RT Journal Article SR Electronic T1 Omalizumab effectiveness in patients with severe allergic asthma according to blood eosinophil count: the STELLAIR study JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1702523 DO 10.1183/13993003.02523-2017 A1 Marc Humbert A1 Camille Taillé A1 Laurence Mala A1 Vincent Le Gros A1 Jocelyne Just A1 Mathieu Molimard YR 2018 UL http://erj.ersjournals.com/content/early/2018/03/09/13993003.02523-2017.abstract AB Omalizumab is a monoclonal anti-immunoglobulin E antibody used to treat severe allergic asthma (SAA). The aim of the STELLAIR study was to determine the importance of pre-treatment blood eosinophil count (EOS) as a predictive measure for response to omalizumab. This retrospective real-life study was conducted in France between December 2015 and September 2016 using medical records of SAA omalizumab-treated patients. Response to omalizumab was assessed by three criteria: physician evaluation, reduction of ≥40% in annual exacerbation rate, and combination of both. Response rate was calculated according to blood EOS count measured in the year prior to omalizumab initiation. 872 SAA omalizumab-treated patients were included by 78 physicians (723 adults and 149 minors aged 6–17 years). EOS was ≥300/µl in 52.1% of adults and 73.8% of minors. By physician evaluation, 67.2% of adults and 77.2% of minors were responders and 71.1% adults and 78.5% minors had a 40% reduction in exacerbation rate. In adults, response rate for combined criteria was 58.4% (95% CI 53.2–63.4) in EOS ≥300 (n=377) and 58.1% (95% CI 52.7–63.4) in EOS <300 (n=346). This study shows that a large proportion of patients with SAA have EOS ≥300 and suggests that omalizumab effectiveness is similar in high and low EOS subgroups.Omalizumab is a treatment option for severe allergic asthma irrespective of blood eosinophil countFootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. Humbert reports personal fees from Astrazeneca, personal fees from GSK, personal fees from Novartis, personal fees from Roche, personal fees from TEVA, personal fees from Sanofi/Regeneron, during the conduct of the study.Conflict of interest: Dr. Taillé reports personal fees from Kappa Santé, during the conduct of the study; personal fees and other from AstraZeneca, personal fees and other from Boeringher, personal fees from Chiesi, grants, personal fees and other from GSK, personal fees and other from Novartis, personal fees from Teva, personal fees and other from ALK, other from Sanofi, outside the submitted work.Conflict of interest: Dr. Mala reports other from NOVARTIS PHARMA SAS, during the conduct of the study; other from NOVARTIS PHARMA SAS, outside the submitted work.Conflict of interest: Dr. Le Gros reports other from NOVARTIS PHARMA SAS, during the conduct of the study; other from NOVARTIS PHARMA SAS, outside the submitted work.Conflict of interest: Dr. just reports personal fees from ALK, personal fees from STALLERGENE, grants and personal fees from NOVARTIS, outside the submitted work.Conflict of interest: Dr. Molimard reports personal fees from Novartis Pharma, personal fees from GSK, personal fees from Boehringer Ingelheim, personal fees from University of Bordeaux, during the conduct of the study; grants from Novartis Pharma, outside the submitted work .