Bioequivalence and food effect assessment for vildagliptin/metformin fixed-dose combination tablets relative to free combination of vildagliptin and metformin in Japanese healthy subjects.

OBJECTIVE: To assess the bioequivalence of vildagliptin/metformin fixeddose combination (FDC) tablets (50/250 mg and 50/500 mg) to free combinations of vildagliptin and metformin and the effect of food on the pharmacokinetics (PK) of vildagliptin and metformin following administration of 50/500 mg FDC tablets. METHODS: Two openlabel, randomized, single-center, singledose, 2-period crossover studies were conducted in Japanese healthy male volunteers. Participants were administered vildagliptin/ metformin FDC tablets (study I: 50/250 mg, study II: 50/500 mg) or their free combinations under fasted condition. Food effect (standard Japanese breakfast: fat, 20 - 30% with ~ 600 kcal in total) was assessed during an additional period in study II (50/500 mg). PK parameters (AUC, C(max), t(max), t(1/2)) were calculated for vildagliptin and metformin. RESULTS: In both studies, vildagliptin/metformin FDC tablets were bioequivalent to their respective free combinations. Administration of FDC tablets after meals had no effect on vildagliptin PK parameters. The rate of absorption of metformin decreased when administered under fed condition, as reflected by a prolonged t(max) (3 hours in fasted state vs. 4 hours in fed state) and decrease in C(max) by 26%, however, the extent of absorption (AUC(last)) was similar to that in the fasted state. CONCLUSIONS: Vildagliptin/metformin FDC tablets were bioequivalent to their free combinations. Food decreased the C(max) of metformin by 26%, while AUC(last) was unchanged, consistent with previous reports. No food effect was observed on the C(max) or AUC(last) of vildagliptin. Thus, food had no clinically relevant effects on the PK of metformin or vildagliptin.

Ethnic sensitivity assessment - pharmacokinetic comparability between Japanese and non-Japanese healthy subjects on selected mAbs.

OBJECTIVE: Ethnic sensitivity studies (ESSs), where safety and pharmacokinetics (PK) are assessed in Japanese subjects, are routinely conducted according to Japanese regulatory requirement before the subsequent clinical studies. The necessity of ESSs is questionable in case of mAbs, where inherent IgG characteristics are considered ethnically insensitive. This report investigated PK profiles and immunogenicity (IG) following a single administration of mAbs in Japanese and non-Japanese healthy subjects. RESEARCH DESIGN AND METHODS: PK and IG comparison between Japanese and non-Japanese healthy subjects was made on mAbs data available from public domain and unpublished internal reports. PK comparison was made based on statistical approach as well as assumed typical IgG profile using modeling and simulation. RESULTS: When compared directly, most mAbs showed no difference between ethnic groups. When profiles of various mAbs were fit to an assumed typical IgG PK model, the majority of mAbs follow the expected behavior regardless of ethnicities. Deviations from this behavior did not appear to be due to inherent ethnic differences. When the incidence of IG was assessed, only Adalimumab showed apparent ethnic difference. CONCLUSIONS: The overall lack of observational difference may facilitate discussion of mAbs' early clinical development in Japan, including the utility of dedicated ESSs.

Population pharmacokinetic analysis for 10-monohydroxy derivative of oxcarbazepine in pediatric epileptic patients shows no difference between Japanese and other ethnicities.

Oxcarbazepine is an anti-epileptic drug, which is almost completely metabolized by cytosolic enzymes in the liver to the active 10-monohyroxy metabolite (MHD) following oral administration. The pharmacokinetic (PK) profiles of MHD were evaluated in pediatric epileptic patients and a possible ethnic difference in PK of MHD between Japanese and non-Japanese pediatric patients was assessed. A non-linear mixed effect modeling approach was used to determine the PK of MHD. A one-compartment population model with first-order absorption appropriately described the PK of MHD. No clinically relevant differences were found for using body surface area or weight to explain between-patient variability, therefore the final model included the effects of body weight on apparent clearance (CL/F) and apparent volume of distribution (V/F) of MHD, and in addition, the effect of 3 concomitant anti-epileptic drugs (carbamazepine, phenobarbital and phenytoin) on CL/F of MHD. Inclusion of ethnicity as a covariate in the final model, concluded no ethnic difference with respect to CL/F of MHD between Japanese and non-Japanese patients. Hence, oxcarbazepine can be generally applied using the same dosage and administration for the treatment of partial onset seizures in pediatric patients, regardless of ethnicity.