IL5 and asthma: Mepolizumab, an anti-interleukin (IL)-5 therapy, was approved in 2015 for add-on maintenance treatment of patients with severe asthma ≥ 12 years of age and with an eosinophilic phenotype; in 2018 the EU license was extended to include patients with severe asthma ≥ 6 years of age.