Efficacy and safety of mepolizumab in a real-world cohort of patients with severe eosinophilic asthma

Background: The interleukin 5 (IL-5) pathway is an important component in the pathophysiology of severe eosinophilic asthma. Mepolizumab is a monoclonal antibody that targets the IL-5 pathway. Clinical trials showed efficacy of Mepolizumab in patients with severe eosinophilic asthma. However, reports on experience with treatment in a real-world cohort are limited. Objectives: Evaluation of the efficacy and safety of Mepolizumab for treatment of severe eosinophilic asthma in a real-world cohort of patients. Methods: A clinical prospective observational trial included all patients >18 years treated with Mepolizumab between March 2016 to March 2019 at Rabin Medical Center. The composite primary outcome measures evaluated: increase in FEV1 by≥ 200 ml and/or decrease in exacerbation rate of ≥50% and/or cessation of oral corticosteroids (OCS) treatment or ≥50% decrease in dosage. Also evaluated: blood eosinophil count, adverse events and quality of life. Results: Of 61 patients, 50 (82.0%) achieved the primary outcome. The number of patients who suffered from frequent exacerbations decreased from 52 (85.2%) to 8 (13.1%) (p < 0.001). Twenty-two patients (68%) stopped OCS treatment or received >50% reduced dosage (p < 0.001). Mean FEV1 increased from 1.72 ± 0.78 liters to 1.87 ± 0.85 liters (p = 0.043). Response to therapy was seen within six months. Forty-nine patients (80%) reported an improvement in quality of life (p < 0.001). Only minor adverse events were reported. Conclusion: Treatment with mepolizumab was well tolerated and significantly lowered the exacerbation rate and OCS dependence in a real-world cohort of severe eosinophilic asthma patients. Response to therapy was within six months and treatment effect was sustained over time.