Safety and Efficacy of Reslizumab for Children and Adolescents With Eosinophilic Esophagitis Treated for 9 Years

Abstract

To report the efficacy and long-term safety of reslizumab (RSZ) for the treatment of pediatric eosinophilic esophagitis (EoE).This was a single-center study including 12 patients (7–16 years old) previously enrolled in a parent multicenter randomized controlled trial receiving either 2 mg/kg RSZ or placebo. All patients had active EoE, esophageal symptoms, and endoscopic findings at enrollment and were permitted to be on a proton pump inhibitor and dietary avoidance. None were on topical steroids. Of the initial 12 patients, 8 patients elected to receive RSZ in an expanded access program (open label and compassionate use) from July 2008 to January 2012, with 3 remaining until 2017 and using RSZ for 9 years.The patients participating in the extension program were treated with 2 mg/kg intravenous RSZ every 28 days and were re-evaluated annually. During the monthly infusion encounters, patients were assessed through a questionnaire, and adverse events were recorded. If clinically indicated, RSZ could be increased to 3 mg/kg. Clinical remission was defined as resolution of all EoE symptoms, normal endoscopic findings, and histology <5 eosinophils per high-power field.Over the 9-year study, the 12 patients received ∼501 doses of RSZ (1–3 mg/kg intravenously). RSZ treatment median duration was 3 years, and all patients reported improved esophageal symptoms at follow-up. Ninety-two percent of patients demonstrated a reduced eosinophil count to <5 eosinophils per high-power field (P < .001). The 3 subjects who remained on prolonged RSZ also continued to have histologic remission. RSZ was well tolerated and safe throughout the duration of the study. Five patients (42%) experienced at least 1 adverse event, including nasal congestion or cough. None of the patients experienced adverse events that were attributed to or required the discontinuation of RSZ.RSZ shows promise as an effective and safe long-term treatment of pediatric EoE.RSZ is an interleukin-5 antagonist approved for adults for the treatment of severe asthma. This study is limited by its small sample size, restricting its opportunity to detect differences. Another confounding variable is that participants were allowed to restrict food triggers and take a proton pump inhibitor, both of which are treatments for EoE. The authors importantly recognized the declining participation but noted it was not related to any adverse events. Despite these limitations, RSZ seems to be an effective and safe drug for a select pediatric EoE population.