Two-Year Pulmonary Safety and Efficacy of Inhaled Human Insulin (Exubera) in Adult Patients With Type 2 Diabetes

OBJECTIVE—The purpose of this study was to evaluate the 2-year pulmonary safety of inhaled human insulin (Exubera [EXU]) in 635 nonsmoking adults with type 2 diabetes. RESEARCH DESIGN AND METHODS—Patients were randomly assigned to receive prandial EXU or subcutaneous insulin (regular or short-acting) plus basal (intermediate- or long-acting) insulin. The primary end points were the annual rate of decline in forced expiratory volume in 1 s (FEV(1)) and carbon monoxide diffusing capacity (DL(CO)). RESULTS—Small differences in FEV(1) favoring subcutaneous insulin developed during the first 3 months but did not progress. Adjusted treatment group differences in FEV(1) annual rate of change were −0.007 l/year (90% CI −0.021 to 0.006) between months 0 and 24 and 0.000 l/year (−0.016 to 0.016) during months 3–24. Treatment group differences in DL(CO) annual rate of change were not significant. Both groups sustained similar reductions in A1C by month 24 (last observation carried forward) (EXU 7.7–7.3% vs. subcutaneous insulin 7.8–7.3%). Reductions in fasting plasma glucose (FPG) were greater with EXU than with subcutaneous insulin (adjusted mean treatment difference −12.4 mg/dl [90% CI −19.7 to −5.0]). Incidence of hypoglycemia was comparable in both groups. Weight increased less with EXU than with subcutaneous insulin (−1.3 kg [−1.9 to −0.7]). Adverse events were comparable, except for a higher incidence of mild cough and dyspnea with EXU. CONCLUSIONS—Two-year prandial EXU therapy showed a small nonprogressive difference in FEV(1) and comparable sustained A1C improvement but lower FPG levels and less weight gain than seen in association with subcutaneous insulin in adults with type 2 diabetes.