 Patients will then enter the cross-over study design during which they will receive one of the two study treatments: indacaterol 110 μgGlycopyrronium 50 μg Ultibro once a day or Tiotropium 18 μg Spiriva once a day. The treatment period will be three weeks. There will be a 2-week washout period between the two treatment phases. Total study duration will thus be 11 weeks. 