Omalizumab effectiveness in patients with severe allergic asthma according to blood eosinophil count: the STELLAIR study

Eur Respir J. 2018 May 10;51(5):1702523. doi: 10.1183/13993003.02523-2017. Print 2018 May.


Omalizumab is a monoclonal anti-IgE 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 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 a combination of both. Response rate was calculated according to blood eosinophil count measured in the year prior to omalizumab initiation.872 SAA omalizumab-treated patients were included by 78 physicians (723 adults (age ≥18 years) and 149 minors (age 6-17 years)). Blood eosinophil count was ≥300 cells·µL-1 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 the exacerbation rate. In adults, the response rate for combined criteria was 58.4% (95% CI 53.2-63.4%) for blood eosinophils ≥300 cells·µL-1 (n=377) and 58.1% (95% CI 52.7-63.4%) for blood eosinophils <300 cells·µL-1 (n=346).This study shows that a large proportion of patients with SAA have a blood eosinophil count ≥300 cells·µL-1, and suggests that omalizumab effectiveness is similar in "high" and "low" eosinophil subgroups.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Anti-Asthmatic Agents / administration & dosage
  • Anti-Asthmatic Agents / adverse effects
  • Asthma* / blood
  • Asthma* / diagnosis
  • Asthma* / drug therapy
  • Child
  • Drug Monitoring / methods
  • Eosinophils*
  • Female
  • France
  • Humans
  • Immunoglobulin E / blood
  • Leukocyte Count / methods
  • Male
  • Omalizumab* / administration & dosage
  • Omalizumab* / adverse effects
  • Retrospective Studies
  • Severity of Illness Index
  • Symptom Flare Up
  • Treatment Outcome


  • Anti-Asthmatic Agents
  • Omalizumab
  • Immunoglobulin E