PHILADELPHIA — Treatment with an antibody to IgE led to improved symptoms in patients with urticaria in two pilot studies and a case series reported at the annual meeting of the American Academy of Allergy, Asthma, and Immunology.
The antibody, omalizumab, probably is effective for urticaria because of the role that IgE-mediated activation of basophils and mast cells has in causing the disorder. Omalizumab is a recombinant, humanized antibody that binds to human IgE, and therefore has the potential to block this urticaria trigger. This was tested in a study of 20 patients with chronic idiopathic urticaria who were randomized to treatment with either omalizumab or placebo at Johns Hopkins Medical Center in Baltimore, Dr. Laura M. Gober reported in a poster at the meeting.
In a second, independent study, 12 patients with chronic, autoimmune urticaria were treated with omalizumab in an open-label study at the National Allergy, Asthma & Urticaria Centers of Charleston (S.C.), reported Dr. Allen P. Kaplan.
And results from a case series presented at the meeting showed that 22 patients in a single practice treated with omalizumab for asthma had resolution of their food allergies, reported Dr. Caroline Watson, an allergist in private practice at the Allergy & Asthma Care Center in Los Angeles.
Omalizumab (Xolair) is marketed by Genentech Inc. and Novartis Pharmaceuticals Corp. as a treatment for asthma. The urticaria study at Johns Hopkins was sponsored by Genentech, and Dr. Kaplan's study in Charleston was sponsored by Novartis; the case series reported by Dr. Watson did not have commercial sponsorship. Dr. Gober, Dr. Kaplan, and Dr. Watson reported having no financial relationships with the two companies, but the senior researcher in the Johns Hopkins study, Dr. Sarbjit S. Saini, has served as a consultant to Genentech and Novartis.
The controlled study at Johns Hopkins enrolled 20 patients with chronic, idiopathic urticaria who had active disease despite receiving standard antihistamine treatment. The patients ranged in age from 22 to 64 years. They were randomized to receive either the approved dosage for treating asthma or placebo, reported Dr. Gober and her associates. Treatment was by subcutaneous injection every 4 weeks for 16 weeks, and then patients were followed for an additional 8 weeks.
The average urticaria severity scores were identical at baseline in both treatment arms. Both the physician-rated and patient-rated scores among the patients treated with omalizumab were significantly reduced, compared with the placebo group as quickly as 2 weeks after the initial dose, and stayed significantly lower throughout the balance of the study.
After 16 weeks of treatment, following the final dose, the patients in the omalizumab group showed “marked improvements” in their scores for quality of life, emotions, and functioning, compared with the placebo group, and they also had a significant increase in number of symptom-free days. After 16 weeks of treatment, an average of 50% of days were symptom free in the omalizumab-treated patients, compared with an average of about 5% of days in the placebo group.
These benefits were maintained during the next 8 weeks without treatment, but severity scores in the omalizumab group began to increase from their level during active treatment. There were no reports of serious adverse effects with omalizumab.
Further study is needed to find the optimal omalizumab regimen in those with chronic idiopathic urticaria, said Dr. Gober, a pediatric allergist at Johns Hopkins.
The open-label study at the National Allergy, Asthma & Urticaria Centers of Charleston included 12 patients with chronic autoimmune urticaria who remained symptomatic despite high-dose treatment with a nonsedating antihistamine and hydroxyzine. After 4 weeks on placebo, they received a standard dose of omalizumab every 2 or 4 weeks for 16 weeks. This produced complete resolution of symptoms in seven patients and partial improvement in four patients, and had no effect in one patient, said Dr. Kaplan, a professor of medicine at the Medical University of South Carolina, Charleston.
In Dr. Watson's case-series study, the impact of omalizumab on food allergies was assessed in 82 patients with asthma who received regular treatment with omalizumab as patients at the Allergy & Asthma Care Center. In this group, 46 also had a history of a food allergy, and 22 of these patients reported exposure to the triggering food. All 22 patients reported a substantial reduction in symptoms following their food exposure when treated with omalizumab, Dr. Watson noted in a poster.
The patients were allergic to fish, shellfish, tree nuts, egg, soy, dairy, avocado, and wheat. Allergic reactions that were reduced in the patients included asthma, angioedema, anaphylaxis, atopic dermatitis, rhinosinusitis, and urticaria.