D3.121 - Evaluation of small airway dysfunction in severe asthma treated with anti-IgE and anti-eosinophilic therapies: A prospective comparative study

Little is known about small airway dysfunction (SAD) in severe asthma (SA) on biologic therapy. Our aim was to evaluate SAD before and after anti-IgE and anti-eosinophilic therapies in SA patients, and compare it between in

This prospective study recruited SA patients having a blood eosinophil value of ≥150 cells/µL and atopy detected by specific IgE/skin prick test with a total IgE level of >30 IU/mL. The subjects with obstructive sleep apnea, vocal cord dysfunction, gastroesophageal reflux symptoms, parenchymal lung disease and angiotensin converting enzyme inhibitory use were excluded. They were randomly treated with anti-IgE (group A) or anti-eosinophilic therapy (group B). Clinical outcomes and SAD values were assessed at first and four months later following biologic therapy. The initial and post-treatment values in each group, and alterations in clinical parameters were compared between two groups. SAD was assessed according to the forced expiratory flow rate between 25 and 75% (FEF25–75) by spirometry and, resistance fall from 5 to 20 Hz (R5–R20) by Impulse Oscillometry (IOS). 

Twenty-two patients were randomly included in group A and 22 (16 benralizumab, 6 mepolizumab), in group B.  Seventeen (77.3%) subjects were female in both groups (p>0.05). Eosinophil counts, systemic steroid use, presence of NERD (non-steroid anti-inflammatory-exacerbated-respiratory-disease) and nasal polyps were higher in group B than in group A (p<0.001, p:0.004, p:0.036, p<0.001). A significant improvement was observed in hospitalization, emergency visit and asthma attack rates, asthma control test (ACT) scores, VAS quality of life (QoL) values, SABA and systemic steroid use over a 4-month follow-up in both groups (Table-1). An increase in total IgE levels in group A (p:0.002) and a decline in blood eosinophil (p<0.001) and lymphocyte count (p: 0.023) in group B were observed. 

This is the first, but pre-liminary, study comparing anti-IgE and anti-eosinophilic therapies regarding SAD in asthma. Both treatment strategies significantly improved clinical outcomes in SA patients without a significant difference between two groups. Although the first results showed no significant improvements in spirometry and IOS values, one-year follow-up will help us to show the changes in SAD values in the long-term period.