Background: Biological therapies, such as mepolizumab, have transformed the treatment of severe eosinophilic asthma. While mepolizumab's short-term effectiveness is established, there is limited evidence on its ability to achieve long-term clinical remission. Objective: To evaluate the long-term effectiveness and safety of mepolizumab, explore its potential to induce clinical and sustained remission, and identify baseline factors associated with the likelihood of achieving remission over 24 months. Methods: The REMI-M is a retrospective, real-world, multicenter study that analyzed 303 severe eosinophilic asthma patients who received mepolizumab. Clinical, demographic, and safety data were collected at baseline, 3, 6, 12, and 24 months. The most commonly used definitions of clinical remission, which included no exacerbations, no oral corticosteroids (OCS) use, and good asthma control with or without assessment of lung function parameters, were adopted. Sustained remission was defined as reaching clinical remission at 12 months and maintaining it until the end of the 24-month period. Results: Clinical remission rates ranged from 28.6% to 43.2% after 12 months and from 26.8% to 52.9% after 24 months, based on the different remission definitions. The proportion of patients achieving sustained remission varied between 14.6% to 29%. Factors associated with the likelihood of achieving clinical remission included the presence of aspirin-exacerbated respiratory disease, better lung function, male sex, absence of anxiety/depression, gastro-esophageal reflux disease, bronchiectasis, and reduced OCS consumption. Adverse events were infrequent. Conclusions: This study demonstrates the real-world effectiveness of mepolizumab in achieving clinical remission and sustained remission in severe eosinophilic asthma over 24 months. The identification of distinct factors associated with the likelihood of achieving clinical remission emphasizes the importance of comprehensive management of comorbidities and timely identification of patients who may benefit from biologics.

CC has received honoraria for lectures from F&P, ResMed, Vitalaire, GSK, AstraZeneca, Sanofi. The other authors declare no conflicts of interest.

This study did not receive any funding

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This study adhered to the Declaration of Helsinki and received approval from the Ethics Committee Catania 1 at the Policlinico University Hospital (Protocol Number 33/2020/PO). The institutional review boards at all participating centers approved the study protocol prior to the initiation of the study. All patients signed a written informed consent.

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All data produced in the present study are available upon reasonable request to the authors