Switching to Mepolizumab Improved Uncontrolled Asthma for Patients on Omalizumab

Mepolizumab reduced Asthma Control Questionnaire scores from baseline by –1.45 in patients that had uncontrolled asthma with omalizumab.

Ken Chapman, MD, MSc

New trial data has reported that eosinophilic patients with severe and uncontrolled asthma that had been taking omalizumab (Xolair, Genentech/Novartis) significantly improved asthma control and reduced exacerbations when switched to mepolizumab (Nucala, GlaxoSmithKline).

The OSMO trial, presented at the 2018 American Academy of Allergy, Asthma, and Immunology (AAAAI)/World Allergy Organization (WAO) Joint Congress in Orlando, Florida, showed that the switch reduced the number of exacerbations that required oral steroid intervention by 64% compared to the previous 12 months on omalizumab—to a rate of 1.18 compared with 3.26.

“Patients participating in this study suffered burdensome day to day asthma symptoms and frequently required access to urgent care when their asthma symptoms significantly worsened,” Ken Chapman, a professor of medicine at the University of Toronto and an investigator in the OSMO study said in a statement. “Like many similar patients, they had both eosinophilic and allergic characteristics, making them eligible to receive treatment with either omalizumab or mepolizumab. OSMO showed us that when these patients remained uncontrolled on omalizumab and were then switched to mepolizumab, they experienced significant improvements - fewer symptoms, better lung function, improved asthma-related quality of life and fewer exacerbations.”

The open-label, single-arm trial took 145 patients aged 12 years and older that had been on omalizumab for an average of 2.5 years without control of their severe asthma and had experienced at least 2 exacerbations in the past year and switched them to mepolizumab for 32 weeks. The primary endpoint was asthma control coupled with clinically significant improvements, evaluated using the Asthma Control Questionnaire (ACQ-5).

At week 32, a mean change in scores from baseline of —1.45 was observed. Additionally, the rates of exacerbations that required emergency department visits were reduced by 69% (from 0.63 to 0.19), and FEV1 measured lung function was improved by 159 mL from baseline.

Quality of life, as measured by the SGRQ, was also improved to from baseline, and by week 4, blood eosinophils were reduced by 80%, which was reportedly sustained until week 32. “This study is a valuable addition to our understanding of how to manage patients with biologic therapies,” Chapman added.

In a post-hoc meta-analysis of the MENSA and MUSCA trials, the GlaxoSmithKline product also showed improvements in lung function for patients with severe asthma with a mean difference in morning peak expiratory flow (AM PEF) of 9 L/min by week 1, and a mean change of AM PEF of 26 L/min in the mepolizumab group compared to just 4 L/min in the placebo group.

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