SAN FRANCISCO – In a University of Toronto case series, 150-mg injections of omalizumab (Xolair) put seven of nine patients with severe, refractory chronic idiopathic urticaria into remission, sometimes after the first injection.
There have been other reports of the anti-IgE monoclonal antibody successfully treating refractory chronic idiopathic urticaria (CIU), but usually at higher doses.
"Because of the cost, we wanted to see if it would work at 150 mg," the standard dose for asthma, said lead investigator Dr. Gordon Sussman, division director of clinical allergy and immunology at the university.
Cost was an issue because the patients paid for the biologic themselves. Although omalizumab carries an asthma indication, it is not yet indicated for chronic urticaria, and so was not covered by the patients’ insurance. A single 150-mg injection costs from $500-$1,000, Dr. Sussman said at the annual meeting of the American Academy of Allergy, Asthma, and Immunology.
"The patients paid for it, and would pay for it again because it’s effective," he said.
"The standard dose seemed to work after one treatment. In some people [hives came back] in sometimes 2 months, sometimes 4 months. But when [they] came back and we treated people again, they seemed to be able to respond to the second treatment," Dr. Sussman said.
The five women and four men in the series were aged 27-66 years (mean 47.7) and had suffered from severe, refractory CIU from 1-13 years (mean 5.5). Initial IgE levels ranged up to 750 mcg/L. Initial urticaria activity scores ranged from about 33 to 40.
They were all taking nonsedating antihistamines, 20- to 50-mg prednisone daily, and other drugs to control their hives, without success.
The first patient was dosed at 225 mg based on an IgE of 384 mcg/L but because of the cost issue, subsequent patients were treated with 150-mg doses. They each received from one to five doses spaced from 2-10 weeks apart, depending on symptoms.
The 225-mg patient and four 150-mg patients went into spontaneous remissions within a week of their first injections. Another two patients went into remission after two 150-mg injections and another patient after three.
Dr. Sussman and his colleagues took those patients off their prednisone, but kept them on their antihistamines, the standard treatment for urticaria.
Three patients have remained symptom free for up to 8 months. Other patients have gotten follow-up omalizumab shots as needed.
A ninth patient went into remission after three doses, but symptoms returned after several months. A second course of three injections had little effect, and the woman is currently on 10-mg dose of prednisone daily.
"She responded at first very well, and then she rebounded. At this point she’s refractory. So it doesn’t work for everyone," Dr. Sussman said.
Initial IgE level "is not really a predictor" of response, he noted. "We don’t think [the effect] is related to IgE. My hypothesis is that maybe it’s related to down-regulation of IgE receptors in some way that we don’t really understand."
Even so, "Xolair seems to work quickly after the first treatment. We think it’s a real effect," Dr. Sussman said.
Dr. Sussman said he had no relevant financial disclosures. The case series received no outside funding.