Dupilumab Maintenance Dose Optimization in Adults with Eosinophilic Esophagitis: A Randomized Controlled Non‑Inferiority Study

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What is this study about?

Dupilumab is a medication given by subcutaneous injection that reduces the allergic inflammation that characterizes Eosinophilic Esophagitis, a condition in which the lining of the food pipe becomes swollen and can cause difficulty swallowing, food getting stuck, and chest discomfort. The drug works by blocking specific signals that cause the immune system to over‑react in the esophagus.

The study’s purpose is to find out whether giving the medication every two weeks can keep patients in the same level of improvement as giving it every week. Success is measured by maintaining clinical remission (absence of symptoms), endoscopic remission (the inside of the esophagus looks normal when examined with a tiny camera), and histologic remission (tissue samples no longer show the inflammatory cells that define the disease).

Participants are assigned in a randomized and single‑blind manner to one of the two dosing schedules and are followed for about a year. During this time they receive regular injections, periodic check‑ups that may include a brief camera examination of the esophagus, questionnaires about daily life and well‑being, and safety monitoring to record any side effects. The study does not involve any other active treatments.

1 first injection and baseline assessment

on the day you join the study, you receive a dupilumab injection of 300 mg given under the skin (subcutaneous injection).

the study staff will record your medical history, current symptoms, and perform an endoscopic examination of the esophagus to collect tissue samples.

2 weekly injections during the initial phase

for the first several weeks you will receive a 300 mg dupilumab injection once every week.

these injections are administered at the clinic or, if allowed, by a trained health professional at home.

you will attend scheduled visits (for example at weeks 4 and 12) where your symptoms, quality of life, and any side effects are reviewed.

3 randomization to dosing schedule

after the initial period, you will be randomly assigned to one of two dosing schedules:

• continue receiving 300 mg dupilumab every week, or

• switch to 300 mg dupilumab every two weeks (every 14 days).

the assignment is made by the study without your input, and you will be informed of the schedule you will follow.

4 maintenance dosing through week 52

you will continue the assigned dosing schedule (weekly or every two weeks) for the remainder of the study, up to week 52.

clinic visits are planned at regular intervals (for example at weeks 24 and 52) to assess clinical symptoms, perform endoscopy, and collect biopsy samples.

questionnaires about quality of life and health status will be completed at each visit.

5 final assessment at week 52

at week 52, a comprehensive evaluation is performed to determine whether complete remission of eosinophilic esophagitis has been maintained.

this includes clinical symptom review, endoscopic examination, histologic analysis of biopsy tissue, and completion of the eosinophilic esophagitis quality‑of‑life questionnaire.

6 ongoing safety monitoring

throughout the study you will be asked to report any adverse events, including severe or serious events.

the study team will record and evaluate these events using standardized medical terminology.

Who Can Join the Study?

Be 18 years of age or older, regardless of gender.
Have a confirmed diagnosis of eosinophilic esophagitis based on an endoscopic biopsy (a small tissue sample taken with a camera tube) that shows a high number of eosinophils (a type of white blood cell) in the lining of the esophagus, specifically at least 15 eosinophils per high‑power field (the area seen under a microscope at high magnification).
Have been receiving the medication dupilumab (an injectable drug) for at least 24 weeks before the screening visit.
Show complete remission at screening, which means:
- Clinical remission: a disease symptom questionnaire score (DSQ) lower than 10.
- Endoscopic remission: an EREFS score (a rating of visible changes in the esophagus) of 2 or less.
- Histologic remission: a peak eosinophil count (PEC) of fewer than 15 eosinophils per high‑power field.

Who Cannot Join the Study?

Any health condition that makes it unsafe to use dupilumab as it is normally prescribed.
Use of swallowed steroid medicines (called corticosteroids) or steroid pills within the 8 weeks before the study starts.
Starting a proton pump inhibitor (a medicine that reduces stomach acid, called a PPI) or changing its dose within 8 weeks before screening; you must stay on the same dose during the study.
Starting or changing a food‑elimination diet (a diet that removes certain foods) or adding back a food that was removed within 6 weeks before screening; you must keep the same diet throughout the study.
Having an oesophageal dilation procedure (stretching the food pipe) within 12 weeks before screening.
Having an esophageal stricture (a narrowing of the food pipe) that cannot be passed by a standard diagnostic tool called an upper endoscope (about 9‑10 mm wide) or a serious narrowing that would need dilation at the time of screening.
Being pregnant, breastfeeding, or planning to become pregnant or breastfeed during the study.

Where you can join this trial?

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Other Sites

Site Name	City	Country	Status
Athnoigfr Uwi	Amsterdam	The Netherlands

Trial status

Country	Status	Recruitment Start
The Netherlands	Not yet recruiting	01.07.2026

Trial locations

Investigated Drugs:

Dupilumab

dupilumab is a medication given as an injection under the skin. It works by blocking specific signals in the immune system that cause inflammation. In this study, dupilumab is being tested to see if giving it less often (every two weeks) can keep the disease under control just as well as giving it every week. The goal is to maintain complete remission of eosinophilic esophagitis, meaning the patients have no symptoms, normal looking esophagus on endoscopy, and no signs of disease in tissue samples.

Investigated Diseases:

Eosinophilic oesophagitis

Eosinophilic Esophagitis – A chronic inflammatory condition in which an excess of eosinophils, a type of white blood cell, accumulates in the lining of the esophagus. This buildup causes swelling and irritation that can make swallowing uncomfortable and lead to food getting stuck. Over time, repeated inflammation may cause the esophageal wall to become stiff and narrow, limiting its ability to move food toward the stomach.

Trial ID:

2026-526348-11-01

Protocol code:

DUET-1

Trial Phase:

Therapeutic confirmatory (Phase III)

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Dupilumab Maintenance Dose Optimization in Adults with Eosinophilic Esophagitis: A Randomized Controlled Non‑Inferiority Study

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?