Pulmonary function over 2 years in diabetic patients treated with prandial inhaled Technosphere Insulin or usual antidiabetes treatment: a randomized trial

Aims: Development of inhaled insulin has increased the need to understand its pulmonary safety. This study evaluated pulmonary function changes in diabetes patients receiving inhaled Technosphere Insulin (TI) or usual antidiabetes treatment (usual care). Methods: This randomized, open‐label study was conducted at 220 sites (25 July 2005 to 29 August 2008). Pulmonary function tests [forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), total lung capacity (TLC) and lung diffusion capacity for carbon monoxide (DLCO)] were prospectively followed over 2 years in patients with type 1 or type 2 diabetes receiving TI (n = 730) or usual care (n = 824), along with a cohort without diabetes not receiving any specific therapy (n = 145). Results: Baseline demographics and pulmonary function were similar between diabetes treatment groups. Lung function declined from baseline in all groups. TI was non‐inferior to usual care for mean change in FEV1 from baseline to month 24 [mean (s.e.m.) 0.037 (0.0119) l; 95% CI 0.014 to 0.060] using mixed‐model repeated‐measure with a pre‐specified non‐inferiority margin of 50 ml/year. After a greater initial decline at month 3 with TI, rate of change (slope) in FEV1, FVC and DLCO (months 3–24) was not statistically different between treatment groups. TI was well tolerated; no serious safety concerns emerged. The most common respiratory event associated with TI was mild, transient cough, occurring within minutes of inhalation. Conclusions: Observed changes in lung function with TI were small, occurred early after therapy initiation, remained non‐progressive over 2 years and were unlikely to be clinically meaningful.