This is a randomised, double-blind, parallel group, placebo-controlled study designed to evaluate the efficacy and safety of a fixed 30 mg dose of benralizumab administered subcutaneously for patients with a history of asthma exacerbations and uncontrolled asthma receiving medium to high-dose inhaled corticosteroid plus long-acting β2-agonist (ICS-LABA) with or without oral corticosteroids and additional asthma controllers.