 Primary endpoint will be the difference in Borg dyspnea score after the 3-min constant rate shuttle walking test after 3 weeks of treatment between indacaterol 110μgGlycopyrronium 50μg Ultibro versus Tiotropium 18μg Spiriva alone. Secondary endpoints will be the difference in Borg dyspnea score after the 3-min constant rate shuttle walking test after 3 weeks of treatment between indacaterol 110μgGlycopyrronium 50μg Ultibro versus baseline value Visit 3 and between Tiotropium 18μg Spiriva alone versus baseline value Visit 3. The dyspnea response after the first dose of therapy will also be assessed. The between-treatment differences in the improvement of pulmonary function FEV1 and inspiratory capacity, TDI and CAT scores from baseline V4 to end of treatment period V5 and V7 will also be evaluated. 