Eosinophilic Esophagitis: the Potential Role of Biologics in its Treatment

Eosinophilic esophagitis (EoE) is a chronic, relapsing inflammatory disease of the esophagus, characterized by the presence of significant esophageal mucosal eosinophilic infiltrates. The clinical presentation of EoE in childhood may include failure to thrive and feeding intolerance. The complication of food impaction is often related to the presence of strictures or narrow caliber esophagus. Over the last decade, there has been tremendous progress in the field of eosinophilic disorders, particularly eosinophilic esophagitis. Conventional treatment of eosinophilic esophagitis involves topical swallowed steroids, systemic steroids, elimination diets, and/or esophageal dilation. However, treatment outcomes with the above modalities are not satisfactory for all patients with EoE and alternative treatments are clearly needed. There has been ongoing research targeting the treatment-refractory population of patients with EoE and the population with long-term consequences of the disease and its treatment. With the significant eosinophilic infiltration that characterizes EoE, anti-IL-5 therapies designed to target eosinophilic inflammation have been some of the most studied anti-inflammatory biologic therapies in EoE. In the studies published to date, while various IL-5 inhibitors have decreased the numbers of esophageal eosinophils, they have not depleted them to the levels consistent with histologic remission of EoE. As additional biologics that modulate Th2-mediated immunity are trialed for the treatment of EoE, we stand to learn more about the inflammatory factors mediating this challenging condition. In this review, we discuss the alternative modes of therapy in EoE that have emerged, with a focus on anti-IL-5 therapies and other biologics, their variation of success, and ultimately, the future of treatment in this field.