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Use of Esophageal String Test to Understand Symptoms, Inflammation, and Function in Eosinophilic Esophagitis

Study Purpose

Presently, the only method available to monitor disease activity in Eosinophilic Esophagitis (EoE) is endoscopy with pathological review of biopsies. The overall goal of this study is to determine the ability of the Esophageal String Test (EST), a minimally invasive capsule based technology, to measure disease activity in children with EoE. Additionally, to determine esophageal distensibility in children presenting with EoE by using the EndoFLIP (functional luminal imaging probe) device during endoscopic procedures.

Recruitment Criteria

Accepts Healthy Volunteers

Healthy volunteers are participants who do not have a disease or condition, or related conditions or symptoms

Study Type

An interventional clinical study is where participants are assigned to receive one or more interventions (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes.

An observational clinical study is where participants identified as belonging to study groups are assessed for biomedical or health outcomes.

Searching Both is inclusive of interventional and observational studies.

Eligible Ages 7 Years - 17 Years
Gender All
More Inclusion & Exclusion Criteria

Inclusion Criteria:

  • - Provide signed and dated informed consent form.
  • - Willing to comply with all study procedures and be available for the duration of the study.
- Male or female, aged 7 to 18 years old, inclusive - Undergoing upper Endoscopy with biopsy for clinical care at CHCO or CHOP - Current or historical diagnosis of EoE, or suspected of having EoE

Exclusion Criteria:

- Known connective tissue disease, other eosinophilic disorders - Past history of caustic injestion, esophageal surgery or other esophageal injury - Known inflammatory bowel disease or esophageal motility disease (achalasia) - Unwilling or unable to swallow the EST - Oral or intravenous steroids in the preceding 60 days (not including swallowed topical fluticasone, budesonide, etc) - Pregnancy - Participation in a clinical study that may interfere with participation in this study

Trial Details

Trial ID:

This trial id was obtained from ClinicalTrials.gov, a service of the U.S. National Institutes of Health, providing information on publicly and privately supported clinical studies of human participants with locations in all 50 States and in 196 countries.


Phase 1: Studies that emphasize safety and how the drug is metabolized and excreted in humans.

Phase 2: Studies that gather preliminary data on effectiveness (whether the drug works in people who have a certain disease or condition) and additional safety data.

Phase 3: Studies that gather more information about safety and effectiveness by studying different populations and different dosages and by using the drug in combination with other drugs.

Phase 4: Studies occurring after FDA has approved a drug for marketing, efficacy, or optimal use.

Lead Sponsor

The sponsor is the organization or person who oversees the clinical study and is responsible for analyzing the study data.

University of Colorado, Denver
Principal Investigator

The person who is responsible for the scientific and technical direction of the entire clinical study.

Calies Menard-Katcher, MD
Principal Investigator Affiliation University of Colorado, Denver
Agency Class

Category of organization(s) involved as sponsor (and collaborator) supporting the trial.

Overall Status Recruiting
Countries United States

The disease, disorder, syndrome, illness, or injury that is being studied.

Eosinophilic Esophagitis
Additional Details

When children are scheduled to undergo an endoscopy, research assistants will contact the family to arrange for the Esophageal String Test (EST) to be performed within one week of the endoscopy. The string test involves swallowing a small capsule with a thin piece of string inside it. The string unravels as the capsule goes down into the stomach. The investigator would tape the end of the string to the child's cheek, leaving it there for one hour. At the end of the hour, the investigator would remove the string by gently pulling it out through the mouth. Prior to swallowing the EST, the patient will complete the PEESS form (Pediatric Eosinophilic Esophagitis Symptom Scores) to assess symptoms. The endoscopy and Endoscopic Reference System (EREFs) and EndoFLIP will be performed. The EndoFLIP is a slender probe covered by a smooth long balloon that is passed into the esophagus and slowly expanded with a salt solution. After standard of care endoscopic visualization, the FLIP, a 16 cm probe (Crospon) will be placed transorally and positioned 3 cm distal to the lower esophageal sphincter. Esophageal cross sectional areas and intrabag pressure will be measured during stepwise distensions beginning with 5 mL and increasing to a maximum of 70mL or intrabag pressure of 50 mmHg is achieved, whichever comes first. FLIP is FDA-approved without age restriction and its use has been approved by our IRBs previously. Primary results will be reported as distensibility plateau (mm). Endoscopic severity: Endoscopic esophageal appearances will be scored using a validated EoE scoring system (EREFS). Five features of EoE will be scored: Edema (0-1), Rings (0-3) Exudates (0-2), Furrows (0-1), Stricture (0-1). Results will be reported as an inflammatory score (edema, exudates, furrows) and fibrostenotic score (rings, stricture). Functional Luminal Imaging Probe (FLIP):

Arms & Interventions


Experimental: Current/historical diagnosis of EoE

Subjects with current or historical diagnosis of EoE, or suspected of having EoE will complete the Esophageal String Test (EST) and EndoFLIP


Device: - Esophageal String Test (EST)

The EST is a gelatin capsule filled with a 90cm nylon string. A trailing end of the string protrudes from one end of the capsule. This end is taped to the cheek and the capsule is swallowed. As the capsule travels to the small intestine, the string inside the capsule is dislodged, leaving a string that goes from the cheek to the small intestine. The capsule dislodges from the string and the string is left in place, in the mouth, esophagus, stomach and small intestine for an hour. During this time, the string rubs against the inside of the esophagus and collects eosinophil proteins. After one hour, the string is removed through the mouth and placed in preservative to save the eosinophil proteins.

Contact a Trial Team

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Children's Hospital Colorado, Aurora, Colorado




Children's Hospital Colorado

Aurora, Colorado, 80045

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