The purpose of the study is to compare the efficacy, safety and tolerability of aclidinium bromide/formoterol fumarate and salmeterol/fluticasone propionate in patients with chronic obstructive pulmonary disease (COPD)

Inclusion Criteria:

• Adult male or non-pregnant, non-lactating female aged ≥40.
• Current or ex-cigarette smoker, with a smoking history of at least 10 pack-years
• Patients with a clinical diagnosis of COPD according to GOLD guidelines 2013, with a post-bronchodilator FEV1 <80%, and FEV1/FVC < 70% at Screening Visits
• Symptomatic patients with a COPD assessment test (CAT) ≥10 at Screening and Randomisation Visits
• Patient must be able to perform repeatable pulmonary function testing for FEV1 according to ATS/ERS 2005 criteria at Screening Visits
• Patients eligible and able to participate in the trial and who consent to do so in writing after the purpose and nature of the investigation have been explained

Exclusion Criteria:

• History or current diagnosis of asthma
• Development of a respiratory tract infection or COPD exacerbation within 6 weeks (or 3 months if hospitalisation was required) before the Screening Visit or during the run-in period
• Clinically significant respiratory conditions
• Type I or uncontrolled Type II diabetes, uncontrolled hypo- or hyperthyroidism, hypokalaemia, or hyperadrenergic state, uncontrolled or untreated hypertension
• Patients who, in the investigator's opinion, may need to start a pulmonary rehabilitation programme during the study and/or patients who started/finished it within 3 months prior to Screening Visit
• Use of long-term oxygen therapy (≥15 hours/day)
• Patients treated on daily basis with triple therapy (LABA+LAMA+ICS) within 4 weeks prior to the Screening Visit
• Patient who does not maintain regular day/night, waking/sleeping cycles including night shift workers
• Clinically significant cardiovascular conditions
• Patient with clinically relevant abnormalities in the results of the clinical laboratory tests, ECG parameters or in the physical examination at the Screening Visit
• Patient with a history of hypersensitivity reaction to inhaled anticholinergics, sympathomimetic amines, or inhaled medication or any component thereof (including report of paradoxical bronchospasm)
• Patient with known narrow-angle glaucoma, symptomatic bladder neck obstruction, acute urinary retention, or patients with symptomatic non-stable prostatic hypertrophy
• Patient with known non-controlled history of infection with human immunodeficiency virus (HIV) and/or active hepatitis
• History of malignancy of any organ system (including lung cancer), treated or untreated, within the past 5 years other than basal or squamous cell skin cancer
• Patient with any other serious or uncontrolled physical or mental dysfunction
• Patient with a history (within 2 years prior to Screening Visit) of drug and/or alcohol abuse that may prevent study compliance based on investigator judgment
• Patient unlikely to be cooperative or that can't comply with the study procedures
• Patient treated with any investigational drug within 30 days (or 6 half-lives, whichever is longer) prior to Screening Visit
• Patient who intend to use any concomitant medication not permitted by this protocol or who have not undergone the required stabilization periods for prohibited medication
• Any other conditions that, in the investigator's opinion, might indicate the patient to be unsuitable for the study