Abstract

Introduction/Background: Biologics (Bx) are known to decrease specific biomarker levels: anti-IL5 reduces blood eosinophils (BEC) and anti-IgE slightly reduces FeNO. Anti-IL5 and anti-IgE are thought to have limited effect on total IgE (IgE).

Aims and Objectives: To assess the proportions of severe asthma patients whose biomarkers (BEC, FeNO, and serum IgE) decrease following anti-IL5 and anti-IgE initiation.

Methods: Patients in the International Severe Asthma Registry (ISAR) with biomarker and Bx data were included. From pre-Bx baseline to the post-Bx time period, the median (IQR) change in biomarker level and the proportion of patients with >25% decrease in biomarkers were determined.

Results: At 2-3 years from Bx initiation, BEC decreased by >25% in 80.7% of anti-IL5 and 41.6% of anti-IgE patients. FeNO decreased by >25% in 41.6% of anti-IL5 and 47.8% of anti-IgE patients. IgE decreased by >25% in 41.7% of anti-IL5 and 15.6% of anti-IgE patients (Figure).

Figure: Median (IQR) biomarker changes and patient proportions with decreased biomarkers in response to Bx.

Conclusions: Anti-IL5 was superior in decreasing BEC and both Bx classes decreased FeNO to a limited extent. The lower proportion of anti-IgE patients with IgE reduction could be attributed to serum total IgE (not free IgE) measurement. Apart from anti-IL5’s effect on BEC, <50% patients had decreased biomarkers; the clinical implications should be explored.