Epicutaneous immunotherapy: A review of safety and efficacy.

Epcutaneous immunotherapy (EPIT) is a novel, non-oral route of allergen immunotherapy, utilizing the skin and its robust density of epidermal Langerhans cells (LC) for antigen presentation. This space is non-vascularized and impermeable, which limits allergen exposure into the bloodstream but preserves antigen presentation to regional lymph nodes to generate gut-homing regulatory T cells. The EPIT patch utilizes natural water loss from the skin to absorb electrosprayed allergen through condensation. EPIT represents an alternative, non-oral route of immunotherapy for food allergy, with good efficacy and strong safety profiles across multiple phase 2 and 3 studies for milk and peanut. Efficacy appears the best in very young children (1-3 years old), which has been shown to continue to enhance with extended treatment duration up to 36 months. Efficacy in slightly older children ages 4-11 years of age is less clear, but appears to be better in children ages 4-7 years of age. In clinical trials of milk and peanut EPIT, most subjects experienced adverse effects, mainly mild-to-moderate skin reactions localized around the patch placement site, which improve with continued duration of wear. Rates of treatment-related anaphylaxis have been very low across all studies and ages, ranging from 1.6% to 4%, and were lowest in the infant and toddler population. While further studies of safety (1- to 3-year-olds) and efficacy (4- to 7-year-olds) are ongoing, EPIT is a potentially valuable addition to the current landscape of food allergy therapies, in particular for infants and toddlers where families may be seeking a non-oral route of treatment.