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. Exclusion Criteria: 1. History or current diagnosis of asthma. 2. Clinically significant respiratory conditions other than COPD at the time of Inform Consent signature 3. Hospitalisation due to COPD exacerbation within the previous 3 months. 4. Signs of a COPD exacerbation or respiratory infection (including the upper respiratory tract) within the previous 6 weeks. 5. Clinically significant cardiovascular conditions 6. Presence of symptomatic prostatic hypertrophy and/or bladder neck obstruction. 7. Presence of narrow-angle glaucoma. 8. QTcB) above 470 milliseconds in the ECG performed at Screening Visit, 9. Patient who does not maintain regular day/night, waking/sleeping cycles