IL-5 is a key cytokine responsible for the maturation, recruitment and survival of eosinophils. The role of eosinophils in pathomechanisms of severe asthma and association of those cells with frequent exacerbations are well accepted. Novel biologic agents including anti-IL-5 antibodies (mepolizumab and reslizumab) as well as anti-IL-5 receptor α chain (benralizumab) have been developed. Benralizumab (Fasenra™) leads to reduced eosinophil counts in airway mucosa, blood, sputum and a clear inhibition of eosinophil differentiation and maturation in the bone marrow. In clinical studies, benralizumab significantly reduces the rate of asthma exacerbations and has a clear oral glucocorticoid sparing effect. The frequency and the type of reported adverse events do not differ between active treatment and placebo arms.