Anti-immunoglobulin E (IgE) and anti-interleukin-5 (IL-5) therapies showed similar efficacy in controlling asthma symptoms, but none were associated with significant improvements in lung function, according to a study findings published in the Journal of Asthma and Allergy.

Pharmacologic therapies have been developed that target IL-5 and IgE, which both play key roles in the pathogenesis of severe eosinophilic and allergic asthma. Mepolizumab is a humanized monoclonal antibody that binds to IL-5, while benralizumab targets the IL-5 receptor alpha subunit (IL-5Rα). Omalizumab is a murine humanized monoclonal antibody that binds to the CH3 domain of IgE to block interactions between IgE and FcεRI.

Because there are very little data that directly compare these different biological therapies, researchers in Australia conducted a single-center, retrospective, observational cohort study of the effects of mepolizumab (n=23), benralizumab (n=12), and omalizumab (n=24) on symptom control and lung function parameters over time. The study also compared the efficacy of mepolizumab and benralizumab on symptom control and lung function outcomes in severe asthma. Participants were all aged 18 years or older, (average age 51.1±16.5 years), with the cohort including approximately equal numbers of men and women. Notably, most patients were either overweight (34% of study participants, with BMI 25 to <30), or obese (51% of participants, with BMI ≥30).

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Participants completed the Asthma Control Questionnaire-5 (ACQ-5) and received lung function tests at baseline, 4 to 6 months after initiating treatment, and after 1 year of therapy. The main outcome measures were 1) changes in ACQ-5 scores; 2) changes in forced expiratory volume in 1 second (FEV1) at bronchodilation; 3) changes in peak expiratory flow rate (PEFR); and 4) reductions in exacerbations requiring systemic glucocorticoids for at least 3 days or requiring an emergency department visit or hospitalization.

The investigators found significant decreases in ACQ-5 scores over time (mepolizumab: 3.3±0.93 to 1.7±0.98; benralizumab: 3.5±0.72 to 1.6±0.89; omalizumab: 3.5±0.95 to 1.7±1.1; P <.0001 for all), indicating significant improvement in symptom control from baseline through 1 year of treatment. With respect to lung function, investigators did not find that any of the therapies studied were associated with significant improvement in these measures. Moreover, although researchers noted some minor differences in FEV1 and PEFR between those taking mepolizumab and benralizumab, and a tendency towards greater control of exacerbations in the benralizumab group, these findings did not reach statistical significance.

The researchers concluded, “Our real-world data show that mepolizumab, benralizumab, and omalizumab all had significant positive effects on symptom control but not lung function as measured by FEV1 and PEFR in this cohort.” The lung function responses in this disproportionately obese study population raises questions about the efficacy of asthma biologics in various patient populations.


AlShareef S, McDonald CF, Lee J. Clinical and lung function outcomes after anti-IgE or anti-IL5 therapy in severe asthma. J Asthma Allergy. Published online February 15, 2022. doi:10.2147/JAA.S348137