A Study to Evaluate the Effect of Umeclidinium (UMEC) as Combination Therapy in Subjects With Chronic Obstructive Pulmonary Disease (COPD)

Inclusion Criteria: * Type of subject: 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 and female subjects are eligible to participate in the study. A female is eligible to enter and participate in the study if she is of: Non-child bearing potential (i.e., physiologically incapable of becoming pregnant, including any female who is post-menopausal or surgically sterile). Surgically sterile females are defined as those with a documented hysterectomy and/or bilateral oophorectomy or tubal ligation. Post-menopausal females are defined as being amenorrhoeic for greater than 1 year with an appropriate clinical profile, e.g., age appropriate, \>45 years, in the absence of hormone replacement therapy. OR Child bearing potential, has a negative pregnancy test at screening, and agrees to one of the following acceptable contraceptive methods used consistently and correctly (i.e., in accordance with the approved product label and the instructions of the physician for the duration of the study - screening to follow-up contact): Abstinence; Oral Contraceptive, either combined or progestogen alone; Injectable progestogen; Implants of levonorgestrel; Estrogenic vaginal ring; Percutaneous contraceptive patches; Intrauterine device (IUD) or intrauterine system (IUS) that meets the Standard Operating Procedure (SOP) effectiveness criteria as stated in the product label; Male partner sterilization (vasectomy with documentation of azoospermia) prior to the female subject's entry into the study, and this male is the sole partner for that subject. For this definition, "documented" refers to the outcome of the investigator's/designee's medical examination of the subject or review of the subject's medical history for study eligibility, as obtained via a verbal interview with the subject or from the subject's medical records; Double barrier method: condom and an occlusive cap (diaphragm or cervical/vault caps) with a vaginal spermicidal agent (foam/gel/film/cream/suppository) * Diagnosis: An established clinical history of COPD in accordance with the definition by the American Thoracic Society/European Respiratory Society * Smoking History: Current or former cigarette smokers with a history of cigarette smoking of \>=10 pack-years \[number of pack years = (number of cigarettes per day / 20) x number of years smoked (e.g., 20 cigarettes per day for 10 years, or 10 cigarettes per day for 20 years)\]. Former smokers are defined as those who have stopped smoking for at least 6 months prior to Visit 1. Pipe and/or cigar use cannot be used to calculate pack year history. * Severity of Disease: A pre and post-albuterol/salbutamol Forced Expiratory Volume in One Second /Forced Vital Capacity (FEV1/FVC) ratio of \<0.70 and post-albuterol/salbutamol FEV1 of \<=70% of predicted normal values at Visit 1 (Screening) calculated using reference values provided by Quanjer. * Current clinically prescribed medication: The subject must be on the dose and frequency of one of the following ICS/LABA combinations approved for COPD at least 30 days prior screening : FSC at a dose of 500/50 mcg twice-daily (i.e. SERETIDE DISKUS™ inhaler or approved generic product such as AIRFLUSAL FORSPIRO inhaler 500/50 mcg twice daily or ROLENIUM ELPENHALER inhaler 500/50 mcg twice daily) ; The combination of budesonide/formoterol (i.e., SYMBICORT TURBUHALER inhaler) at doses of 200/6 mcg twice-daily or 400/12 mcg twice-daily . * Dyspnea: A score of \>=2 on the Modified Medical Research Council (mMRC) Dyspnea Scale at Visit 1. 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. A subject who, in the opinion of the investigator, has any other significant respiratory conditions in addition to COPD should be excluded. Examples may include clinically significant bronchiectasis, pulmonary hypertension, sarcoidosis, or interstitial lung disease. * Other Diseases/Abnormalities: The subject is considered unlikely to survive the duration of the study period or has any rapidly progressing disease or immediately life-threatening illness e.g. cancer. * Contraindications: Any history of allergy or hypersensitivity to any anticholinergic/muscarinic receptor antagonist, beta2-agonist, sympathomimetic, corticosteroid (intranasal, inhaled or systemic) lactose/milk protein or magnesium stearate. * Hospitalization: Hospitalization for COPD or pneumonia within 12 weeks prior to Visit 1. * Lower respiratory tract infection: Subjects with lower respiratory tract infection that required the use of antibiotics within 6 weeks prior to Visit 1. * Lung Resection: Subjects with lung volume reduction surgery within the 12 months prior to Visit 1. * Unstable or life threatening cardiac disease: UMEC should be used with caution in subjects with severe cardiovascular disease. In the opinion of the investigator, use should only be considered if the benefit is likely to outweigh the risk in conditions such as: Myocardial infarction or unstable angina in the last 6 months; Unstable or life threatening cardiac arrhythmia requiring intervention in the last 3 months; New York Heart Association (NYHA) Class IV heart failure * 12-Lead Electrocardiogram (ECG): Investigators will be provided with ECG reviews conducted by a centralized independent cardiologist to assist in evaluation of subject eligibility. The Principle Investigator will determine the clinical significance of each abnormal ECG finding in relation to the subject's medical history and exclude subjects who would be at undue risk by participating in the trial. Subjects with the following abnormalities are excluded from participation in the study: Atrial fibrillation with rapid ventricular rate \>120 beats per minute (bpm); Sustained or nonsustained ventricular tachycardia; Second degree heart block Mobitz type II and third degree heart block (unless pacemaker or defibrillator had been inserted) * Antimuscarinic effects: Subjects with medical conditions such as narrow-angle glaucoma, prostatic hypertrophy, or bladder neck obstruction should only be included if, in the opinion of the study physician, the benefit outweighs the risk. * Interactions: Concomitant administration with beta-blockers and strong Cytochrome P450 3A4 (CYP3A4) inhibitors is only permitted if, in the Investigator's opinion, the likely benefit outweighs the potential risk. * Severe Hepatic Impairment: Patients with severe hepatic impairment (Child-Pugh class C) should be excluded unless, in the opinion of the investigator, the benefit is likely to outweigh the risk. * Medication Prior to Spirometry: Unable to withhold albuterol/salbutamol for the 4 hour period required prior to spirometry testing at each study visit. * Medications Prior to Screening: Use of the following medications according to the following defined time intervals prior to Visit 1: Depot corticosteroids (12 weeks), Systemic, oral or parenteral corticosteroids (6 weeks); Antibiotics (for lower respiratory tract infection) (6 weeks); CYP3A4 strong inhibitors (6 weeks) ; ICS /LABA combination products except SERETIDE and approved FSC 500/50 generic products and SYMBICORT at approved doses and frequencies for COPD (30 days) ; SERETIDE, approved FSC 500/50 generic products, and SYMBICORT at approved doses and frequencies for COPD (12 hours prior to screening); Phosphodiesterase 4 (PDE4) Inhibitor (roflumilast) (14 days); Long-acting muscarinic antagonists (tiotropium, aclidinium, glycopyrronium, UMEC) (7 days); Inhaled long acting beta2 agonists (LABA) (salmeterol, formoterol: 48 hrs) olodaterol, indacaterol (14 days); LAMA/LABA combination products (Apply whichever mono component has the longest washout) Theophyllines (48 hours); Oral beta2-agonists (Long-acting: 48 hours) (Short-acting: 12 hours); Inhaled short acting beta2-agonists (4 hours); Inhaled short-acting anticholinergics (4 hours); Inhaled short-acting anticholinergic/short-acting beta2-agonist combination products (4 hours); Any other investigational medication (30 days or within 5 drug half-lives, whichever is longer). Note: Use of study provided albuterol/salbutamol is permitted during the study, except in the 4-hour period prior to spirometry testing. Intra-articular and epidural corticosteroid injections are permitted. Corticosteroids for short term treatment of COPD exacerbations is allowed * 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., albuterol/salbutamol) via nebulized therapy. * Pulmonary Rehabilitation Program: Participation in the acute phase of a pulmonary rehabilitation program within 4 weeks prior to Visit 1, or who will enter the acute phase of a pulmonary rehabilitation program during the study. 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: A subject will not be eligible for this study if he/she is an immediate family member of the participating investigator, subinvestigator, study coordinator, or employee of the participating investigator. * 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. DISKUS is a trade mark of the GlaxoSmithKline Group of Companies. Other company or product names mentioned herein may be the property of their respective owners.