The effect of omalizumab on free IgE and spirometric measurements in allergic asthmatics with highly elevated IgE levels

INTRODUCTION: Omalizumab has been shown to be well tolerated and effective in the treatment of allergic asthma but the indication is limited to total IgE levels of up to 700 kIU/L. The use of omalizumab in a subgroup of allergic asthmatics with highly elevated IgE has not been reported. OBJECTIVE: To determine whether omalizumab is effective in reducing free IgE levels in patients with total IgE levels of over 700 kIU/L and if this reduction correlates with clinical improvement as measured by spirometry. METHODS: A pilot study of 8 patients with moderate to severe asthma and an elevated IgE levels >1000 kIU/L (+/- 100). Omalizumab was given subcutaneously at a monthly dosage of 0.016mg/kg x total IgE level divided into biweekly, to a maximum of 375 mg per dose. Follow-up was done every six months. Six of 8 patients completed 6 months with free IgE level, spirometry, and asthma classification. Another 2 patients were followed over 2 years. Exhaled nitric oxide (eNO) was measured in one patient for one year.;RESULTS: Total IgE levels did not decrease after 6 months on omalizumab treatment but did show a decreasing trend after one year. A similar trend was seen in the free IgE with continued decrease after 2 years in 2 patients. Spirometric values were not affected despite clinical improvement based on decrease in systemic steroid use and decreasing eNO in one patient.;CONCLUSIONS: Moderate to severe asthma patients with high serum IgE levels of over >1000 kIU/L showed clinical improvement with omalizumab treatment at the current FDA approved dose that directly correlates with reduced free IgE levels after over one year of treatment.