Mepolizumab in patients with severe asthma & BEC ≥150–<300 cells/µL: Benefits at 2 years

Background Although clinical trial evidence exists, there is limited awareness of the real-world effectiveness of mepolizumab in patients with severe asthma and blood eosinophil counts (BEC) ≥150–<300 cells/μL. Methods REALITI-A, an international, prospective, single-arm, observational cohort study enrolled patients with severe asthma initiating mepolizumab. Outcomes assessed over 2 years pre- versus post-mepolizumab exposure included clinically significant exacerbations (CSEs), maintenance oral corticosteroid (mOCS) use, Asthma Control Questionnaire (ACQ)-5 scores, and forced expiratory volume in 1 s (FEV 1 ). Results After 2 years of mepolizumab treatment, compared with pre-exposure, the proportion of patients with BEC ≥150–<300 cells/μL (N=84) experiencing CSEs decreased from 95% to 63%, and the proportion experiencing exacerbations requiring hospitalisation or emergency department visits decreased from 43% to 19%. The rate of CSEs reduced from 4.53 to 1.47 per year (rate ratio [95% confidence interval {CI}]: 0.32 [0.25, 0.41]). After 2 years of mepolizumab exposure, the mean (95% CI) clinic pre-bronchodilator percent predicted FEV 1 was 80.1 (69.4, 90.7) compared with 62.6 (54.1, 71.1) at baseline (28% relative increase). The median average daily dose of mOCS decreased from 10.0 to 1.5 mg·day −1 (85% relative reduction from baseline); 44% of patients discontinued completely. The minimum clinically important difference in ACQ-5 (improvement ≥0.5) was achieved by 82% of patients, with a mean (95% CI) reduction of 1.76 (2.34, 1.19). Conclusions These real-world findings provide evidence for the 2-year sustained benefit following initiation of mepolizumab in patients with severe asthma who have poor disease control and BEC ≥150–<300 cells/μL.