Study Design and Participants

This study was a double-blind, randomized, multicenter, investigator-initiated clinical trial, conducted with 116 participants between November 2012 and June 2015. Four university hospitals participated in the trial—Kyungpook National University Hospital, Keimyung University Dongsan Medical Center, Daegu Catholic University Medical Center, and Yeungnam University Medical Center. The trial was conducted in accordance with Korean Good Clinical Practice and the Helsinki Declaration. The trial followed a protocol that previously approved by the Korean Ministry of Food and Drug Safety, and the Institutional Review Boards of the all participating organizations. All subjects participating in the trial gave their informed, written consent. All procedures and data from the trial were subject to careful monitoring.

Adult men and women, 20–70 years of age, who had complained of GERD symptoms (eg, heartburn and gastric acid reflux), or atypical symptoms (eg, chest pain, globus sensation, etc) for the last 3 months and at least 2 days in the week prior to the trial, and who had been diagnosed with grade A–D esophagitis (LA classification) in an upper gastrointestinal endoscopy examination in the last 5 weeks, were included in the study.

Exclusion criteria were as follows: patients with no GERD symptoms; patients whose symptoms were determined by the investigator to result from irritable bowel syndrome; patients with symptoms indicative of severe or malignant diseases, including unintended weight loss, hematemesis, hematochezia, or jaundice; patients with severe liver dysfunction or liver disease; patients with severe renal diseases, including chronic renal disease or renal dysfunction; patients with uncontrolled diabetes, cerebrovascular disease, or patients diagnosed within the last 3 months with a disease that requires surgery during the clinical trial period; patients diagnosed with Zollinger-Ellison syndrome, primary esophageal motility disorder, esophageal stricture, duodenal or gastric ulcer, malignant disease of the upper gastrointestinal tract, pancreatitis, disorders of absorption, severe cardiovascular disease, or lung disease within the last 3 months; patients who had taken PPIs within the last 28 days, had undergone endoscopy within the last 2 weeks, or had taken daily histamine H2 receptor antagonist, sucralfate, prokinetics, or antacids daily up to the initial visit; and finally, pregnant or breast-feeding women, as well as female patients who were not willing to use contraception for the duration of the clinical trial period.