Himanshu Naik

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamic Properties of the GPR40 Agonist TAK-875: Results From a Double-Blind, Placebo-Controlled Single Oral Dose Rising Study in Healthy Volunteers

TAK‐875 is a selective G‐protein‐coupled receptor 40 agonist in development for the treatment of type 2 diabetes mellitus. This randomized, double‐blind, placebo‐controlled study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of TAK‐875 following administration of a single oral dose of TAK‐875 (25–800 mg) in 60 healthy volunteers. TAK‐875 was eliminated slowly with a mean terminal elimination t1/2 of approximately 28.1 to 36.6 hours. Systemic exposure of TAK‐875 did not exhibit dose‐proportional increases across the dose range evaluated due to a greater than proportional increase in exposure at doses greater than 200 mg. A preliminary food effect assessment indicated that coadministration of TAK‐875 with a high‐fat meal decreased Cmax of TAK‐875 by 40% and AUC by 17%. Clinical adverse experiences were generally mild and transient. No dose‐dependent pattern was observed. In healthy volunteers, no glucose‐lowering effect and no increase in insulin or c‐peptide secretion were evident following administration of TAK‐875; the frequency of plasma glucose concentrations <70 mg/dL was similar in the TAK‐875 and pooled placebo groups. TAK‐875 was well tolerated in the study and has pharmacokinetic characteristics suitable for a once‐daily regimen. The pharmacodynamic data support the notion that TAK‐875, if effective in diabetic patients, may bear a low risk of hypoglycemia.

A Multiple‐Ascending‐Dose Study to Evaluate Safety, Pharmacokinetics, and Pharmacodynamics of a Novel GPR40 Agonist, TAK‐875, in Subjects With Type 2 Diabetes

G‐protein‐coupled receptor 40 (GPR40), highly expressed in pancreatic β‐cells, mediates free fatty acid (FFA)‐induced insulin secretion. This phase I, double‐blind, randomized study investigated the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of a novel, glucose‐lowering GPR40 agonist, TAK‐875 (q.d., orally × 14 days), in type 2 diabetics (placebo, n = 14; at 25, 50, 100, 200, or 400 mg, n = 45). Approximately dose‐proportional increases in AUC0−24 and Cmax occurred. TAK‐875 showed good tolerability with no dose‐limiting side effects. Two subjects (on TAK‐875) had mild hypoglycemia, probably related to prolonged fasting after oral glucose tolerance tests (OGTTs). TAK‐875 showed reductions from baseline in fasting (2 to −93 mg/dl) and post‐OGTT glucose (26 to −172 mg/dl), with an apparent dose‐dependent increase in post‐OGTT C‐peptide over 14 days. Consistent with preclinical data, TAK‐875 apparently acts as a glucose‐dependent insulinotropic agent with low hypoglycemic risk. Its PK is suitable for once‐daily oral administration.

Population pharmacokinetic meta-analysis of vortioxetine in healthy individuals.

The objective was to describe the pharmacokinetics of vortioxetine and evaluate the effect of intrinsic and extrinsic factors in the healthy population. Data from 26 clinical pharmacology studies were pooled. A total of 21,758 vortioxetine quantifiable plasma concentrations were collected from 887 subjects with corresponding demography. The doses ranged from 2.5 to 75 mg (single dose) and 2.5–60 mg (multiple QD doses). The pharmacokinetics of vortioxetine was best characterised by a two‐compartment model with first‐order absorption, lag‐time and linear elimination, with interindividual error terms for absorption rate constant, oral clearance and central volume of distribution. The population mean was 32.7 L/hr for oral clearance and 1.97∙103 L for the central volume of distribution. The average elimination half‐life was 65.8 hr. CYP2D6 inferred metabolic status (ultra, extensive, intermediate or poor metabolisers) and age on oral clearance and height on central volume of distribution were identified as statistically significant covariate–parameter relationships. For CYP2D6 poor metabolisers, CL/F was approximately 50% to that seen in CYP2D6 extensive metabolisers. The impact of height on V2/F and age on CL/F was low and not considered to be clinically relevant. The final model was found to be reliable, stable and predictive. A reliable, stable and predictive pharmacokinetic model was developed to characterise pharmacokinetics of vortioxetine in the healthy population.

The effects of febuxostat on the pharmacokinetic parameters of rosiglitazone, a CYP2C8 substrate

AIMS To determine the effect of febuxostat on cytochrome P450 2C8 (CYP2C8) activity using rosiglitazone as a CYP2C8 substrate. METHODS Healthy subjects received febuxostat 120 mg daily (regimen A) or matching placebo (regimen B) for 9 days along with a single oral dose of rosiglitazone 4 mg on day 5 in a double-blind, randomized, cross-over fashion (≥7 day washout between periods). Plasma samples for analysis of the impact of febuxostat on the pharmacokinetics (PK) of rosiglitazone and its metabolite, N-desmethylrosiglitazone, were collected for 120 h after co-administration. RESULTS Of the 39 subjects enrolled, 36 completed the study and were included in the PK analyses. Rosiglitazone PK parameters were comparable between regimens A and B. Median time to maximal plasma concentration, mean maximal plasma concentration (C(max)), area under the concentration-time curve (AUC) from time zero to the last quantifiable concentration (AUC(0-tlqc)), AUC from time zero to infinity (AUC(0-∞)), and terminal elimination half-life for regimen A were 0.50 h, 308.6 ng ml⁻¹, 1594.9 ng h ml⁻¹, 1616.0 ng h ml⁻¹ and 4.1 h, respectively, and for regimen B they were 0.50 h, 327.6 ng ml⁻¹, 1564.5 ng h ml⁻¹, 1584.2 ng h ml⁻¹ and 4.0 h, respectively. Point estimates for the ratio of regimen A to regimen B (90% confidence intervals) for rosiglitazone C(max) , AUC(0-tlqc) and AUC(0-∞) central values were 0.94 (0.89-1.00), 1.02 (1.00-1.04) and 1.02 (1.00-1.04), respectively. CONCLUSIONS Co-administration of febuxostat had no effect on rosiglitazone or N-desmethylrosiglitazone PK parameters, suggesting that febuxostat can be given safely with drugs metabolized through CYP2C8.

A Population Pharmacokinetic–Pharmacodynamic Meta-Analysis of Vortioxetine in Patients with Major Depressive Disorder

Vortioxetine is approved for the treatment of major depressive disorder (MDD). This analysis aimed to develop pharmacokinetic (PK) and PK/Efficacy models to evaluate the exposure–response relationship for vortioxetine in patients with MDD. PK data from 10 MDD and two generalized anxiety disorder studies of vortioxetine (3160 patients), and efficacy data [Montgomery–Åsberg Depression Rating Scale (MADRS)] from seven MDD studies (2537 patients), were used for the development of PK and PK/Efficacy models. One‐ and two‐compartment models were evaluated as structural PK models, and linear and nonlinear (Emax) models were used to describe the relationship between average vortioxetine concentration at steady‐state (Cav) and change in MADRS score from baseline (ΔMADRS). The impact of selected covariates on the PK and efficacy parameters of vortioxetine was also investigated. PK of vortioxetine was best characterized by a two‐compartment model with first‐order absorption and elimination. Mean estimates for oral clearance (CL/F) and volume of distribution for the central compartment of vortioxetine were 42 L/hr and 2920 L. Creatinine clearance, height and geographic region had statistically significant effects on vortioxetine CL/F, but the effect of each of these covariates was not considered clinically relevant, as they lead to ±26% change in area under the curve or Cmax of vortioxetine. An Emax model best described the relationship between ΔMADRS and Cav. Half‐maximal effective concentration (EC50) and Emax estimates were 24.9 ng/mL and 7.0. No identified covariates, except region, had clinically meaningful effects on vortioxetine efficacy. These PK/Efficacy models adequately characterized the vortioxetine exposure–response relationship.

The effects of xanthine oxidase inhibition by febuxostat on the pharmacokinetics of theophylline.

OBJECTIVE Febuxostat, a non-purine selective xanthine oxidase (XO) inhibitor, may affect the metabolism of theophylline as XO hydroxylates 1-methylxanthine to 1-methyluric acid. The objective of this study was to examine the effects of febuxostat on the pharmacokinetics of theophylline and its metabolites. METHODS 24 healthy subjects received febuxostat 80 mg (Regimen A) or matching placebo (Regimen B) daily for 7 days along with a single oral dose of theophylline 400 mg on Day 5 in a double-blind, randomized, cross-over fashion (≥ 7 day washout between periods) followed by collection of plasma and urine samples for 72 h. RESULTS For Regimens A and B, mean theophylline Cmax values were 4.4 and 4.1 μg/ml, respectively, and mean theophylline AUC0-tlqc was 122.3 and 115.2 μg x h/ml, respectively. The ratios of theophylline Cmax and AUC0-tlqc central values following coadministration with febuxostat or placebo were 1.03 (90% confidence intervals (CIs), 0.917 - 1.149) and 1.04 (90% CI, 0.927 - 1.156). Both 90% CIs fell within the no-effect range of 0.8 and 1.25. Mean excreted amounts in urine for 1-methylxanthine levels were higher in Regimen A vs. B (40.1 vs. 0.1 mg), while 1-methyluric acid levels were lower (3.1 vs. 56.2 mg). Mean excreted amounts of theophylline and other metabolites were comparable between Regimen A and B. CONCLUSIONS No dose adjustment for theophylline is necessary when coadministered with febuxostat 80 mg, as coadministration does not affect the plasma pharmacokinetics of theophylline and neither 1-methylxanthine nor 1-methyluric have any pharmacological effect.

A Population Pharmacokinetic and Pharmacodynamic Analysis of Peginesatide in Patients with Chronic Kidney Disease on Dialysis

Peginesatide (OMONTYS®) is an erythropoiesis-stimulating agent that was indicated in the United States for the treatment of anemia due to chronic kidney disease in adult patients on dialysis prior to its recent marketing withdrawal by the manufacturer. The objective of this analysis was to develop a population pharmacokinetic and pharmacodynamic model to characterize the time-course of peginesatide plasma and hemoglobin concentrations following intravenous and subcutaneous administration. Plasma samples (n = 2,665) from 672 patients with chronic kidney disease (on or not on dialysis) and hemoglobin samples (n = 18,857) from 517 hemodialysis patients (subset of the 672 patients), were used for pharmacokinetic-pharmacodynamic model development in NONMEM VI. The pharmacokinetic profile of peginesatide was best described by a two-compartment model with first-order absorption and saturable elimination. The relationship between peginesatide and hemoglobin plasma concentrations was best characterized by a modified precursor-dependent lifespan indirect response model. The estimate of maximal stimulatory effect of peginesatide on the endogenous production rate of progenitor cells (Emax) was 0.54. The estimate of peginesatide drug concentration required for 50% of maximal response (EC50) estimates was 0.4 µg/mL. Several significant (P<0.005) covariates affected simulated peginesatide exposure by ≤36%. Based upon ≤0.2 g/dL effects on simulated hemoglobin levels, none were considered clinically relevant.

Application of pharmacometric approaches to evaluate effect of weight and renal function on pharmacokinetics of alogliptin

AIMS The aims of the study were to characterize the pharmacokinetics (PK) of alogliptin in healthy and type 2 diabetes mellitus (T2DM) subjects using a population PK approach and to assess the influence of various covariates on alogliptin exposure. METHODS Plasma concentration data collected from two phase 1 studies and one phase 3 study following administration of alogliptin (12.5-400 mg) were used for the PK model development. One- and two-compartment models were evaluated as base structural PK models. The impact of selected covariates was assessed using stepwise forward selection and backward elimination procedures. The predictability and robustness of the final model was evaluated using visual predictive check and bootstrap analyses. The final model was used to perform simulations and guide appropriate dose adjustments. RESULTS A two-compartment model with first-order absorption and elimination best described the alogliptin concentration vs. time profiles. Creatinine clearance and weight had a statistically significant effect on the oral clearance (CL/F) of alogliptin. The model predicted a lower CL/F (17%, 35%, 80%) and a higher systemic exposure (56%, 89%, 339%) for subjects with mild, moderate and severe renal impairment, respectively, compared with healthy subjects. Effect of weight on CL/F was not considered clinically relevant. Simulations at different doses of alogliptin support the approved doses of 12.5 mg and 6.25 mg for patients with moderate and severe renal impairment, respectively. CONCLUSIONS The PK of alogliptin was well characterized by the model. The analysis suggested an alogliptin dose adjustment for subjects with moderate-to-severe renal impairment and no dose adjustments based on weight.