B29-21 Do Not Be Sad: Complete Remission Can Be Achieved

Abstract Introduction Remission represents an ambitious goal in severe asthma treated with biologics. This is based on a multi-domain definition including symptom control, absence of asthma exacerbations, no need for systemic steroids and lung function constancy. Different definitions of the latter, all considering FEV1 have been proposed; however there is no consensus whether improvement, stability, or minimal worsening in FEV1 should be taken into consideration when assessing the functional domain within the concept of remission. We evaluated lung function using a more comprehensive set of functional parameters, including proximal and small airway data at spirometry and impulse-oscillometry, in patients undergoing biologic therapy for at least 12-months and compared subjects achieving remission to those failing the outcome. Methods This observational study was performed at Fondazione Policlinico Universitario A. Gemelli IRCCS. Demographic (gender, age, BMI), clinical (ACT, n. of exacerbations and OCS courses) and functional (FEV1, FEV1/FVC post bronchodilator (BD) and R5-R20) data were recorded at baseline (T0) and after 12 months (T12) of biologic initiation. The table summarises the different FEV1 definitions (S1, S2, N, I1, I2) used to define remission. Data were expressed as mean±SD or median (IQR) depending on distribution and compared accordingly, with a significance threshold of p 0.05. Results Fifty-five adult severe asthmatics (F = 36; mean age 58.9±12.9 and BMI 28.9 ± 5.4 kg/m²) eligible for biologic therapy were followed-up for 12 months. Among them, 20 met remission criteria for S1, 18 for S2, 10 for N, 15 for I1, and 11 for I2. FEV₁ and FEV₁/FVC post-bronchodilator significantly improved in both remission and non-remission groups across all five definitions. After 12 months, FEV₁/FVC post-BD went above the median value of 70% in the remission group but remained below 70% in the non-remission group, regardless the FEV1 definition considered. Concomitantly, the median R5-R20 value increased significantly from baseline to one year only in patients achieving remission across all definitions (see Table). Conclusions Our real-life analysis showed that both remission and non-remission patients experienced significant FEV₁ and FEV1/FVC post BD improvement after one year of biologic therapy. However, only patients in remission, according to all functional definitions considered, showed resolution of persistent airflow limitation (PAL) and significant improvement in small airway disease assessed by impulse oscillometry. Incorporating peripheral airway assessment into the functional criteria for remission may therefore be more accurate and appropriate to refine the current definition and better capture the multidimensional nature of asthma remission. This abstract is funded by: None