Inhaled corticosteroids (ICS) are appreciated for their long term anti-inflammatory effects in chronic asthma. However, they also have largely unappreciated early effects when initiated as a controller therapy in a steroid-naïve population. Impulse oscillometry might reveal such an early effect better than spirometry. The investigators sought to examine the onset of action and sustained effects over 4 weeks treatment of mometasone furoate as measured by Impulse Oscillometry System (IOS) versus spirometry.

Inclusion Criteria:

• Age between 18-65 years inclusive.
• Written informed consent (conducted according to the GCP and ICH guidelines) to participate in the study. Ability to comply with all study requirements.
• Mild to moderate persistent asthma with symptoms at least 2 times per week, managed by as-needed SABA only.
• A 35% or greater improvement in small airway dysfunction defined by IOS AX after inhaled SABA.
• Allergic response to one or more common allergens at screening via skin test.
• Male, or female of childbearing potential using a medically approved birth control method.
• Evidence of SAD manifested by an index of peripheral airway reactance of > 10.5 cm H2O/L (3 times the upper limit of adult normal).
• Symptoms of airflow obstruction (i.e. dyspnea on exertion greater than peers at similar exercise levels, wheeze, or cough > 3 weeks without respiratory infection, or nocturnal dyspnea, and use of SABA > 2 times per week)

Exclusion Criteria:

• Subjects with severe persistent asthma and/or subjects taking inhaled or systemic corticosteroids or long acting beta agonists (LABA).
• Subjects < 18 years of age or > 65 years.
• Pregnant or lactating females.
• History of diabetes.
• Acute infections within 4 weeks prior to Screening.
• Concurrent medical condition that might interfere with the interpretation of efficacy and safety data during the study.
• Contraindications and warnings according to the specific label for Asmanex.
• Chronic inhaled or systemic corticosteroid treatment (> 7 consecutive days of treatment) within 30 days prior to Screening.
• Investigational drug treatment within 30 days prior to Screening. Treatment with any drug with a known and frequent toxicity to a major organ system within the past 60 days.