Respiratory Biologics and Asthma Exacerbation Trends
Key Takeaways
- Exacerbations were rising before 2015 and then fell after respiratory biologics became more widely available.
- Larger reductions were reported in patients with frequent baseline exacerbations and in those with eosinophil counts of at least 450 cells/μL.
- Improvement was reported across age, sex, BMI, smoking, and insurance groups, the moderate-to-severe versus mild asthma gap narrowed, and the authors said the findings support biologic effectiveness.
The study used health records from 5,269 adults with asthma in specialty allergy and pulmonology clinics within a large Boston health system. Records spanned 2006 to 2025, and the cohort had a mean age of 51.9 years, with 71.4% female and 62.4% privately insured. Annual exacerbations increased by 155.4 events per 1,000 patients per year from 2006 to 2015, then fell by 474.1 after 2015. They continued decreasing by 206.5 per 1,000 patients per year through 2025, marking a clear break from the earlier upward trajectory. It linked that period to antieosinophilic and anti–interleukin-4 receptor alpha therapies, and it noted six respiratory biologics approved in recent years, including four approved between 2015 and 2018.
Among patients with at least two annual baseline exacerbations, events dropped by 808.2 per 1,000 patients per year immediately after 2015, followed by a further decline of 374.5 per 1,000 patients per year. Among patients with baseline eosinophil counts of 450 cells/μL or higher, events dropped by 1,799.8 per 1,000 patients per year immediately after 2015, followed by a further decline of 443.4 per 1,000 patients per year. Improvement was also reported across age, sex, BMI, smoking, and insurance subgroups, indicating that the direction of change was not confined to one demographic or coverage group.
The abstract described the pre-2015 exacerbation pattern as evidence of a persistent burden of uncontrolled asthma despite standard controller therapies. Researchers also reported that the post-2015 pattern closed the outcome gap between moderate-to-severe asthma and mild asthma over time. They said the findings support biologic effectiveness. Because this was an observational cohort pattern tied to timing, the results do not show that biologics alone caused the decline or explain every contributor.