Omalizumab-facilitated peanut oral immunotherapy: outcomes at year 6
Published online: September 26, 2018
The rising incidence of peanut allergy has led to an ever-increasing number of patients at risk for life-threatening reactions. Oral immunotherapy (OIT) is a therapeutic modality that is gaining significant interest. Highly peanut-allergic patients may be particularly motivated to pursue OIT as a potential alternative to strict avoidance, but OIT carries alternative risks of allergic reactions and complications. Practicality and outcomes of long-term peanut OIT are only starting to be examined.
In an article recently published in The Journal of Allergy and Clinical Immunology: In Practice, Yee, et. al. reported long-term follow-up of 13 highly peanut allergic children who received peanut oral immunotherapy. The patients were treated with omalizumab, an anti-IgE monoclonal antibody, for 6 weeks before starting peanut OIT. Patients were desensitized rapidly over 8 weeks to a maintenance dose of 2000 mg dose of peanut protein (~8 peanuts), after which omalizumab was stopped and OIT was continued. The authors followed these patients for 6 years to study the long-term effects of peanut OIT, including the clinical outcomes, quality of life, and peanut allergy biomarkers.
After 6 years, 7 (54%) of the 13 highly peanut allergic patients who began the study were continuing peanut OIT while 6 (46%) stopped primarily because of allergic reactions. Over time, most patients changed the dose of peanut protein and the type of commercially available peanut products consumed. The change was well tolerated without associated reactions. Maintenance doses varied from 500-3500 mg (about ~2 to 15 peanuts). Significant taste aversion was reported in 7 patients (54%). All the patients experienced at least one allergic reaction to peanut OIT. There was a total of 12 anaphylactic reactions in 6 patients (46%) that were treated with epinephrine. Amongst several food allergy biomarkers followed over time, peanut-specific IgE and Arah2-IgE, were found to be elevated at 1 year into the study in patients who discontinued peanut OIT. The patients and parents in the study reported that their quality of life improved during the study, even after discontinuing OIT.
The authors concluded that while omalizumab allowed for rapid desensitization in highly peanut allergic patients, almost half discontinued peanut OIT primarily because of reactions. Elevated Arah2 and peanut specific IgE were associated with discontinuation. Future studies of peanut OIT might benefit from further consideration of the time and speed of the initial build-up to the maintenance OIT dose and duration of omalizumab therapy. It remains to be seen whether choice of the maintenance dose affects the rate of allergic reactions and continuation in the long-term, and if specific biomarkers may predict loss of ability to tolerate OIT long-term.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.