Omalizumab (Xolair) effective against chronic idiopathic urticaria

The monoclonal antibody omalizumab (anti-IgE), given at doses higher than those used in asthma, rapidly reduced urticaria activity scores.

The study followed up an unexpected observation that, in asthma patients with urticaria, the skin condition often responded quickly when they were treated with omalizumab (trade name Xolair). This was an "unanticipated benefit" because "a lot of urticaria is not necessarily allergic-oriented."

The primary endpoint was the change from baseline in the 7-day urticaria activity score (UAS7), which is a diary-based combined score of severity of itch and number of hives. The maximum score is 42.

Patients who received 300 mg of omalizumab had a UAS7 decline of 19.93 points, down from a baseline average of 27.72.

The effect was rapid, patients in the 300-mg group had an average 13-point drop in the UAS7 one week after the single dose.

Omalizumab is expensive, but for urticaria the benefit appears with only a single dose.

References:
Single-dose omalizumab (300mg) in patients with H1-antihistamine–refractory chronic idiopathic urticaria leads to improvement within 1-2 weeks. JACI, 2011.

Single dose of omalizumab (one 300 mg injection) relieves chronic idiopathic urticaria refractory to H1-antihistamines. Medscape, 2011.

ACAAI: Asthma Drug Effective in Skin Condition. MedPage Today.

Images: Mechanisms of action of omalizumab. JACI, 02/2008.
Image source: Wikipedia, public domain.