D1.149 - Healthcare Professionals Typically Apply Higher Blood Eosinophil Count Thresholds for Biologic Selection Versus Clinical Guidelines in Severe Asthma

The Global Initiative for Asthma 2025 guidelines recommend phenotyping asthma to identify type 2 (T2) inflammation using biomarkers such as blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) with thresholds of 150 cells/μL and 20 ppb, respectively. In practice, BEC is often associated with “eosinophilic asthma”, rather than recognised as a marker of T2 inflammation. This difference in terminology may shape healthcare professionals’ (HCP) perceptions of BEC thresholds and influence biologic selection. The current analysis explored these perceptions in severe asthma (SA) management.

Data were obtained from two multi-country surveys conducted on the Sermo and Evidera online platforms. The Sermo survey included HCPs in the United States (US), Germany, Italy, Spain, United Kingdom (UK) and France (July–September 2025) and assessed the BEC thresholds HCPs used to define patients with SA with T2 inflammation. The Evidera survey included HCPs in Germany, Italy, Spain, UK and France who provided de-identified BEC profile data at biologic initiation from patients with SA (February–June 2025); data were stratified by country and biologic. 

In total, 700 HCPs (US, n=200; Germany, n=100; Italy, n=100; Spain, n=100; UK, n=100; France, n=100) provided BEC threshold perception data and BEC profile data were provided by HCPs for 1660 patients (Germany, n=289; Italy, n=352; Spain, n=344; UK, n=329; France, n=346). In the Sermo survey, the median (interquartile range [IQR]) BEC HCPs associated with SA with T2 inflammation was 300 (100) cells/μL; this was the most common threshold by country. Overall, only 15% of HCPs reported a BEC threshold of 150 cells/μL while 22% reported a threshold of 500 cells/μL. In the Evidera survey, 67% of patients overall had a BEC ≥300 cells/μL at biologic initiation. Of the patients on mepolizumab or benralizumab, 87% had a BEC ≥300 cells/μL at treatment initiation while only 7–10% had a BEC ≥150–299 cells/μL (Table). 

HCPs commonly applied a BEC threshold of 300 cells/μL or higher for phenotyping and biologic eligibility in SA, in contrast with clinical guidelines. This discordance (alongside potential factors such as health insurance reimbursement thresholds) influenced treatment patterns for patients with SA. These findings highlight an opportunity to align clinical practice with guidelines, ensuring appropriate access to biologics for all patients with SA.

Funding: GSK