Characteristics of Asthmatic Responders to Mepolizumab after Failed Response to Omalizumab
Saturday, March 3, 2018
South Hall A2 (Convention Center)
Geetika Sabharwal, MD, Faoud Terrence Ishmael, MD, PhD, FAAAAI
RATIONALE: It is not clear when monoclonal antibody treatment should be targeted to IgE vs. IL-5 in allergic, eosinophilic asthmatics. We sought to identify phenotypic features of mepolizumab responders and determine whether mepolizumab was effective in asthmatics who failed to respond to omalizumab.

METHODS: After IRB approval, a retrospective analysis was performed on asthmatics treated with mepolizumab (n=27). Patients were labeled as treatment responders if they had: ≥ 5% increase in FEV1, increase in ACT score of at least 3 points, or reduction in albuterol use of 50% or more.

RESULTS: Of the 27 patients treated with mepolizumab, 15 were monoclonal treatment-naïve and 12 were previously treated with omalizumab and did not respond. Twenty patients responded to mepolizumab (mean +/- SD pre- vs. post-treatment: ACT: 10.2+/-5.6 vs. 18.3+/-6.3, p=0.016; FEV1%: 54.3+/-16.9 vs. 63.2+/-16.7, p=0.018). Mepolizumab non-responders were younger (12.4+/- 21 Vs 22+/-22, p=0.21), but otherwise did not differ by specific IgE, total IgE, blood eosinophil level, lung function, or other clinical parameters. Mean BMI was lower in responders vs non-responders (32±6 vs 48±14, p=0.019). In patients who failed to respond to omalizumab, 9/12 (75%) met criteria for response to mepolizumab (mean +/- SD pre- vs. post-treatment: ACT: 10.1+/-6.8 vs. 17.4+/-17.7, p=0.037; FEV1: 1.44+/ 0.30 vs. 1.60+/- 0.31, p=0.078).

CONCLUSIONS: Mepolizumab may be effective in allergic asthmatics who do not respond to omalizumab. Better biomarkers are needed to predict response to each medication.