Evaluation of the Clinical Features and Laboratory Data of Patients with Severe Eosinophilic Asthma Classified as Super-Responders, Partial Responders, or Nonresponders to Mepolizumab Treatment: A Real-Life Study.

Introduction: Mepolizumab is a treatment option in patients with severe eosinophilic asthma, which inhibits interleukin-5. The aim of this study was to evaluate the clinical features and laboratory data of patients with severe eosinophilic asthma who were classified as super-responders, partial responders, or nonresponders to mepolizumab treatment.

Methods: In this retrospective real-life study, the clinical features and laboratory data were compared between groups of patients with severe eosinophilic asthma who were classified as super-responders, partial responders, or nonresponders to mepolizumab treatment.

Results: Evaluation was made of a total of 55 patients, comprising 17 (30.9%) males and 38 (69.1%) females with a mean age of 51.28 ± 14.32 years. All the patients were receiving mepolizumab treatment for severe eosinophilic asthma, with 17 (30.9%) patients evaluated as super-responders, 26 (47.3%) as partial responders, and 12 (21.8%) as nonresponders. After mepolizumab treatment, there was a statistically significant decrease in asthma exacerbations, the number of oral corticosteroids (OCSs) used, the rate of hospitalization due to asthma attacks, and the eosinophil count (cells/µL) (p < 0.001, p < 0.001, p < 0.001, and <0.001, respectively). A statistically significant increase was determined in the forced expiratory volume in 1 s (FEV1) value (p = 0.010) and asthma control test (ACT) score (p < 0.001) after mepolizumab treatment. The baseline eosinophil count, eosinophil/lymphocyte ratio and FEV1 (%) values were significantly higher in the super-responder and partial responder groups (p < 0.001, p = 0.002, and p = 0.002, respectively). The baseline ACT score and the rate of chronic sinusitis with nasal polyps were significantly higher in the partial responder group (p = 0.004, p = 0.015, respectively). The rate of regular OCS use before mepolizumab treatment was significantly higher in the nonresponder group (p = 0.049). As a result of the receiver operating characteristics curve analysis, the blood eosinophil count (area under the curve [AUC]: 0.967, p < 0.001), eosinophil/lymphocyte ratio (AUC: 0.921, p < 0.001), and FEV1 (%) (AUC: 0.828, p = 0.002) were found to have diagnostic value in predicting the response to mepolizumab treatment in patients with severe eosinophilic asthma.

Conclusion: Baseline eosinophil count, eosinophil/lymphocyte ratio, and FEV1 (%) were found to be important predictors of response to mepolizumab treatment. Further studies are needed to define the characterization of mepolizumab responders in the real world.