The purpose of this study is to investigate the effectiveness of inhaled mometasone/formoterol versus inhaled fluticasone/salmeterol on peripheral airway function in treatment of asthma.

Peripheral airway dysfunction is associated with poor asthma outcome including asthma exacerbation and more symptoms. The peripheral or small airway is anatomically defined by airways with 2 mm diameter or less. Several techniques have been used for evaluating peripheral airways such as spirometry, body plethysmography, impulse oscillometry and imaging studies. Since inhaled corticosteroid is corner stone for treatment of asthma, the addition of long acting beta agonist is indicated in severe asthma with poorly controlled disease despite of high dose inhaled corticosteroid.

The inhaled corticosteroid and long acting beta agonists are available for treating asthma. There were different results in comparison studies of different inhaled corticosteroid and long acting beta agonist. These differences are related to type of inhaled formulation, potency of inhaled corticosteroid or dose and outcome measurements. The previous short term studies shown that inhaled budesonide/formoterol is superior to inhaled fluticasone/salmeterol combination for reducing of peripheral airway resistance measured by impulse oscillometry. However, the active drug was delivered by using dry powder inhaler. There is no direct comparison between inhaled mometasone/formoterol and inhaled fluticasone/salmeterol administered using metered dose inhalers. For these reasons, we conduct the open label study comparing the effect of two inhaled corticosteroid and long acting beta agonist in newly diagnosed asthma who are eligible for being treated with such combination therapies.

Eligible patients who have clinically diagnosed asthma requiring treatment with combined inhaled corticosteroid and long acting beta agonist according to Global Initiative for Asthma (GINA) guideline. The patients will be randomized to receive either inhaled mometasone/formoterol (100/5 microgram) 2 puffs twice daily or inhaled fluticasone/salmeterol (125/25 microgram) 2 puffs twice daily administered using metered dose inhalers.

The primary outcome is peripheral airway function measured by airway resistance at 5 and 20 Hz frequency from impulse oscillometry. The secondary outcome are peak expiratory flow rate, forced expiratory flow at 1 second, forced vital capacity, forced expiratory flow at 25-75% of vital capacity (FEF25-75%) measured by spirometry, residual volume per total lung capacity ratio measured by body plethysmography ,asthma control test score and asthma control questionaire-7 version. All outcome are measured at baseline and 6-week post treatments in both arms.

Inclusion Criteria:

1. Newly diagnosed asthma according to Global Initiative for Asthma (GINA) guideline 2014 without previous treatment of inhaled corticosteroid and long acting beta agonists
2. Patients with asthma symptoms of most days or wake up due to asthma one time per week or more
3. Patients with the presence of any risk factors of asthma according to Global Initiative for Asthma (GINA) guideline 2014
4. Patients with severe uncontrolled asthma
5. Patients with previous asthma exacerbation
6. Patients give consent form

Exclusion Criteria:

1. Patients with contra-indication for performing spirometry according to American Thoracic Society (ATS) and European Respiratory Society (ERS) statement of standardization for spirometry
2. Patients refuse to participate study -