The goals of control status of asthma have been changed with the improvement of its management as a chronic disease; many steps should be taken to achieve asthma control as defined by the GINA/NIH guidelines. There are good results with single variables, but overall asthma control should be addressed in different ways. Most traditional clinical studies provide an incomplete assessment of disease control, despite good clinical practice. The association of inhaled corticosteroid (IC) and long-action beta 2 agonist (LABA) has already showed their efficacy to reduce asthma symptoms, exacerbations and cost for moderate and severe asthma patients as well as the improvement in their quality of life. On the other hand, even with the use of first line maintenance medication, as recommended by guidelines, some asthmatic patients fail in obtaining a total control of the disease. This lack of efficacy, led us to hypothesize, that these patients who fail in response, would present chronic and fixed airway obstruction as a consequence of persistent inflammation and airway remodeling. This study has the purpose of looking for an adequate composite measure to provide an indicator of overall asthma status more accurately and meaningfully as reflect of treatment effectiveness and disease control. For this, we will test by a randomized control trial if an additional oral corticosteroid treatment could modify spirometric and plethysmography values, nasal and low airway cytology and HRCT (to evaluate small airway) in regularly treated stable asthma patients who have a positive bronchodilator response.