Efficacy and Safety Study of Omalizumab (Xolair®) to Treat Chronic Urticaria

Chronic urticaria can be defined as the occurrence of widespread daily or almost daily wheals for at least 6 weeks, which may be accompanied by angioedema. While the wheals are transient, the resolution of angioedema is slower than wheals and could take up to 72 hours. The natural course of chronic urticaria is self-limited, with spontaneous remissions and occasional relapses. The investigators calculated a 0.6% (95% CI(Confidence Interval): 0.4-0.8) prevalence in a population study. It has a great impact on patients' quality of life. In a recent national survey on patients attending Allergy Department, chronic urticaria was the disease with greater impact on mental quality of life out of all allergic diseases. In spite of the high morbidity of this disease and the impact in quality of life, there is no available treatment. Last guidelines recommend initiating treatment with antihistamine and if there is no response to increase the dose off-label up to four-fold; systemic corticosteroids are also recommended in short tapering and if no response, the only treatment with clinical evidence to be employed is cyclosporine. As additional data, the treatment cost of this disease has been calculated in 2047$/year. In past years it has been employed the monoclonal humanized anti-Immunoglobulin IgE (iGE) antibody (Omalizumab) to treat moderate to severe asthma with good results. The rationale for this approach in chronic urticaria is that Omalizumab inhibits the binding of IgE to the high affinity IgE receptor (FceRI) which decreases the FceRI expression on the surface of mast cells and basophils so that immunoglobulin G cross linking of the alpha subunit and basophil degranulation is prevented.The hypothesis the investigators are working on is that monoclonal IgE antibody Omalizumab could be effective in controlling chronic urticaria symptoms in patients non respondent to conventional therapy. The investigators hypothesize that Omalizumab is able to revert the basophil or