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Ground-breaking new study from ISAR uncovers the power of asthma tests BEC and FeNO to predict effectiveness of biologic therapies in Severe Asthma

A new real-world research study from ISAR, the International Severe Asthma Registry, reveals the strength of the asthma tests (biomarkers) BEC (Blood Eosinophil Count) and FeNO (Fractional exhaled Nitric Oxide) in predicting which severe asthma patients will benefit the most from treatment with biologics, driving critical progress in delivery of targeted, precision medicine in asthma care.

The study, published in Frontiers in Immunology and entitled Association between pre-biologic T2-biomarker combinations and response to biologics in patients with severe asthma" utilises data across 23 countries and 3,751 patients. Crucially, the results indicated BEC and FeNO levels were strongly linked to the magnitude of lung function improvement following commencement of biologic therapy (specifically anti-IL5/5R [Anti-Interleukin 5/5R] or anti-IgE, [Anti-Immunoglobulin E]). Patients with the highest baseline (prior to biologic treatment) levels of the biomarkers achieved average improvements of 200 mL in the lung function result FEV1 (Forced Expiratory volume in one second), compared to patients with the lowest levels who achieved less than a third of the average improvement in FEV1 (Figure 1).

Figure 1: Association between improvement in lung function and highest pre-biologic Blood Eosinophil Count. Anti IgE: Anti-Immunoglobulin E, Anti-IL-5/5R: Anti-Interleukin 5/5R, Anti-IL4Rα: Anti-Interleukin 4α, BEC: Blood Eosinophil Count, FEV1: Forced Expiratory volume in one second.


In addition, the findings highlight a clear link between improvement in asthma symptoms and BEC for patients receiving the biologic therapy anti-IL5/5R. Following the treatment, the likelihood of having uncontrolled asthma symptoms among those with high BEC levels was almost half that of those with low pre-biologic BEC. Notably, pre-biologic biomarkers were not found to be strongly linked to extent of reduction specifically to asthma attacks before and after biologic treatment, with most patients having clear improvements in asthma attack frequency with biologic therapy regardless of drug type or biomarker levels.

Professor David Price, a lead researcher and corresponding author, comments “Our study advances understanding of the associations between biomarkers and asthma outcomes, offering results which can be harnessed as tools in selection of the most effective treatments for individual patients, and driving positive change in asthma care”.

Conducting the study through ISAR offered a unique opportunity to study the connections between biomarkers and asthma outcomes following biologic therapy in a large group of severe asthma patients in real-world practice. Patients in the study had a high burden of disease prior to commencing biologics, with almost 70% having uncontrolled asthma symptoms, underscoring the urgency for change. This study brings to light new possibilities in targeting of asthma therapy and, moreover, emphasises the potential for earlier intervention and prevention of lung function decline in asthma patients.


To learn more about the study, please read the full publication in Frontiers in Immunology, as well as the accompanying slide deck.

About ISAR

The International Severe Asthma Registry is a global collaborative initiative to gather anonymous, longitudinal, real-life data for patients with severe asthma. ISAR offers a rich source of real-life data for scientific research to understand and improve symptoms, treatments, and patient outcomes for severe asthma. To learn more please visit our website:


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