IL-33, inflammation and mucus in COPD: the final FRONTIER?

COPD is the third leading cause of death worldwide and a disease in desperate need of novel therapies [1, 2]. The recent positive results with dupilumab, targeting the interleukin (IL)-4/IL-13 receptor, are exciting and open the potential for patients with eosinophilic inflammation to benefit from a biological therapy that can reduce exacerbations by approximately 30% on top of standard of care, such as inhaled corticosteroids and bronchodilators [3]. Nevertheless, the benefit of dupilumab is observed in patients with eosinophilic COPD defined by an eosinophil count >300 cells·μL⁻¹ [3]. Estimates suggest this represents 10–20% of COPD patients after exclusion of co-existing asthma [4, 5].