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): 1.0-5.0,  Asthma All patients' parents (or legal guardians) must sign and date an informed consent consistent with ICH-GCP guidelines and local legislation prior to participation in the trial. Where appropriate, participants should assent to enroll in the study. 2. Male or female patients between 1 and 5 years of age. 3. By a physician documented (at least 6 month) history of persistent asthma symptoms, including (but not limited to) wheezing, cough, and/or shortness of breath. (persistent = need for inhalation corticosteroid maintenance therapy to control asthma symptoms) 4. For patients aged 5 years and capable of performing technically acceptable Pulmonary Function tests (PFTs): documented impaired lung function (i.e. pre-bronchodilator Forced Expiratory Volume in 1 second (FEV1) is smaller or equal to 90% of predicted normal). 5. All patients must have been on maintenance treatment with an inhaled corticosteroid at stable dose, either as mono treatment or in combination with another controller medication, for at least 4 weeks before Visit 1. 6. All patients must be symptomatic (partly controlled) as defined by the Global Initiative for Asthma (GINA) guideline for children aged 5 years and younger in the week prior to Visit 1 (screening) and in the week prior to randomisation (Visit 2). Further apply  Patients with a significant disease other than asthma. 2. Patients with clinically relevant abnormal screening haematology or blood chemistry will be excluded if the abnormality defines a significant disease as defined in criterion 1. 3. Patients with a history of congenital or acquired heart disease, or patients who have been hospitalised for cardiac syncope or failure during the past year. 4. Patients with any unstable or life-threatening cardiac arrhythmia, including cardiac arrhythmia requiring intervention (e.g. pacemaker implantation) or a change in drug therapy within the past year. 5. Patients with a malignancy for which the patient has undergone resection, radiation therapy or chemotherapy. 6. Patients with clinically significant lung diseases other than asthma. 7. Alternative causes (other causes than asthma) that can lead to respiratory symptoms of wheeze, cough and shortness of breath. 8. Patients with known active tuberculosis. 9. Patients who have undergone thoracotomy with pulmonary resection. 10. Patients who are currently in a pulmonary rehabilitation program or have completed a pulmonary rehabilitation program in the 6 weeks prior to the screening visit (Visit 1). Further apply