Effectiveness of Omalizumab in Asthmatics with Baseline Serum IgE>1500 IU/Ml Using a Novel Method for Assessing Response: Reality Study

Rationale: Omalizumab has been approved for asthmatics with IgE levels of 30-700IU/mL. It has even been used with IgE>1500IU/mL, although few studies have confirmed the efficacy at these levels.  A standardized criterion for assessing response to omalizumab is needed. Study is designed to apply a novel method using multiple independent modules comparing response to omalizumab in patients with IgE<700 vs IgE>1500 IU/mL.

Methods: Retrospective analysis of response to omalizumab in patients with elevated baseline IgE after one year of treatment. Response to therapy (one-year pre- to one-year post-treatment) was defined by multiple modules:[Module1,M1]-complete control or marked improvement in asthma-symptoms based on Global Evaluation of Treatment Effectiveness(GETE) scores; [Module2,M2]-improvement in at least three of six of the following:50% reduction in asthma exacerbations, steroid-bursts, ER-visits, hospitalizations; improvement in FEV1(≥200c), improved ACT-score≥3; [Module3,M3,True responder]-patient that meets both M1 and M2 response criteria.

Results: 157 patients with baseline IgE≥30IU/mL received omalizumab for one year: G1[30-700IU/mL],G2[701-1500IU/mL] and G3[>1500IU/mL]. Number of patients per group were: G1[101(64.3%)]; G2[20(12.7%)] and G3[36(22.9%)]. Mean (SD) for baseline IgE:G1[278(194)]; G2[1,054(165)] and G3[3,486(2,661)]. Overall true response (M3) was 64.3%. Response rate for G1 vs. G3 are respectively 82.2% and 86.1% by M1, 68.3% and 80.6% by M2, and 61.4% and 69.4% by M3. Using M3 response for G1 and G3, statistical p-value is 0.083.

Conclusions: After one year, there was no significant difference in true response to therapy (M3) between patients with baseline IgE<700 compared to those with baseline IgE>1500. Positive response by subjective physician’s assessment was consistently higher than response by clinical parameters.