A New Drug Application (NDA) has been submitted to the FDA for aclidinium bromide, a long-acting inhaled antimuscarinic agent developed for the treatment of COPD. The submission includes efficacy data from a phase III double-blind placebo-controlled programme in which patients received aclidinium bromide 400 mcg or 200 mcg twice daily or placebo. In the pivotal studies, aclidinium 400 mcg twice-a-day, the proposed to-be-marketed dose, produced statistically significant improvement in morning trough FEV1 vs. placebo at week 12 (p<0.0001), the primary endpoint assessed as support for the US NDA, and at week 24 (p<0.0001), the primary endpoint assessed in one study as support for a European filing. The most commonly reported adverse reactions were headache and nasopharyngitis.