- 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