Effects of biologics on systemic and airway inflammation in severe asthma: a real-life study

<b>Background:</b> Biologics for the treatment of severe T2 high asthma result in significant exacerbations reduction and disease control improvement. <b>Aim:</b> To evaluate the effects of biologics on inflammation, disease control, lung function and the correlation between systemic and airway inflammation in severe asthma patients after 6-month treatment. <b>Methods:</b> An observational study was conducted in a referral centre for severe asthma. A comparison of clinical, functional and inflammatory (induced sputum eosinophils-SE and blood eosinophils-BE) characteristics was performed at T0 and after 6-month treatment. <b>Results:</b> Out of 51 adult patients [median(IQR) age 56(49-62) years; 13(25%) males] 28(55%) were on Mepolizumab, 14(27%) on Benralizumab, 9(18%) on Omalizumab. In all patients a significant decrease in SE% (p=0.001) and BE count (p&lt;0.001) between T0 and T6 was found. These results were confirmed in intra-group analysis for Mepolizumab and Benralizumab while no significant differences were observed for Omalizumab. BE count and SE% were significantly correlated at T0 (r=0.54, p&lt;0.001) and at T6 (r=0.67, p&lt;0.001). Δ_(T6-T0)FEV1 % and L were negatively correlated with Δ_(T6-T0)SE% (respectively r=-0.58, p=0.001, and r=-0.53, p=0.002). Δ_(T6-T0)SE% was an independent contributor to Δ_(T6-T0)FEV1 (% and L) (p=0.001, r2=0.30). Significant lower rate of exacerbations, OCS dose and ACQ score were observed (p&lt;0.0001) at T6. <b>Conclusions:</b> After 6-month treatment biologics significantly improved disease control, lung function, systemic and airway inflammation.&nbsp;Lung function improvement was related to airway eosinophilia reduction but not to blood eosinophilia decrease underlying the key role of airway inflammation.