Benefits of Switching From Omalizumab to Mepolizumab in Severe Eosinophilic Asthma

Eosinophil cells
Eosinophil cells
Patients who have severe eosinophilic asthma that is uncontrolled on omalizumab may be effectively switched to mepolizumab.

Patients who have severe eosinophilic asthma that is uncontrolled on omalizumab may be effectively switched to mepolizumab to achieve clinically important improvements in efficacy outcomes, according to study results published in Respiratory Research.1

Results from the Omalizumab to Mepolizumab Switch Study in Severe Eosinophilic Asthma Patients study (OSMO; Identifier: NCT02654145) demonstrated that after directly switching from omalizumab to mepolizumab, patients with uncontrolled severe eosinophilic asthma experienced clinically significant improvements in asthma control, health-related quality of life (HRQoL), lung function, and the rate of clinically significant exacerbations, with no tolerability issues reported.2

To determine what proportion of patients responded to mepolizumab treatment and whether patient characteristics affect this response after switching from omalizumab, researchers conducted a post hoc analysis of the OSMO study. They assessed the proportion of patients achieving predefined improvements in up to 4 efficacy outcomes and the relationship between patient baseline characteristics and treatment response.1

A total of 145 patients with severe eosinophilic asthma uncontrolled by high-dose inhaled corticosteroids, other controller(s), and omalizumab subcutaneously (≥4 months) were switched to mepolizumab 100 mg administered subcutaneously. Of these patients, 94%, 83%, 63%, and 31% were responders for ≥1, ≥2, ≥3, and 4 outcomes, respectively. A total of 75% and 78% of patients were considered Asthma Control Questionnaire (ACQ)-5  and St George’s Respiratory Questionnaire (SGRQ) score responders (≥0.5 and ≥4-point improvement, respectively), and 50% and 69% were prebronchodilator forced expiratory volume in 1 second (FEV1) and exacerbation responders (≥100 mL improvement), respectively.

Subgroup analyses demonstrated improvements irrespective of baseline blood eosinophil count, prior omalizumab treatment regimen/duration, comorbidities, prior exacerbation history, maintenance oral corticosteroid use, ACQ-5 and SGRQ scores, and body weight/body mass index (BMI).

“After switching to mepolizumab, almost all patients with uncontrolled severe eosinophilic asthma on omalizumab achieved a beneficial response in ≥1 clinical outcome,” the study authors stated.1 “The analysis also suggests that patients with higher baseline blood eosinophil counts or comorbid nasal polyps may benefit the most from a direct switch to mepolizumab from omalizumab.”

Disclosure: This research was supported by GlaxoSmithKline. Please see the original reference for a full list of disclosures.


1. Liu MC, Chipps B, Munoz X, et al. Benefit of switching to mepolizumab from omalizumab in severe eosinophilic asthma based on patient characteristics. Respir Res. 2021;22:144. doi:10.1186/s12931-021-01733-9

2. Chapman KR, Albers FC, Chipps B, et al. The clinical benefit of mepolizumab replacing omalizumab in uncontrolled severe eosinophilic asthma. Allergy. 2019;74(9):1716-176. doi:10.1111/all.13850