Allergen Immunotherapy for the Treatment of Eosinophilic Esophagitis. An EAACI Task Force Systematic Review.

BACKGROUND

Multiple routes of allergen immunotherapy (AIT) are approved for several IgE-mediated allergic diseases; however, the use of AIT in eosinophilic esophagitis (EoE) remains controversial and is supported by limited evidence. This review, conducted within the frame of an EAACI Task Force, aims to systematically evaluate the use of AIT as a potential treatment for EoE.

METHODS

The protocol was registered and prepared in accordance with PRISMA guidelines. The literature search was conducted across three online databases (PubMed, Embase, and Scopus) and included studies published through January 31st, 2025. Risk of Bias was assessed for each eligible study.

RESULTS

Four articles met the inclusion criteria. Three articles evaluated EPIT for milk-induced EoE in pediatric patients, all from the SMILEE (Study of Efficacy and Safety of Viaskin Milk for milk-induced EoE) trial and its extensions. These included a randomized, placebo-controlled trial, its open-label extension, and a pilot immunological study. The SMILEE trial found no statistically significant difference in tissue eosinophilia between the active (EPIT) and control (placebo) arms in the intention-to-treat population, while 47% of treated EoE patients tolerated milk without recurrence of esophageal eosinophilia. This finding was further supported by a subsequent open-label study with a 2-year follow-up. In the third publication, the researchers found that EPIT was associated with decreased Th2-related transcripts and increased regulatory T-cell-associated transcripts. Only one eligible study evaluated the use of SCIT for treating EoE. It was a retrospective case-control study reporting that SCIT had a neutral effect and yielded inconclusive findings regarding the course of EoE.

CONCLUSION

There is insufficient high-quality evidence to support the effectiveness of alternative routes of AIT for the treatment of EoE, either as an add-on or a standalone treatment.