The study is a multicenter, randomized, 2-period, open-label, two arm, cross-over study to show the superior effect of a 4 week treatment each with QVA149 versus tiotropium on lung function. Similarly, this study aims to evaluate patient preference after experiencing both treatment regimens in patients with a clinical diagnosis of COPD (GOLD 2013) and a moderate to severe airflow limitation who are symptomatic (defined as CAT score of at least 10) at screening despite being treated with tiotropium

Inclusion Criteria:

• signed an Informed Consent Form
• stable COPD according to current guidelines (GOLD 2013)
• airflow limitation indicated by a post-bronchodilator FEV1/FVC ratio of <0.70 and a post-bronchodilator FEV1 of ≥30% and <80% of predicted normal values at Visit 2.
• current or ex-smokers who have a smoking history of at least 10 pack years
• Patients on stable tiotropium (18 µg/d) monotherapy for at least 8 weeks before Visit 1
• Symptomatic patients defined as patients with CAT score ≥ 10 at Visit 1 (Screening).

Exclusion Criteria:

• Pregnant or breast feeding mothers
• Patients with conditions contraindicated for treatment
• Patients with a history of clinically significant diseases
• Patients who have a clinically significant renal disease
• Patients with myocardial infarctions less than 6 months prior to study entry
• Patients with recent (less than 1 year) history of NYHA Class III/IV left ventricular failure.
• Patients with narrow-angle glaucoma, symptomatic prostatic hyperplasia or bladder-neck obstruction or urinary retention
• Patients with a history of malignancy of any organ system
• Patients who have had a COPD exacerbation that required treatment with antibiotics, and/or systemic steroids (oral or intravenous) and/or hospitalization in the 6 weeks prior to Screening
• Patients who have had a respiratory tract infection within 6 weeks prior to Screening
• Patients with any history of asthma.