Efficacy and safety of three doses of aclidinium bromide compared to placebo and to an active comparator in Chronic Obstructive Pulmonary Disease (COPD) patients.

Inclusion Criteria

• 1. Males and non-pregnant, non-lactating females aged ≥ 40.
• 2. Patients with a clinical diagnosis of stable moderate to severe COPD, according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines: (http://www.goldcopd.com) and stable airway obstruction. Post-salbutamol FEV1/FVC < 70% at Screening Visit (Visit 1) (i.e., 100xpost-salbutamol FEV1/FVC <70%).
• 3. Current, or ex-cigarette smoker with a smoking history of at least 10 pack-years.
• 4. Patient whose FEV1 at the Screening Visit measured between 10-15 minutes post inhalation of salbutamol is 30% < FEV1 <80% of the predicted normal value (i.e., 100 x Post-salbutamol FEV1/ Predicted FEV1 must be < 80% and ≥ 30%).
• 5. Female patients at least 1 year post-menopausal, surgically sterile (defined as having a hysterectomy or tubal ligation), or practicing a medically approved and highly effective method of contraception.
• 6. Patients who understand the study procedures and are willing to participate in the study as indicated by signing the informed consent.