Intrasubject variability of inhaled insulin in type 1 diabetes: a comparison with subcutaneous insulin

We compared intrasubject variability of insulin and glucose profiles after a standardized meal between insulin inhaled via the AERx insulin Diabetes Management System (AERx iDMS, Aradigm Corp., Hayward, CA) and given as a subcutaneous injection. In this single-center, parallel, randomized, open-labeled trial, 17 male, non-smoking patients with type 1 diabetes (mean age, 27.7 years; body mass index, 23.4 kg/m(2)) received a fixed, individualized dose of human insulin, on four treatment days followed by an individualized breakfast, administered either by inhalation via AERx iDMS (n = 9) or by subcutaneous injection. Serum insulin and serum glucose levels were determined at regular intervals for 6 h postdose. Intrasubject variability was expressed as coefficient of variation. No statistically significant differences in intrasubject variability were observed between the treatments for the areas under the insulin curves for 0-6 h [27% vs. 19% (inhaled insulin vs. subcutaneous)] and areas under the glucose curves 0-6 h (30% vs. 23%). Intrasubject variability values for insulin half-life, terminal elimination rate constant, and mean residence time were significantly less in the inhaled insulin group compared with the subcutaneous insulin group (P = 0.01-0.02). Only one potentially trial product-related adverse event (an audible wheeze) was reported, and no clinically relevant changes in pulmonary function were detected. The intrasubject variability was comparable between patients receiving inhaled insulin and subcutaneous insulin, thereby confirming the reproducibility of administering insulin via AERx iDMS. Inhaled insulin was well tolerated and is a feasible alternative to subcutaneous insulin in patients with type 1 diabetes.