Clin Exp Allergy

Background Dupilumab is a monoclonal anti‐IL‐4Rα antibody developed for the treatment of severe asthma (SA). An early access programme for dupilumab was opened in France in SA patients experiencing unacceptable steroids side‐effects and/or life‐threatening exacerbations. Objective To assess changes in asthma control between baseline and 12 months of treatment. Methods Multi‐centre (n = 13) retrospective real‐life cohort study. This study is registered on ClinicalTrials.gov (NCT04022447). Results Overall, 64 patients with SA (median age 51, interquartile range [44‐61]; 53% females) received dupilumab as add‐on therapy to maximal standard of care; and 76% were on oral daily steroids at baseline. After 12 months, median asthma control test score improved from 14 [7‐16] to 22 [17‐24] (P < .001); median forced expiratory volume in 1 seconds increased from 58% [47‐75] to 68% [58‐88] (P = .001); and daily prednisone dose was reduced from 20 [10‐30] to 5 [0‐7] mg/d (P < .001). Annual exacerbations decreased from 4 [2‐7] to 1 [0‐2] (P < .001). Hypereosinophilia ≥1500/mm3 was observed at least once during follow‐up in 16 patients (25%), persisting after 6 months in 8 (14%) of them. Increase in blood eosinophil count did not modify the clinical response during the study period. Injection‐site reaction was the most common side effect (14%). Three deaths were observed, none related to treatment by investigators. Conclusion & clinical relevance In this first real‐life cohort study of predominantly steroid‐dependent SA, dupilumab significantly improved asthma control and lung function and reduced oral steroids use and exacerbations rate. Despite limitations due to the retrospective study, these results are consistent with controlled trials efficacy data. Further studies are required to assess the clinical significance and long‐term prognosis of sustained dupilumab‐induced hypereosinophilia