The simple, modern approach to anti-histamine resistant chronic spontaneous urticaria (CSU) relies on omalizumab. It was found to be effective in trials with more than 900 patients. Serious adverse events have not been seen.
What is omalizumab response rate?
65% of patients respond to omalizumab. A response rate of 65% is seen in patients resistant to antihistamines as well as to histamine2 blockers and leukotriene antagonists
How effective is omalizumab?
40% of patients were completely free of hives as long as therapy is continued.
Only cyclosporine can match this response rate (excluding steroids), but the adverse effect profile (blood pressure and renal function) is worse.
Chronic Urticaria Treatment Options in 6 Steps (click to enlarge the image).
What are the alternatives to omalizumab?
Double-blind, placebo-controlled studies of other agents often listed as alternatives are lacking (ie, whether their success rate exceeds the 25%-30% placebo response is uncertain).
How does omalizumab work?
The mechanism by which omalizumab works in CSU is not clear because the response rate is unrelated to the autoimmune profile and can occur rapidly (ie, within a few days).
The author of this review in Ann Allergy Asthma Immunol. concluded: Omalizumab has exceptional efficacy for antihistamine-resistant CSU with an excellent adverse effect profile.
It sounds great. However, the abstract did not mention the price tag of omalizumab ($2,000 per month) and the ongoing FDA review of its cardiovascular safety.
Therapy of chronic urticaria: a simple, modern approach. Kaplan AP. Ann Allergy Asthma Immunol. 2014 Mar 20. pii: S1081-1206(14)00129-X. doi: 10.1016/j.anai.2014.02.014. [Epub ahead of print]