Real-world effects of asthma biologics on blood eosinophil levels: data from the CHRONICLE study

OBJECTIVE: High blood eosinophil counts (BECs) are associated with increased asthma exacerbation risk. Studies show anti-IL-5/5R biologics meaningfully reduce BEC; however, there are limited data describing the real-world effects of anti-IgE and anti-IL-4R biologics on BECs. This analysis aimed to describe BECs before and after initiation of different biologics in a real-world cohort of patients with severe asthma (SA). METHODS: CHRONICLE (NCT03373045) was an observational study of subspecialist-treated adults with SA in the US receiving biologics or maintenance systemic corticosteroids or whose disease was persistently uncontrolled on high-dosage inhaled corticosteroids and additional controllers. This analysis included patients enrolled between February 2018 and November 2023 who initiated omalizumab, mepolizumab, benralizumab, or dupilumab treatment. Patients' highest BECs in the 12 months before, 2 to