Pharmacokinetic and pharmacodynamic evaluation of linagliptin in African American patients with type 2 diabetes mellitus

AimThis was an open label, multicentre phase I trial to study the pharmacokinetics and pharmacodynamics of the dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin in African American patients with type 2 diabetes mellitus (T2DM). MethodsForty-one African American patients with T2DM were included in this study. Patients were admitted to a study clinic and administered 5mg linagliptin once daily for 7 days, followed by 7 days of outpatient evaluation. ResultsPrimary endpoints were area under the plasma concentration-time curve (AUC), maximum plasma concentration (C-max) and plasma DPP-4 trough inhibition at steady-state. Linagliptin geometric mean AUC was 194 nmoll(-1)h (geometric coefficient of variation, 26%), with a C-max of 16.4nmoll(-1) (41%). Urinary excretion was low (0.5% and 4.4% of the dose excreted over 24h, days 1 and 7). The geometric mean DPP-4 inhibition at steady-state was 84.2% at trough and 91.9% at maximum. The exposure range and overall pharmacokinetic/pharmacodynamic profile of linagliptin in this study of African Americans with T2DM was comparable with that in other populations. Laboratory data, vital signs and physical examinations did not show any relevant findings. No safety concerns were identified. ConclusionsThe results of this study in African American patients with T2DM support the use of the standard 5mg dose recommended in all populations.