The non-recurrence rate (at 52 weeks) was determined by the endoscopy central review panel who were blinded to the investigator's assessment, based on the modified Los Angeles Classification using endoscopy photos were submitted by each of the institutions. Participants showing Grade A or above based on the modified Los Angeles Classification were included as a recurrence.

Central assessment Full Analysis Set (FAS) was defined as all randomized participants who received at least one dose of the study drug, and from whom the results of at least one endoscopic assessment was available. Data analysis excluded participants with missing data.

The non-recurrence rate (up to 52 weeks) was determined by the endoscopy central review panel who were blinded to the investigator's assessment, based on the modified Los Angeles Classification using endoscopy photos were submitted by each of the institutions. Participants showing Grade A or above based on the modified Los Angeles Classification were included as a recurrence. The 95% CI was calculated by normal approximation.

Central assessment FAS. Data analysis excluded participants with missing data.

Non-recurrence rate at Week 52 was estimated using the Kaplan-Meier method.

Central assessment FAS

A comparison of the rabeprazole 10 mg once daily group and the rabeprazole 10 mg twice daily group was performed for participants who did not exhibit daytime or nighttime heartburn at Week 0 of the Maintenance Therapy Period. Heartburn is a burning sensation in the stomach or lower chest; it is worsened by bending or pressure on the abdomen. Heartburn frequency was rated from 0-day (no) to 7-day (always) and severity was graded on a 3-point scale (mild, moderate, severe). Heartburn was evaluated in the daytime (from wake-up time to time for bed) and nighttime (from time for bed to wake-up time).

Central assessment FAS - LOCF. Analysis was carried out on participants who were determined to be free of symptoms at maintenance therapy entry.

A comparison of rabeprazole 10 mg once daily group and the rabeprazole 10 mg twice daily group shall be performed for participants who did not exhibit daytime or nighttime heartburn at 0 weeks of the maintenance therapy period. Daytime and nighttime heartburn, and nighttime sleep disorders shall likewise be compared. For the participants who had recurrence, values at the final evaluation were imputed using a last observation carried forward (LOCF) method.

Central assessment FAS

A comparison of the rabeprazole (10 mg once daily group) and the rabeprazole (10 mg twice daily group) was performed for participants who did not exhibit daytime or nighttime heartburn at Week 0 of the Maintenance Therapy Period. The presence or absence of heartburn was assessed by the investigators during medical interviews. The heartburn incidence during each of the 7-day periods immediately before visiting the hospital was assessed on a scale of five stages based on the number of days with symptoms: 0 (no symptoms), 1 to 2 (occasional symptoms), 3 to 4 (sometimes had symptoms), 5 to 6 (often had symptoms), and 7 (always had symptoms). The incidence was tabulated by an analysis classifying the states into two groups: "no symptom group" (0 days with symptoms) and "with symptoms group" (1 day or more with symptoms). The severity of heartburn was as below: Mild (feel heartburn but tolerable), Moderate (feel heartburn and hard), and Severe (feel heartburn and terrible).

Central assessment FAS - LOCF

Sleep disorders were defined as the condition of lack of dead sleep and arousal during sleep arising from heartburn or acid reflux. Sleep disorders during each of the 7-day periods immediately before visiting the hospital were assessed. Evaluation of sleep disorders arising from heartburn or acid reflux included recording if sleep-inducing drugs were being taken before enrollment; their type, method of use, and dosage. It was requested that no changes in sleep-inducing drug be made after enrollment. Sleep disorders were rated from 0-day (no) to 7-day (always). The incidence of sleep disorder was tabulated by an analysis classifying the stages into two groups: "No" (0 days with sleep disorder) and "Yes" (1 or more days with sleep disorder). Heartburn was evaluated prior to 7 days of each visit.

Central assessment FAS. Participants who did not have sleep disorder due to nighttime heartburn or swallowing at the time of maintenance of the Maintenance Therapy Period, participants whose visit data was not missing.

Sleep disorders were defined as the condition of lack of dead sleep and arousal during sleep arising from heartburn or acid reflux. Evaluation of sleep disorders arising from heartburn or acid reflux included recording if sleep-inducing drugs were being taken before enrollment; their type, method of use, and dosage. It was requested that no changes in sleep-inducing drug be made after enrollment. Sleep disorders were rated from 0-day (no) to 7-day (always). Heartburn was evaluated prior to 7 days of each visit.

Central assessment FAS

Safety was assessed by monitoring and recording all adverse events (AEs) and SAEs, regular monitoring of hematology, clinical chemistry, urine values, and regular measurement of vital signs. All AEs were graded on a 3-point scale; 1) mild was defined as discomfort that did not interfere with normal daily activities, 2) moderate was defined as discomfort that interfered with normal activities, and 3) severe was defined as discomfort that interfered with the ability to work or normal daily activities were impossible. SAEs were medical events that led to death, were life-threatening, required hospitalization or prolongation of hospitalization, caused persistent disability, or resulted in a congenital abnormality. TEAEs were AEs with an onset date on or after the first dose of study drug and up to 30 days after receiving the last dose of study drug. Treatment-related AEs were medical events that were considered by the investigator to be possibly or probably related to rabeprazole.

Safety analysis set was the group of participants who received at least one dose of study drug (rabeprazole) in the Treatment Period or Maintenance Period and had at least one post-dose safety assessment.