Eosinophilic esophagitis (EoE) is a prevalent chronic inflammatory condition of the esophagus characterized by esophageal eosinophilia that can lead to inflammation and stricture formation. To assess remission, esophagogastroduodenoscopies (EGD) with biopsies are performed. This can lead to multiple EGDs, which are invasive and costly procedures. EsoCheck is a promising noninvasive device. It is an encapsulated balloon that can be easily swallowed and collect cells from the distal esophagus. The primary aim of this study is to determine the feasibility and safety of EsoCheck compared with standard endoscopy and biopsies in the assessment of EoE. This will be a prospective cross-sectional study of adult patients (greater than or equal to 22 years of age) at the University of Pennsylvania with a diagnosis of EoE scheduled for a clinically indicated upper endoscopy.

Background Eosinophilic esophagitis (EoE) is a chronic inflammatory condition of the esophagus characterized by esophageal eosinophilia that can lead to esophageal remodeling and stricture formation. To assess remission, upper endoscopy (EGD) with biopsies is performed. This is an invasive procedure and contributes to cost burden for patients. It is important to assess non-invasive techniques to sample the cells of the esophagus.

There have been a few non-invasive testing modalities suggested, including the esophageal string test and Cytosponge. These involve swallowing a string or capsule that ultimately collects esophageal cells. The string test study showed a significant correlation with traditional biopsy pathology, however, limitations included the string remaining in overnight and potential contamination from oral flora. Katzka et al showed that the Cytosponge had an 86% specificity with limitations including gelatin allergy, local esophageal abrasions and similar potential oral contamination as the esophageal string test.

Another promising device is EsoCheck. This is an encapsulated balloon that can be easily swallowed and collect cells from the distal esophagus. It is well tolerated and, in Barrett's esophagus, detected metaplasia with 91.7% specificity. The primary aims of this study are to determine the feasibility and safety of EsoCheck compared with standard endoscopy and biopsies in the assessment of EoE. Secondary aims include specific and sensitivity of EsoCheck as well as specificity and sensitivity of brush cytology given that EsoCheck is a cytology device.

Detailed Description Study design This is a prospective pilot study at the University of Pennsylvania to evaluate feasibility and safety. Inclusion criteria include patients at least 22 years of age with known EoE diagnosed in accordance with consensus guidelines previously scheduled upper endoscopy at the University of Pennsylvania. Exclusion criteria include: known or suspected contraindication for esophageal intubation, esophageal stricture with inability to pass an endoscope, history of esophageal perforation, history of esophageal resection, esophageal diverticula, esophageal fistula, pill dysphagia, pill swallowing phobia, food impaction, esophageal varices, coagulopathy, active anticoagulation or antithrombotics, active GI bleeding and pregnancy.

Consecutive patients will be approached for consent until a total of 20 patients are enrolled. Patients will be approached during the same clinic visit if they meet inclusion criteria that arranges for the EGD or via telephone up to 2 weeks prior to scheduled EGD. Charts will be reviewed and patients will be asked medical and surgical history questions to assess if any exclusion criteria. Written consent will be obtained on the day of endoscopy. Charts will be reviewed and patients called at 1 week follow up to assess if any adverse events.

EsoCheck Description The investigational product is called EsoCheck. EsoCheck is an encapsulated, inflatable, surface-textured balloon that is pill-sized (16x9mm) attached to a thin 2.16 mm silicone catheter. The device is swallowed with water. The catheter will be held without any tension to facilitate easy delivery to the stomach. The balloon is then inflated by injecting 5 cc of air through the catheter. This will be gently withdrawn until the tension from the esophageal sphincter is felt by the endoscopist. It is then pulled slowly to sample the esophagus. The balloon is then deflated while still in the distal esophagus using a syringe and inverted back into the capsule.

EsoCheck Administration and Upper Endoscopy During the intervention period of the trial, patients will arrive early for their scheduled endoscopy. This involves swallowing the balloon device while unsedated. They will then undergo their previously scheduled endoscopy with standard biopsies taken as well as brush cytology performed as EsoCheck is a cytology device to best compare histology.

EsoCheck and Brush Cytology Sample Processing and Handling:

After retrieval of the capsule through the mouth, the balloon will be re-inflated, cut from the capsule at the junction of the balloon and the holding capsule. This will be immediately placed into a pre-labeled vial of Preservcyt transport medium. Vials will be stored on site in locked cabinets at room temperature. They will be shipped in small batches with de-identified patient study numbers and sent to the Cytology Department c/o Dr. Joseph Willis, University Hospitals Cleveland Medical Center.

Specimens will be processed according to the standard operating procedures of the Department of Pathology at the University Hospitals Cleveland Medical Center. The vial containing the balloon is vortexed for 5 minutes, after which the balloon is then discarded. After centrifugation, the vial is then loaded onto the ThinPrep processor along with required assembly elements - including a pre-labeled slide corresponding to the received specimens. The ThinPrep filter rotates within the specimen vial creating turbulence that is strong enough to separate cells, debris and mucus. In cell collection, a vacuum collects cells on the exterior of the membrane of the filter. In cell transfer, the filter is inverted and gently pressed against the ThinPrep microscope slide. Slight positive air pressure causes the cells to adhere to the microscope slide resulting in an even distribution of cells in a circular area. A ThinPrep slide is then generated and is deposited in an alcohol fixative bath. The slide is then stained with a Hematoxylin and Eosin stain and cover slipped. After the ThinPrep slides are made, attempts will be made to prepare cell blocks from the reminder of the material Cytology brush samples will be analyzed at the University Hospitals Cleveland Medical Center as well with specimens processed according to the standard operating procedures.

Histologic and cytologic assessment EsoCheck derived samples will be analyzed at the University Hospitals Cleveland Medical Center. ThinPrep slidesare given to a trained gastroenterology cytopathologist for review. As the ThinPrep technology smears collected cells onto the slide in a uniform manner using a membrane-based technology, the cytopathologist will count eosinophils in one quadrant of the ThinPrep slide. These results will then be compared with the clinical and pathological features of the study individuals. The cell blocks will also be reviewed and results correlated with the ThinPrep slide results.

Assessment of brush cytology specimens will be performed at the Department of Pathology at the University Hospitals Cleveland Medical Center to include assessing eosinophil count per high power field (hpf).

Histologic assessment of esophageal biopsies will be performed as part of standard of care at the University of Pennsylvania Department of Pathology and will include assessing eosinophil count/hpf.

Surveys: Endoscopists will be surveyed regarding perceived anxiety level and comfort level during procedure. Patients will be surveyed before and afterwards regarding confidence level, anxiety level, satisfaction, willingness to undergo it again, and preference of EsoCheck compared with EGD. This survey will be repeated at a 1 week telephone follow up.

Statistical Plan: Baseline and demographic characteristics will be summarized by standard descriptive statistics (including mean and standard deviation for continuous variables such as age and standard percentages for categorical variables such as gender). The primary endpoint will be descriptive statistics of feasibility and patient safety assessed based on the answers to surveys as listed above. Secondary endpoints include the sensitivity and specificity of Esocheck with EGD and biopsy as gold standard. Secondary endpoints also include sensitivity and specificity of brush cytology with EGD and biopsy as gold standard. All subjects entered into the study will have detailed information collected on adverse events for the overall study safety analysis

Inclusion Criteria:

• Greater than or equal to 22 years of age
• Known EoE
• Previously scheduled upper endoscopy at the University of Pennsylvania

Exclusion Criteria:

• do not meet inclusion criteria
• do not want to participate
• known or suspected contraindication for esophageal intubation
• esophageal stricture with inability to pass an endoscope
• history of esophageal perforation
• history of esophageal resection
• esophageal diverticula
• esophageal fistula
• pill dysphagia
• pill swallowing phobia
• food impaction
• esophageal varices
• coagulopathy
• active anticoagulation or antithrombotic
• active GI bleeding
• pregnancy.