Clinical remission (CR) has been shown to be an achievable goal in severe uncontrolled asthma (SUA) treated with biological therapy (BT). Blood eosinophil count (BEC) and FeNO are currently used to identify T2 phenotypes of SUA but more precise biomarkers are needed. We aimed to explore the role of bronchial biopsy in predicting CR in SUA patients treated with BT.

Methods: Patients with SUA candidates to BT underwent bronchoscopy and bronchial biopsy with submucosal eosinophil count (SEC) previous to the initiation of BT. CR was defined as no exacerbations, asthma control test (ACT)>19, no use of oral corticosteroids and FEV1 improvement>10% and/or 100 ml after 6 months of BT. A T2 score including BEC and FeNO pre-BT was calculated. Receiving operating characteristic curves were performed to explore the association between SEC or T2 score and CR.

Results: 50 patients with SUA were included. 23 patients (46%) fulfilled criteria of CR. SEC was significantly higher in patients achieving CR compared to those who did not (13.36 ± 14.59 vs 5.54 ± 7.80 cels/field, p=0.027, respectively). SEC showed a significantly better area under the curve to predict CR than the T2 score (0.732±0.073, p=0.005 vs 0.639±0.082, p=0.101, respectively).

Conclusions: CR is an achievable goal for patients with SUA treated with BT. SEC in bronchial biopsy is a better biomarker to predict CR in these patients than a T2 score. Supported by ISCIII FIS FIS19/01521