Lung Cancer-Related Mortality With Inhaled Insulin or a Comparator: Follow-Up Study of patients previously enrolled in Exubera Controlled Clinical Trials (FUSE) Final Results

The Follow-Up Study of patients previously enrolled in Exubera controlled clinical trials (FUSE) was designed to evaluate whether patients previously treated with Exubera (EXU; insulin human [rDNA origin], inhaled powder) in controlled clinical trials died because of incident primary lung cancer at a substantially higher rate than patients treated with a comparator. FUSE is a hybrid, randomized, controlled trial/cohort study including participants of 17 prior EXU clinical trials. Pooled patient data from these trials were used, and the subset of patients enrolled in the follow-up cohort study was followed prospectively for 2 years in order to evaluate the incidence of fatal and nonfatal primary lung cancers and all-cause mortality. There were 24,409 person-years (PY) of observation among 7,439 trial patients, with 4,017 PY (16.5%) from the period after the trials but before the prospective follow-up and 5,299 PY (21.7%) from the prospective follow-up. Just over half of the 2,631 patients (51.6%) in the prospective follow-up were randomized to EXU in the original trial. The incidence density ratio was 2.8 (95% CI 0.5, 28.5) for lung cancer-related mortality and 3.7 (95% CI 1.0, 20.7) for incident primary lung cancer. The hazard ratio for all-cause mortality was 0.81 (95% CI 0.60, 1.10). These data cannot exclude an increased risk of lung cancer-related mortality associated with EXU use. If real, the absolute increased risk of lung cancer-related mortality was small (0.48 cases per 1,000 PY). For all-cause mortality-the most reliably measured end point with the clearest interpretation-EXU users did not experience an excess all-cause death rate (relative or absolute) compared with users of other diabetes treatments over the study period.