Effects of Leukotriene Modulator Montelukast on Cough Variant Asthma

Study groups: 99 patients diagnosed with CVA will be randomised into three groups as follows: Group 1: inhaled corticosteroid+β2 agonist The patients with cough variant asthma received Symbicort Turbuhaler (Budesonide 160µg and Formoterol 4.5µg) 1puff Q12h for 8 weeks. Group 2: montelukast The patients with cough variant asthma received montelukast 10mg QN for 8 weeks, without any other corticosteroid or β2 agonist. Group 3: montelukast combined with inhaled corticosteroid+β2 agonist The patients with cough variant asthma received montelukast 10mg QN combined with Symbicort Turbuhaler (Budesonide 160µg and Formoterol 4.5µg) 1puff Q12h for 8 weeks.. The study will be divided into following phases: 1. First Visit (Visit 1, day -6): A full medical history and physical examination to be undertaken to determine whether patients meet the inclusion/exclusion criteria. After the informed consent has been signed, the following samples are obtained from all patients: blood samples for routine clinical laboratory tests (haematology, biochemistry and chest x-ray). A urine pregnancy test will be performed in women of childbearing potential. Bronchial provocation test by methacholine inhalation are performed to determined the presence of bronchial non-specific hyper-responsiveness. Patients are given the Diary Card. 2. Screening Period ( day -6 to day 0, 6 Days) Patients took two medications as bellows for 3 days and followed by 3 days of wash-out period. Patients should completed 6 days diary card, starting from day -6 to week 0. Bambuterol HCI (Bambec, brand name), 10 mg qn po Theophylline tablet sustained release, 100mg bid po 3. Second Visit (Visit 2, Week 0): A physical examination were to be performed. All laboratory tests results are obtained to determine whether patients meet the inclusion/exclusion criteria. Concurrent medication were recorded. The Diary Card were collected, reviewed and assessed whether ICS, bronchodilator or ICS/BD treatment is efficient for cough symptom (symptom score improved 1 at least). Capsaicin challenge test and FENO were performed and hypertonic saline induced sputum samples for cell differential, urine leukotriene, serum IgE, were taken from enrolled patients. Enrolled patients were randomized into different groups, and the study medication were dispensed. 4. During Treatment 1(Week 0 to Week 4, 14 days): Patients were to take study medication for 28 days and completed Diary Card for 7 days from Week 3 to Week 4. 5. Third Visit (Visit 3, Week 4): A physical examination were to be performed. The Diary Card were collected and reviewed. Adverse events, secondary complications, concurrent medication will be recorded. Capsaicin challenge test and FENO were performed and hypertonic saline induced sputum samples for cell differential were taken from enrolled patients. 6. During Treatment 2 (Week 4 to Week 8, 14 days): Patients were to take study medication for 28 days and completed Diary Card for 7 days from Week 7 to Week 8. 7. Forth Visit (Visit 4, Week 8): A physical examination and were to be performed. The Diary Card were collected and reviewed. Residual (unused) medications were to be returned. Adverse events, secondary complications, concurrent medication will be recorded. Capsaicin challenge test and FENO were performed and hypertonic saline induced sputum samples for cell differential, urine leukotriene, serum IgE, were taken from enrolled patients. Blood samples for routine clinical laboratory tests (haematology and biochemistry) were obtained, if a clinically significant laboratory abnormal result was noted at the visit 4, AE and a follow-up visit would be considered.