Page 95 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma

The third question refers to a practical issue. How to best identify the mepolizumab responder in ordinary clinical practice? In the two previous proof-of-concept studies [10;11] refractory eosinophilic asthma was defined on the basis of ≥3% eosinophils in induced sputum. By using this criterion, the authors were able to show a decrease of 43% in the number of exacerbations with 750 mg mepolizumab monthly for 1 year [10], which is very similar to the result of the DREAM study. However, in the latter study patients could also be selected on the basis of less direct markers of eosinophilic airway inflammation, including blood eosinophil counts >0.3 x 10E9/L, exhaled nitric oxide levels > 50 ppb or prompt deterioration of asthma control following a > 25% reduction in regular maintenance inhaled or oral corticosteroids. The use of these indirect criteria, specially the blood eosinophil counts, makes the identification of anti-IL-5 responders much easier, and this is an important step towards implementation of this targeted therapy into clinical practice.
The next step will be to assess the steroid-sparing effects of mepolizumab in a large population of patients who are oral corticosteroid-dependent. For this purpose, large-scale oral corticosteroid tapering studies with mepolizumab are already underway. It would be ideal if anti-IL-5 treatment not only reduced the number of exacerbations, but also facilitated the tapering of oral corticosteroids, thereby preventing serious steroid-induced side effects. If this could be confirmed, a real dream would come true for the most severely affected patients with asthma.
Targeting IL-5 in severe asthma
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