Exenatide – pharmacokinetics, pharmacodynamics, safety and tolerability in patients >= 75 years of age with Type 2 diabetes

OBJECTIVE: This study evaluated pharmacokinetics, pharmacodynamics,safety, and tolerability of single doses of exenatide in elderly Type 2 diabetes (T2D)patients. METHODS: This placebo-controlled,patient-blind, crossover study compared elderly patients (≥ 75 y, n = 15) to controls( ≥ 45 to ≤ 65y, n = 15) with T2D. Patients were randomized to single subcutaneous doses of exenatide 5μg, placebo or exenatide 10 μg (Sequence 1) or placebo, exenatide 5 μg or exenatide 10 μg (Sequence 2) before a standardized breakfast over three consecutive days. Serial blood samples were collected for plasma exenatide and serum glucose concentrations.Pharmacokinetic data from this study were also integrated with those from six other clinical pharmacology studies to further evaluate the impact of age on plasma exenatide apparent clearance (CL/F) (139 controls ( ≤ 65 y); 28 elderly patients (> 65 y)). RESULTS: Mean ± SD ages for control and elderly patients were 57 ± 6 y and 78 ± 3 y, respectively.All elderly patients had renal impairment at baseline, as compared with one third of controls. Dose-normalized plasma exenatide maximum concentration and exposure were greater in elderly patients, but between-age group differences were neither statistically significant nor considered clinically relevant. The integrated pharmacokinetic analysis showed a significant linear relationship between plasma exenatide CL/F and renal clearance (test of slope = 0, p < 0.001),with no additional effect from age. Exenatide dose-dependently blunted postprandial serum glucose excursions in both age groups. No hypoglycemia or serious adverse events were reported, and exenatide was generally well tolerated in both age groups. CONCLUSIONS: Exenatide dose adjustments should be determined by renal function rather than age in elderly T2D patients.