Efficacy of Omalizumab Similar in Severe Allergic Asthmatics Irrespective of the Eosinophilic Counts

Introduction

Large scale and real-life studies have demonstrated the benefits of omalizumab, a humanized anti-IgE monoclonal antibody in uncontrolled persistent severe allergic asthma (SAA). Novel therapies are emerging for the treatment of severe eosinophilic asthma (SEA) in patients with a blood eosinophil count >300 cells/µl. a significant proportion of patients with SAA also have a blood eosinophil count >300 cells/µl.

Aim

The STELLAIR (next Step Towards personalized care: EvaLuating responders to XoLAIR treatment in patients with SAA) study evaluates the utility of pre-treatment eosinophil counts in predicting response to omalizumab.

Methods

Study design

• Multicenter, non-interventional, retrospective observational study
• Patients >6 years of age who had been treated with omalizumab for poorly controlled SAA
• Blood eosinophil count and number of exacerbations recorded 12 months prior to omalizumab therapy
• Patients had a documented physician evaluation of response 4-6 months after therapy and number of exacerbations were recorded

Endpoints

• Physician evaluation of response to omalizumab therapy according to the Global Evaluation of Treatment Effectiveness (GETE) scale was assessed at 4-6 months (T_4-6)
• Reduction of >40% in annual exacerbation rate
• Combination of GETE evaluation and >40% reduction in annual exacerbation rate

Results

• 872 patients comprising of 723 adults (>18 years) and 149 minors (6-17 years) were evaluated by 78 physicians
• Omalizumab was continued in 656 adults and 148 minors at T_4-6 and in 577 adults and 129 minors at 12 months post therapy initiation (T₁₂) respectively
• 52.1% of adults and 73.8% of minors had blood eosinophil count >300 cells/µl
• As per the physician evaluation, 67.2% and 77.2% of the adults and minors respectively were responders at T_4-6
• Reduction of >40% in annual exacerbation rate was reported by 71.1% adults and 78.5% minors
• A combined response rate was observed in 67.8% and 58.2% of minors and adults respectively
• The response rate for combined criteria was 58.4% and 58.1% in adults with blood eosinophils >300 cells/µl and <300 cells/µl respectively
• The rate of response at first assessment stratified based on blood eosinophil counts is shown in figure 1 and 2.

Conclusion

• Significant percentage of patients with severe allergic asthma (SAA) have blood eosinophil counts >300 cells/µl
• The efficacy of omalizumab therapy is similar in high and low eosinophil subgroups.

Eur Respir J. 2018; 51:1702523.