Pharmacokinetic, pharmacodynamic, and tolerability profiles of the dipeptidyl peptidase-4 inhibitor linagliptin: a 4-week multicenter, randomized, double-blind, placebo-controlled phase IIa study in Japanese type 2 diabetes patients.

BACKGROUND: The dipeptidyl-peptidase-4 (DPP-4) inhibitor linagliptin is under clinical development for treatment of type 2 diabetes mellitus (T2DM). In previous studies in white populations it showed potential as a once-daily oral antidiabetic drug. OBJECTIVES: In compliance with regulatory requirements for new drugs intended for use in the Japanese population, this study investigated the pharmacokinetics, pharmacodynamics, and tolerability of multiple oral doses of linagliptin in Japanese patients with T2DM. METHODS: In this randomized, double-blind, placebo-controlled multiple dose study, 72 Japanese patients with T2DM were assigned to receive oral doses of linagliptin 0.5, 2.5, or 10 mg or placebo (1:1:1:1 ratio) once daily for 28 days. For analysis of pharmacokinetic properties, linagliptin concentrations were determined from plasma and urinary samples obtained throughout the treatment phase, with more intensive samplings on days 1 and 28. DPP-4 inhibition, glycosylated hemoglobin A1c (HbA(1c)) levels, and plasma glucose and glucagon-like peptide-1 (GLP-1) levels were compared by mixed effect model. Tolerability was assessed throughout the study by physical examination, including blood pressure and pulse rate measurements, 12-lead ECG, and laboratory analysis. RESULTS: Baseline demographic characteristics were well balanced across the 4 treatment groups (mean [SD] age, 59.7 [6.4] years in the placebo group, 60.8 [9.2] years in the 0.5 mg group, 60.2 [6.4] years in the 2.5 mg group, and 59.1 [8.6] years in the 10 mg group; mean [SD] weight, 67.2 [10.0] kg in the placebo group, 64.5 [9.0] kg in the 0.5 mg group, 69.6 [9.4] kg in the 2.5 mg group, and 63.5 [12.2] kg in the 10 mg group; mean [SD] duration of T2DM diagnosis, 5.1 [4.2] years in the placebo group, 5.2 [4.7] years in the 0.5 mg group, 5.9 [4.8] years in the 2.5 mg group, and 2.6 [2.3] years in the 10 mg group). The majority of the patients treated were male (76.4%). Use of previous antidiabetic medication was more common in the 2.5 mg linagliptin group (44%) than in the 0.5 or 10 mg linagliptin (15.8% and 22.2%, respectively) or placebo groups (35.3%). Total systemic exposure in terms of linagliptin AUC and C(max) (which occurred at 1.25-1.5 hours) increased in a less than dose-proportional manner. The terminal half-life was long (223-260 hours) but did not reflect the accumulation half-life (10.0-38.5 hours), resulting in a moderate accumulation ratio of <2.9 that decreased with increasing dose. Urinary excretion increased with linagliptin doses but was <7% at steady state for all dose groups. Inhibition of plasma DPP-4 at 24 hours after the last dose on day 28 was approximately 45.8%, 77.8%, and 89.7% after linagliptin 0.5, 2.5, and 10 mg, respectively. At steady state, linagliptin was associated with dose-dependent increases in plasma GLP-1 levels, and the postprandial GLP-1 response was enhanced. Statistically significant dose-dependent reductions were observed in fasting plasma glucose levels at day 29 for all linagliptin groups (-11.5, -13.6, and -25.0 mg/dL for the 0.5, 2.5, and 10 mg groups, respectively; P < 0.05 for all linagliptin groups). Linagliptin also produced statistically significant dose-dependent reductions from baseline for glucose area under the effect curve over 3 hours after meal tolerance tests (-29.0 to -68.1 mg × h/dL; P < 0.05 for all 3 linagliptin groups). For the 0.5 and 10 mg linagliptin-treated groups, there were statistically significant reductions in HbA(1c) from baseline compared with placebo, despite the relatively low baseline HbA(1c) (7.2%) and small sample size (P < 0.01 for both groups). The greatest reduction in HbA(1c) (-0.44%) was seen in the highest linagliptin dose group (10 mg). On dosing for up to 28 days, linagliptin was well tolerated with no reported serious adverse events or symptoms suggestive of hypoglycemia. Overall, fewer adverse events were reported by patients after linagliptin than after placebo (11 of 55 [20%] vs 6 of 17 [35%]). CONCLUSIONS: Linagliptin demonstrated a nonlinear pharmacokinetic profile in these Japanese patients with T2DM consistent with the findings of previous studies in healthy Japanese and white patients. Linagliptin treatment resulted in statistically significant and clinically relevant reductions in HbA(1c) as soon as 4 weeks after starting therapy in these Japanese patients with T2DM, suggesting that clinical studies of longer duration in Japanese T2DM patients are warranted.

Linagliptin, a dipeptidyl peptidase-4 inhibitor in development for the treatment of type 2 diabetes mellitus: a Phase I, randomized, double-blind, placebo-controlled trial of single and multiple escalating doses in healthy adult male Japanese subjects.

BACKGROUND: The dipeptidyl peptidase-4 (DPP-4) inhibitor linagliptin is in clinical development for the treatment of type 2 diabetes mellitus (T2DM). In previous studies in non-Japanese populations, linagliptin showed potential as a once-daily oral antidiabetic drug. OBJECTIVE: This study investigated the tolerability, pharmacokinetics, and pharmacodynamics of linagliptin in healthy adult male Japanese volunteers, in compliance with Japanese regulatory requirements for new drugs intended for use in humans. METHODS: This was a Phase I, randomized, doubleblind, placebo-controlled study in healthy volunteers. Linagliptin or placebo was administered as single escalating doses of 1, 2.5, 5, and 10 mg, or as multiple escalating doses of 2.5, 5, and 10 mg once daily for 12 days. Three quarters of subjects in each dose group were randomized to active drug and one quarter to placebo. Blood and urine samples for determination of pharmacokinetic parameters were obtained before administration of the first dose of study drug and at regular time points after administration, with more frequent blood sampling on days 1 and 12 in subjects receiving multiple doses. Inhibition of DPP-4 activity and plasma concentrations of glucagon-like peptide-1 (GLP-1) and glucose were also determined. Tolerability was assessed throughout the study based on physical examinations, 12-lead ECGs, and standard laboratory tests. RESULTS: Eight subjects were enrolled in each dose group, 6 receiving active drug and 2 receiving placebo. Baseline demographic characteristics were comparable in the single-dose groups (mean [SD] age, 24.5 [3.6] years; mean weight, 61.2 [6.2] kg; mean height, 171.5 [5.3] cm) and multiple-dose groups (mean age, 25.4 [3.7] years; mean weight, 61.6 [5.2] kg; mean height, 170.9 [4.9] cm). Linagliptin displayed nonlinear pharmacokinetics. Total systemic exposure (AUC and C(max)) increased in a manner that was less than dose proportional. T(max) ranged from 1.50 to 6.00 hours, and elimination t((1/2)) ranged from 96.9 to 175.0 hours. Total CL increased with increasing dose (from 140 mL/min in the 1-mg group to 314 mL/min in the 10-mg group), as did apparent V(d) (from 1260 to 3060 L with doses up to 10 mg). Steady state was attained within 2 to 3 days. The accumulation t((1/2)) ranged from approximately 10 to 15 hours. The accumulation ratio with multiple dosing was <1.5 and decreased with increasing dose (approximately 1.2 in the 10-mg dose). Urinary excretion increased with increasing dose and over time in all dose groups, although it did not exceed 7% in any dose group on day 12. Linagliptin inhibited plasma DPP-4 activity in a dose-dependent manner. Mean DPP-4 inhibition was >or=80% over 24 hours after a single dose of 10 mg and after multiple doses of 5 and 10 mg for 12 days. Postprandial plasma GLP-1 concentrations increased from preprandial concentrations by 2- to 4-fold after administration of single doses and by 2- to 2.5-fold on day 12 after administration of multiple doses. Baseline (premeal) plasma GLP-1 concentrations were higher on day 12 than on day 1 in all linagliptin groups. A total of 3 adverse events were reported in 1 subject each: an increase in histamine concentration in a subject receiving a single dose of linagliptin 5 mg, vasovagal syncope in a subject receiving a single dose of linagliptin 10 mg, and pharyngitis in a subject receiving multiple doses of linagliptin 10 mg. None of these events was considered drug related. No episodes of hypoglycemia occurred during the study. CONCLUSIONS: In this short-term study in healthy adult male Japanese volunteers, multiple oral doses of linagliptin inhibited plasma DPP-4 activity and elevated active GLP-1 concentrations in a dose-dependent manner, with no episodes of hypoglycemia. Multiple dosing of linagliptin for 12 days was well tolerated and exhibited a pharmacokinetic/pharmacodynamic profile consistent with a once-daily regimen. Clinical studies in Japanese patients with T2DM appear to be warranted.