Profile of anti-IL-5 mAb mepolizumab in the treatment of severe refractory asthma and hypereosinophilic diseases

Asthma is a complex disorder frequently associated with a poor symptom control, concomitant morbidity, mortality, and significant health care costs due to lack of compliance or inadequate therapeutic options. Interleukin-5 (IL-5) plays a key role in the pathogenesis of eosinophilic disorders, and in the latest years has become a definite target for treatment. Besides asthma, other hypereosinophilic disorders include the hypereosinophilic syndrome, eosinophilic granulomatosis with polyangiitis, sinonasal polyposis, COPD with eosinophilic airway inflammation, allergic rhinitis, atopic dermatitis, eosinophilic esophagitis. The introduction of mepolizumab, a fully humanized monoclonal antibody that binds to IL-5, may represent a useful therapeutic option to control exacerbations and improve asthma-related quality of life in a subgroup of patients with persistent airway eosinophilia and moderate to severe asthma. Several studies carried out in recent years allow, at present, a careful patient selection for appropriate individualized treatment in severe asthma. Further research is anyway needed in order to better understand the pathogenetic mechanisms of asthma and to find new biomarkers. The high costs of biological agents as compared with standard drugs may be largely offset by increased clinical efficacy and good safety profile in selected patients.