Patient description: The patient is a 15-year-old boy with asthma diagnosed a year ago. He presents with shortness of breath, chest tightening and cough. According to his mother, he didn't respond to the usual corticosteroid inhaler. He was admitted to the emergency department with diagnosis of severe asthma exacerbation. He is a candidate for general corticosteroid therapy. Spirometry revealed a forced expiratory volume in the first second (FEV1) of 60% of the predicted. His past medical history is non-significant. His family history is significant for asthma in his mother and his uncle. He used to be treated with combination of inhaled corticosteroids and Zafirlukast.

Clinical trial eligibility criteria: eligible ages (years): 12.0-999.0,  Asthma Subjects must be 12 years of age or older of either gender, who (and their parent/guardian if the subject is under the age of 20) must demonstrate their willingness to sign and write informed consent Subjects must have had a history of asthma for at least 6 months The subject must be diagnosed mild persistent or moderate persistent asthma and his/her FEV1 must be >= 60% of predicted normal at both the Screening and Baseline visits, when short-acting inhaled beta agonists have been withheld for at least six hours and long-acting inhaled beta agonists have been withheld for at least 12 hours Subjects must demonstrate an increase in absolute FEV1 of >= 12%, with an absolute volume increase of at least 200 mL, after reversibility testing at the Screening visit, or historically within the past 12 months; Subjects without documented absolute FEV1 of >= 12% in reversibility test within the past 12 months need to demonstrate a positive result in Methacholine challenge test If Subjects with ICS treatment have been using ICS on a daily basis for at least 4 weeks prior to Screening. For the two weeks prior to Screening, subjects must have been on a stable regimen of ICS. Each ICS dose is shown in following Flunisolide between 1000 to 2000 mcg/day Budesonide between 400 to 800 mcg/day Triamcinolone acetonide between 600 to 1600 mcg/day Beclomethasone Dipropionate between 252 to 840 mcg/day Fluticasone propionate between 200 to 500 mcg/day  Female subjects who are pregnant, breast-feeding, or are pre-menarcheal Subjects who are heavy smokers (more than 10 pack years) or who smoked within previous 6 months Subjects who have required daily or alternate day oral corticosteroid treatment for more than a total of 14 days during the 3 months immediately prior to the Screening visit, and/or subjects who have required a course of systemic corticosteroids within the previous month Subjects who used Leukotriene modifiers within 2 weeks of screening Subjects who took immunosuppressive agents within the previous 3 months Subjects who use daily nebulized ß2-adrenergic agonists Subjects who have had either an asthma exacerbation or a clinically relevant change in asthma medication within the last 4 weeks Subjects who have been admitted to the hospital for asthma control within the previous 3 months or have needed emergency service for asthma more than once within the previous 6 months Subjects who have required ventilator support for respiratory failure secondary to their asthma within the last 5 years Subjects who have used any investigational drug in the 30 days prior to Baseline, or subjects who have been treated with any investigational antibody for asthma in the 90 days prior to Baseline