The introduction of respiratory biologics has been associated with significant reductions in asthma exacerbations at the population level, according to a large cohort study. Researchers found that adults with asthma experienced both immediate and sustained declines in exacerbation rates following the approval of multiple biologic therapies, with the greatest improvements observed among patients with more severe disease.
The findings suggest that respiratory biologics may be helping to narrow the longstanding outcome gap between patients with moderate-to-severe asthma and those with milder forms of the disease.
Asthma Outcomes Improved Following Biologic Approvals
Respiratory biologics have transformed the management of severe asthma over the past decade by targeting key inflammatory pathways, particularly in patients with eosinophilic disease. However, their impact at the population level has remained largely unexplored.
To investigate this, researchers analysed electronic health record data from 5,269 adults with physician-diagnosed asthma treated at specialty allergy and pulmonology clinics within a large healthcare system in Boston between 2006 and 2025.
The year 2015 was selected as a key time point because it marked the beginning of a period of rapid regulatory approval for respiratory biologics, with four of the six currently available therapies receiving approval between 2015 and 2018.
Using an interrupted time series analysis, investigators examined changes in annual asthma exacerbation rates before and after the introduction of these treatments.
Significant Declines in Exacerbation Rates
Between 2006 and 2015, asthma exacerbations were increasing steadily among the study population. Following 2015, however, researchers observed a significant immediate reduction in exacerbation rates, which was followed by sustained yearly declines throughout the study period.
The most pronounced improvements were seen in patients with more severe asthma. Individuals who experienced two or more exacerbations annually demonstrated larger reductions than patients with fewer exacerbations.
Similarly, patients with elevated eosinophil counts—an important biomarker of type 2 inflammation—experienced some of the greatest improvements after biologics became available. Those with eosinophil levels of 450 cells/μL or higher showed substantially larger reductions in exacerbation rates than patients with lower eosinophil counts.
Benefits Observed Across Patient Groups
The reduction in asthma exacerbations was observed across a wide range of demographic and clinical subgroups, including differences in age, sex, smoking status, body mass index, and insurance status.
Although smokers and individuals living in inner-city areas continued to experience higher overall exacerbation rates, these groups also benefited from the downward trends observed following the introduction of biologic therapies.
Importantly, the authors note that patients with moderate-to-severe asthma experienced improvements that helped narrow the gap in outcomes traditionally seen between them and patients with mild asthma, who are generally not eligible for biologic treatment.
Supporting the Role of Biologics in Severe Asthma Care
The researchers conclude that respiratory biologics have been associated with meaningful improvements in asthma outcomes at a population level. While observational studies cannot establish causality, the timing and consistency of the observed reductions support the important role these therapies may play in managing severe asthma.
The findings add to growing evidence that biologics not only improve outcomes in clinical trials but may also deliver substantial benefits when implemented in routine clinical practice, particularly among patients at highest risk of asthma exacerbations.
Reference
Tu Y et al . Population-Level Trends in Asthma Exacerbations After Introduction of Respiratory Biologics. JAMA Netw Open. 2026;9(6):e2620272.
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