Cross-Over Study in Subjects With COPD, Evaluating Lung Function Response After Treatment With Once Daily Umeclidinium 62.5mcg, Vilanterol 25mcg, and Umeclidinium/Vilanterol 62.5/25mcg

Inclusion Criteria: * Type of Patient: Outpatient * Informed Consent: A signed and dated written informed consent prior to study participation * Age: Subjects 40 years of age or older at Visit 1 * Gender: Male or female subjects. * COPD diagnosis: As defined by the American Thoracic Society/European Respiratory Society (ATS/ERS) * Severity of disease: A pre- and post-salbutamol FEV1/FVC ratio of \<0.70 and a pre- and post-salbutamol FEV1 of ≤ 70% of predicted normal values at Visit 1 * Smoking History: Current or former cigarette smokers with a history of cigarette smoking of ≥ 10 pack-years at Visit 1 * Female subject of non child-bearing potential OR a female subject of child bearing potential, with a negative pregnancy test at screening, and agreeing to consistently and correctly use one of the acceptable contraceptive methods Exclusion Criteria: * Pregnancy: Women who are pregnant or lactating or are planning on becoming pregnant during the study * Asthma: A current diagnosis of asthma * Other Respiratory Disorders: Known alpha-1 antitrypsin deficiency, active lung infections (such as tuberculosis), and lung cancer are absolute exclusionary conditions. * Other Diseases/Abnormalities: Subjects with historical or current evidence of clinically significant cardiovascular, neurological, psychiatric, renal, hepatic, immunological, endocrine (including uncontrolled diabetes or thyroid disease) or hematological abnormalities that are uncontrolled and/or a previous history of cancer in remission for \< 5 years prior to Visit 1 * Contraindications: A history of allergy or hypersensitivity to any anticholinergic/muscarinic receptor antagonist, beta2-agonist, lactose/milk protein or magnesium stearate or a medical condition such as of narrow-angle glaucoma, prostatic hypertrophy or bladder neck obstruction that, in the opinion of the study physician contraindicates study participation or use of an inhaled anticholinergic. * Hospitalization: Hospitalization for COPD or pneumonia within 12 weeks prior to Visit 1. * Lung Resection: Subjects with lung volume reduction surgery within the 12 months prior to Visit 1. * 12-Lead ECG: An abnormal and significant ECG finding from the 12-lead ECG conducted at Visit 1 * Screening Labs: Significantly abnormal finding from clinical chemistry or hematology tests at Visit 1 as determined by the study investigator. * Medication Prior to Spirometry: Unable to withhold salbutamol for the 4 hour period required prior to spirometry testing at each study visit and at each spirometry test performed at home. * Medications Prior to Screening: Use of the prohibited medications according to defined time intervals prior to Visit 1 * Oxygen: Use of long-term oxygen therapy (LTOT) described as oxygen therapy prescribed for greater than 12 hours a day. As-needed oxygen use (i.e., ≤ 12 hours per day) is not exclusionary. * Nebulized Therapy: Regular use (prescribed for use every day, not for as-needed use) of short-acting bronchodilators (e.g., salbutamol, ipratropium bromide) via nebulized therapy * Pulmonary Rehabilitation Program: Participation in the acute phase of a pulmonary rehabilitation program within 4 weeks prior to Visit 1. Subjects who are in the maintenance phase of a pulmonary rehabilitation program are not excluded. * Drug or Alcohol Abuse: A known or suspected history of alcohol or drug abuse within 2 years prior to Visit 1. * Affiliation with Investigator Site: Is an investigator, sub-investigator, study coordinator, employee of a participating investigator or study site, or immediate family member of the aforementioned that is involved in this study. * Inability to read: In the opinion of the Investigator, any subject who is unable to read and/or would not be able to complete a questionnaire