The overall objective is to assess the effect of once daily tiotropium + olodaterol fixed dose combination compared to 5 µg tiotropium (both delivered with the Respimat® inhaler) on moderate to severe COPD exacerbation in patients with severe to very severe COPD.

Inclusion criteria:

• Male or female patients, 40 years of age or older.
• Diagnosis of COPD with a documented post-bronchodilator Forced expiratory volume in one second (FEV1)< 60% of predicted normal and a post-bronchodilator FEV1/ forced vital capacity (FVC) <70% at Visit 1
• Documented history of at least one moderate to severe COPD exacerbation in the previous 12 months requiring treatment with systemic corticosteroids and/or antibiotics and/or related hospitalization.
• Symptomatically stable as defined by: no evidence of COPD exacerbation requiring use of either antibiotics and/or steroids 4 weeks prior to visit 1 and no evidence of change in their usual COPD medication 4 weeks prior to visit 1.
• Current or ex-smokers with a smoking history of more than 10 pack years.

Exclusion criteria:

• Significant disease other than COPD.
• Clinically relevant abnormal baseline haematology, blood chemistry or creatinine > x2 ULN will be excluded regardless of clinical condition. ( A repeat laboratory evaluation can be conducted if deemed necessary by the investigator.)
• Current documented diagnosis of asthma. For patients with allergic rhinitis or atopy, source documentation is required to verify that the patient does not have asthma
• A diagnosis of thyrotoxicosis
• A history of myocardial infarction within 6 months of screening visit.
• Life-threatening cardiac arrhythmia.
• Known active tuberculosis.
• Any malignancy unless free of disease for at least 5 years (patients with treated basal cell carcinoma or squamous cell skin cancers are allowed).
• A history of cystic fibrosis.
• Clinically relevant bronchiectasis.
• Patients with severe emphysema requiring endobronchial interventions within 6 months prior to screening
• A history of significant alcohol or drug abuse in the opinion of the investigator.
• Patients who have undergone thoracotomy with pulmonary resection
• Patients being treated with oral or patch ß-adrenergics.
• Patients being treated with oral corticosteroid medication at unstable doses
• Patients being treated with antibiotics for any reasons within 4 weeks of screening visit
• Patients being treated with PDE4 inhibitors within 3 months of screening visit
• Patients who have taken an investigational drug within one month or six half-lives
• Pregnant or nursing women.
• Women of childbearing potential not using a highly effective method of birth control.