RBV-free pan-genotypic regimen with SOF and velpatasvir (SOF/VEL) on patient-reported outcomes (PROs) of patients with genotype 2 and 3 has not been described.

METHODS

PROs data were collected from participants of ASTRAL-2 and ASTRAL-3 studies before, during, and after treatment using 4 PRO instruments (Short Form-36, Chronic Liver Disease Questionnaire-HCV, Functional Assessment of Chronic Illness Therapy-Fatigue, and Work Productivity and Activity Index: Specific Health Problem), and compared between the SOF/VEL and SOF + RBV groups.

RESULTS

A total of 818 HCV patients were included: 78% treatment naive, 25% cirrhosis. The rates of nearly all adverse events were lower in the RBV-free SOF/VEL group (all P < .03). The SOF/VEL group also experienced improvement of their PROs by treatment week 4 (+1.8% on average across all PROs), which continued throughout treatment (+4.1%) and post-treatment (+5.5%). In contrast, those in the SOF + RBV group had a modest decline in their PROs starting at treatment week 4 (up to -3.7%), which lasted until the end of treatment (up to -6.4%). In multiple regression analysis, the association of a treatment regimen with end-of-treatment PROs was significant for nearly all PROs; the average beta was +5.0% for the use of SOF/VEL (reference: SOF + RBV).

CONCLUSIONS

Patients receiving ribavirin-free SOF/VEL reported significantly better PRO scores during treatment compared with those receiving the RBV-containing regimen. Furthermore, the interferon- and ribavirin-free SOF/VEL regimen resulted in a rapid improvement of PROs in HCV GTs 2 and 3 patients during treatment and after achieving sustained virologic response.

Hepatitis C virus resistance to the new direct-acting antivirals

INTRODUCTION

The treatment of hepatitis C virus (HCV) infection has dramatically improved in recent years with the widespread use of interferon-free combination regimens. Despite the high sustained virological response (SVR) rates (over 90%) obtained with direct-acting antivirals (DAAs), drug resistance has emerged as a potential challenge. The high replication rate of HCV and the low fidelity of its RNA polymerase result in a high degree of genetic variability in the HCV population, which ultimately explains the rapid selection of drug resistance associated variants (RAVs).

AREAS COVERED

Results from clinical trials and real-world experience have both provided important information on the rate and clinical significance of RAVs. They can be present in treatment-naive patients as natural polymorphisms although more frequently they are selected upon treatment failure. In patients engaged in high-risk behaviors, RAVs can be transmitted.

EXPERT OPINION

Although DAA failures generally occur in less than 10% of treated chronic hepatitis C patients, selection of drug resistance is the rule in most cases. HCV re-treatment options are available, but first-line therapeutic strategies should be optimized to efficiently prevent DAA failure due to baseline HCV resistance. Considerable progress is being made and next-generation DAAs are coming with pangenotypic activity and higher resistance barrier.

Impact of HCV genotype on treatment regimens and drug resistance: a snapshot in time

The introduction of highly potent direct-acting antivirals (DAAs) has revolutionized hepatitis C virus treatment. Nevertheless, viral eradication worldwide remains a challenge also in the era of DAA treatment, because of the high associated costs, high numbers of undiagnosed patients, high re-infection rates in some risk groups and suboptimal drug efficacies associated with host and viral factors as well as advanced stages of liver disease. A correct determination of the HCV genotype allows administration of the most appropriate antiviral regimen. Additionally, HCV genetic sequencing improves our understanding of resistance-associated variants, either naturally occurring before treatment, acquired by transmission at HCV infection, or emerging after virological failure. Because treatment response rates, and the prevalence and development of drug resistance variants differ for each DAA regimen and HCV genotype, this review summarizes treatment opportunities per HCV genotype, and focuses on viral genetic sequencing to guide clinical decision making. Although approval of the first pan-genotypic DAA-only regimen is expected soon, HCV genetic sequencing will remain important because when DAA therapies fail, genotyping and resistance testing to select a new active DAA combination will be essential. Copyright © 2016 John Wiley & Sons, Ltd.

CIHR Canadian HIV Trials Network Coinfection and Concurrent Diseases Core Research Group: 2016 Updated Canadian HIV/Hepatitis C Adult Guidelines for Management and Treatment

Background. Hepatitis C virus (HCV) coinfection occurs in 20-30% of Canadians living with HIV and is responsible for a heavy burden of morbidity and mortality. Purpose. To update national standards for management of HCV-HIV coinfected adults in the Canadian context with evolving evidence for and accessibility of effective and tolerable DAA therapies. The document addresses patient workup and treatment preparation, antiviral recommendations overall and in specific populations, and drug-drug interactions. Methods. A standing working group with HIV-HCV expertise was convened by The Canadian Institute of Health Research HIV Trials Network to review recently published HCV antiviral data and update Canadian HIV-HCV Coinfection Guidelines. Results. The gap in sustained virologic response between HCV monoinfection and HIV-HCV coinfection has been eliminated with newer HCV antiviral regimens. All coinfected individuals should be assessed for interferon-free, Direct Acting Antiviral HCV therapy. Regimens vary in content, duration, and success based largely on genotype. Reimbursement restrictions forcing the use of pegylated interferon is not acceptable if optimal patient care is to be provided. Discussion. Recommendations may not supersede individual clinical judgement. Treatment advances published since December 2015 are not considered in this document.

Pharmacologic Therapies in Gastrointestinal Diseases

Several key areas in gastroenterology pharmacotherapy are rapidly evolving, including the treatment of hepatitis C virus (HCV), irritable bowel syndrome, gastroesophageal reflux disease (GERD) and peptic ulcer disease. HCV treatment has radically changed in the past 2 years and now most patients are treatment candidates and have a high likelihood of permanent cure. Pharmacotherapy is now first-line treatment for patients with moderate to severe symptoms of irritable bowel syndrome. Proton pump inhibitors (PPIs) are the mainstay of therapy in gastric and duodenal ulcers and GERD, although long-term use carries the risk of several side effects that should be considered.

Sofosbuvir/velpatasvir improves patient-reported outcomes in HCV patients: Results from ASTRAL-1 placebo-controlled trial

BACKGROUND & AIMS

The new pan-genotypic regimen [sofosbuvir (SOF) and velpatasvir (VEL)] for hepatitis C virus (HCV) has been associated with high efficacy. The aim of this study was to assess patient-reported outcomes (PROs) of this regimen.

METHODS

The PRO data (CLDQ-HCV, SF-36, FACIT-F, WPAI) came from the ASTRAL-1 study, a multicenter multinational blinded placebo-controlled phase 3 clinical trial of a fixed dose combination of SOF 400mg and VEL 100mg for patients with genotype 1, 2, 4, 5, and 6 compared to placebo for 12weeks.

RESULTS

624 patients received active treatment [618 achieved sustained virologic response (SVR)], and 116 received placebo. The baseline PRO scores were similar. By treatment week 4, patients receiving SOF/VEL experienced improvements in general health (on average, +2.3points), emotional well-being (+3.4), FACIT-F (+1.3), and all domains of CLDQ-HCV (+2.1 to +7.3) (all p<0.005). On the other hand, the only PRO that improved in patients receiving placebo was the worry domain of CLDQ-HCV: +4.6 (p=0.002). By the end of treatment, improvement in PRO scores with SOF/VEL continued, and no improvement was noted in the placebo. Improvement in PROs were also noted 12 and 24weeks post-treatment: +3.7, on average, in patients with SVR-12 after SOF/VEL vs. -2.6, on average, in the placebo arm (p<0.005). Multivariate analysis showed that treatment-emergent changes in PROs were predicted by receiving SOF/VEL for some summary PRO score (p<0.005).

CONCLUSIONS

This placebo-controlled trial shows that patients treated with SOF/VEL experience significant improvement of their PROs during treatment and after achieving SVR.

LAY SUMMARY

In patients with chronic hepatitis C infection, health-related quality of life and work productivity are often impaired due to HCV-related fatigue. Treatment of hepatitis C with interferon-based regimens, which was the standard of care for all HCV patients until recently, had substantial and potentially debilitating side effects. These regimens caused additional impairment in health-related quality of life and work productivity during treatment and shortly after treatment cessation. The newly developed interferon-free combination of sofosbuvir and velpatasvir has been shown to improve health-related quality of life during treatment, and lead to an improvement in a number of indicators of patient-reported outcomes after successful clearance of HCV and achieving sustained virologic response.

Update on Current Evidence for Hepatitis C Therapeutic Options in HCV Mono-infected Patients

PURPOSE OF REVIEW

Therapies for hepatitis C (HCV) are evolving rapidly with the advent of novel direct-acting antiviral agents (DAAs). We review evidence for currently or imminently available regimens to aide clinicians in understanding current therapeutic options.

RECENT FINDINGS

A number of DAA combinations have completed clinical trials and are available for use. Current combinations are often genotype-specific, and combine HCV protease inhibitors, NS5A inhibitors and/or NS5B inhibitors to suppress HCV replication, leading to eradication. Current potential combinations for genotype 1 infection include sofosbuvir-ledipasvir, paritaprevir/ritonavir-ombitasvir-dasabuvir, sofosbuvir with daclatasvir, and grazoprevir-elbasvir. These regimens have been associated with sustained virologic response (SVR) rates of over 95 % for treatment naïve individuals after 12 weeks of therapy regardless of cirrhosis, and some sub-groups of patients may be successfully treated with just 8 weeks of sofosbuvir-ledipasvir. Regimens for genotype 2 and 3 include sofosbuvir with ribavirin, sofosbuvir with daclatasvir, or with velpatasvir, which may offer highest SVR rates when available. The development of HCV drug resistance, particularly against NS5A agents, may impact subsequent regimens. The need for baseline screening for resistant variants is unclear for most regimens, but likely would affect only a minority of patients. All-oral curative regimens for HCV are now possible for most patients.

Interferon-Free Treatments for Chronic Hepatitis C Genotype 1 Infection

Hepatitis C virus (HCV) infection affects as many as 185 million people globally, many of whom are chronically infected and progress over time to cirrhosis, decompensated liver disease, hepatocellular carcinoma, and eventually death without a liver transplant. In the United States, HCV genotype 1 constitutes about 75% of all infections. While interferon and ribavirin therapy was the cornerstone of treatment for many years, interferon-free treatments have become the standard of care with the emergence of new direct-acting agents, resulting in more effective treatment, shorter duration of therapy, better tolerability, lower pill burden, and ultimately better adherence. This review will summarize the evidence for the currently available combination therapies as well as emerging therapies in phase 3 trials for treatment of HCV genotype 1.

The safety of daclatasvir for the treatment of hepatitis C

INTRODUCTION

The direct acting antiviral daclatasvir is an NS5A replication inhibitor active against the entire range of hepatitis C virus genotypes. It is a key step in establishing the goal of an all-oral, ribavirin-free, pan-genotypic regimen against hepatitis C.

AREAS COVERED

We review current literature including published abstracts and manuscripts. Evidence was obtained through PubMed/Medline search using listed keywords and through review of published abstracts.

EXPERT OPINION

Daclatasvir introduces a degree of pangenotypic potency currently lacking in other NS5A agents. Emerging literature suggests that daclatasvir in combination with other DAAs will represent a promising option in this difficult to treat populations including posttransplant, genotype 3 and HIV patients.

Significant publications on infectious diseases pharmacotherapy in 2014

PURPOSE

The most important articles on infectious diseases (ID) pharmacotherapy published in the peer-reviewed literature in 2014, as nominated and selected by panels of pharmacists and others with ID expertise, are summarized.

SUMMARY

Members of the Houston Infectious Diseases Network were asked to nominate articles published in 2014 from prominent peer-reviewed journals that were felt to have a major impact in the field of ID pharmacotherapy. A list of 19 nominated articles on general ID-related topics and 9 articles specifically related to human immunodeficiency virus (HIV) infection or acquired immunodeficiency syndrome (AIDS) was compiled. In a national online survey, members of the Society of Infectious Diseases Pharmacists (SIDP) were asked to select from the list 10 general ID articles believed to have made a significant contribution to the field of ID pharmacotherapy and 1 article contributing to HIV/AIDS pharmacotherapy. Of the 291 SIDP members surveyed, 134 (46%) and 56 (19%) participated in the selection of general ID-related articles and HIV/AIDS-related articles, respectively. The 11 highest-ranked papers (10 general ID-related articles, 1 HIV/AIDS-related article) are summarized here.

CONCLUSION

With the vast number of articles published each year, it is difficult to remain up-to-date on current, significant ID pharmacotherapy publications. This review of significant publications in 2014 may be helpful by lessening this burden.

Safety and Efficacy of Ombitasvir/Paritaprevir/Ritonavir Plus Dasabuvir With or Without Ribavirin in HCV-Infected Patients Taking Concomitant Acid-Reducing Agents

OBJECTIVES

Acid-reducing agents (ARAs) and proton-pump inhibitors (PPIs) that increase gastric pH can alter the bioavailability of antiviral drugs, particularly relevant in patients with advanced liver disease caused by chronic hepatitis C virus (HCV) infection seeking therapy. Using integrated data from six phase 3 studies, we report the safety and efficacy of the 3-direct-acting antiviral (DAA) regimen containing ombitasvir (OBV, an NS5A inhibitor), ritonavir-boosted paritaprevir (PTV/r, an NS3/4A protease inhibitor), and dasabuvir (DSV, an NS5B polymerase inhibitor) with or without ribavirin (RBV) for HCV genotype 1 patients taking concomitant ARAs and PPIs.

METHODS

Treatment-naïve or peginterferon/RBV treatment-experienced patients with or without compensated cirrhosis received OBV/PTV/r and DSV with or without weight-based RBV. Rates of sustained virologic response (SVR), defined as HCV RNA below the lower limit of quantification, 12 weeks post-treatment (SVR12) and safety were evaluated in patients who were receiving concomitant ARAs.

RESULTS

Among 2,053 patients enrolled and dosed with study drug, 410 (20%) were receiving concomitant ARAs; of these, 308 (15%) were taking concomitant PPIs. Rates of SVR12 were 95.9% (95% confidence interval (CI) 93.5-97.4%) among patients receiving an ARA, and 96.3% (95% CI 95.3-97.2%) in patients not receiving a concomitant ARA. Similarly, among patients receiving a PPI or not, SVR12 was achieved in 95.1% (95% CI 92.1-97.0%) and 96.4% (95% CI 95.5-97.2%), respectively. Response rates were high regardless of treatment regimen (with or without RBV), and among patients receiving a standard or high dose of PPIs. Regarding safety, adverse events and serious adverse events were more frequently reported in patients taking concomitant ARAs, though baseline population differences may have played a role.

CONCLUSIONS

In phase 3 trials of OBV/PTV/r plus DSV and RBV in HCV genotype 1-infected patients, SVR12 rates were high regardless of ARA/PPI use or PPI dose. These data support the co-administration of this regimen with ARAs including PPIs.

Economic and Public Health Impacts of Policies Restricting Access to Hepatitis C Treatment for Medicaid Patients

BACKGROUND

Interferon-free hepatitis C treatment regimens are effective but very costly. The cost-effectiveness, budget, and public health impacts of current Medicaid treatment policies restricting treatment to patients with advanced disease remain unknown.

OBJECTIVES

To evaluate the cost-effectiveness of current Medicaid policies restricting hepatitis C treatment to patients with advanced disease compared with a strategy providing unrestricted access to hepatitis C treatment, assess the budget and public health impact of each strategy, and estimate the feasibility and long-term effects of increased access to treatment for patients with hepatitis C.

METHODS

Using a Markov model, we compared two strategies for 45- to 55-year-old Medicaid beneficiaries: 1) Current Practice-only advanced disease is treated before Medicare eligibility and 2) Full Access-both early-stage and advanced disease are treated before Medicare eligibility. Patients could develop progressive fibrosis, cirrhosis, or hepatocellular carcinoma, undergo transplantation, or die each year. Morbidity was reduced after successful treatment. We calculated the incremental cost-effectiveness ratio and compared the costs and public health effects of each strategy from the perspective of Medicare alone as well as the Centers for Medicare & Medicaid Services perspective. We varied model inputs in one-way and probabilistic sensitivity analyses.

RESULTS

Full Access was less costly and more effective than Current Practice for all cohorts and perspectives, with differences in cost ranging from $5,369 to $11,960 and in effectiveness from 0.82 to 3.01 quality-adjusted life-years. In a probabilistic sensitivity analysis, Full Access was cost saving in 93% of model iterations. Compared with Current Practice, Full Access averted 5,994 hepatocellular carcinoma cases and 121 liver transplants per 100,000 patients.

CONCLUSIONS

Current Medicaid policies restricting hepatitis C treatment to patients with advanced disease are more costly and less effective than unrestricted, full-access strategies. Collaboration between state and federal payers may be needed to realize the full public health impact of recent innovations in hepatitis C treatment.

Efficacy of Direct-Acting Antiviral Combination for Patients With Hepatitis C Virus Genotype 1 Infection and Severe Renal Impairment or End-Stage Renal Disease

BACKGROUND & AIMS

Although hepatitis C virus (HCV) infection is common in patients with end-stage renal disease, highly efficacious, well-tolerated, direct-acting antiviral regimens have not been extensively studied in this population. We investigated the safety and efficacy of ombitasvir co-formulated with paritaprevir and ritonavir, administered with dasabuvir (with or without ribavirin) in a prospective study of patients with stage 4 or 5 chronic kidney disease (CKD).

METHODS

We performed a single-arm, multicenter study of treatment-naïve adults with HCV genotype 1 infection, without cirrhosis and with CKD stage 4 (estimated glomerular filtration rate, 15-30 mL/min/1.73 m(2)) or stage 5 (estimated glomerular filtration rate, <15 mL/min/1.73 m(2) or requiring hemodialysis). Twenty patients were given ombitasvir co-formulated with paritaprevir and ritonavir, administered with dasabuvir for 12 weeks. Patients with HCV genotype 1a infections also received ribavirin (n = 13), whereas those with genotype 1b infection did not (n = 7). The primary end point was sustained virologic response (serum HCV RNA <25 IU/mL) 12 weeks after treatment ended (SVR12). We collected data on on-treatment adverse events (AEs), serious AEs, and laboratory abnormalities.

RESULTS

All 20 patients completed 12 weeks of treatment. Eighteen of the 20 patients achieved SVR12 (90%; 95% confidence interval: 69.9-97.2). One patient death after the end of the treatment (unrelated to the treatment) and 1 relapse accounted for the 2 non-SVRs. Adverse events were primarily mild or moderate, and no patient discontinued treatment due to an AE. Four patients experienced serious AEs; all were considered unrelated to treatment. Ribavirin therapy was interrupted in 9 patients due to anemia; 4 received erythropoietin. No blood transfusions were performed.

CONCLUSIONS

In a clinical trial, the combination of ombitasvir, paritaprevir, and ritonavir, administered with dasabuvir, led to an SVR12 in 90% of patients with HCV genotype 1 infection and stage 4 or 5 CKD. The regimen is well tolerated, though RBV use may require a reduction or interruption to manage anemia. ClinicalTrials.gov ID NCT02207088.

New combination antiviral for the treatment of hepatitis C

PURPOSE

The pharmacology, pharmacokinetics, clinical efficacy, and safety of Viekira, as well as its place in hepatitis C virus (HCV) therapy, are reviewed.

SUMMARY

Ombitasvir 25 mg-paritaprevir 150 mg-ritonavir 100 mg plus dasabuvir 250 mg (Viekira) is approved in the United States as a combination direct-acting antiviral agent for treatment-naive or treatment-experienced patients with HCV genotype 1 infection, including those with compensated cirrhosis. It is the first coformulated direct-acting antiviral that targets different stages of the virus's life cycle. Viekira is administered as an oral, interferon-free regimen. Phase III clinical trials demonstrated that Viekira administered with or without ribavirin can achieve sustained virological response rates of ≥90%. These results are notable because they show that high virological cure rates can be achieved without peginterferon and ribavirin. Viekira is also effective for special patient populations, such as individuals coinfected with HIV, liver transplant recipients, and those with advanced renal disease. The most frequently reported adverse effects among patients associated with Viekira without ribavirin were nausea, pruritus, and insomnia. During clinical trials, the most common adverse effects among patients receiving Viekira with ribavirin were fatigue, nausea, pruritus, insomnia, and weakness.

CONCLUSION

Viekira, the first coformulated direct-acting antiviral that targets different stages of the HCV life cycle, is an interferon-free treatment for HCV genotype 1 infection. It is associated with a virological cure rate of ≥90% and treatment durations of 12 and 24 weeks. Viekira is also effective and safe for patients who have undergone liver transplantation, are coinfected with HIV, or have advanced kidney disease.

Geno2pheno[HCV] - A Web-based Interpretation System to Support Hepatitis C Treatment Decisions in the Era of Direct-Acting Antiviral Agents

The face of hepatitis C virus (HCV) therapy is changing dramatically. Direct-acting antiviral agents (DAAs) specifically targeting HCV proteins have been developed and entered clinical practice in 2011. However, despite high sustained viral response (SVR) rates of more than 90%, a fraction of patients do not eliminate the virus and in these cases treatment failure has been associated with the selection of drug resistance mutations (RAMs). RAMs may be prevalent prior to the start of treatment, or can be selected under therapy, and furthermore they can persist after cessation of treatment. Additionally, certain DAAs have been approved only for distinct HCV genotypes and may even have subtype specificity. Thus, sequence analysis before start of therapy is instrumental for managing DAA-based treatment strategies. We have created the interpretation system geno2pheno_[HCV] (g2p_[HCV]) to analyse HCV sequence data with respect to viral subtype and to predict drug resistance. Extensive reviewing and weighting of literature related to HCV drug resistance was performed to create a comprehensive list of drug resistance rules for inhibitors of the HCV protease in non-structural protein 3 (NS3-protease: Boceprevir, Paritaprevir, Simeprevir, Asunaprevir, Grazoprevir and Telaprevir), the NS5A replicase factor (Daclatasvir, Ledipasvir, Elbasvir and Ombitasvir), and the NS5B RNA-dependent RNA polymerase (Dasabuvir and Sofosbuvir). Upon submission of up to eight sequences, g2p_[HCV] aligns the input sequences, identifies the genomic region(s), predicts the HCV geno- and subtypes, and generates for each DAA a drug resistance prediction report. g2p_[HCV] offers easy-to-use and fast subtype and resistance analysis of HCV sequences, is continuously updated and freely accessible under http://hcv.geno2pheno.org/index.php. The system was partially validated with respect to the NS3-protease inhibitors Boceprevir, Telaprevir and Simeprevir by using data generated with recombinant, phenotypic cell culture assays obtained from patients’ virus variants.

Paritaprevir/ritonavir-ombitasvir and dasabuvir, the 3D regimen for the treatment of chronic hepatitis C virus infection: a concise review

The treatment for chronic hepatitis C has been revolutionized with the development of direct-acting antiviral agents. Several regimens have been approved and are currently used in clinical practice, treating a wide range of patient populations infected with hepatitis C. The interferon-free combination of paritaprevir/ritonavir-ombitasvir and dasabuvir (PrOD or the three-drug [3D] regimen) with or without ribavirin is indicated for the treatment of chronic hepatitis C in both treatment-naïve and experienced patients infected with genotype 1, including those coinfected with HIV and patients post-liver transplantation. More recently, paritaprevir/ritonavir-ombitasvir (PrO, or 2D regimen) has been approved in hepatitis C virus patients infected with genotype 4. This review will summarize pharmacokinetic and clinical efficacy data for the 3D regimen in an attempt to help the clinicians delineate its place in the ever-increasing direct-acting antiviral armamentarium for the treatment of chronic hepatitis C.

History and future of antiviral therapy of chronic hepatitis C

Hepatitis C virus (HCV) infection often leads to chronic diseases, and antiviral therapy is an important way to prevent chronic hepatitis C from progressing to end-stage liver disease. Up to now, hepatitis C antiviral therapy has successively experienced eras of interferon monotherapy, interferon and ribavirin combination therapy, and combination therapy of pegylated-interferon (PEG-IFN) and ribavirin. Now we are entering into a new era of direct-acting antiviral agents (DAAs). Just like acquired immune deficiency syndrome (AIDS) cocktails, combination therapy consists of two or more antiviral agents. DAAs will be the primary antiviral therapy for hepatitis C in the future for their better tolerance, lower drug resistance, higher sustained virological response and shorter treatment course. In this article, we review the history and future of antiviral therapy of HCV infection.

Pharmacokinetics and tolerability of paritaprevir, a direct acting antiviral agent for hepatitis C virus treatment, with and without ritonavir in healthy volunteers

AIMS

Paritaprevir is a direct acting antiviral agent for use as part of a multidrug hepatitis C virus infection treatment regimen. To characterize the pharmacokinetics, safety, and tolerability of paritaprevir and determine an optimal dosing regimen for subsequent evaluations, clinical studies were conducted with paritaprevir alone or with ritonavir, a cytochrome P450 3A4 inhibitor anticipated to increase paritaprevir exposure.

METHODS

Two phase 1, double-blind, placebo-controlled, parallel group studies were conducted in healthy volunteers (NCT00850044 and NCT00931281). Single dose study participants (n = 87) were randomized to one time administration of either paritaprevir or placebo, or paritaprevir with ritonavir or placebo. Participants (n = 38) enrolled in the multiple dose study received paritaprevir with ritonavir or placebo once or twice daily for 14 days. Pharmacokinetics, safety and tolerability were assessed throughout the study treatment periods.

RESULTS

After single or multiple dose administration, paritaprevir displayed non-linear pharmacokinetics, with maximum plasma concentration and area under the plasma concentration-time curve increasing in a greater than dose proportional manner. Concomitant administration of 100 mg ritonavir increased paritaprevir exposure from a 300 mg dose approximately 30- to 50-fold and extended paritaprevir half-life. The tolerability of paritaprevir was similar with or without ritonavir. Asymptomatic, transient increases in bilirubin were observed but were not associated with abnormalities in other liver function tests.

CONCLUSIONS

Paritaprevir exhibits non-linear pharmacokinetics with greater than dose proportional increases in exposure after single or multiple dosing. Co-administration with ritonavir increases paritaprevir exposure and half-life without adversely influencing tolerability.

Genotype 1 hepatitis C virus and the pharmacist's role in treatment

PURPOSE

The treatment of hepatitis C virus (HCV) genotype 1 has changed rapidly with recently approved direct-acting antiviral (DAA) regimens. The role of the pharmacist in the management of HCV therapy has increased.

SUMMARY

Chronic HCV infection is the main cause of end-stage liver disease and the primary reason for liver transplantation, liver-related death, and hepatocellular carcinoma in the United States. The recent approval of several DAAs has led to improved tolerability, sustained virological response (SVR) rates, and shorter treatment durations compared with treatment with pegylated interferon and ribavirin. Most HCV cases can be treated with the currently available regimens, and expected SVR rates exceed 90%. Several fixed-dose and pangenotypic antiviral regimens are currently in various phases of clinical trials. Pharmacists are well equipped to assist the medical team and patients with comprehensive management of HCV treatment. Pharmacists in various settings can play an instrumental role in access to HCV medications, selection of HCV treatment, detection of drug-drug interactions, and education of patients about potential adverse effects and the importance of adherence and laboratory test monitoring during HCV treatment. However, the high cost of HCV treatment poses challenges for ubiquitous treatment.

CONCLUSION

Available DAA regimens have improved HCV treatment outcomes and are selected based on efficacy, potential drug interactions, and the patient's ability to obtain medication coverage. Each of these factors provides an opportunity for pharmacist involvement in HCV management.

Direct-acting antiviral-based therapy for chronic hepatitis C virus in HIV-infected patients

PURPOSE OF REVIEW

The aim of this review was to detail the current therapies and treatments for chronic hepatitis C virus in coinfected patients, focusing on HCV antiviral agents currently used in practice today or scheduled to enter the open market soon.

RECENT FINDINGS

Several direct-acting antiviral (DAA) combinations show high sustained virologic response (SVR) rates in HIV/HCV-coinfected patients, which are often close to those observed in HCV-monoinfected patients. Most recommendations regarding treatment stem from trials with coinfected patients. However, data are lacking for some aspects of HCV-treatment in coinfection, so extrapolations must be made from data obtained predominately from monoinfected patients.

SUMMARY

HIV/HCV-coinfected patients, who, not too long ago, had inferior outcomes in capturing SVR, now enjoy similar fates as the monoinfected patients. They should thus be prioritized for treatment, since HCV and liver disease have become major causes of morbidity and mortality in this population. However, potential drug-drug interactions between antiretroviral agents and DAAs have to be systematically anticipated before initiating HCV therapy.