Publications

Background: Omalizumab is an effective and well-tolerated treatment for chronicspontaneous urticaria (CSU). Markers and predictors of response are largelyunknown, but needed to optimize omalizumab treatment. Omalizumab targets IgE,and IgE levels may be linked to the effects of treatment. We evaluated whetherresponse rates to treatment with omalizumab in patients with CSU are linked totheir baseline IgE levels, their IgE levels after omalizumab treatment, and the ratioof on treatment IgE and baseline IgE levels.

Methods: Chronic spontaneous urticaria (CSU) patients (n=113) were treated withomalizumab 300 mg/4 weeks for 12 weeks, when their treatment responses, thatis, no, partial, or complete response, were assessed by use of the urticaria activityscore, physician and patient visual analog scale, and treatment effectiveness score.Total IgE levels were measured before treatment (bIgE) with omalizumab and4 weeks thereafter (w4IgE).

Results: Nonresponders to omalizumab had significantly lower bIgE levels (17.9,17.0-55.0 IU/mL) than partial responders (82.0, 46.2-126.5 IU/mL,P=.008) andcomplete responders (73.7, 19.45-153.8 IU/mL,P=.032). Nonresponders also hadlower w4IgE levels and lower ratios of w4IgE/bIgE levels than partial and completeresponders (P<.001). Nonresponse to omalizumab was best predicted by patients’w4IgE/bIgE ratios, significantly better than by bIgE levels (P=.016).

Conclusions: In CSU, total IgE levels and their change predict the response to treat-ment with omalizumab. The assessment of pre- and post-treatment IgE levels andtheir ratio may help to improve the management of CSU in patients who requireomalizumab treatment.