A real-life cohort of mepolizumab treatment in severe eosinophilic asthma

Background. Mepolizumab, a monoclonal antibody that interacts with IL-5, was the first anti-IL-5 approved for uncontrolled severe eosinophilic asthma. In several randomized, placebo-controlled trials, treatment with mepolizumab has shown a significant improvement in asthma symptoms and the need to use of oral corticosteroids (OCS). Several studies have correlated blood levels of eosinophil cationic protein (ECP) with the degree of eosinophilic inflammation, which could make it an indirect marker of eosinophilic activity. Methods. This was a single-center retrospective study that included all patients diagnosed with severe eosinophilic asthma under treatment with mepolizumab. We recorded the number of exacerbations, daily prednisone intake, asthma control test scores and forced expiratory volume in the first second. Results. We followed 22 patients, 14 of whom were OCS-dependent with a mean daily dose of 15.85 +/- 15.62 mg prednisone. After 12 months, only five continued taking OCS and the mean daily dose was reduced by up to 2.50 +/- 3.84 mg (p < 0.007). The exacerbation rate at baseline was 2.91 +/- 2.27 and decreased to 0.82 +/- 1.14 in the following year (p < 0.001). ACT scores increased significantly from 16.00 +/- 5.85 to 20.71 +/- 4.45 after six months (p = 0.003). We also observed a decrease in ECP from 81.46 +/- 43.99 ug/L to 19.12 +/- 18.80 ug/L (p > 0.001). Conclusions. These real-life results are consistent with previous clinical trials demonstrating the efficacy and safety of mepolizumab in routine clinical practice for severe uncontrolled eosinophilic asthma. We observed a significant decrease in blood eosinophil counts and in ECP levels, suggesting a reduction in eosinophil activity following mepolizumab treatment.