Response to Omalizumab May Depend on Asthma Severity, Eosinophil Counts

Patients with a high eosinophil count or with clinical markers of greater asthma severity may experience a more significant reduction in asthma exacerbations when treated with omalizumab, according to a study published by Allergy.

Researchers identified 1071 adults and adolescents in 2 phase 3 clinical trials who were randomly assigned to receive omalizumab (n=542) or placebo (n=529), and observed them during a 16-week inhaled corticosteroid (ICS) dose-stable phase, followed by a 12-week ICS dose-reduction phase. The aim of the study was to observe the number of asthma exacerbations requiring systemic corticosteroids or double ICS dose in both treatment groups.

The rates of participants requiring ≥3 days of systemic corticosteroid treatment were 0.066 and 0.147 for those treated with omalizumab and placebo, respectively. An overall 55% relative rate reduction was identified in patients treated with omalizumab (95% CI, 32%-70%; P =.002). In addition, reduction rates for individuals treated with omalizumab by baseline blood eosinophil strata were ≥200/µL, 55% (95% CI, 25%-73%; P =.002); ≥300/µL, 67% (95% CI, 36%-84%; P =.001); and ≥400/µL, 74% (95% CI, 40%-88%; P =.001).

The investigators concluded that overall, treatment with omalizumab resulted in fewer asthma exacerbations requiring systemic corticosteroids compared with patients treated with placebo. In addition, a higher blood eosinophil level at baseline was associated with a more significant response to omalizumab in patients with severe allergic asthma.

Reference

Casale TB, Chipps BE, Rosén K, et al. Response to omalizumab using patient enrichment criteria from trials of novel biologics in asthma [published online August 31, 2017]. Allergy. doi:10.1111/all.13302