Mepolizumab decreases the recruitment and survival of eosinophils, inhibits smooth muscle proliferation and remodeling by decreasing eosinophil-derived tumor growth factor secretion, reduces tissue damage by decreasing eosinophil cationic protein and eosinophil peroxidase secretion, decreases mucus secretion and basophil activation by decreasing IL-13, and suppresses BHR by decreasing leukotriene synthesis.[14,15] Looking at the clinical reflection mepolizumab reduced asthma exacerbations, improved asthma control, and reduced oral glucocorticoid requirement in this patient group.[16–18]. This evidence concerns the gene EPX and asthma.