Individuals with a peanut allergy who received oral peanut protein for 2 years achieved desensitization, but subsequently reducing the dose increased the likelihood of regaining clinical reactivity to peanut, according to study results published in the Lancet.
In the Peanut Oral Immunotherapy Study: Safety, Efficacy and Discovery (POISED; ClinicalTrials.gov Identifier: NCT02103270) trial, the proportion of participants with a peanut allergy who passed a double-blind placebo-controlled food challenge (DBPCFC) was compared between groups. Group 1 received 4000 mg peanut protein through week 104 then discontinued peanut protein (peanut-0), Group 2 received 4000 mg peanut protein through week 104 then 300 mg peanut protein daily (peanut-300), and Group 3 received oat flour (placebo group). Treatment was randomly assigned via computer and participants, the study team, and the statisticians were masked throughout.
Of the 152 patients assessed for eligibility, 120 were enrolled in the study and randomly assigned to the peanut-0 (n=60), peanut-300 (n=35), or placebo groups (n=25). Success in passing a DBPCFC with no clinical reaction was significantly different between the placebo group and the combined peanut treatment groups (peanut-0 and peanut-300) at all challenge time points. Reaction thresholds at all challenge time points in both peanut groups improved from the baseline food challenge. In the peanut-0 group, 8 participants were successful in tolerating the DBPCFC at week 156. However, compared with the peanut-0 group, the peanut-300 group had greater success at week 156 (37% vs 13%).
The most common adverse events were mild gastrointestinal symptoms, which were seen in 52 participants in the peanut-0 group, 29 participants in the peanut-300 group, and 12 participants in the placebo group.
“We found that OIT with peanut was able to desensitize people with peanut allergy to 4000 mg of peanut protein, but that discontinuation of peanut, or even a reduction to 300 mg daily, increased the likelihood of regaining clinical reactivity to peanut,” the researchers wrote. “Optimal maintenance dosing and regimens still need to be further elucidated for improved safety and must involve informed conversations with patients to identify attainable goals.”
Chinthrajah RS, Purington N, Andorf S, et al. Sustained outcomes in oral immunotherapy for peanut allergy (POISED study): a large, randomised, double-blind, placebo-controlled, phase 2 study [published September 12, 2019]. Lancet. doi:10.1016/S0140-6736(19)31793-3