A multicenter, randomized, double-blind dose-ranging study of glycopyrrolate/formoterol fumarate fixed-dose combination metered dose inhaler compared to the monocomponents and open-label tiotropium dry powder inhaler in patients with moderate-to-severe COPD

•Of the dose-range evaluated, GFF MDI 18/9.6 μg was the most effective at improving lung function.•GFF MDI 18/9.6 μg significantly improved FEV1 AUC0−12 vs GP MDI 18 μg, FF MDI 9.6 μg and open-label tiotropium.•All doses of GFF MDI (except 1.2/9.6 μg) significantly improved FEV1 AUC0–12 vs comparators, in a dose-ordered manner.•Adverse event profiles were similar across all treatment groups.•GP 18 μg was determined as the optimal dose to combine with FF MDI 9.6 μg for Phase III trials.