Methods: OSMO was a multi-center, open-label, single-arm, 32-week study in patients with SEA and ≥2 exacerbations in the past year despite regular high-dose inhaled glucocorticoids plus other controller(s) and omalizumab (for ≥4 months) (204471/NCT02654145). At baseline, patients with poor asthma control (Asthma Control Questionnaire-5 [ACQ-5] score ≥1.5) discontinued omalizumab to receive subcutaneous mepolizumab 100 mg every 4 weeks (last dose: Week 28). Endpoints included (at Week 32): mean change from baseline in ACQ-5 (primary) and St. George’s Respiratory Questionnaire (SGRQ) total score, pre- and post-bronchodilator forced expiratory volume in 1 second (FEV1) (all analyzed using Mixed Model Repeated Measures with covariate adjustment); and responder analysis of ACQ-5 and SGRQ. Exacerbation and safety outcomes will be reported elsewhere.
Results: In the intent-to-treat population (n=145), over the treatment period, least squares (LS) mean (standard error [SE]) ACQ-5 score improved by –1.45(0.11) points, with 77% experiencing the minimal clinically important difference (MCID) of ≥0.5-point reduction. LS mean (SE) SGRQ total score improved by –19.0(1.6) points; 79% experienced MCID of ≥4-point reduction. LS mean (SE) pre- and post-bronchodilator FEV1 increased by 159(41) mL and 120(36) mL, respectively, at Week 32.
Conclusions: In uncontrolled patients with SEA, switching directly from omalizumab to mepolizumab resulted in clinically significant improvements in asthma control, health status, and lung function.
Funding: GSK (204471/NCT02654145)