Mepolizumab: A Review in Eosinophilic Asthma

Mepolizumab (Nucala(®)) is a humanized monoclonal antibody against interleukin-5, a cytokine involved in the development, recruitment and activation of eosinophils (cellular mediators of airway inflammation, hyper-responsiveness and tissue remodelling). The drug is indicated as an add-on treatment for severe eosinophilic asthma, on the basis of its clinical benefit in this setting in the placebo-controlled DREAM, MENSA and SIRIUS trials. Based on the 52-week, phase II, DREAM study (which assessed varying intravenous mepolizumab dosages), intravenous mepolizumab 75 mg every 4 weeks (q4w) and the corresponding (recommended) subcutaneous dosage of 100 mg q4w were studied in the 32- and 24-week phase III MENSA and SIRIUS trials. In patients aged ≥12 years with severe eosinophilic asthma in the phase III studies, adding subcutaneous mepolizumab 100 mg q4w to current asthma therapy significantly reduced the rate of clinically relevant asthma exacerbations and, in those dependent on oral glucocorticoids (OCSs) for asthma control, enabled the daily OCS dose to be significantly reduced, relative to adding placebo. This mepolizumab regimen also significantly improved asthma control, health-related quality of life and (in one of the two studies) lung function, and had acceptable tolerability (with headache the most common adverse event). In the MENSA and SIRIUS extension, COSMOS, mepolizumab provided durable clinical benefit over up to 84 weeks' therapy with no new tolerability concerns. Thus, mepolizumab is a valuable add-on treatment option for adults and adolescents aged ≥12 years who have severe eosinophilic asthma despite optimized standard therapies.