In contrast, clinical trials of IL-33/ST2 axis therapies (itepeximab, astegolimab, tozoracimab) in asthma and COPD have reported predominantly mild to moderate events such as nasopharyngitis, upper respiratory tract infections, and headache, with low rates of serious treatment-related adverse events [118–120]. Here, IL33 is linked to chronic obstructive pulmonary disease.