The aim of this research is to investigate the extent and clinical relevance of small airways disease in severe eosinophilic asthma patients treated with anti-IL5/5R therapy.

Inclusion Criteria:

• Severe asthma patients treated with anti-IL5/5R therapy (i.e. mepolizumab, benralizumab, reslizumab) for at least 4 months.

Exclusion Criteria:

• No information about lung function at baseline, or after both 4 months and 12 months.
• No information about clinical response (i.e. number of exacerbations, reduction of mOCS/ maintenance oral corticosteroid dose, ACQ, AQLQ) after both 4 months and 12 months.
• Treatment with another anti-IL5/5R therapy before

The study population consists of all severe eosinophilic asthma patients in the MCL, treated with anti-IL5/5R therapy (i.e. mepolizumab, benralizumab, reslizumab) for at least 4 months.