Safety and efficacy of epicutaneous immunotherapy for food allergy

Food allergy is increasingly common in children, affecting about 4%-8%. The mainstays of management remain allergen avoidance and emergency preparedness to treat allergic reactions with emergency medications. Unfortunately, these approaches are unsatisfactory for many patients and their families as the restrictions, constant vigilance, and unpredictable severity of allergic reactions negatively impact quality of life. In recent decades, there has been significant interest in developing treatments for food allergy that lead to desensitization to increase thresholds for triggering allergic reactions and decrease the risk of reacting to allergen-contaminated food products. Epicutaneous immunotherapy (EPIT) is a novel therapy that is currently under investigation, delivering allergen via repeated applications to the skin and targeting antigen-presenting cells in the superficial skin layers. Murine models have demonstrated that allergen uptake is an active process by skin dendritic cells with subsequent migration to draining lymph nodes. Allergen exposure to the non-vascularized epidermis limits systemic absorption, contributing to the high-safety profile. Results from murine experiments showed that EPIT has comparable efficacy as subcutaneous immunotherapy in terms of challenge outcomes, airway hyper-responsiveness, and immunologic parameters. Several clinical trials of EPIT have recently been completed or are ongoing. Results support the high safety and tolerability of this approach. Efficacy data suggest that the change in threshold eliciting dose following 1year of therapy is less than that seen compared to high-dose (2-4g peanut protein) oral immunotherapy, but more prolonged treatment with EPIT appears to lead to increasing desensitization. Additional data from larger-scale studies should provide a more robust assessment of safety and efficacy of EPIT.