New pill could ease swallowing for EoE patients

NCT ID NCT06851559

Disease control Sponsor: Phathom Pharmaceuticals, Inc. Source: ClinicalTrials.gov ↗

First seen Jun 27, 2026 · Last updated Jun 30, 2026 · Updated 2 times

Summary

This study tests a once-daily pill called vonoprazan against a placebo in 80 adults with eosinophilic esophagitis (EoE), a condition that makes swallowing difficult. The main goal is to see if the drug reduces inflammation in the esophagus after 12 weeks. Researchers will also check if it improves swallowing and other symptoms over 24 weeks.

Why investors are watching

Phathom Pharmaceuticals is running a phase 2 trial of its drug vonoprazan in patients with eosinophilic esophagitis, a chronic allergic condition of the esophagus. The trial compares 12 weeks of vonoprazan against placebo, measuring whether the drug reduces esophageal inflammation to a specific level. For a small company, this readout matters because vonoprazan is a core asset, and a positive result could expand its use beyond its current approved indications.

If it works: If the trial succeeds, Phathom could gain a new treatment option for a disease with few approved therapies. That result may support further development and a potential new product label.

If it fails: Phase 2 trials often fail to show a clear benefit over placebo. If vonoprazan does not meet the primary endpoint, Phathom would face a setback in its pipeline and may need to redirect resources.

AI-written from the trial record. Speculative, and not investment advice.

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Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2

Tests whether the treatment actually works, and watches for side effects, in a larger group.

Participants

95 people

The number who actually took part.

Started

Oct 2025

Expected to finish

Jan 2027

An estimate. End dates often move.

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 years and older

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * The participant is ≥18 years of age at the time of informed consent signing. * In the opinion of the investigator or subinvestigators, the participant is capable of understanding and complying with protocol requirements, including completion and compliance with the electronic diary. The diary must be completed on at least 11 of the last 14 days in the 2 weeks prior to Visit 2 (Day -1). * The participant signs and dates a written informed consent form (ICF) and any required privacy authorization prior to the initiation of any study procedures. * The participant has a peak eosinophil count of at least 15 eos/hpf \[X 400\] from at least 2 of the 3 esophageal levels on screening endoscopy as measured in at least 6 biopsies, at least 2 each from the proximal, mid, and distal segments of the esophagus based on central reading. * The participant has 4 or more days with dysphagia episodes documented via electronic diary in the 2 weeks prior to Visit 2 (Day -1). * The participant must remain on a stable diet for at least 6 weeks prior to the Screening Period and is expected to remain on a stable diet during the course of the study; stable diet is defined as not initiating new elimination diets or reintroducing previously eliminated foods. * A female participant of childbearing potential who is or may be sexually active with a non-sterilized male partner agrees to routinely use adequate contraception from the signing of informed consent until 4 weeks after the last dose of study drug. Exclusion Criteria: * The participant is on a pure liquid diet. * The participant has documented erosive esophagitis at the screening endoscopy. * The participant has other known causes of esophageal eosinophilia or either of the following conditions: hypereosinophilic syndrome, or eosinophilic granulomatosis with polyangiitis (Churg-Strauss Syndrome). * The participant has a documented diagnosis of eosinophilic gastritis, duodenitis, jejunitis, ileitis, proctitis, or colitis. * The participant has endoscopic Barrett's esophagus (\>1 cm of columnar-lined esophagus) or dysplastic changes in the esophagus. * The participant has a history of achalasia, Crohn's disease, ulcerative colitis, or celiac disease. * The participant has a known active Helicobacter pylori infection. * The participant has any other clinically significant structural conditions affecting the esophagus, including: esophageal varices, viral or fungal infection, and history of radiation therapy, radiofrequency ablation, endoscopic mucosal resection, cryotherapy to the esophagus, caustic or physiochemical trauma (including sclerotherapy or esophageal variceal band ligation), or esophageal surgery. * The participant has a history of surgery or non-EoE endoscopic intervention, such as gastric bypass, fundoplication, gastric sleeve, or a history of gastric or duodenal surgery (except endoscopic removal of benign polyps). * The participant has gastric ulcer(s) or duodenal ulcer(s) within 4 weeks before the first dose of study drug. * The participant has had clinically significant upper or lower gastrointestinal bleeding within 4 weeks prior to the Screening Period. * The participant has esophageal stricture(s) unable to be passed with an 8 to 10 mm endoscope, clinically requires dilation, or has a history of dilation within the 3 months prior to the Screening Period. * Use of prescription or non-prescription PPIs or PCABs within 2 months prior to the Screening Period. * Use of swallowed topical corticosteroid or budesonide oral suspension for EoE within 2 months prior to the Screening Period. * Use of systemic corticosteroid for any condition within 3 months prior to the Screening Period. * Use of inhaled or nasal glucocorticoids within 3 months prior to the Screening Period, except stable dose for at least 3 months prior to the Screening Period for any condition (should not be changed during the study). * Use of dupilumab within 3 months prior to the Screening Period. * The participant has received any investigational compound within 30 days or any investigational biologic within 3 months prior to the start of the Screening Period (including those in post-marketing studies) or vonoprazan in a clinical trial at any time. A participant who has been screen failed from another clinical study and who has not been dosed may be considered for enrollment in this study. * The participant has used immunomodulatory therapy within 3 months prior to the Screening Period or anticipates using immunomodulatory therapy during the study (except for any ongoing regimen of allergy therapy). * The participant is a study site employee, an immediate family member, is in a dependent relationship with a study site employee who is involved in the conduct of this study (eg, spouse, parent, child, sibling), or who may have consented under duress. * The participant has a history of hypersensitivity or allergies to vonoprazan (including the formulation excipients: D-mannitol, microcrystalline cellulose, hydroxypropyl cellulose, ascorbic acid, fumaric acid, croscarmellose sodium, magnesium stearate, hypromellose, macrogol 8000, titanium oxide, or red ferric oxide). Skin testing may be performed according to local standard practice to confirm hypersensitivity. * The participant has a history of alcohol abuse, illegal drug use, drug addiction or regularly consumes alcohol within the 12 months prior to the Screening Period (based on self-report). Participants must have a negative urine drug screen for non-prescribed medications at screening. Participants taking prescription drugs will be allowed. Occasional, recreational use of cannabis is allowed. However, participants with a cannabis use disorder (eg, frequent use, functional-social impairment, withdrawal symptoms) per the opinion of the investigator should be excluded. * The participant is taking any excluded medications or treatments listed in the protocol. * If female, the participant is pregnant, lactating, or intending to become pregnant before, during, or within 4 weeks after participating in this study, or intending to donate ova during such time period. * The participant has a history or clinical manifestations of significant central nervous system, cardiovascular, pulmonary, metabolic, other gastrointestinal, urological, endocrine, or hematological disease that, in the opinion of the investigator, would confound the study results or compromise participant safety. * The participant has a history of malignancy (including MALToma) or has been treated for malignancy within 5 years prior to the start of the Screening Period (Visit 1). The participant may be included in the study if he/she has recovered from cutaneous basal cell carcinoma or cervical carcinoma in situ. * The participant has acquired immunodeficiency syndrome or human immunodeficiency virus infection, or tests positive for the hepatitis B surface antigen, hepatitis C virus (HCV) antibody, or HCV-ribonucleic acid (RNA). However, participants who test positive for HCV antibody but negative for HCV-RNA are permitted to participate. * The participant has Zollinger-Ellison syndrome or other gastric acid hypersecretory conditions. * The participant requires hospitalization or has surgery scheduled during the course of the study or has undergone major surgical procedures within 30 days prior to the Screening Period. * The participant has moderate to severe hepatic impairment (Child-Pugh Class B and Child-Pugh Class C). * The participant has severe renal impairment (estimated glomerular filtration rate \<30 mL/min). * The participant has any of the following abnormal laboratory test values at the start of the Screening Period: 1. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) \>2 × the upper limit of normal (ULN) or total bilirubin \>2 × ULN (except participants with Gilbert Syndrome). 2. Creatinine levels: \>2 mg/dL (\>177 μmol/L) * The participant is refractory to prior PPI therapy as judged by the investigator.

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Conditions

The condition(s) this trial relates to.

eosinophilic esophagitis

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Eosinophilic esophagitis

Contacts and locations

Locations

Advanced Research Institute

Reno, Nevada, 89511, United States
Advanced Research Institute

Ogden, Utah, 84405, United States
Advanced Research Institute

Sandy City, Utah, 84070, United States
Biopharma Informatic, LLC

McAllen, Texas, 78503, United States
Blue Ridge Medical Research

Lynchburg, Virginia, 25402, United States
Boston Specialists

Boston, Massachusetts, 02111, United States
Brigham and Women's Hospital

Boston, Massachusetts, 02115, United States
Care Access - Ogdon

Ogden, Utah, 84403, United States
Combined Gastro, LLC

Lafayette, Louisiana, 70503, United States
Connecticut Clinical Research Institute

Bristol, Connecticut, 06010, United States
Encore Borland-Groover Clinical Research

Jacksonville, Florida, 32256, United States
GCGA Physicians, LLC dba/Gastro Health Research

Cincinnati, Ohio, 45219, United States
GI Alliance

Cedar Park, Texas, 78613, United States
GI Alliance - Gurnee

Gurnee, Illinois, 60031, United States
GW Research, Inc

Chula Vista, California, 91910, United States
Galen Medical Group - Galen Digestive Health

Chattanooga, Tennessee, 37404, United States
Gastroenterology Associates of Central Georgia, LLC

Macon, Georgia, 31201, United States
Gastroenterology Research of San Antonio

San Antonio, Texas, 78229, United States
Grand Teton Research Group

Idaho Falls, Idaho, 83404, United States
Great Lakes Gastroenterology Research LLC

Mentor, Ohio, 44060, United States
Houston Endoscopy and Research Center

Houston, Texas, 77079, United States
Huron Gastroenterology Associates

Ypsilanti, Michigan, 48197, United States
International Center for Research

Tampa, Florida, 33614, United States
Nature Coast Clinical Research

Inverness, Florida, 34452, United States
Northwestern Medicine Digestive Health Center

Chicago, Illinois, 60611, United States
Pearland Physicians

Pearland, Texas, 77581, United States
Preferred Research Partners, Inc

Little Rock, Arkansas, 72211, United States
Quality Medical Research

Nashville, Tennessee, 37211, United States
Research Physicians Network, LLC

Houston, Texas, 77089, United States
Rocky Mountain Gastroenterology

Lakewood, Colorado, 80228, United States
Southern California Research Institute Medical Group

Los Angeles, California, 90045, United States
Tandem Clinical Research GI, LLC

Marrero, Louisiana, 70072, United States
Texas Digestive Specialists

Harlingen, Texas, 78550, United States
Texas Gastro Consultants

Tomball, Texas, 73375, United States
The Hospitals of Providence Memorial Campus

El Paso, Texas, 79902, United States
Treasure Valley Medical Research

Boise, Idaho, 83706, United States
UNC Clinical & Translational Research Center

Chapel Hill, North Carolina, 27514, United States
University of Pennsylvania

Philadelphia, Pennsylvania, 19104, United States
Weill Cornell Medicine, New York Presbyterian Hospital

New York, New York, 10065, United States
Western States Clinical Research, Inc.

Wheat Ridge, Colorado, 80033, United States
Woodholme Gastroenterology Associates

Glen Burnie, Maryland, 21061, United States

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