Omalizumab (Xolair) Facilitates Rapid Oral Desensitization for Peanut Allergy

A blinded, controlled study on the use of omalizumab (Xolair) in oral immunotherapy for peanut allergy is currently in press at the Journal of Allergy and Clinical Immunology. Funded largely by FARE, the multi-center Phase 2 trial PRROTECT (Peanut Reactivity Reduced by Oral Tolerance in an Anti-IgE Clinical Trial) tested whether the drug could improve peanut OIT.

Omalizumab binds to IgE antibodies that mediate allergic reactions; it is currently used to treat uncontrolled asthma and chronic hives. Earlier research showed that patients given omalizumab were better able to tolerate milk OIT, but the drug did not significantly increase the fraction of patients who achieved sustained unresponsiveness (persistent protection after OIT was discontinued).

In the PRROTECT trial, treatment success was defined by several outcomes: successfully completing a one-day rapid desensitization up to 250 milligrams of peanut protein, tolerating a 2000-mg maintenance dose 6 weeks after drug treatment ended, and passing a 4000-mg oral food challenge 12 weeks after the last dose of omalizumab. Each of these outcomes was reached by more than 80 percent of the children in the omalizumab group who started peanut OIT, while only 1 of the 8 OIT recipients given placebo met these treatment benchmarks. Sustained unresponsiveness was not evaluated.

One-seventh of the omalizumab-treated patients had significant reactions during rapid desensitization, versus three-quarters of the patients receiving placebo. However, patients in both groups had reactions that required epinephrine, and a small number in each group discontinued peanut consumption after developing eosinophilic esophagitis.