Real–World Experience With Peanut Oral Immunotherapy: Lessons Learned From 270 Patients

Abstract

This retrospective record review reports observations on the treatment of 270 patients with peanut allergy with peanut oral immunotherapy (POIT).The study included 270 patients between the ages of 4 and 18 years who received POIT in a single practice between 2009 and 2017. A total of 96.7% of patients had a history of an immunoglobulin E–mediated reaction, 70.7% had experienced anaphylaxis, 26% had a peanut-specific immunoglobulin E (PSIgE) concentration of >100 kU/mL, and 9.6% had a positive peanut challenge result within 2 years of inception of POIT. No patient was excluded on the basis of severity of previous reaction(s) or PSIgE concentration. Patients with a history of eosinophilic esophagitis or gastroenteritis were excluded.The treatment protocol began with 2.5 µg of peanut protein. Dose increases were administered under direct observation. Patients reached a target dose of 3000 mg of peanut protein, underwent a 6000-mg challenge, and then began a 2000-mg maintenance dose administered at home 1 to 2 times per day for a minimum of 3 years. The treatment team made dose adjustments and decisions regarding discontinuation of therapy on the basis of collaborative clinical judgment. Patients and caregivers were instructed to report any adverse reactions more significant than transient, self-limited oral pruritis or abdominal discomfort.A total of 214 of 270 patients (79%) completed POIT dose escalation. Age (P < .001) and PSIgE (P < .001) correlated inversely with completion of dose escalation. For each year increase in patient age after 5, there was a 17% decrease in the odds ratio of reaching the escalation target (P < .001). One hundred epinephrine-treated reactions occurred in 63 patients (23%) during escalation. Intermittent asthma and higher PSIgE levels increased the risk of epinephrine-treated reactions (P = .035 and .019, respectively). Eosinophilic esophagitis–like oral immunotherapy–related syndrome occurred in 37 patients (13.7%). Intermittent asthma and higher PSIgE levels increased the risk of eosinophilic esophagitis–like oral immunotherapy–related syndrome (P = .014 and <.001, respectively). After 3 years of maintenance treatment, 14 patients were able to achieve sustained peanut unresponsiveness, defined as tolerance of 6000 mg of peanut protein after avoiding peanut for 30 days. The best predictors of sustained unresponsiveness were a pretreatment PSIgE level <20 kU/L and a prechallenge PSIgE level <1 kU/L.In an allergy office practice, 79% of patients were able to complete a POIT desensitization protocol and maintain a desensitized state with daily peanut dosing.This study demonstrates that patients can achieve successful peanut desensitization despite a history of previous reaction(s) or markedly elevated PSIgE levels. Epinephrine-treated reactions did occur during POIT, demonstrating that risk of significant allergic reactions was not eliminated. Reduced likelihood of achieving the target dose with increasing age makes early intervention attractive. Additional future studies are necessary to improve risk assessment and identification of patients likely to achieve sustained unresponsiveness.