An antibody against IL-5 reduces numbers of esophageal intraepithelial eosinophils in children with eosinophilic esophagitis.

BACKGROUND & AIMS: The role of interleukin (IL)-5 in the pathogenesis of eosinophilic esophagitis (EoE) has been established in animal models; anti-IL-5 therapy has been reported to be effective in adults. We investigated whether IL-5 has a role in accumulation of esophageal eosinophils in children with EoE and whether therapy with mepolizumab, an antibody against IL-5, reduces the number of esophageal intraepithelial eosinophils in children with EoE. METHODS: We performed an international, multicenter, double-blind, randomized, prospective study of 59 children with EoE, defined as baseline peak count of esophageal intraepithelial eosinophils of ≥ 20 in at least 1 high-power field (hpf). Patients received an infusion every 4 weeks (a total of 3 infusions) of 0.55, 2.5, or 10 mg/kg mepolizumab. No placebo group was used. RESULTS: Baseline peak and mean esophageal intraepithelial eosinophil counts were (mean ± SE) 122.5 ± 8.78 and 39.1 ± 3.63 per hpf, respectively. Four weeks after the third infusion, peak eosinophil counts were <5 per hpf in 5 of 57 children (8.8%); we did not observe differences among groups given different doses of mepolizumab. Reduced peak and mean eosinophil counts, to <20 per hpf, were observed in 18 of 57 (31.6%) and 51 of 57 (89.5%) children, respectively. Peak and mean esophageal intraepithelial eosinophil counts decreased significantly to 40.2 ± 5.17 and 9.3 ± 1.25 per hpf, respectively (P < .0001). An analysis to evaluate predictors of response associated a higher mean baseline esophageal intraepithelial eosinophil count with a greater reduction in mean count (P < .0001). CONCLUSIONS: IL-5 is involved in the pathogenesis of EoE in children. Mepolizumab, an antibody against IL-5, reduces esophageal eosinophilic inflammation in these patients.

Patient and caregiver perspective on pediatric eosinophilic esophagitis and newly developed symptom questionnaires*.

OBJECTIVE: Eosinophilic esophagitis (EE), a rare chronic inflammatory condition of the esophagus, is predominantly observed in children and is primarily manifested with feeding difficulties. To our knowledge, no self- or caregiver-reported questionnaires are available to assess pediatric EE symptoms and their impact as reported directly by children or their parents/caregivers. The objectives of this study were to characterize the symptoms and impact of EE among children as reported by patients and parents/caregivers and to assess the content validity of two newly developed pediatric eosinophilic esophagitis symptom questionnaires, one parent/caregiver-reported questionnaire for ages 2-7 years and one child-reported questionnaire for ages 8-17 years. The questionnaires were developed based on a review of the literature and clinical expert consultation. RESEARCH DESIGN AND METHODS: This cross-sectional study involving one-on-one interviews with patients and caregivers was conducted at an American Partnership for Eosinophilic Disorders conference. Parents of patients aged 2-7 years (n = 12) and patients aged 8-17 years (n = 16) were first asked about symptoms and their impact on everyday life, using open-ended questions. Participants then completed the appropriate symptom questionnaire and were asked to provide feedback on the relevance, comprehensiveness, and clarity of each item and other questionnaire issues (time to complete, length, format, etc.). All reported symptoms were enumerated, and the feedback on the symptom questionnaires was analyzed qualitatively. RESULTS: The majority of study participants were white (82%) and male (86%). The most frequently reported symptoms of 2-7-year olds were vomiting (92%), "reflux" (50%), dysphagia (25%), abdominal pain (25%), and trouble sleeping (25%). The 8-17-year group reported abdominal pain (56%), vomiting (31%), throat pain (25%), diarrhea (25%), and food getting stuck (25%). Symptoms and treatment were reported to have a major impact on daily life, particularly on school, after-school activities and social events, feeling frustrated regarding symptoms and treatment, and feeling "different". Overall, participants thought that the questionnaires were clear, relevant, and appropriate for symptom assessment. LIMITATION: This study was based on a small and convenient sample of participants attending an EE conference and hence may not be representative of the general EE patient population. CONCLUSIONS: EE is associated with a range of symptoms that vary in terms of the type, frequency and severity across and within patients. The results provide adequate support for the content validity of the self- and caregiver-reported versions of the symptom-specific questionnaires. Minor modifications were made based on the feedback obtained. A psychometric evaluation of the revised questionnaires is needed next to assess the construct validity, reliability, and responsiveness of the measures.

P2-P3 conformationally constrained ketoamide-based inhibitors of cathepsin K.

An orally bioavailable series of ketoamide-based cathepsin K inhibitors with good pharmacokinetic properties has been identified. Starting from a potent inhibitor endowed with poor drug properties, conformational constraint of the P(2)-P(3) linker and modifications to P(1') elements led to an enhancement in potency, solubility, clearance, and bioavailability. These optimized inhibitors attenuated bone resorption in a rat TPTX hypocalcemic bone resorption model.