A pilot randomised clinical trial of mepolizumab in COPD with eosinophilic bronchitis

Airflow limitation in chronic obstructive pulmonary disease (COPD) is associated with influx of various inflammatory cells (e.g. eosinophils, neutrophils, lymphocytes, macrophages) into the airways. Approximately one-third of stable COPD patients and one in five COPD exacerbations are associated with eosinophilic bronchitis that usually responds to inhaled or ingested corticosteroids [1]. Specific anti-eosinophil agents like mepolizumab, a humanised monoclonal antibody against interleukin 5 (IL-5), reduce severe asthma exacerbations and improve lung function [2–4]. The improvement in forced expiratory volume in 1 s (FEV1) is also associated with a decrease in biomarkers of airway remodelling, such as sputum hyaluronan and versican, over a 6-month treatment period [5]. It is not known if the same benefits are observed in patients with COPD and eosinophilia in whom the airflow obstruction is due to cigarette smoke-related bronchitis and emphysema. Eosinophils may not directly contribute to luminal obstruction in COPD although they may predict steroid response http://ow.ly/b3Au308wA0m