Evaluation of pharmacokinetic interactions between lobeglitazone, empagliflozin, and metformin in healthy subjects.

Concomitant administration of lobeglitazone, empagliflozin, and metformin is expected to enhance blood glucose-lowering effects and improve medication compliance in patients with diabetes mellitus. In this study, we investigated the pharmacokinetic (PK) interactions and safety of lobeglitazone and co-administered empagliflozin and metformin, which are approved agents used in clinical settings. Two randomized, open-label, multiple-dose, 2-treatment, 2-period, 2-sequence crossover clinical trials (parts 1 and 2) were conducted independently. In part 1, lobeglitazone monotherapy or lobeglitazone, empagliflozin, and metformin triple therapy was administered for 5 days. In part 2, empagliflozin and metformin dual therapy or the abovementioned triple therapy were administered for 5 days. Serial blood samples were collected up to 24 hours after the last dose in each period for PK evaluation. The primary PK parameters (AUCtau,ss, Cmax,ss) of treatment regimens in each study part were calculated and compared. For lobeglitazone, the geometric mean ratios (GMRs) with 90% confidence intervals (CI) for triple therapy over monotherapy were 1.08 (1.03-1.14) for Cmax,ss and 0.98 (0.90-1.07) for AUCtau,ss. For empagliflozin, the GMRs and 90% CIs for triple therapy over dual therapy were 0.87 (0.78-0.97) for Cmax,ss and 0.97 (0.93-1.00) for AUCtau,ss. For metformin, the GMRs and 90% CIs for triple therapy over dual therapy were 1.06 (0.95-1.17) for Cmax,ss and 1.04 (0.97-1.12) for AUCtau,ss. All reported adverse events were mild. The triple therapy consisting of lobeglitazone, empagliflozin, and metformin did not show any clinically relevant drug interactions in relation to the PKs and safety of each drug substance. Trial Registration: ClinicalTrials.gov Identifier: NCT04334213.

Development of a population pharmacokinetic model and optimal dosing regimen of leflunomide in Korean population.

PURPOSE: Leflunomide is an immunosuppressive drug indicated for the treatment of rheumatoid arthritis (RA). While the pharmacokinetics (PK) of its active metabolite A771726 reportedly show large interindividual variability, no efficient dose individualization strategy is currently available. The goal of this work was to develop a population PK model for A771726 and propose an optimal individualized dosing strategy. METHODS: A771726 plasma concentration data were collected from 50 healthy male volunteers participating in two leflunomide PK studies given a single oral dose of 40 mg. Concentrations were elevated in low body weight (WT) subjects and showed multiple peaks. Thus, A771726 PK modeling was conducted incorporating allometry scaling and enterohepatic circulation (EHC). For dose optimization, simulating a set of 1000 virtual subjects from the developed model and dividing the subjects into 5 groups with WT of 50, 60, 70, 80, 90 kg, respectively, the optimal dose was explored that achieves the drug concentration most similar to the target, which was defined as the concentration for the 70 kg subject treated with the current standard dosage regimen (the loading dose of 100 mg QD for 3 days, followed by the maintenance dose of 20 mg QD). RESULTS: The data were best described by a two compartment model with first order absorption incorporating EHC with the bile released into the intestine. None of the covariates tested was found to be significant other than WT used in allometry. Simulation showed that the optimal loading dose increased by 15 mg for every 10 kg increment in WT while the optimal maintenance dose was 15 and 25 mg for 50 and 90 kg groups, respectively, and the same (= 20 mg) for the others. Large concentration differences from the target observed in low and high WT groups disappeared when optimal doses were given. CONCLUSIONS: This work demonstrates the importance of a population PK model-based dose optimization approach in maintaining drug therapeutic concentrations in leflunomide treatment.

Effect of Rifampicin on the Pharmacokinetics of Evogliptin in Healthy Volunteers.

Purpose: Evogliptin (DA-1229) is a novel, potent, and selective dipeptidyl peptidase 4 (DPP-4) inhibitor for treating type 2 diabetes mellitus. This study investigates the effect of rifampicin on evogliptin pharmacokinetics. Patients and Methods: An open-label, crossover, one-sequence study was conducted on 12 healthy subjects. Reference baseline pharmacokinetic samples were collected on day 1 after the subjects were administered a single dose of 5 mg evogliptin. After a washout period, the subjects were administered 600 mg rifampicin once daily for 10 days, from days 8 to 17, for full induction of hepatic enzyme activity. On day 17, single doses of evogliptin (5 mg) were administered along with rifampicin (600 mg). The test pharmacokinetic samples were collected with a sampling schedule identical to that used for the reference. Results: Maximum concentration (Cmax) and area under the plasma drug concentration-time curve (AUC0-96h) of evogliptin with and without co-administration of rifampicin were compared. Reference and test Cmax and AUC0-96h values of evogliptin were 4.70 ng/mL vs 4.86 ng/mL and 153.97 ng∙h/mL vs 58.83 ng∙h/mL, respectively. All adverse events were mild in intensity and considered unrelated to evogliptin administration. Conclusion: Rifampicin decreased the AUC0-96h of evogliptin by 61.8% without significantly affecting Cmax. The mechanism underlying the decrease in AUC0-96h is thought to be the induction of cytochrome P450 (CYP), especially 3A, by rifampicin. The adverse events, none of which were serious, were not significantly altered by the concomitant administration of evogliptin and rifampicin. Nevertheless, it would be prudent that evogliptin dosing should be carefully considered when co-administered with CYP3A inducers.