Daclatasvir plus simeprevir with or without ribavirin for the treatment of chronic hepatitis C virus genotype 1 infection.

BACKGROUND & AIMS: We evaluated the combination of daclatasvir (pan-genotypic NS5A inhibitor) and simeprevir (NS3/4A protease inhibitor), with or without ribavirin, in hepatitis C virus genotype 1-infected patients. METHODS: This phase II, open-label study enrolled treatment-naive patients or prior null responders with genotype 1b (n=147) or 1a (n=21) infection. Genotype 1b-infected patients were randomized 1:1 to receive daclatasvir 30mg plus simeprevir 150mg once daily with or without ribavirin; those who completed the initial 12-week treatment were re-randomized 1:1 to stop treatment or continue treatment through to week 24. Genotype 1a-infected patients received daclatasvir plus simeprevir with ribavirin for 24weeks. The primary endpoint was the proportion of patients with sustained virologic response at posttreatment week 12 (SVR12). RESULTS: For genotype 1b, 84.9% (45/53) and 74.5% (38/51) of treatment-naive patients and 69.6% (16/23) and 95.0% (19/20) of prior null responders to peginterferon and ribavirin achieved SVR12 with daclatasvir plus simeprevir alone and with ribavirin, respectively. Treatment duration did not have a well-defined impact on response. For genotype 1a, daclatasvir plus simeprevir with ribavirin provided a 66.7% (8/12) response rate in treatment-naive patients and was not effective in prior null responders. Data suggest that baseline resistance polymorphisms influenced SVR12 rates. Daclatasvir plus simeprevir was well tolerated with or without ribavirin with low incidences of serious adverse events and adverse events leading to discontinuation. CONCLUSIONS: Daclatasvir plus simeprevir, with or without ribavirin, was effective with a 12- or 24-week duration in genotype 1b-infected patients and was well tolerated. ClinicalTrials.gov identifier: NCT01628692.

Single- and multiple-ascending dose studies to evaluate the safety, tolerability, and pharmacokinetics of daclatasvir and asunaprevir in healthy male Japanese subjects.

OBJECTIVES: Assess the safety, tolerability, and pharmacokinetic (PK) profiles of daclatasvir (DCV) and asunaprevir (ASV) in healthy male Japanese subjects. METHODS: AI444-007 and AI447-005 were phase I, double-blind, placebo-controlled, sequential, single-ascending dose (SAD), and multiple-ascending dose (MAD) studies assessing DCV or ASV, respectively. Eight subjects per panel were randomized to study drug or placebo (3 : 1). In the SAD part of each study, subjects received single oral dose DCV 1/10/50/100/200 mg or ASV 200/400/600/900/1,200 mg. In MAD, subjects received 14-day oral multiple dose DCV 1/10/100 mg once-daily or ASV 200/400/600 mg every 12 hours. Serial PK blood sampling occurred from predose to 72-hours postdose or post-last-dose. Safety and tolerability was assessed throughout. RESULTS: 64 (SAD, n = 40; MAD, n = 24) and 65 (SAD, n = 40; MAD, n = 25) subjects were enrolled in AI444-007 and AI447-005, respectively. DCV and ASV were generally well tolerated, with no serious adverse events or clinicallyrelevant changes in vital signs or ECG parameters. Baseline demographic characteristics were comparable across treatment groups in both studies. DCV was readily absorbed, with median tmax of ~ 1 - 2 hours postdose and concentrations declining in a multi-phasic manner. Exposure generally increased dose-proportionally within dose-range studied. Steady-state was achieved between days 4 and 5 of multiple dosing. ASV was readily absorbed, with median tmax of ~ 2 - 4 hours postdose and concentrations declining in a biphasic manner. Exposure generally increased dose-proportionally within dose-range studied. Steady-state appeared to be achieved between days 3 - 5 of multiple dosing. CONCLUSIONS: Results suggest no clinically significant short-term safety signals with DCV and ASV at single or multiple doses in this population.

Practical and efficient strategy for evaluating oral absolute bioavailability with an intravenous microdose of a stable isotopically-labeled drug using a selected reaction monitoring mass spectrometry assay.

A strategy of using selected reaction monitoring (SRM) mass spectrometry for evaluating oral absolute bioavailability with concurrent intravenous (i.v.) microdosing a stable isotopically labeled (SIL) drug was developed and validated. First, the isotopic contribution to SRM (ICSRM) of the proposed SIL drug and SIL internal standard (IS) was theoretically calculated to guide their chemical synthesis. Second, the lack of an isotope effect on drug exposure was evaluated in a monkey study by i.v. dosing a mixture of the SIL and the unlabeled drugs. Third, after the SIL drug (100 µg) was concurrently i.v. dosed to humans, at T(max) of an oral therapeutic dose of the unlabeled drug, both drugs in plasma specimens were simultaneously quantified by a sensitive and accurate SRM assay. This strategy significantly improves bioanalytical data quality and saves time, costs, and resources by avoiding a traditional absolute bioavailability study or the newer approach of microdoses of a radio-microtracer measured by accelerator mass spectrometry.

Calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry assays and its application in supporting microdose absolute bioavailability studies.

A methodology for the accurate calculation and mitigation of isotopic interferences in liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) assays and its application in supporting microdose absolute bioavailability studies are reported for the first time. For simplicity, this calculation methodology and the strategy to minimize the isotopic interference are demonstrated using a simple molecule entity, then applied to actual development drugs. The exact isotopic interferences calculated with this methodology were often much less than the traditionally used, overestimated isotopic interferences simply based on the molecular isotope abundance. One application of the methodology is the selection of a stable isotopically labeled internal standard (SIL-IS) for an LC-MS/MS bioanalytical assay. The second application is the selection of an SIL analogue for use in intravenous (i.v.) microdosing for the determination of absolute bioavailability. In the case of microdosing, the traditional approach of calculating isotopic interferences can result in selecting a labeling scheme that overlabels the i.v.-dosed drug or leads to incorrect conclusions on the feasibility of using an SIL drug and analysis by LC-MS/MS. The methodology presented here can guide the synthesis by accurately calculating the isotopic interferences when labeling at different positions, using different selective reaction monitoring (SRM) transitions or adding more labeling positions. This methodology has been successfully applied to the selection of the labeled i.v.-dosed drugs for use in two microdose absolute bioavailability studies, before initiating the chemical synthesis. With this methodology, significant time and cost saving can be achieved in supporting microdose absolute bioavailability studies with stable labeled drugs.

Case report of successful peginterferon, ribavirin, and daclatasvir therapy for recurrent cholestatic hepatitis C after liver retransplantation.

A recurrent hepatitis C virus (HCV) infection after liver transplantation (LT) can lead to accelerated allograft injury and fibrosis. The aim of this article is to report the first ever use of daclatasvir (DCV; also known as BMS-790052), a potent orally administered nonstructural 5A replication complex inhibitor, in combination with peginterferon α (PEG-IFNα) and ribavirin in an LT recipient. A 49-year-old female developed a severe recurrent HCV genotype 1b infection 4 months after transplantation with severe cholestasis on biopsy, an HCV RNA level of 10,000,000 IU/mL, an alkaline phosphatase level of 1525 IU/mL, and a total bilirubin level of 8.4 mg/dL. Despite partial virological suppression with PEG-IFNα and ribavirin, progressive allograft failure ensued and culminated in retransplantation at 9 months. Three months after the second transplant, DCV (20 mg/day), PEG-IFNα2a (180 µg/week), and ribavirin (800 mg/day) were prescribed for early recurrent cholestatic HCV. Serum HCV RNA became undetectable at week 3 of treatment and remained undetectable during 24 weeks of triple therapy and during the posttreatment follow-up. DCV was well tolerated, and the trough drug levels were within the targeted range throughout the treatment. The cyclosporine trough levels were also stable during and after therapy. In conclusion, the lack of anticipated drug-drug interactions between DCV and calcineurin inhibitors and the potent antiviral efficacy of DCV make this agent (in combination with PEG-IFN and ribavirin) an attractive antiviral regimen worthy of further study in LT recipients with recurrent HCV.

Multiple ascending dose study of BMS-790052, a nonstructural protein 5A replication complex inhibitor, in patients infected with hepatitis C virus genotype 1.

UNLABELLED: The antiviral activity, resistance profile, pharmacokinetics (PK), safety, and tolerability of BMS-790052, a nonstructural protein 5A (NS5A) replication complex inhibitor, were evaluated in a double-blind, placebo-controlled, sequential panel, multiple ascending dose study. Thirty patients with chronic hepatitis C virus (HCV) genotype 1 infection were randomized to receive a 14-day course of BMS-790052 (1, 10, 30, 60, or 100 mg once daily or 30 mg twice daily) or placebo in a ratio of 4:1. The mean maximum decline from baseline in HCV RNA ranged from 2.8 to 4.1 log(10) IU/mL; the placebo group showed no evidence of antiviral activity. Most patients experienced viral rebound on or before day 7 of treatment with BMS-790052 monotherapy; viral rebound was associated with viral variants that had been previously implicated in resistance development in the in vitro replicon system. The PK profile was supportive of once-daily dosing with median peak plasma concentrations at 1-2 hours postdose and mean terminal half-life of 12-15 hours. Steady state was achieved following 3-4 days of daily dosing. BMS-790052 was well tolerated in all dose groups, with adverse events occurring with a similar frequency in BMS-790052- and placebo-treated groups. There were no clinically relevant changes in vital signs, laboratory, or electrocardiogram parameters. CONCLUSION: BMS-7590052 is the first NS5A replication complex inhibitor with multiple dose proof-of-concept in clinic. At doses of 1-100 mg daily, BMS-790052 was well tolerated, had a PK profile supportive of once-daily dosing, and produced a rapid and substantial decrease in HCV-RNA levels in patients chronically infected with HCV genotype 1.

Genotypic and phenotypic analysis of variants resistant to hepatitis C virus nonstructural protein 5A replication complex inhibitor BMS-790052 in humans: in vitro and in vivo correlations.

UNLABELLED: The NS5A replication complex inhibitor, BMS-790052, inhibits hepatitis C virus (HCV) replication with picomolar potency in preclinical assays. This potency translated in vivo to a substantial antiviral effect in a single-ascending dose study and a 14-day multiple-ascending dose (MAD) monotherapy study. However, HCV RNA remained detectable in genotype 1a-infected patients at the end of the MAD study. In contrast, viral breakthrough was observed less often in patients infected with genotype 1b, and, in several patients, HCV RNA declined and remained below the level of quantitation (<25 IU/mL) through the duration of treatment. Here, we report on the results of the genotypic and phenotypic analyses of resistant variants in 24 genotype 1-infected patients who received BMS-790052 (1, 10, 30, 60, and 100 mg, once-daily or 30 mg twice-daily) in the 14-day MAD study. Sequence analysis was performed on viral complementary DNA isolated from serum specimens collected at baseline and days 1 (4, 8, and 12 hours), 2, 4, 7, and 14 postdosing. Analyses of the sequence variants (1) established a correlation between resistant variants emerging in vivo with BMS-790052 treatment and those observed in the in vitro replicon system (major substitutions at residues 28, 30, 31, and 93 for genotype 1a and residues 31 and 93 for genotype 1b); (2) determined the prevalence of variants at baseline and the emergence of resistance at different times during dosing; and (3) revealed the resistance profile and replicative ability (i.e., fitness) of the variants. CONCLUSION: Although resistance emerged during monotherapy with BMS-790052, the substantial anti-HCV effect of this compound makes it an excellent candidate for effective combination therapy.

Quantification of 4-beta-hydroxycholesterol in human plasma using automated sample preparation and LC-ESI-MS/MS analysis.

It has recently been proposed that plasma levels of 4ß-hydroxycholesterol (4ßHC) may be indicative of cytochrome P450 3A4 (P450 3A) activity and therefore could be used to probe for P450 3A-mediated drug-drug interactions. With this in mind, we describe a highly sensitive and precise liquid chromatography-electrospray ionization-tandem mass spectrometry method for the measurement of 4ßHC in human plasma with a lower limit of quantification established at 2 ng/mL using 50 µL of plasma. The entire sample preparation scheme including saponification and derivatization of 4ßHC to the corresponding dipicolinyl ester (DPE) was completed in less than 8 h using an automated sample preparation scheme enabling higher-throughput capabilities. Chromatographic resolution of 4ßHC from 4α-hydroxycholesterol and other endogenous isobaric species was achieved in 11-min using an isocratic gradient on a C18 column. Because of endogenous concentrations of 4ßHC in plasma, a stable isotope labeled (SIL) analogue, d7-4ßHC, was used as a surrogate analyte and measured in the standard curve and quality control samples prepared in plasma. A second SIL analogue, d4-4ßHC, was used as the internal standard. The intraday and interday accuracy for the assay was within 6% of nominal concentrations, and the precision for these measurements was less than 5% relative standard deviation. Rigorous stability assessments demonstrated adequate stability of endogenous 4ßHC in plasma and the corresponding DPE derivative for the analysis of clinical study samples. The results from clinical samples following treatment with a potent P450 3A inducer (rifampin) or inhibitor (ketoconazole) are reported and demonstrate the potential future application for this highly precise and robust analytical assay.

Lack of an effect of human immunodeficiency virus coinfection on the pharmacokinetics of entecavir in hepatitis B virus-infected patients.

Entecavir is a guanosine nucleoside analogue approved for the treatment of chronic hepatitis B virus (HBV) infection. The impact of human immunodeficiency virus (HIV) coinfection on the pharmacokinetics (PK) of entecavir was examined by nonlinear mixed-effects modeling. Plasma concentration data from HIV- and HBV-coinfected patients were analyzed in conjunction with data from HBV-monoinfected patients, and HIV coinfection was tested as a covariate on oral clearance (CL/F). The estimated population averages of intercompartmental clearance and the volumes of distribution in the central and peripheral compartments obtained with a 1-mg dose were 34.2 liters/h (interindividual variability, 30.2%), 115 liters (interindividual variability, 39.2%), and 1,830 liters (interindividual variability, 74%), respectively. CL/F was found to be a function of creatinine clearance, but HIV confection did not show any effect on CL/F. The geometric mean (GM) of individual Bayesian estimates of the steady-state area under the concentration-time curve following 1-mg daily doses were 39.3 and 38.8 ng x h/ml in HIV- and HBV-coinfected and HBV-monoinfected patients, respectively. The adjusted GM ratio (1.01; 90% confidence interval, 0.91 to 1.12) was within the bioequivalence criteria boundary (0.80 to 1.25). In conclusion, the proposed model adequately described the entecavir PK in HBV- and HIV-coinfected patients and HBV-monoinfected patients, and the entecavir exposures were comparable in the two patient populations.

Population Pharmacokinetic Analysis of Asunaprevir in Subjects with Hepatitis C Virus Infection.

INTRODUCTION: Asunaprevir (ASV) is a potent, pangenotypic, twice-daily hepatitis C virus (HCV) NS3 inhibitor indicated for the treatment of chronic HCV infection. METHODS: A population pharmacokinetic (PPK) model was developed using pooled ASV concentration data from 1239 HCV-infected subjects who received ASV either as part of the DUAL regimen with daclatasvir or as part of the QUAD regimen with daclatasvir and peg-interferon/ribavirin. RESULTS: A two-compartment model with first-order elimination from the central compartment, an induction effect on clearance, and an absorption model consisted of zero-order release followed by first-order absorption adequately described ASV PK after oral administration. A typical value for ASV clearance (CL/F) was 50.8 L/h, increasing by 43% after 2 days to a CL/F of 72.5 L/h at steady-state, likely due to auto-induction of cytochrome P450 3A4 (CYP3A4). Factors indicative of hepatic function were identified as key influential covariates on ASV exposures. Subjects with cirrhosis had an 84% increase in ASV area under the concentration time curve (AUC) and subjects with baseline aspartate aminotransferase (AST) above 78 IU/L had a 58% increase in area under the concentration time curve (AUC). Asians subjects had a 46% higher steady-state AUC relative to White/Caucasian subjects. Other significant covariates were formulation, age, and gender. CONCLUSION: The current PPK model provided a parsimonious description of ASV concentration data in HCV-infected subjects. Key covariates identified in the model help explain the observed variability in ASV exposures and may guide clinical use of the drug. FUNDING: Bristol-Myers Squibb.

Absence of a pharmacokinetic interaction between entecavir and adefovir.

This study evaluated the effect of entecavir on the pharmacokinetics of adefovir and the effect of adefovir on the pharmacokinetics of entecavir using a fixed-sequence crossover design in healthy adult subjects. Subjects received 10 mg of adefovir once daily on days 1 to 4, 1 mg of entecavir on days 5 to 14, and 1 mg of entecavir plus 10 mg of adefovir on days 15 to 24. Pharmacokinetic assessments were performed on days 4 and 24 for adefovir and on days 14 and 24 for entecavir. The geometric mean ratios (90% confidence interval) for area under the plasma concentration-time curve in 1 dosing interval, peak plasma concentration, and 24-hour postdose plasma concentration of entecavir when coadministered with adefovir and of adefovir when coadministered with entecavir were within the prespecified 0.80 to 1.25 no-effect range. Entecavir and adefovir were well tolerated when administered in combination. Therefore, the pharmacokinetic data generated in this study indicate that entecavir and adefovir can be coadministered without the need for dosage adjustment.

Population Pharmacokinetic Analysis of Daclatasvir in Subjects with Chronic Hepatitis C Virus Infection.

BACKGROUND AND OBJECTIVE: Daclatasvir is a potent, pangenotypic once-daily hepatitis C virus (HCV) NS5A inhibitor that is approved for the treatment of chronic HCV infection. The objective of this analysis was to characterize the pharmacokinetics of daclatasvir in subjects with chronic HCV infection. METHODS: A population pharmacokinetic (PPK) model was developed to evaluate effects of covariates on daclatasvir pharmacokinetics in subjects with chronic HCV infection (n = 2149 from 11 studies). All significant demographic, laboratory, prognostic and treatment covariates (p < 0.05) from univariate screening were included in the full model. The final model was reached by backward elimination (p < 0.001) and simulations were performed to further evaluate the effects of covariates on daclatasvir exposures. The plasma pharmacokinetics of daclatasvir was described by a two-compartment model with linear elimination. Absorption was modeled as a zero-order release followed by a first-order absorption into the central compartment. RESULTS: The typical value of apparent clearance (CL/F) was 5.7 L/h (1.58% relative standard error [RSE]) and of apparent volume of the central compartment (V c/F) was 58.6 L (2.00% RSE). Modest inter-individual variability was estimated for CL/F (35.1%) and V c/F (29.5%). Statistically significant covariates in the final model were sex, race, virus genotype, baseline creatinine clearance, and alanine aminotransferase (ALT) on CL/F and sex, race, and body weight on V c/F. Covariate effects demonstrated a 30% higher area under the plasma concentration-time curve at steady state (AUCss) in female subjects; effects of all other covariates were <16%. CONCLUSIONS: The model adequately described the daclatasvir pharmacokinetics and estimated relatively small covariate effects. Considering the exposure range for the therapeutic dose of daclatasvir 60 mg once daily and the favorable safety profile, the small difference in exposures due to these covariates is not considered clinically relevant.

Entecavir pharmacokinetics, safety, and tolerability after multiple ascending doses in healthy subjects.

A double-blind, placebo-controlled, multiple oral dose escalation study was conducted to investigate the pharmacokinetics, safety, and tolerability of entecavir in healthy subjects. Eight subjects were assigned to each of the 3 dose panels (0.1 mg, 0.5 mg, and 1 mg or matched placebo once daily for 14 days). Blood and urine samples were collected for pharmacokinetic analyses. Entecavir was rapidly absorbed, with peak plasma concentration occurring within 1 hour of dosing. Steady-state plasma concentrations of entecavir were achieved by 10 days following the initial dose. At steady state, the mean area under the plasma concentration-time curve over 1 dosing interval, increased approximately proportional to dose. Entecavir had a mean terminal half-life ranging from 128 to 149 hours and an effective half-life of approximately 24 hours. Elimination was predominantly through renal excretion, with mean urinary recovery ranging from 62% to 73%. Entecavir was safe and well tolerated when administered at doses ranging from 0.1 mg to 1 mg/d for 14 days.

Using Population Pharmacokinetic and Pharmacodynamic Analyses of Entecavir in Pediatric Subjects to Simplify Dosing Recommendations.

BACKGROUND: Entecavir is an orally administered guanosine nucleoside analog with activity against hepatitis B virus (HBV) polymerase, which is approved for the treatment of chronic hepatitis B (CHB) infection in adults and children ≥2 years old (USA and EU). OBJECTIVE: To develop simplified entecavir dosing recommendations for young children infected with CHB. METHODS: Data from recent clinical trials were used to develop a population pharmacokinetic (PPK) model, which allowed us to estimate entecavir exposures in children and compare them to ranges known to be efficacious in adults. A population pharmacodynamic (PPD) model was generated to describe the concentration/effect relationship for entecavir in lamivudine treatment-naïve children. The PPK dataset comprised three pediatric cohorts: 2 to <6 years (n = 36); 6 to <12 years (n = 43); and 12 to <18 years (n = 74). Data from 177 adults were also included to enhance model stability and to aid in the covariate search. RESULTS: Entecavir concentration-time profiles were well-described by a two-compartment model with first-order absorption and first-order elimination. Age was not a statistically significant covariate after accounting for weight. For the PPD model, the HBV DNA concentration following entecavir exposure was adequately described using a direct effect inhibitory maximum effect (E max) model with additive residual error. CONCLUSION: Model-estimated, steady-state entecavir area under the concentration-time curve, in both the original (15 weight groups) and simplified (eight weight groups) pediatric dosing regimens, provided entecavir exposures consistent with those observed to be efficacious in adults, and resulted in the simplified dose algorithm for pediatric patients that is approved for the current entecavir label.

A Review of Daclatasvir Drug-Drug Interactions.

The treatment of hepatitis C virus (HCV) infection has been revolutionized in recent years by the development of direct-acting antiviral regimens that do not contain peginterferon (pegIFN) and/or ribavirin (RBV). While direct-acting antiviral-based regimens have been shown to be greatly superior to pegIFN/RBV-based regimens in terms of efficacy and safety, they have a greater susceptibility to drug-drug interactions (DDIs). Daclatasvir (DCV)-the benchmark pangenotypic nonstructural protein 5A inhibitor-has been shown to be efficacious and generally well tolerated in partnership with other HCV direct-acting antivirals, including sofosbuvir, asunaprevir (ASV), and ASV plus beclabuvir. DCV may be the object of a DDI via the induction or inhibition of cytochrome P450 (CYP) 3A4 and/or P-glycoprotein (P-gp) by the concomitant medication, or the precipitant of a DDI via DCV-based induction/inhibition of CYP 3A4 or inhibition of P-gp, organic anion transporting polypeptide 1B1/B3, and/or breast cancer resistance protein. This article presents an overview of the drug interaction studies conducted during the clinical development of DCV, the findings of these studies that led to the guidance on concomitant medication use and dosage along with any required DCV dose modifications, and the use of the known metabolic pathway of DCV to guide concomitant dosing where direct drug-drug studies have not been conducted. The robust characterization of the DCV clinical pharmacology program has demonstrated that DCV has few or no clinically relevant DDIs with medications with which it is likely to be co-administered, and the majority of DDIs that do occur can be predicted and easily managed. FUNDING: Bristol-Myers Squibb.

An open-label investigation into drug-drug interactions between multiple doses of daclatasvir and single-dose cyclosporine or tacrolimus in healthy subjects.

BACKGROUND AND OBJECTIVE: Chronic hepatitis C virus (HCV) infection is a major cause of liver transplantation. Drug-drug interactions (DDIs) with cyclosporine and tacrolimus hindered the use of first-generation protease inhibitors in transplant recipients. The current study investigated DDIs between daclatasvir-a pan-genotypic HCV NS5A inhibitor with clinical efficacy in multiple regimens (including all-oral)-and cyclosporine or tacrolimus in healthy subjects. METHODS: Healthy fasted subjects (aged 18-49 years; body mass index 18-32 kg/m(2)) received single oral doses of cyclosporine 400 mg on days 1 and 9, and daclatasvir 60 mg once daily on days 4-11 (group 1, n = 14), or a single oral dose of tacrolimus 5 mg on days 1 and 13, and daclatasvir 60 mg once daily on days 8-19 (group 2, n = 14). Blood samples for pharmacokinetic analysis [by liquid chromatography with tandem mass spectrometry (LC-MS/MS)] were collected on days 1 and 9 for cyclosporine (72 h), on days 1 and 13 for tacrolimus (168 h) and on days 8 and 9 (group 1) or on days 12 and 13 (group 2) for daclatasvir (24 h). Plasma concentrations were determined by validated LC-MS/MS methods. RESULTS: Daclatasvir did not affect the pharmacokinetic parameters of cyclosporine or tacrolimus, and tacrolimus did not affect the pharmacokinetic parameters of daclatasvir. Co-administration of cyclosporine resulted in a 40 % increase in the area under the concentration-time curve of daclatasvir but did not affect its maximum observed concentration. CONCLUSION: On the basis of these observations in healthy subjects, no clinically relevant DDIs between daclatasvir and cyclosporine or tacrolimus are anticipated in liver transplant recipients infected with HCV; dose adjustments during co-administration are unlikely to be required.

Single-dose pharmacokinetics and safety of daclatasvir in subjects with renal function impairment.

BACKGROUND: Daclatasvir (DCV) is a pangenotypic inhibitor of the HCV NS5A replication complex approved in Japan and Europe for combination treatment of HCV. AI444-063 was an open-label, two-stage, adaptive study assessing DCV pharmacokinetics and safety in HCV-uninfected subjects with renal impairment. METHODS: Stage 1 included 12 subjects with end-stage renal disease (ESRD) on dialysis and 12 healthy controls (creatinine clearance [CLcr]≥90 ml/min, Cockcroft-Gault) matched by sex, age and weight. All participants received a single DCV 60-mg dose on day 1. DCV plasma levels were measured through day 4. Prespecified criteria for study expansion (ESRD versus control area under the curve extrapolated to infinite time [AUC∞] geometric mean ratio [GMR] upper 90% CI>1.5) were met; therefore, 12 subjects with moderate or severe renal impairment (estimated glomerular filtration rate, 30-59 and 15-29 ml/min/1.73m(2), respectively) were included in stage 2. RESULTS: All 36 participants (30 male, mean age 54 years) completed the study. DCV AUC∞ was higher in ESRD subjects versus controls (GMR 1.264, 90% CI 0.989, 1.616). Compared with normal CLcr (90 ml/min), GMR and 90% CI for unbound DCV AUC∞ at CLcr 60, 30 and 15 ml/min were 1.18 (1.07, 1.30), 1.39 (1.14, 1.70) and 1.51 (1.18, 1.94), respectively. DCV was generally well tolerated in subjects with normal renal function, ESRD, or moderate or severe renal impairment. CONCLUSIONS: Observed DCV exposure increases were within the normal range of variability and were not associated with an elevated risk of adverse events. DCV can be administered in subjects with renal impairment, including ESRD, without dose modification. ClinicalTrials.gov NCT01830205.

Effect of the coadministration of daclatasvir on the pharmacokinetics of a combined oral contraceptive containing ethinyl estradiol and norgestimate.

BACKGROUND: Daclatasvir is a highly selective NS5A replication complex inhibitor currently in development for the treatment of chronic hepatitis C infection. Daclatasvir is active at picomolar concentrations and demonstrates in vitro activity against a broad range of HCV genotypes. The primary objective of this study was to assess the effect of daclatasvir on the pharmacokinetics of a combined oral contraceptive containing ethinyl estradiol and norgestimate (Ortho Tri-Cyclen(®)). METHODS: In this open-label single-sequence study, 20 healthy female subjects received ethinyl estradiol and norgestimate for three cycles, with coadministration of daclatasvir in cycle 3. Pharmacokinetics of ethinyl estradiol and the active metabolites of norgestimate (norelgestromin and norgestrel) were assessed in cycles 2 and 3. RESULTS: Adjusted ratios of geometric means and 90% CIs were estimated for the maximum observed plasma concentration (ethinyl estradiol 1.11 [1.02, 1.20], norelgestromin 1.06 [0.99, 1.14] and norgestrel 1.07 [0.99, 1.16]) and area under the plasma concentration-time curve in one dosing interval (ethinyl estradiol 1.01 [0.95, 1.07], norelgestromin 1.12 [1.06, 1.17] and norgestrel 1.12 [1.02, 1.23]). CONCLUSIONS: Coadministration of daclatasvir resulted in no clinically relevant effects on exposure to ethinyl estradiol, norelgestromin or norgestrel.

Evaluation of drug-drug interaction between daclatasvir and methadone or buprenorphine/naloxone.

INTRODUCTION: Daclatasvir (DCV) is a potent hepatitis C virus (HCV) NS5A replication complex inhibitor with pangenotypic (1-6) activity in vitro. Methadone (MET) and buprenorphine (BUP) are opioid medications used to treat opioid addiction; patients on HCV therapy may require MET or BUP treatment. The effect of DCV on the pharmacokinetics (PK) of MET or BUP/naloxone (NLX) was assessed in subjects on stable MET or BUP. MATERIALS AND METHODS: An open-label, two-part study assessed the effect of steady-state oral administration of DCV on the PK of MET (Part 1, P1) or BUP/NAL (Part 2, P2). Safety/tolerability and pharmacodynamics (PD, opioid withdrawal scales/overdose assessment) were also assessed. Subjects (P1, N=14; P2, N=11) received daily single-dose oral MET (40-120mg) or BUP/NLX (8/2-24/6mg) based on their prescribed stable dose throughout, in addition to DCV (60mg QD) on Days 2-9. Serial PK sampling occurred predose and postdose till 24 hours on Day 1 (MET/BUP) and Day 10 (MET/BUP/DCV). Noncompartmental PK were derived. Geometric mean ratios (GMR) and 90% confidence intervals (90% CI) for MET/BUP/norBUP Cmax and AUCTAU were derived from linear mixed effects models. RESULTS: Subjects were aged 19-39 years, mostly white (P1, 93%; P2, 100%) and male (P1, 71%; P2, 91%). All subjects completed the study. No clinically meaningful effect was demonstrated as the GMR and 90% CIs fell within the prespecified interval (P1, 0.7-1.4; P2, 0.5-2.0: see Table 1). DCV coadministration was well-tolerated: overall, six (43%) subjects had adverse events (AEs) (all mild and resolved without treatment). DCV had no clinically significant effect on the PD of MET or BUP/NLX. CONCLUSIONS: Steady-state administration of DCV 60mg QD had no clinically meaningful effect on the PK of MET or BUP/NLX and was generally well-tolerated, suggesting that no dose adjustments will be required.

The pharmacokinetics of daclatasvir and asunaprevir administered in combination in studies in healthy subjects and patients infected with hepatitis C virus.

BACKGROUND AND OBJECTIVES: The combination of direct-acting antiviral agents in patients with chronic hepatitis C virus (HCV) infection has demonstrated clinical benefit; however, evaluation of potential drug-drug interactions is required prior to therapy. METHODS: An open-label study assessed the pharmacokinetics and tolerability of the HCV NS5A replication complex inhibitor daclatasvir and the HCV NS3 protease inhibitor asunaprevir when co-administered in healthy subjects. Daclatasvir 60 mg once daily and asunaprevir 600 mg twice daily were dosed for 7 days alone followed by combination dosing for 14 days at 30 mg once daily and 200 mg twice daily, respectively. Further assessments were provided comparing exposures from the current study with those from studies in HCV-infected patients receiving either the same or higher doses of daclatasvir or asunaprevir administered alone or together. RESULTS: Dose-normalized daclatasvir and asunaprevir morning exposures were comparable with control in healthy subjects, with geometric mean area under the concentration-time curve ratios of 1.202 (90 % CI 1.113-1.298) and 0.868 (90 % CI 0.726-1.038), respectively. In HCV patients daclatasvir and asunaprevir exposures were largely comparable, when administered together or alone. CONCLUSIONS: Additional data support the conclusion that there is no clinically meaningful interaction between daclatasvir and asunaprevir in either healthy subjects or HCV-infected patients, including those also receiving peginterferon-α/ribavirin, and that the combination of daclatasvir 60 mg once daily and asunaprevir 200 mg twice daily is generally well-tolerated.