A Study to Investigate Safety and Tolerability of NDX-3315 and NDX-3324 in Healthy Participants and Patients With Eosinophilic Esophagitis

An open-label phase 2 study to assess the safety and exploratory diagnostic performance of the oral radiopharmaceutical agent NDX-3315 and NDX-3324 in healthy participants and patients with eosinophilic esophagitis (EoE).

This study is a multi-site, Phase 2, open-label study of orally administered NDX-3315 or NDX-3324 and esophageal imaging in healthy participants and participants with EoE. Study details include: * The study duration or period will be up to around 10 weeks. * Participants will receive either one or two doses of NDX-3315 or NDX-3324 depending on their assigned regimen arm. EoE participants will receive two doses; healthy participants will receive one dose. There will be a SPECT/CT scan performed at each dose. * The visit frequency will be three site visits for healthy participants and four site visits for EoE participants followed by one follow-up phone call visit within the study period.