Abstract
Background: Omalizumab is a treatment option for patients whose asthma is poorly controlled with inhaled corticosteroids and long-acting beta2 agonist bronchodilators. Omalizumab reduces IgE mediated airway inflammation and improves the control of asthma, but its effect on airway hyperresponsiveness is controversial. In this study, we evaluated the methacholine responsiveness in patients with allergic asthma treated with omalizumab.
Methods: We studied 16 patients (8 males; mean age 38 years) with moderate to severe allergic asthma treated with omalizumab according to guidelines. Pulmonary function was measured at baseline and after 12 months of treatment, while airway responsiveness to methacholine was measured in patients who reached a FEV1 ≥ 80% of the predicted value after 12 months of treatment. Spirometry and methacholine tests were performed according to standardized guidelines (ATS 1999). Airway hyperresponsiveness was defined by a methacholine PD20 value (provocative dose inducing a 20% drop in FEV1).
Results: The mean FEV1 at baseline was 67.8% of the predicted value (DS 11.3) and 87.3% (DS 14.6) after 12 months of treatment. Eleven of 16 patients reached a FEV1 ≥ 80% after 12 months of treatment and seven among these patients agreed to perform methacholine challenge. The methacholine PD20 was mild (400-1600 mcg) in 5/7 patients, severe (50-100 mcg) in 1/7 patients and normal (>1600 mcg) in 1/7 patients.
Conclusions: These results suggest that the benefits of omalizumab in the control of asthma were accompanied by the persistency of pathological condition in airway hyperresponsiveness to methacholine. Thus further studies are needed to identify a possible modulation of airway hyperresponsiveness by omalizumab.
- Copyright ©ERS 2015
