Impact of Baseline IgE levels on Exacerbations and Asthma Symptom Control After Omalizumab Initiation
Sunday, March 4, 2018: 4:30 PM
South Hall A2 (Convention Center)
Thomas B. Casale, MD FAAAAI, Erika G. Gonzalez-Reyes, MD FAAAAI, Ming Yang, PhD, Benjamin L. Trzaskoma, MS, Noelle M. Griffin, PhD, Bradley E. Chipps, MD FAAAAI

RATIONALE: IgE is important in asthma pathogenesis; omalizumab is the only biologic to specifically target IgE, with dosing in asthma customized to IgE levels. However, confusion abounds as to whether IgE is a biomarker for response.

METHODS: Patients ≥12 y/o identified as omalizumab candidates by their treating physicians and with access to treatment through insurance or other funding were enrolled in PROSPERO (n=801); US-based, multicenter, prospective, 48-week observational study of patients with allergic asthma initiating treatment with omalizumab. Asthma-related exacerbations and ACT scores were recorded over 48 weeks. Outcomes were analyzed by baseline IgE level in 100IU/mL intervals (<100 to >700).

RESULTS: At baseline median (range) IgE levels were 193.3IU/mL (1.1-68,628). Patients reported mean (SD) 3.0 (3.28) exacerbations in the 12 months prior to study entry and 0.78 (1.37) exacerbations at the end of the study. Reductions in exacerbations were consistent regardless of baseline IgE levels (Spearman’s corr. = -0.05, p=0.18). Patients reported poorly controlled asthma at baseline, mean (SD) ACT 13.94 (4.98), which improved to 18.37 (4.85) at the end of the study irrespective of IgE levels (Spearman’s corr. = 0.06, p=0.08). Average change in ACT exceeded the MID (3) in all IgE subgroups. Adverse events were consistent with the safety profile described in the current product label.

CONCLUSIONS: In a real-world setting, patients treated with omalizumab had improved asthma control with decreased asthma exacerbations and increased ACT scores regardless of baseline IgE levels suggesting that although important in omalizumab dosing, IgE may not be a predictive biomarker for response to omalizumab.