Mepolizumab long-term remodeling effect in severe asthma responders: the MESILICO study

MESILICO study has provided evidence on the effect of mepolizumab, an anti-IL-5 biologic, on airway remodeling in severe asthma at 12 months post-treatment (NCT04612556).

We continued to investigate the longer-term effect of mepolizumab on airway structural remodeling.

Forty-seven patients were recruited, who initiated mepolizumab, of whom 41 were enrolled in the bronchoscopy sub-study. At 3-years the participants underwent further bronchoscopic airway sampling and remodeling indices were measured, along with sub-mucosal eosinophils, tissue immunoexpression of Muc-5AC, E-cadherin and number of FOXP3+ regulatory-like cells.

Thirty-five patients of the initial 47 cohort completed 3 years of treatment, associated with significant improvements in lung function, in biomarkers and a decrease in exacerbation events (p<0.05). Twenty-five of the 41 patients enrolled in the sub-study were submitted to bronchoscopy post 3-years of treatment. There was a significant sustained reduction from baseline in sub-basement membrane thickness, airway smooth muscle area and layer thickness and epithelial damage, as well as a decrease in tissue eosinophil numbers (all p<0.001). Additional improvements were seen at 3 years for Muc-5AC and E-cadherin histoscores and FOXP3+ regulatory-like cells.

This is the first study supporting the possibility that sustained IL-5 blockade may contribute to long-term structural airway improvement and may be consistent with disease modification in severe eosinophilic asthma.