Selective 5-HT4 Receptor Agonist and Proton Pump Inhibitor (PPI) in Subjects With Gastroesophageal Reflux Disease (GERD)

Inclusion Criteria: 1. Written Informed Consent Form signed voluntarily before the first study-related activity. 2. Aged between 18 and 70 years, inclusive. 3. Subjects with a history of the cardinal symptoms of GERD (both heartburn and regurgitation) prior to PPI therapy. 4. Subjects with symptoms of GERD for at least 6 months prior to the Screening Visit. 5. Subjects who have persistent symptoms of regurgitation for 3 or more days over the past week with or without heartburn while on PPI. 6. Subjects have at least some improvement to the symptom of heartburn while on PPI therapy. 7. Subjects on PPI therapy for at least 8 weeks prior to the Screening Visit of which the last 4 weeks are on a stable labeled dose for any GERD indication according to the country label, where a change of PPI therapy would not impact the symptoms (twice-daily dosing of PPI is not allowed in the last 4 weeks) Exclusion Criteria: 1. Subjects who show no response to heartburn while on PPI therapy. 2. Subjects with dyspepsia symptoms that are more predominant than their GERD symptoms (heartburn and/or regurgitation). 3. Subjects with prior endoscopic anti-reflux procedure or major GI surgery or subjects with major GI disorders. 4. Presence of severe and clinically uncontrolled cardiovascular, liver, lung or neurologic disease, cancer or AIDS. 5. Alarm symptoms suggestive of malignancies or organic disease.