Patient description: A 39-year-old man came to the clinic with cough and shortness of breath that was not relieved by his inhaler. He had these symptoms for 5 days during the past 2 weeks. He doubled his oral corticosteroids in the past week. He is a chef with a history of asthma for 3 years, suffering from frequent cough, wheezing, and shortness of breath and chest tightness. The symptoms become more bothersome within 1-2 hours of starting work every day and worsen throughout the work week. His symptoms improve within 1-2 hours outside the workplace. Spirometry was performed revealing a forced expiratory volume in the first second (FEV1) of 63% of the predicted. His past medical history is significant for seasonal allergic rhinitis in the summer. He doesn't smoke or use illicit drugs. His family history is significant for asthma in his father and sister. He currently uses inhaled corticosteroid (ICS) and fluticasone 500 mcg/salmeterol 50 mcg, one puff twice daily.

Clinical trial eligibility criteria: eligible ages (years): 12.0-999.0,  Persistent Asthma Key 1. Written informed consent, and assent if applicable, must be obtained before any assessment is performed. 2. Male or female patients 12 years of age and older 3. Confirmed diagnosis of persistent asthma, as defined by national and international asthma guidelines (e.g., GINA; NIH; etc.) for at least 1 year prior to study enrollment. 4. PEF≥50% of predicted normal value. 5. Current and appropriate use of one of the treatments listed in the protocol for asthma. 6. Recent asthma exacerbation between 30 days and 12 months prior to randomization that either required treatment with systemic corticosteroids (tablets, suspension, or injection) or required hospitalization (defined as an inpatient stay or >24-hour stay in an observation area in an emergency room or other equivalent facility) Key  History of life-threatening asthma episode that required intubation and/or was associated with hypercapnia requiring non-invasive ventilatory support. 2. Current evidence of pneumonia, pneumothorax, atelectasis, pulmonary fibrotic disease, allergic bronchopulmonary aspergillosis, cystic fibrosis, bronchopulmonary dysplasia, or other respiratory abnormalities other than asthma. 3. Current evidence of, or past physician assessment of, chronic bronchitis, emphysema, or chronic obstructive pulmonary disease. 4. History of smoking ≥ 10 pack years. 5. Exercise induced asthma (as the only asthma-related diagnosis) not requiring daily asthma control medicine. 6. Suspected or documented bacterial or viral infection of the upper or lower respiratory tract, sinus or middle ear that is not resolved at randomization. 7. Worsening/Unstable asthma within 7 days prior to randomization. 8. Any asthma exacerbation requiring systemic corticosteroids within 30 days of randomization or more than 4 separate exacerbations in the 12 months preceding randomization. 9. Two or more hospitalizations for greater than 24 hours duration for treatment of asthma in the 12 months preceding randomization. 10. History of hypersensitivity to any beta2-agonist, sympathomimetic drug, inhaled corticosteroids, or systemic corticosteroid therapy or any component of the possible study treatments in this trial, including severe milk protein hypersensitivity. 11. Use of anti-IgE (e.g., omalizumab) or any other monoclonal antibody, in the 6 months prior to randomization. 12. Use of (Beta) β-blockers within 1 day prior to first dose of study medication. 13. Use of ICS, LABA, ICS+LABA, LTRAs, leukotriene modifiers, anticholinergics, or theophylline must be discontinued prior to the first dose of investigational treatment. 14. Use of a potent CYP3A4 inhibitor within 4 weeks of randomization (e.g., ritonavir, atazanavir, clarithromycin, indinavir, itraconazole, nefazodone, nelfinavir, saquinavir, ketoconazole, telithromycin)