The goal of this clinical trial was to evaluate the effectiveness and safety of fexuprazan 40 mg for relieving symptoms of gastroesophageal reflux disease (GERD) in adults. The study also compared fexuprazan with esomeprazole 40 mg, a commonly used treatment for GERD.

The main questions this study aimed to answer were:

• Did fexuprazan reduce GERD symptoms such as heartburn and acid regurgitation?
• Was fexuprazan safe and well tolerated compared with esomeprazole?

Researchers compared fexuprazan with esomeprazole to determine whether fexuprazan provided similar symptom relief and safety.

Participants in the study:

• Were randomly assigned to receive fexuprazan 40 mg or esomeprazole 40 mg once daily
• Took the study medication for 4 weeks, with treatment extended up to 8 weeks if symptoms did not improve
• Attended scheduled clinic visits for evaluations
• Completed symptom questionnaires and a daily symptom diary
• Were monitored for side effects and overall safety throughout the study

This multicenter, randomized, open-label, active-controlled clinical study was conducted to evaluate the efficacy and safety of fexuprazan 40 mg, a potassium-competitive acid blocker (P-CAB), compared with esomeprazole 40 mg, a proton pump inhibitor (PPI), in adult patients with gastroesophageal reflux disease (GERD).

GERD is a chronic condition characterized by reflux-related symptoms such as heartburn and acid regurgitation, which can significantly impair quality of life. Although PPIs are widely used as first-line therapy, limitations including delayed onset of action and insufficient control of nocturnal symptoms have been reported. Fexuprazan, a novel P-CAB, inhibits gastric acid secretion through reversible and potassium-competitive inhibition of the H⁺/K⁺-ATPase and has demonstrated rapid onset and sustained acid suppression in prior clinical studies.

Eligible participants were randomized in a 1:1 ratio to receive either fexuprazan 40 mg or esomeprazole 40 mg administered orally once daily. The initial treatment period was 4 weeks. Participants who did not achieve adequate symptom relief after the initial treatment period were eligible to continue the assigned treatment for an additional 4 weeks, for a total treatment duration of up to 8 weeks.

Efficacy was assessed primarily through patient-reported symptom evaluation using validated questionnaires and daily symptom diaries. Safety assessments included monitoring of adverse events, vital signs, physical examinations, and laboratory evaluations throughout the study and during follow-up.

The study was conducted in accordance with the principles of the Declaration of Helsinki, International Council for Harmonisation Good Clinical Practice (ICH-GCP), and applicable local regulatory requirements. Written informed consent was obtained from all participants prior to the performance of any study-related procedures.

Inclusion Criteria:

• Adults aged 18 to 60 years at the time of providing written informed consent

• Male or female participants

• History of gastroesophageal reflux disease (GERD) symptoms, including heartburn and/or acid regurgitation

• GERD symptoms confirmed by:

  • GERD-Q score greater than 7, and
  • Heartburn and/or acid regurgitation occurring on more than 3 days within the last 7 days

• Able to understand the study procedures and complete questionnaires and a daily symptom diary

• Willing and able to provide written informed consent

Exclusion Criteria:

Gastrointestinal conditions:

• Diagnosis of inflammatory bowel disease (Crohn's disease, ulcerative colitis), primary esophageal motility disorders, or pancreatitis
• History of gastric or esophageal surgery affecting acid secretion (except appendectomy, cholecystectomy, or endoscopic polypectomy of benign polyps)
• Alarm symptoms suggestive of gastrointestinal malignancy (e.g., severe dysphagia, odynophagia, gastrointestinal bleeding, anemia, unexplained weight loss), unless malignancy was ruled out

Medical history

• Clinically significant hepatic, renal, endocrine, hematologic, oncologic, or urinary system disease
• History of malignancy within the past 5 years (except non-digestive malignancies that were completely treated with no recurrence for ≥5 years)
• History of psychosis, substance abuse, or alcohol abuse
• Known HIV infection, active hepatitis B, or hepatitis C infection (HCV RNA-positive)

Medication and treatment

• Use of prohibited concomitant medications within 2 weeks prior to enrollment or need for continuous prohibited medication during the study, including:

  • Proton pump inhibitors, potassium-competitive acid blockers, H2-receptor antagonists, or other acid-suppressive agents
  • Certain psychotropic drugs, anticholinergic drugs, antispasmodics, systemic steroids, or mucoprotective agents

• Use of another investigational product within 4 weeks prior to study drug administration

Laboratory findings

• Alanine aminotransferase (ALT), aspartate aminotransferase (AST), or total bilirubin ≥2 times the upper limit of normal
• Serum creatinine or blood urea nitrogen ≥2 times the upper limit of normal

Reproductive status

• Pregnant or breastfeeding women
• Women of childbearing potential or male participants who were unwilling to use appropriate contraception during the study

Other

• Known hypersensitivity to the investigational product or comparator drug
• Any condition that, in the opinion of the investigator, made the participant unsuitable for study participation

Individual participant data (IPD) will not be shared because the study protocol and informed consent did not include provisions for data sharing beyond the study investigators. In addition, the data contain sensitive participant information, and sharing IPD is restricted to protect participant confidentiality and comply with local regulations and institutional policies.