Safety, Tolerability, Pharmacodynamics and Pharmacokinetics of Intravenous Siponimod: A Randomized, Open-label Study in Healthy Subjects.

PURPOSE: The goal of this study was to assess the safety, tolerability, pharmacodynamics (PD) and pharmacokinetics (PK) of intravenous (IV) siponimod in healthy subjects. METHODS: This randomized, open-label study was conducted in 2 parts. In Part 1, a total of 16 eligible subjects received either a single oral dose of siponimod (0.25 mg) followed by a single IV infusion (0.25 mg/3 h) in Sequence 1, or vice versa in Sequence 2. In Part 2, a total of 17 eligible subjects received single IV infusions of siponimod (1 mg/24 h). FINDINGS: No clinically relevant effect on mean 5-minute or hourly average heart rate was observed following the siponimod IV dosing regimens and both remained above 50 beats/min. Observed atrioventricular blocks and sinus pauses were asymptomatic. The mean change in absolute lymphocyte count from baseline was comparable for the siponimod 0.25 mg oral regimen and the two IV siponimod regimens. Oral siponimod displayed a good absolute bioavailability of 84%. The mean peak exposure of oral siponimod was approximately 48% lower than that of IV siponimod. The M17 metabolite was found to be the most prominent systemic metabolite of siponimod in humans. IMPLICATIONS: Siponimod IV infusions were well tolerated, with safety and PD (absolute lymphocyte count) profiles similar to those of oral siponimod. The PD/PK findings supported the development of an innovative rapid IV titration regimen for patients with intracerebral hemorrhage.

Siponimod pharmacokinetics, safety, and tolerability in combination with the potent CYP3A4 inhibitor itraconazole in healthy subjects with different CYP2C9 genotypes.

PURPOSE: To evaluate the PK and safety of siponimod, a substrate of CYP2C9/3A4, in the presence or absence of a CYP3A4 inhibitor, itraconazole. METHODS: This was an open-label study in healthy subjects (aged 18-50 years; genotype: CYP2C9 *1*2 [cohort 1; n = 17] or *1*3 [cohort 2; n = 13]). Subjects received siponimod 0.25-mg single dose in treatment period 1 (days 1-14), itraconazole 100 mg twice daily in treatment period 2 (days 15-18), and siponimod 0.25-mg single dose (day 19) with itraconazole until day 31 (cohort 1) or day 35 (cohort 2) in treatment period 3. PK of siponimod alone and with itraconazole and safety were assessed. RESULTS: Overall, 29/30 subjects completed the study. In treatment period 1, geometric mean AUCinf, T1/2, and median Tmax were higher while systemic clearance was lower in cohort 2 than cohort 1. In treatment period 3, siponimod AUC decreased by 10% (geo-mean ratio [90% confidence intervals]: 0.90 [0.84; 0.96]) and 24% (0.76 [0.69; 0.82]) in cohorts 1 and 2, respectively. Siponimod Cmax was similar between treatment periods 1 and 3. In both cohorts, the Cmax and AUC of the metabolites (M17, M3, and M5) decreased in the presence of itraconazole. All adverse events were mild. CONCLUSIONS: The minor albeit significant reduction in plasma exposure of siponimod and its metabolites by itraconazole was unexpected. While the reason is unclear, the results suggest that coadministration of the two drugs would not cause a considerable increase of siponimod exposure independent of CYP2C9 genotype.

Siponimod pharmacokinetics, safety, and tolerability in combination with rifampin, a CYP2C9/3A4 inducer, in healthy subjects.

PURPOSE: To assess the potential pharmacokinetic (PK) interactions between siponimod and rifampin, a strong CYP3A4/moderate CYP2C9 inducer, in healthy subjects. METHODS: This was a confirmatory, open-label, multiple-dose two-period study in healthy subjects (aged 18-45 years). In Period 1 (Days 1-12), siponimod was up-titrated from 0.25 to 2 mg over 5 days (Days 1-6) followed by 2 mg once daily on days 7-12. In Period 2, siponimod 2 mg qd was co-administered with rifampin 600 mg qd (Days 13-24). Primary assessments included PK of siponimod (Days 12 and 24; maximum steady-state plasma concentration [Cmax,ss], median time to achieve Cmax,ss [Tmax, ss], and area under the curve at steady state [AUCtau,ss]). Key secondary assessments were PK of M3 and M5 metabolites, and safety/tolerability including absolute lymphocyte count (ALC). RESULTS: Of the 16 subjects enrolled (age, mean ± standard deviation [SD] 31 ± 8.3 years; men, n = 15), 15 completed the study. In Period 1, siponimod geometric mean Cmax,ss (28.6 ng/mL) was achieved in 4 h (median Tmax,ss; range, 1.58-8.00) and the geometric mean AUCtau,ss was 546 h × ng/mL. In Period 2, the siponimod geometric mean Cmax,ss and AUCtau,ss decreased to 15.7 ng/mL and 235 h × ng/mL, respectively; median Tmax remained unchanged (4 h). Rifampin co-administration increased M3 Cmax,ss by 53% while M5 Cmax,ss remained unchanged. The AUCtau,ss of M3 and M5 decreased by 10% and 37%, respectively. The majority of adverse events reported were mild, with a higher frequency during Period 2 (86.7%) versus Period 1 (50%). The mean ALC increased slightly under rifampin co-administration but remained below 1.0 × 109/L. CONCLUSIONS: The study findings suggest that in the presence of rifampin, a strong CYP3A4/moderate CYP2C9 inducer, siponimod showed significant decrease in Cmax,ss (45%) and AUCtau,ss (57%) in healthy subjects.

Reduction of a Whole-Body Physiologically Based Pharmacokinetic Model to Stabilise the Bayesian Analysis of Clinical Data.

Whole-body physiologically based pharmacokinetic (PBPK) models are increasingly used in drug development for their ability to predict drug concentrations in clinically relevant tissues and to extrapolate across species, experimental conditions and sub-populations. A whole-body PBPK model can be fitted to clinical data using a Bayesian population approach. However, the analysis might be time consuming and numerically unstable if prior information on the model parameters is too vague given the complexity of the system. We suggest an approach where (i) a whole-body PBPK model is formally reduced using a Bayesian proper lumping method to retain the mechanistic interpretation of the system and account for parameter uncertainty, (ii) the simplified model is fitted to clinical data using Markov Chain Monte Carlo techniques and (iii) the optimised reduced PBPK model is used for extrapolation. A previously developed 16-compartment whole-body PBPK model for mavoglurant was reduced to 7 compartments while preserving plasma concentration-time profiles (median and variance) and giving emphasis to the brain (target site) and the liver (elimination site). The reduced model was numerically more stable than the whole-body model for the Bayesian analysis of mavoglurant pharmacokinetic data in healthy adult volunteers. Finally, the reduced yet mechanistic model could easily be scaled from adults to children and predict mavoglurant pharmacokinetics in children aged from 3 to 11 years with similar performance compared with the whole-body model. This study is a first example of the practicality of formal reduction of complex mechanistic models for Bayesian inference in drug development.

Application of a Bayesian approach to physiological modelling of mavoglurant population pharmacokinetics.

Mavoglurant (MVG) is an antagonist at the metabotropic glutamate receptor-5 currently under clinical development at Novartis Pharma AG for the treatment of central nervous system diseases. The aim of this study was to develop and optimise a population whole-body physiologically-based pharmacokinetic (WBPBPK) model for MVG, to predict the impact of drug-drug interaction (DDI) and age on its pharmacokinetics. In a first step, the model was fitted to intravenous (IV) data from a clinical study in adults using a Bayesian approach. In a second step, the optimised model was used together with a mechanistic absorption model for exploratory Monte Carlo simulations. The ability of the model to predict MVG pharmacokinetics when orally co-administered with ketoconazole in adults or administered alone in 3-11 year-old children was evaluated using data from three other clinical studies. The population model provided a good description of both the median trend and variability in MVG plasma pharmacokinetics following IV administration in adults. The Bayesian approach offered a continuous flow of information from pre-clinical to clinical studies. Prediction of the DDI with ketoconazole was consistent with the results of a non-compartmental analysis of the clinical data (threefold increase in systemic exposure). Scaling of the WBPBPK model allowed reasonable extrapolation of MVG pharmacokinetics from adults to children. The model can be used to predict plasma and brain (target site) concentration-time profiles following oral administration of various immediate-release formulations of MVG alone or when co-administered with other drugs, in adults as well as in children.

Model-based evaluation of the impact of formulation and food intake on the complex oral absorption of mavoglurant in healthy subjects.

PURPOSE: To compare the pharmacokinetics of intravenous (IV), oral immediate-release (IR) and oral modified-release (MR) formulations of mavoglurant in healthy subjects, and to assess the food effect on the MR formulation's input characteristics. METHODS: Plasma concentration-time data from two clinical studies in healthy volunteers were pooled and analysed using NONMEM®. Drug entry into the systemic circulation was modelled using a sum of inverse Gaussian (IG) functions as an input rate function, which was estimated specifically for each formulation and food state. RESULTS: Mavoglurant pharmacokinetics was best described by a two-compartment model with a sum of either two or three IG functions as input function. The mean absolute bioavailability from the MR formulation (0.387) was less than from the IR formulation (0.436). The MR formulation pharmacokinetics were significantly impacted by food: bioavailability was higher (0.508) and the input process was shorter (complete in approximately 36 versus 12 h for the fasted and fed states, respectively). CONCLUSIONS: Modelling and simulation of mavoglurant pharmacokinetics indicate that the MR formulation might provide a slightly lower steady-state concentration range with lower peaks (possibly better drug tolerance) than the IR formulation, and that the MR formulation's input properties strongly depend on the food conditions at drug administration.

Effect of cimetidine, a model drug for inhibition of the organic cation transport (OCT2/MATE1) in the kidney, on the pharmacokinetics of glycopyrronium.

OBJECTIVE: Glycopyrronium (NVA237), a novel once-daily long-acting muscarinic antagonist (LAMA), has recently been approved for maintenance treatment of COPD. This study evaluated the effect of organic cation transporter inhibition on inhaled glycopyrronium disposition using cimetidine as a probe inhibitor. METHODS: In this open-label, two-period, two-sequence, crossover study, 20 healthy subjects received two treatments. A single dose of 100 µg glycopyrronium was inhaled alone and on Day 4 of a 6-day treatment with oral cimetidine 800 mg b.i.d. Trough plasma concentrations of cimetidine were determined throughout cimetidine dosing. Plasma concentrations and urinary excretion of glycopyrronium were determined up to 72 hours post glycopyrronium dose. The primary pharmacokinetics (PK) parameters were plasma peak concentration (Cmax), AUC up to the last measured concentration (AUClast), and renal clearance (CLr) of glycopyrronium. RESULTS: Cimetidine trough concentrations indicated that PK steady state of cimetidine was reached prior to single dose inhalation of glycopyrronium. Inhalation of glycopyrronium in the presence of cimetidine resulted in an increase in total systemic exposure (AUClast) of glycopyrronium by 22% (geometric mean ratio 1.22; 90% CI: 1.12 - 1.32). This exposure increase correlated with a slight decrease of 23% in CLr (geometric mean ratio 0.77; 90% CI: 0.70 - 0.85). Cmax was not affected. Both treatments were safe and well tolerated without any deaths or severe adverse events. CONCLUSION: Based on the magnitude of the PK changes seen in this study, no relevant drug interaction is expected when glycopyrronium is co-administered with cimetidine or other inhibitors of the organic cation transport.

Validation of an LC-MS/MS method for the quantitative determination of mavoglurant (AFQ056) in human plasma.

A simple, sensitive, and selective liquid chromatography/tandem mass spectrometry method was validated for the identification and quantification of mavoglurant (AFQ056) in human plasma. The chromatographic separation was performed using a Cosmosil 5 C18 (150 × 4.6 mm, 5 µm) column at 40 ± 0.5 °C with a mobile phase consisting of acetic acid in water (0.1%, v/v)/methanol (10:90, v/v) with a flow rate of 1.0 mL/min followed by quantification with tandem mass spectrometry, operating with electrospray ionization in positive ion mode and applying multiple reaction monitoring. The validated method described in this paper presents high absolute recovery with precision and accuracy meeting the acceptance criteria. The method was precise and accurate for 2- and 10-fold dilution of samples. The method was validated using sodium heparin as specific anticoagulant, and the anticoagulant effect was tested by lithium heparin and K(3)EDTA. The method was successfully cross-validated between two bioanalytical sites. The method was specific for mavoglurant within the given criteria for acceptance (apparent peak area at the retention time of mavoglurant in zero samples was less than 20% compared with the mean peak area at LLOQ) in human plasma. The method was fully validated for the quantitative determination of mavoglurant in human plasma between the range of 2.00 and 2,500 ng/mL.