Omalizumab in Chronic Urticaria

Posted by • March 8th, 2013

A new randomized, placebo-controlled trial showed the efficacy of omalizumab, an injectable anti–IgE humanized monoclonal antibody, in the treatment of chronic idiopathic urticaria.

The impairment accompanying this disorder has been likened to that seen in patients with ischemic heart disease, with patients feeling a similar lack of energy, social isolation, and emotional upset as those with ischemic heart disease.

Clinical Pearls

•  What is chronic spontaneous urticaria?

Chronic spontaneous urticaria (also called chronic idiopathic urticaria) is defined as itchy hives that last for at least 6 weeks, with or without angioedema, and that have no apparent external trigger. The condition generally has a prolonged duration of 1 to 5 years (persisting for >5 years in 11 to 14% of patients).

•  What is the mechanism of action of omalizumab?

Omalizumab, a recombinant humanized monoclonal antibody approved as add-on therapy for moderate-to-severe persistent allergic asthma, reduces the levels of free IgE and the high-affinity receptor for the Fc region of IgE (Fc[epsilon]RI), both of which are essential in mast-cell and basophil activation.

Morning Report Questions

Q: What were the primary study results in this phase 3, randomized, double-blind study evaluating the efficacy of omalizumab in patients with moderate-to-severe chronic spontaneous urticaria?

A: Omalizumab administered as three doses of 150 mg or 300 mg at 4-week intervals significantly reduced symptoms, as compared with placebo, in patients with chronic spontaneous urticaria who remained symptomatic despite the use of approved doses of H1-antihistamines. Significant and clinically meaningful effects were seen for patients receiving either 150 mg or 300 mg of omalizumab in the change from baseline in the weekly itch score (primary end point).

Q: What adverse effects were associated with the administration of omazilumab?

A: The percentages of patients with at least one adverse event were similar across the treatment groups: 61% in the placebo group, 59% in those receiving 75 mg of omalizumab, 67% in those receiving 150 mg of omalizumab, and 65% in those receiving 300 mg of omalizumab. During the 28-week study period, there were reports of nine serious adverse events, with five reported in the group receiving 300 mg of omalizumab (6%), two in the placebo group (3%), and one each in the groups receiving 75 mg and 150 mg of omalizumab (1% for each). Most of the adverse events were reported in the 150-mg and 300-mg groups during the follow-up period, when no drug was being administered. No deaths or episodes of anaphylactic shock were reported during the study.

Table 3. Adverse Events (Safety Population).

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