Pharmacokinetic, pharmacodynamic, and tolerability profiles of the dipeptidyl peptidase-4 inhibitor alogliptin: a randomized, double-blind, placebo-controlled, multiple-dose study in adult patients with type 2 diabetes.
BACKGROUND
Alogliptin is a highly selective dipeptidyl peptidase-4 (DPP-4) inhibitor that is under development for the treatment of type 2 diabetes (T2D).


OBJECTIVES
This study was conducted to evaluate the pharmacokinetic (PK), pharmacodynamic (PD), and tolerability profiles and explore the efficacy of multiple oral doses of alogliptin in patients with T2D.


METHODS
In this randomized, double-blind, placebo-controlled, parallel-group study, patients with T2D between the ages of 18 and 75 years were assigned to receive a single oral dose of alogliptin 25, 100, or 400 mg or placebo (4:4:4:3 ratio) once daily for 14 days. PK profiles and plasma DPP-4 inhibition were assessed on days 1 and 14. Tolerability was monitored based on adverse events (AEs) and clinical assessments. Efficacy end points included 4-hour postprandial plasma glucose (PPG) and insulin concentrations, and fasting glycosylated hemoglobin (HbA(1c)), C-peptide, and fructosamine values.


RESULTS
Of 56 enrolled patients (57% women; 93% white; mean age, 55.6 years; mean weight, 89.8 kg; mean body mass index, 31.7 kg/m(2)), 54 completed the study. On day 14, the median T(max) was ~1 hour and the mean t(1/2) was 12.5 to 21.1 hours across all alogliptin doses. Alogliptin was primarily excreted renally (mean fraction of drug excreted in urine from 0 to 72 hours after dosing, 60.8%-63.4%). On day 14, mean peak DPP-4 inhibition ranged from 94% to 99%, and mean inhibition at 24 hours after dosing ranged from 82% to 97% across all alogliptin doses. Significant decreases from baseline to day 14 were observed in mean 4-hour PPG after breakfast with alogliptin 25 mg (-32.5 mg/dL; P=0.008), 100 mg (-37.2; P=0.002), and 400 mg (-65.6 mg/dL; P<0.001) compared with placebo (+8.2 mg/dL). Significant decreases in mean 4-hour PPG were also observed for alogliptin 25, 100, and 400 mg compared with placebo after lunch (-15.8 mg/dL [P=0.030]; -29.2 mg/dL [P=0.002]; -27.1 mg/dL [P=0.009]; and +14.3 mg/dL, respectively) and after dinner (-21.9 mg/dL [P=0.017]; -39.7 mg/dL [P<0.001]; -35.3 mg/dL [P=0.003]; and +12.8 mg/dL). Significant decreases in mean HbA(1c) from baseline to day 15 were observed for alogliptin 25 mg (-0.22%; P=0.044), 100 mg (-0.40%; P<0.001), and 400 mg (-0.28%; P=0.018) compared with placebo (+0.05%). Significant decreases in mean fructosamine concentrations from baseline to day 15 were observed for alogliptin 100 mg (-25.6 micromol/L; P=0.001) and 400 mg (-19.9 micromol/L; P=0.010) compared with placebo (+15.0 micromol/L). No statistically significant changes were noted in mean 4-hour postprandial insulin or mean fasting C-peptide. No serious AEs were reported, and no patients discontinued the study because of an AE. The most commonly reported AEs for alogliptin 400 mg were headache in 6 of 16 patients (compared with 0/15 for alogliptin 25 mg, 1/14 for alogliptin 100 mg, and 3/11 for placebo), dizziness in 4 of 16 patients (compared with 1/15, 2/14, and 1/11, respectively), and constipation in 3 of 16 patients (compared with no patients in any other group). No other individual AE was reported by >2 patients receiving the 400-mg dose. Apart from dizziness, no individual AE was reported by >1 patient receiving either the 25- or 100-mg dose.


CONCLUSIONS
In these adult patients with T2D, alogliptin inhibited plasma DPP-4 activity and significantly decreased PPG levels. The PK and PD profiles of multiple doses of alogliptin in this study supported use of a once-daily dosing regimen. Alogliptin was generally well tolerated, with no dose-limiting toxicity.