In patients with severe allergic asthma (SAA), omalizumab is equally effective in those with high and low blood eosinophil count, according to research published in the European Respiratory Journal.
The study used the medical records of 872 patients (including 149 minors) with SAA receiving add-on omalizumab. Response was assessed by three criteria: physician evaluation, reduction of at least 40 per cent 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.
Blood eosinophil count was ≥300cells/µL in more than 52 per cent of adults and almost 74 per cent of minors. By physician evaluation, 67.2 per cent of adults and 77.2 per cent of minors were responders. Over 70 per cent of adults and 78.5 per cent of minors had a reduction in exacerbation rate of at least 40 per cent. In adults, the response rate for combined criteria was 58.4 per cent for blood eosinophils ≥300cells/µL and 58.1 per cent for blood eosinophils <300cells/µL.
The authors say the findings deserve to be further investigated in prospective studies assessing the effectiveness of biologics targeting overlapping populations of patients with persistent SAA and high eosinophil count.