Anti-IL-5 therapy reduces exacerbations in coexisting asthma and COPD

Real-world data suggests that anti-IL-5 biologics offer significant clinical benefit to patients with overlapping asthma and chronic obstructive pulmonary disease (COPD). In a retrospective analysis, both moderate and severe exacerbations were markedly reduced following treatment with mepolizumab or benralizumab.

The study, presented by Prof. Lies Lahousse (Ghent University Hospital, Belgium) at ATS 2025, evaluated 807 adults in Belgium who initiated anti-IL-5 therapy between 2017 and 2020, with 79% receiving mepolizumab and 21% benralizumab [1]. Of these, 191 patients had diagnoses of both asthma and COPD. Exacerbation rates in the year prior to and following treatment initiation were compared, using national claims data. Severe exacerbations were defined as hospitalisations, while moderate events included those treated with oral corticosteroids (OCS), antibiotics, or both.

Across the entire cohort, severe exacerbation rates declined from 40 to 17 events per 100 patient-years after treatment (P<0.001), equating to a 56% relative risk reduction (RRR) and a number needed to treat (NNT) of 4. The greatest benefit was observed in patients with both asthma and COPD, where hospitalisations fell from 119 to 53 events per 100 patient-years (RRR 55%, NNT=2). In contrast, asthma-only patients experienced a smaller reduction, from 15 to 6 events per 100 patient-years (NNT=11), reflecting the more severe baseline burden in the co-diagnosed group.

Moderate exacerbations also declined across several categories. Among asthma-only patients, antibiotics-only events were reduced by 18%, and OCS + antibiotics events dropped by 41%. In patients with both asthma and COPD, antibiotics-only events decreased by 20%, and OCS + antibiotics events by 21%. However, OCS-only events did not improve significantly in this subgroup (P=0.288), particularly among current smokers, where biologics were less effective in reducing corticosteroid use but still delivered a 64% RRR in hospitalisations (NNT=1).

These findings provide further support for the use of blood eosinophil counts as a biomarker to guide treatment decisions in patients with overlapping airway diseases. The analysis highlights that biologic therapies targeting IL-5 can meaningfully reduce the burden of exacerbations and limit hospital-based care in complex, comorbid populations, offering value beyond traditional trial cohorts. With hospitalisations representing a major component of healthcare costs in respiratory disease, these results underscore the utility of mepolizumab and benralizumab in reducing system strain while improving patient outcomes.

1. Lahousse L, et al. Real-life Impact of Anti-IL5 Therapy on Exacerbation Types in Patients With Obstructive Lung Disease. Abstract P290, ATS International Conference, 16–21 May 2025, San Francisco, CA, USA.

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Posted on 26 May 202526 May 2025