Halpin DMG, et al. - Researchers evaluated the suitability of peak expiratory flow (PEF) as an alternative primary lung function endpoint for clinical trials in adolescent and adult patients with asthma. The correlation between pre-dose forced expiratory volume in one second and pre-dose PEF, measured under supervision in the clinic, was calculated post hoc. In addition, they used findings from the 8 Phase III parallel-group trials of the global clinical development programme with tiotropium Respimat in patients with asthma aged 12 to 75 years in order to determine the correlations between supervised clinic and unsupervised home measurements for both lung function parameters. Findings are suggestive of the possible utility of pre-dose PEF measured at home to be an alternative primary lung function endpoint for trials in adolescent and adult patients with asthma. The benefits of using home-measured PEF could be the facilitation of trial conduct as well as the enhancement of the convenience for patients by relocating scheduled evaluations from the clinic to the patient’s home.