Eosinophilic esophagitis is a chronic allergic disease with insufficient treatment options. Results from animal studies suggest that IL-5 induces eosinophil trafficking in the esophagus.

We sought to evaluate the effect of reslizumab, a neutralizing antibody against IL-5, in children and adolescents with eosinophilic esophagitis.

Patients with symptom severity scores of moderate or worse and an esophageal biopsy specimen with 24 or more intraepithelial eosinophils per high-power field were randomly assigned to receive infusions of 1, 2, or 3 mg/kg reslizumab or placebo at weeks 0, 4, 8, and 12. The coprimary efficacy measures were changes in peak esophageal eosinophil count and the physician's global assessment score at week 15 (end of therapy).

Two-hundred twenty-six patients received study medication. Median reductions from baseline to the end of therapy in peak esophageal eosinophil counts were 59%, 67%, 64%, and 24% in the 1, 2, and 3 mg/kg reslizumab (all P < .001) and placebo groups, respectively. All treatment groups, including the placebo group, showed improvements in physician's global assessment scores; the differences between the reslizumab and placebo groups were not statistically significant. The most common adverse events in the reslizumab groups were headache, cough, nasal congestion, and upper respiratory tract infection. One patient in each reslizumab group and 2 in the placebo group had serious adverse events; none were considered related to the study medication.

Reslizumab significantly reduced intraepithelial esophageal eosinophil counts in children and adolescents with eosinophilic esophagitis. However, improvements in symptoms were observed in all treatment groups and were not associated with changes in esophageal eosinophil counts.