Asthma Exacerbations Fell After Respiratory Biologic Approvals Expanded

Asthma exacerbations declined significantly after 2015, when several respiratory biologics became available, according to a cohort study published in JAMA Network Open.

The study evaluated population-level trends in asthma exacerbations among adults with physician-diagnosed asthma who were seen in specialty allergy and pulmonology clinics within a large Boston health care system. Researchers designated 2015 as the exposure change point because it marked the start of a rapid approval period for respiratory biologics, with 4 of 6 respiratory biologics approved between 2015 and 2018.

The analysis included 5269 adults with asthma seen from January 2006 to May 2025. The primary outcomes were changes in the intercept and slope of annual exacerbations per 1000 asthma patients per year. Exacerbations were defined as acute worsening of asthma requiring an emergency department visit, hospital admission, or a 3- to 28-day oral corticosteroid prescription. Before 2015, exacerbations increased by 155.4 events per 1000 patients per year. After 2015, researchers reported an immediate reduction of 474.1 events per 1000 patients per year, followed by a sustained annual decline of 206.5 events per 1000 patients per year.

Patients with more severe disease and elevated eosinophil counts experienced the largest reductions. Among patients with 2 or more baseline exacerbations, the sustained decline after 2015 was 374.5 events per 1000 patients per year. Patients with baseline eosinophil levels of 450 cells/μL or greater had an immediate reduction of 1799.8 events per 1000 patients per year and a sustained yearly decline of 443.4 events per 1000 patients per year.

The authors noted that, because the study was observational and population based, causality could not be definitively established and not all patients received biologic therapy. However, they reported that subgroup analyses and sensitivity analyses supported their conclusion that post-2015 improvements were largely attributable to biologics.

Source: Tu YF, Stein DW, Akenroye A. Population-level trends in asthma exacerbations after introduction of respiratory biologics. JAMA Netw Open. 2026;9(6):e2620272. doi:10.1001/jamanetworkopen.2026.20272