Published Online: December 9, 2013
Peanut allergy is a major public health problem affecting 1% of the population. In addition to the condition's wide reach, there is no effective therapy for peanut allergy aside from avoiding peanuts and having ready access to epinephrine in the event of an accidental exposure. There have been numerous clinical trials showing that oral desensitization can be effective in increasing the amount of peanuts tolerated by peanut allergic individuals. However, oral desensitization takes months to years to complete and is often fraught with allergic reactions, which at times can be severe. As a result of these reactions, as many as 30% of patients with peanut allergy are not able to complete the desensitization process.
In an article recently published in The Journal of Allergy & Clinical Immunology (JACI), Schneider et al theorized that treatment with omalizumab (Xolair, anti-IgE monoclonal antibody), a potent anti-allergy medication, would reduce the frequency of allergic reactions in peanut allergic patients during oral desensitization, greatly facilitating their acceptance of the treatment. (The FDA has approved omalizumab to treat older children and adults with moderate to severe allergic asthma.) In their study, the investigators focused on peanut allergic individuals at high risk for developing significant allergic reactions from exposure to small amounts of peanuts and only enrolled patients with high levels of peanut-specific IgE. Previous research shows that such patients are resistant to oral food desensitization.
Thirteen children were enrolled in a pilot study. The median peanut-specific IgE was 229 kUA/L (normal <0.35), and all subjects failed an initial double-blind placebo controlled food challenge at doses <100 mg peanut flour (about a quarter of a peanut). After pre-treatment with omalizumab, all 13 subjects tolerated the initial 11 desensitization doses given on the first desensitization day, including the maximum dose of 500 mg peanut flour (cumulative dose equivalent to >2 peanuts), requiring minimal or no rescue therapy. Twelve subjects then reached the maximum maintenance dose of 4,000 mg peanut flour/day in a median time of 8 weeks, at which point omalizumab was discontinued. All 12 subjects continued on 4,000 mg peanut flour/day and subsequently tolerated a challenge with 8,000 mg peanut flour.
As demonstrated by the study, treatment with omalizumab may facilitate rapid oral desensitization and qualitatively improve the desensitization process among children with high-risk peanut allergy. If confirmed with larger double-blind placebo-controlled studies, using omalizumab to facilitate oral desensitization could change the clinical approach for large numbers of patients with clinically significant peanut allergy.
The Journal of Allergy and Clinical Immunology (JACI) is an official scientific journal of the AAAAI, and is the most-cited journal in the field of allergy and clinical immunology.