Efficacy and Safety of Mepolizumab in Uncontrolled Patients with Severe Eosinophilic Asthma Following a Switch from Omalizumab (OSMO Study): Asthma Control, Quality of Life and Lung Function Outcomes
Monday, March 5, 2018
South Hall A2 (Convention Center)
Frank C. Albers, MD, PhD, Mark C. Liu, MD FAAAAI, Bradley E. Chipps, MD, Kenneth R. Chapman, MD, Xavier Muñoz, MD, Miguel Angel Bergna, MD, Jay Azmi, PhD, Dalal Mouneimne, PhD, Sandra Joksaite, MSc, Dmitry Galkin, MD, PhD
Rationale: Mepolizumab and omalizumab are indicated in distinct asthma phenotypes, although some patients with severe eosinophilic asthma (SEA) are eligible for both biologics. We investigated asthma control in patients not optimally controlled with omalizumab, who switched directly to mepolizumab.

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)