Analysis of the drop-out rate in patients receiving mepolizumab for severe asthma in real life

Mepolizumab (anti IL-5, monoclonal antibody) is commercially available in Italy since more than one year for the treatment of severe hypereosinophilic asthma. Its efficacy and safety were evaluated in several regulatory trials. The characteristics of this drug in real life began to be assessed only recently. We describe herein the dropout rate observed with mepolizumab in real life, because this datum can indirectly reflect the safety and tolerability aspects. The demographic and clinical data of patients receiving mepolizumab for severe asthma were collected, and the number and reasons for discontinuation of the treatment were analyzed. The database involves 143 patients (67 male, age range 19-80 year) who received at least one dose of mepolizumab. The observed discontinuation rate was 6/143 (4.2%). Five out of 6 discontinuations were due to lack of response, and one was an adverse event (urticaria) probably related to the treatment. There was no clinical difference between the drop-out group and the patients still ongoing. As compared to the clinical trials published the discontinuation rate was lower in our population, especially for adverse events (7% vs 23.7%). Thus, the tolerability of mepolizumab, as derived from discontinuations, seems to be better in real-life than in clinical trials.