Vonoprazan Study in Patients With Erosive Esophagitis to Evaluate Long-term Safety

Inclusion Criteria

Healing Phase:

• Participants endoscopically diagnosed with EE of grades A to D by the LA Classification Grading System at the start of treatment (Week 0 of the healing phase)
• Participants with H. pylori negative
• Participants who, in the opinion of the principal investigator or investigator, are capable of understanding the content of the clinical research and complying with the research protocol requirements.
• Participants who can sign and date an informed consent form and information sheet prior to the conduction of the clinical research procedures.
• Male or female participants aged 20 years or older at the time of informed consent
• Therapeutic category: Ambulatory

Maintenance Phase:

• Participants who have endoscopically confirmed EE healing* (mucous membrane disorder is not observed) at completion of the healing phase (Week 4 or 8 of the healing phase)
• Participants who are classified as grade 0 according to severity classification of EE (See Table 9.b)
• Participants who have been determined to be appropriate as subjects for maintenance treatment of EE by the principal investigator or investigator

Exclusion Criteria

Healing Phase:

• Participants with concurrent peptic ulcer (except scarred stage) or Zollinger-Ellison syndrome
• Participants who received treatment with PPIs (including vonoprazan) within 4 weeks (Week -4 to Week 0) prior to the start of healing phase (Week 0 of the healing phase)
• Participants with a history of H. pylori eradication.
• Participants who have received surgery or treatment affecting gastroesophageal reflux (fundoplication or dilation for esophageal stenosis [excluding Schatzki's ring], etc.)
• Participants with an esophagus-related complication (eosinophilic esophagitis, esophageal varices, scleroderma, viral or fungal infection, esophageal stenosis, etc.), a history of radiotherapy or cryotherapy of the esophagus, a caustic or physiochemical trauma (esophageal sclerotherapy, etc.). However, participants with Schatzki's ring (mucosal tissue ring around inferior esophageal sphincter) or Barrett's esophagus are allowed to be included.
• Participants with clinically apparent hepatic impairment (e.g., AST or ALT levels at the time of informed consent: >1.5 times the upper limit of normal (ULN).
• Participants with renal impairment or renal failure [creatinine clearance (CCr) ˂30 mL/min, etc.]
• Participants with a history of hypersensitivity or allergy for PPIs.
• Participants with a history of gastrectomy, gastrointestinal resection, or vagotomy
• Participants with a malignant tumor
• Participants who are pregnant, breast-feeding, possibly pregnant, or planning to become pregnant
• Participants with one of the diseases listed under administration contraindication in the vonoprazan or lansoprazole package insert
• Participants planning to take prohibited concomitant medications during the research period
• Participants participating in other clinical studies
• Participants who have been determined to be inappropriate as subjects in the study by the principal investigator or investigator

Maintenance Phase:

• Participants who have taken PPIs other than the study drug or the control drug during the healing phase
• Participants who have been determined to be inappropriate as subjects in the study by the principal investigator or investigator