Abstract

Introduction: Delayed initiation of mepolizumab may influence long-term disease control and the achievement of clinical and functional outcomes in patients with uncontrolled severe asthma (SUA), but no definitive conclusions have yet been established regarding the optimal timing for biologic initiation. The aim of this study was to evaluate, in a real-world clinical setting, the effect of delayed mepolizumab initiation—from the moment patients first met EMA eligibility criteria—on the treatment response (using the EXACTO scale), clinical remission (according to SEPAR-REMAS criteria) and lung function at 12 months and 3 years after treatment initiation. Material and Methods: We conducted a retrospective observational cohort study including 148 patients with SUA treated with mepolizumab from January 2017 to November 2024 in our hospital. Patients were stratified into tertiles according to delay: ≤5 months, 6–19 months, and >19 months. Baseline demographic, clinical, and lung function characteristics were analyzed. Results: Patients with shorter delay exhibited distinct significance baseline profiles, including higher eosinophil counts, lower BMI and current smoker, and better pre-treatment lung function (p < 0.05). Shorter delay was significantly associated with higher rates of good/complete response according to the EXACTO scale at both 12 months and 3 years (p < 0.05). Clinical remission rates were numerically higher in the early-treatment group, although differences did not reach statistical significance. No significant differences in lung function outcomes were observed between delay groups at either 12 months or 3 years. Conclusions: In conclusion, earlier initiation of mepolizumab after meeting EMA criteria is associated with improved clinical response, although it does not significantly influence remission rates or lung function recovery. These findings underscore the importance of timely treatment initiation and reinforce the relevance of accurate phenotypic and endotypic characterization to optimize biologic selection in SUA.

IPC Classification

Keywords