Severe uncontrolled asthma with bronchiectasis: a pilot study of an emerging phenotype that responds to mepolizumab

Background: Asthma and bronchiectasis are different conditions that frequently coexist. The prevalence of bronchiectasis rises considerably in subjects with severe asthma (25%-51%). Objective: We evaluated the clinical and biological efficacy of mepolizumab on our pilot population of severe uncontrolled asthmatics with bronchiectasis not related to other pathologies. Patients and methods: Four patients with severe uncontrolled asthma and diagnosed as bronchiectasis were recruited and started biological treatment with mepolizumab. Standard investigations were performed in all four patients at baseline (T0), after 3 months (T1) and after 1 year (T2) of treatment. Results: After 1 year (T2) of therapy with mepolizumab, patients showed a significant increment of asthma control test value (12 +/- 1.1 vs 24.5 +/- 0.3, P<0.01), a reduction of the number of exacerbations/year (5 +/- 0.7 vs 0.75 +/- 0.75, P<0.01), an increase of pre-bronchodilator FEV1 (1,680 +/- 500 vs 1,860 +/- 550 mL, P<0.01) and a reduction of eosinophils in blood (0.75 +/- 0.14 vs 0.12 +/- 0.02 cells/mu L, P<0.01), in the sputum (9.6%+/- 2.1% vs 5.6%+/- 2.7%, P<0.05) and in nasal cytology (++ vs +). Conclusion: The efficacy of mepolizumab in terms of reduction of inflammation and increase of control that we observed in our patients might suggest that targeting the IL-5 in severe eosinophilic asthma with bronchiectasis may be a good therapeutic strategy.