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Phase 2
Age: 18Years +
All Genders
ID06851559

A Phase 2, Randomized, Double-Blind, Multi-Center Study in Adults With Eosinophilic Esophagitis to Evaluate Vonoprazan 20 mg Compared to Placebo After 12 Weeks and Up to 24 Weeks

Led by Phathom Pharmaceuticals, Inc. · Updated on 2026-04-28

80

Participants Needed

41

Research Sites

12 weeks

Total Duration

On this page

AI-Summary

What this Trial Is About

Researchers are evaluating vonoprazan, a drug taken once daily at 20 mg, in adults with eosinophilic esophagitis EoE, a condition characterized by a high number of eosinophils in the esophagus. The study aims to compare vonoprazan to a placebo to see how many participants achieve a peak eosinophil count below 15 eosinophils per high-power field after 12 weeks of treatment. This phase 2, randomized, double-blind study is sponsored by Phathom Pharmaceuticals, Inc. and involves adult participants who meet specific clinical and diagnostic criteria for EoE. Participants are randomly assigned to receive either vonoprazan 20 mg daily for 12 weeks followed by an additional 12 weeks at the same dose, or placebo for 12 weeks followed by 12 weeks of vonoprazan 20 mg daily. The study is conducted across multiple centers and includes a double-blind design to compare the safety and efficacy of vonoprazan against placebo initially and then evaluate continued treatment effects up to 24 weeks. During the trial, participants will be monitored through various assessments including esophageal biopsies to measure eosinophil counts, electronic diaries documenting dysphagia episodes, and endoscopic scoring for EoE severity. The main outcome is the number of participants achieving reduced eosinophil levels at week 12. Secondary assessments include changes in dysphagia days, endoscopic reference scores, and eosinophil counts from baseline to week 12. Safety and adherence will be tracked throughout the study period, with participant involvement expected for up to 24 weeks.

CONDITIONS

Brief Title

A Study in Adult Participants With EoE to Evaluate Vonoprazan 20 mg Compared to Placebo After 12 Weeks and to Evaluate Vonoprazan 20 mg Up to 24 Weeks

Who Can Participate

Age: 18Years +
All Genders

Eligibility Criteria

Eligible

You may qualify if you...

  • The participant is 18 years of age or older at the time of informed consent signing.
  • The participant is capable of understanding and complying with protocol requirements, including completing an electronic diary on at least 11 of the last 14 days before Visit 2.
  • The participant signs and dates a written informed consent form and any required privacy authorization.
  • The participant has a peak eosinophil count of at least 15 eosinophils per high-power field from at least 2 of 3 esophageal levels on screening endoscopy.
  • The participant has 4 or more days with dysphagia episodes documented in the 2 weeks prior to Visit 2.
  • The participant has maintained a stable diet for at least 6 weeks before screening and is expected to continue this during the study.
  • Female participants of childbearing potential who may be sexually active agree to use adequate contraception from consent until 4 weeks after the last dose of study drug.
Not Eligible

You will not qualify if you...

  • The participant is on a pure liquid diet.
  • The participant has documented erosive esophagitis at screening.
  • The participant has other causes of esophageal eosinophilia such as hypereosinophilic syndrome or eosinophilic granulomatosis with polyangiitis.
  • The participant has eosinophilic gastritis, duodenitis, jejunitis, ileitis, proctitis, or colitis.
  • The participant has Barrett's esophagus longer than 1 cm or dysplastic changes.
  • The participant has a history of achalasia, Crohn's disease, ulcerative colitis, or celiac disease.
  • The participant has active Helicobacter pylori infection.
  • The participant has structural esophageal conditions like varices, infections, prior radiation, or surgery.
  • The participant has had gastric or duodenal ulcers, recent gastrointestinal bleeding, or esophageal strictures requiring dilation.
  • Use of PPIs, PCABs, corticosteroids, dupilumab, immunomodulatory therapy, or investigational compounds within specific timeframes prior to screening.
  • The participant has hypersensitivity to vonoprazan or its components.
  • The participant has a history of substance abuse or positive drug screening.
  • The participant is pregnant, lactating, or planning pregnancy during the study period.
  • The participant has significant medical conditions or malignancies that may affect safety or results.
  • The participant has infectious diseases such as HIV, hepatitis B, or active hepatitis C.
  • The participant has gastric acid hypersecretory conditions.
  • The participant requires hospitalization or surgery during the study or has severe liver or kidney impairment.
  • The participant has abnormal laboratory values above specified limits.
  • The participant is refractory to prior PPI therapy as judged by the investigator.

Research Team

P

Phathom Medical Information

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