Predictors of histologic response to mepolizumab in pediatric eosinophilic esophagitis

BACKGROUND: Eosinophilic esophagitis (EoE) is a chronic, allergic disease of the esophagus. Current treatment options are limited. One experimental therapy is antibodies against interleukin-5 (IL-5). However, it is unknown why some patients respond to anti-IL-5 treatment whereas others do not. We sought to delineate predictors of histologic response to anti-IL-5 therapy in pediatric EoE. METHODS: This post hoc analysis of a multicenter, double-blind clinical trial (ClinicalTrial.gov identifier: NCT00358449) evaluated mepolizumab for the treatment of EoE in pediatric patients. Predictors were assessed for their association with a histologic response at week 12 of treatment. A histologic response was defined as either <15 eosinophils per hpf or a reduction in peak eosinophil counts by ≥50%. Predictors on univariate analysis with P  < 0.10 were included in multivariate logistic regression models. Statistical significance for multivariate comparisons was set at P  < 0.05. RESULTS: Patients with a higher BMI were more likely to attain histologic response at week 12, defined as <15 eosinophils per hpf [aOR, 1.31; 95% confidence interval (CI), 1.07-1.60; P  = 0.008]. Higher BMI (aOR, 1.70; 95% CI, 1.06-2.74; P  = 0.029) and signs of exudate plaques on endoscopy (aOR, 18.30; 95% CI, 2.11-158.53; P  = 0.008) were significant predictors of histologic response at week 12 where a histologic response was defined as a reduction in peak eosinophil counts by ≥50. CONCLUSION: Higher BMI and signs of exudative plaques on endoscopy may be predictors of histologic response in pediatric EoE patients treated with antibodies against IL-5. Further studies are needed to validate our findings.