Gastroenterology · Clinical trials
Eosinophilic Oesophagitis Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About eosinophilic oesophagitis — and why its trials are hard
Eosinophilic oesophagitis (EoE) is a chronic, immune/antigen-mediated disease characterized by eosinophil-predominant inflammation of the oesophagus, driven largely by type 2 (Th2) immunity and often food allergens. Clinically it causes dysphagia, food impaction, and chest or epigastric pain in adults, and feeding difficulties, vomiting, and failure to thrive in children. Diagnosis requires oesophageal biopsy demonstrating at least 15 eosinophils per high-power field alongside symptoms, after excluding other causes. Untreated inflammation can progress to fibrostenotic remodeling with strictures. Historically, management relied on off-label swallowed topical corticosteroids, proton pump inhibitors, and dietary elimination, with endoscopic dilation for strictures. The therapeutic era changed with dupilumab, an IL-4 receptor alpha antibody blocking IL-4/IL-13 signaling, which became the first FDA-approved EoE therapy in 2022. A purpose-formulated budesonide oral suspension (Eohilia) followed in 2024 as the first oral treatment approved specifically for EoE. Treatment targets both symptomatic improvement and histologic remission, reflecting the disease's dual clinical and inflammatory burden, though long-term remodeling outcomes remain under study.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| dupilumab (Dupixent) | 2022 | EoE in patients aged 12 and older (first approved therapy); later expanded to ages 1-11 | LIBERTY-EoE-TREET (Parts A and B) | Co-primary: histologic remission (<=6 eos/hpf) and change in Dysphagia Symptom Questionnaire (DSQ) | Histologic remission ~60% with weekly dupilumab vs ~5% placebo; significant DSQ improvement |
| budesonide oral suspension (Eohilia) | 2024 | EoE in patients aged 11 and older (first oral therapy specifically approved for EoE) | Phase 3 SHP621-301 / -302 | Histologic remission (peak <=6 eos/hpf) and dysphagia symptom improvement over 12 weeks | Histologic response markedly higher vs placebo (~53% vs ~1% in pivotal data); improved dysphagia days |
| fluticasone propionate (orodispersible) (swallowed topical corticosteroid (off-label in US; budesonide orodispersible Jorveza approved in EU)) | (unverified US-specific EoE approval) | Topical corticosteroid historically used for EoE | Multiple randomized trials of swallowed corticosteroids | Histologic and symptomatic response | Consistent histologic response vs placebo across trials (magnitude varies) |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in eosinophilic oesophagitis development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| mepolizumab (anti-IL-5) — Randomized phase 2/3 EoE studies | Reduced oesophageal eosinophilia but did not consistently produce meaningful symptom improvement | Dissociation between histologic eosinophil reduction and clinical/dysphagia benefit; no EoE approval |
| reslizumab (anti-IL-5) — Pediatric randomized controlled trial | Lowered eosinophil counts without significant symptom benefit over placebo | High placebo symptom response and weak histologic-symptom correlation; not approved for EoE |
Choosing the right endpoint
Primary endpoints that matter in eosinophilic oesophagitis trials
- Peak eosinophil count (eos/hpf) — Peak eosinophils per high-power field on biopsy; histologic remission thresholds of <=6 or <15 are standard primary endpoints.
- Dysphagia Symptom Questionnaire (DSQ) — Validated patient-reported measure of swallowing difficulty, used as the co-primary symptomatic endpoint in dupilumab trials.
- EoE Histologic Scoring System (EoEHSS) — Grades and stages histologic features beyond eosinophil count, including basal-zone hyperplasia and fibrosis.
- Endoscopic Reference Score (EREFS) — Scores endoscopic features (edema, rings, exudates, furrows, strictures) to assess inflammatory and fibrostenotic burden.
How iNGENū runs eosinophilic oesophagitis trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Eosinophilic Oesophagitis clinical trials — FAQs
What was the first FDA-approved treatment for EoE?
Is there an oral medication approved for EoE?
Why did anti-IL-5 antibodies fail in EoE?
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