There are several biological drugs currently available to treat severe asthma: anti-IL-5 (mepolizumab, reslizumab, benralizumab), anti-IgE (omalizumab), anti-IL-4/IL-13 (dupilumab), and anti-TSLP (tezepelumab) agents (Table 1). This evidence concerns the gene IL4 and asthma.