AMPLIFY - D6571C00001 Duaklir USA Phase III Study

Inclusion Criteria: * Adult male or non-pregnant, non-lactating female patients aged ≥40. * Patients with diagnosis of moderate to very severe stable COPD: post-bronchodilator FEV1 \< 80% of the predicted normal and post-bronchodilator FEV1/FVC \< 70% at Screening Visit. * Symptomatic patients with a CAT score ≥10 at Screening and Randomization visit (Visits 1 and 2). * Current or former-smokers, with a smoking history of ≥ 10 pack-years. * Patients able to perform acceptable and repeatable pulmonary function testing for FEV1 according to the American Thoracic Society (ATS)/European Respiratory Society (ERS) 2005 criteria at Visit 1. * Patients eligible and able to participate in the study and who had signed an Informed Consent Form prior to initiation of any study-related procedures. Exclusion Criteria: * Involvement in the planning and/or conduct of the study (applies to AstraZeneca staff and/or site staff), or patients employed by or relatives of the employees of the site or sponsor. * Previous randomization in the present study D6571C00001. * Patients with predominant asthma. * Any respiratory tract infection (including the upper respiratory tract) or COPD exacerbation (including the mild COPD exacerbation) within 6 weeks prior to screening or during the run-in period. * Patients hospitalized for a COPD exacerbation (an emergency room visit for longer than 24 hours is considered a hospitalization) within 3 months prior to Screening Visit. * Clinically significant respiratory conditions other than COPD. * Patients who in the Investigator's opinion may need to start a pulmonary rehabilitation program during the study and/or patients who started/finished it within 3 months prior to Screening. * Use of long-term oxygen therapy (≥ 15 hours/day). * Patients who do not maintain regular day/night, waking/sleeping cycles including night shift workers. * Clinically significant cardiovascular conditions. * Patients with uncontrolled Type I or Type II diabetes, uncontrolled hypo-or hyperthyroidism, hypokalaemia, or hyperadrenergic state, uncontrolled hypertension. * Patients with history of long QT syndrome or whose QTc (calculated according to Fridericia's Formula QTc=QT/RR1/3) \> 470 ms as indicated in the centralised reading report assessed at Screening. * Patients with clinically significant abnormalities in the laboratory tests, ECG parameters (other than QTc) or in the physical examination at Screening Visit that might comprise patient safety. * Patient with known non-controlled history of infection with human immunodeficiency virus and/or active hepatitis. * Patient with a history of hypersensitivity reaction to inhaled medication or any component thereof, including paradoxical bronchospasm. * Patients with known narrow-angle glaucoma, symptomatic bladder neck obstruction, acute urinary retention or symptomatic non-stable prostate hypertrophy. * 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. * Patients with any other serious or uncontrolled physical or mental dysfunction. * Patients with a history (within 2 years prior to screening) of drug and/or alcohol abuse that may prevent study compliance based on the Investigator judgment. * Patients unlikely to be cooperative or that cannot comply with the study procedures. * Patients treated with any investigational drug within 30 days (or 6 half-lives, whichever is longer) prior to Screening. * Patients who intended to use any concomitant medication not permitted by this protocol or who had not undergone the required washout period for a particular prohibited medication. * Patients unable to give consent, or patients of consenting age but under guardianship, or vulnerable patients. Patients who demonstrate \< 80% compliance with the electronic diary during the run-in period.