Chronic obstructive pulmonary disease (COPD) is associated with eosinophilic airway inflammation in 10-20% of patients. Benralizumab, a monoclonal antibody, has been shown to decrease the number of blood and sputum eosinophils. In this trial of 101 patients with COPD whether benralizumab reduces the number of acute exacerbations was investigated. Benralizumab was found to be no more effective at preventing acute COPD exacerbations than placebo overall. However, the authors conclude that subgroup analyses suggest more research into the use of benralizumab in patients with COPD and eosinophilia is required.