Background: Co-Suspension™ Delivery Technology offers a novel pharmaceutical platform for inhaled drug therapy. This randomized, double-blind, placebo-controlled, single-dose study (NCT01349868) evaluated the efficacy of a range of doses for formoterol fumarate (FF) delivered using Co-Suspension delivery technology via a pressurized metered dose inhaler (MDI) versus placebo in patients with moderate-to-severe chronic obstructive pulmonary disease (COPD). Secondary objectives included determination of non-inferior efficacy and systemic exposure compared with open-label Foradil® 12 μg (Foradil® Aerolizer®; formoterol fumarate dry powder inhaler). Methods: Patients received each of the 6 study treatments (FF MDI [7.2, 9.6 and 19.2μg], placebo MDI and open-label Foradil® [12 and 24µg]), separated by 3-10 days. Spirometry was performed 60 and 30 minutes prior to and at regular intervals up to 12 hours post-administration of study drug. The primary outcome measure was the change in forced expiratory volume in 1 second (FEV1) area under the curve between 0 and 12 hours (AUC0-12) relative to test day baseline. Results: A total of 50 patients were randomized to study treatment sequences. All doses of FF MDI demonstrated superiority to placebo (p<0.0001) and non-inferiority to Foradil® 12μg, on bronchodilator outcome measures. No serious adverse events were reported during the study. Conclusions: This study demonstrates non-inferiority of bronchodilator response and bioequivalent exposure of FF MDI 9.6μg to Foradil® 12μg, with both agents exhibiting a similar safety profile in patients with moderate-to-severe COPD. This study supports the selection of FF MDI 9.6µg for further evaluation in Phase III trials.