INTRODUCTION AND OBJECTIVES: We aimed to analyse long-term evolution of clinical, inflammatory and lung function parameters in patients with refractory eosinophilic asthma treated with Mepolizumab over 3 years and to identify treatment's predicting factors for success.

METHODS: Multicentre study in routine clinical practice in 76 patients followed over 3 years from 3 hospitals. Clinical (demographic, disease control (ACT), annual severe exacerbations, hospital admissions, oral and inhaled steroid doses), functional (FEV1, FEV1/FVC, FVC) and inflammatory (blood eosinophilia, FENO) factors, were assesed at baseline and after 3 years of treatment. The response was scored according to the multidimensional scale (EXACTO) of the 2022 Spanish Asthma Consensus.

RESULTS: We included 76 patients (female 73.7%). Evaluable patients were 67, excluding withdrawals due to side effects (6), pregnancy (2) and deaths (1). Significant improvements in ACT (12.2 vs. 21.2), number of exacerbations (4.4 vs. 0.3), emergency visits (3.7 vs. 0.24), and oral steroid cycles (4.4 vs. 0.28) were observed. FEV1 improved by more than 245 cc from baseline and blood eosinophilia was significantly reduced. Treatment response was complete in 15 patients (22.4%), good in 20 (29.8%), partial in 14 (20.9%) and no response in 18 (26.9%). In the multivariate analysis the predictors for complete response were baseline eosinophilia, for good+complete response also baseline BMI.

CONCLUSIONS: At 3 years of treatment, patients had significant improvements in ACT, number of exacerbations, hospital admissions, oral steroid therapy and lung function. Predictors of treatment success were baseline eosinophilia and low BMI.