Interaction Between Baseline Participant Factors and Treatment Effects Following Peanut Oral Immunotherapy

The Probiotic Peanut Oral Immunotherapy-003 multicenter randomized trial found that both probiotic peanut oral immunotherapy (PPOIT) and peanut OIT alone (OIT) were effective compared with placebo in inducing clinical remission after 18 months of treatment, and improving health-related quality of life (HRQL) at 12 months after treatment. Understanding treatment effect modifiers can optimize outcomes through precision care. This post hoc study examined baseline clinical and demographic participant factors that modified treatment effects. The study sample included 201 children (aged 1-10 years) with challenge-confirmed peanut allergy. Exposure variables were baseline clinical and demographic factors. Outcomes were remission (double-blind, placebo-controlled food challenge, cumulative 4,950-mg peanut protein at 8 weeks after treatment) and HRQL (change in Food Allergy Quality of Life Questionnaire–Parent Form score). Interactions between baseline factors and treatment effects on remission and HRQL were explored with regression models. A higher degree of peanut sensitivity (large peanut skin prick test, high peanut specific IgE, and low reaction-eliciting dose at study entry challenge) and other concurrent allergic conditions (multiple food allergies, asthma, or wheeze) were associated with the decreased likelihood of attaining remission after both PPOIT and OIT treatment. History of anaphylaxis was associated with the reduced likelihood of remission after PPOIT compared with OIT. For the HRQL outcome, there was evidence that sex, history of anaphylaxis, and age modified treatment effects. Baseline participant factors modify PPOIT and OIT effects on remission and HRQL. Considering modifiers of treatment effect during participant selection may optimize treatment success and clinical trial design toward specific outcomes, such as the achievement of remission.