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): 12.0-50.0,  Asthma Informed consent: Subjects must give their signed and dated written informed consent to participate prior to commencing any study related activities Age Range: 12 to 50 years of age, inclusive, at Visit 1 (Screening) Diagnosis: A diagnosis of asthma, as defined by the National Institutes of Health for at least 12 weeks prior to Visit 1 Asthma Severity: Subjects must have a pre-bronchodilator FEV1 of >=70 percent of the predicted normal value. Predicted values will be based upon Global Lung Function Initiative equations for spirometry reference values Evidence of EIB: Subjects must answer "Yes" to at least 2 of the following 3 questions reflecting on the previous 12 months Are you short of breath during exercise or other physical exertion? Do you wheeze after exercise or other physical exertion? Do you cough after exercise or other physical exertion? Concurrent Anti-Asthma Therapy: Subjects must be taking low to moderate dose inhaled steroids for 12 weeks prior to Visit 1 in order to participate with no change in dose for the 4 weeks prior to Visit 1  Intermittent Asthma, Seasonal Asthma, or Exercise-Induced Bronchoconstriction Only: Subjects with only intermittent or seasonal asthma or only exercise-induced asthma are excluded from participation in this study History of Life-threatening Asthma: Defined for this protocol as an asthma episode that required intubation and/or was associated with hypercapnia, respiratory arrest or hypoxic seizures within the last 10 years Asthma Exacerbation: Any asthma exacerbation requiring oral corticosteroids within 12 weeks of Visit 1 or that resulted in an overnight hospitalization requiring additional treatment for asthma within 6 months prior to Visit 1 Symptomatic Allergic Rhinitis: Subjects with symptomatic allergic rhinitis at Visit 1 may be treated for up to four weeks with intranasal corticosteroids followed by a repeat screening visit to determine prior to entry into the study. Subjects that continue to be symptomatic after up to four weeks of treatment will be excluded Lead Electrocardiogram (ECG): A subject is not eligible if he/she has an abnormal, clinically significant ECG as determined by the investigator at the Screening Visit Pregnancy: Women who are pregnant or lactating or are planning on becoming pregnant during the study Respiratory Infection: Culture-documented or suspected bacterial or viral infection of the upper or lower respiratory tract, sinus or middle ear that is not resolved within 4 weeks of Visit 1 and led to a change in asthma management or, in the opinion of the investigator, is expected to affect the subject's asthma status or the subject's ability to participate in the study Concurrent Respiratory Disease: A subject must not have current evidence of: 1. Atelectasis 2. Bronchopulmonary dysplasia 3. Chronic bronchitis 4. Chronic obstructive pulmonary disease (COPD) (current or past diagnosis including asthma/COPD overlap) 5. Pneumonia 6. Pneumothorax 7. Interstitial lung disease 8. Or any evidence of concurrent respiratory disease other than asthma Other Concurrent Diseases/Abnormalities: A subject must not have any clinically significant, uncontrolled condition, or disease state that, in the opinion of the investigator, would put the safety of the subject at risk through study participation or would confound the interpretation of the efficacy results if the condition/disease exacerbated during the study Investigational Medications: A subject must not have used any investigational drug within 30 days prior to Visit 1 or within five half-lives (t1/2) of the prior investigational study, whichever is longer of the two periods