Aliskiren Exhibits Similar Pharmacokinetics in Healthy Volunteers and Patients with Type 2 Diabetes Mellitus

Background: The renin system is an attractive target for antihypertensive therapy in patients with diabetes mellitus. However, diabetes is associated with changes in gastrointestinal, renal and hepatic function that may affect the absorption and disposition of oral drugs. This study compared the pharmacokinetics and pharmacodynamics of the orally active direct renin inhibitor, aliskiren, in healthy volunteers and patients with type 2 diabetes.

Methods: This was an open-label study conducted in 30 patients with type 2 diabetes and 30 healthy volunteers matched for age, bodyweight and race. Following a 10-hour fast, all participants received a single oral dose of aliskiren 300mg. Blood samples were taken at frequent intervals for 96 hours post-dose for determination of plasma concentrations of aliskiren (using a high-performance liquid chromatography-tandem mass spectroscopy method). Plasma renin activity (PRA) and renin concentration (RC) were also measured for 24 hours after dosing.

Results: Aliskiren exhibited similar pharmacokinetics in patients with type 2 diabetes and healthy volunteers. Exposure to aliskiren was slightly higher in patients with type 2 diabetes compared with healthy volunteers (mean area under the plasma concentration-time curve from 0 to 24 hours 1859 vs 1642 ng · h/mL; maximum observed plasma drug concentration 394 vs 348 ng/mL), while apparent clearance corrected for bioavailability was slightly lower (205 vs 234 L/h) and elimination half-life slightly longer (44 vs 39.9 hours), but there were no statistically significant differences for any pharmacokinetic parameters. There was no significant correlation between glycaemic control (% glycosylated haemoglobin) and any of the measured pharmacokinetic parameters in patients with type 2 diabetes. Aliskiren caused sustained suppression of PRA for at least 24 hours after dosing despite increasing RC; there were no major differences in the pharmacodynamic effects of aliskiren between patients with type 2 diabetes and healthy volunteers. Aliskiren was well tolerated in both patient groups, with no clinically significant changes in laboratory values and a low risk of adverse events.

Conclusion: Aliskiren showed a similar pharmacokinetic profile in healthy volunteers and patients with type 2 diabetes, and administration of a single oral 300mg dose of aliskiren was well tolerated by both patients and healthy volunteers. The pharmacodynamic effects of aliskiren were also similar in healthy volunteers and diabetic patients, with sustained inhibition of renin system activity observed for at least 24 hours after dosing.