Safety and Efficacy of Dexlansoprazole Modified Release Formulation to Treat Gastroesophageal Reflux Disease

Inclusion Criteria: * Subjects identifying their main symptom as a burning feeling in the mid epigastric area and/or chest area (ie, heartburn). * Subject has a history of episodes of heartburn for 6 months or longer prior to Screening. * Subject must have a history of episodes of heartburn for 4 or more days during the 7 days prior to Day -1. Exclusion Criteria: * Endoscopic Barrett's esophagus and/or definite dysplastic changes. History of dilatation of esophageal strictures. * Subjects with erosive esophagitis (EE) as shown by endoscopy. * Evidence of uncontrolled systemic disease. Co-existing diseases affecting the esophagus. Current or history of Zollinger-Ellison syndrome. * Subject has abnormal laboratory values. * Subjects with active gastric or duodenal ulcers within 4 weeks of the first dose. * Subject known to have acquired immunodeficiency syndrome (AIDS). * Known hypersensitivity to any proton pump inhibitor (PPI), any component of Dexlansoprazole MR, or antacid. * Use of prescription or non-prescription PPIs, histamine (H2) receptor antagonists, or sucralfate. * Chronic (\>12 doses per month) use of nonsteroidal anti-inflammatory drugs (NSAIDs) or cyclo-oxygenase-2 (COX-2) inhibitors. * Use of antacids (except for study-supplied Gelusil® ). * Use of drugs with significant anticholinergic effects. * Subjects who cannot discontinue the use of misoprostol or prokinetics * Need for continuous anticoagulant therapy. * Females who are pregnant or lactating. * History of gastrointestinal surgery except for simple oversew of ulcer. * History of cancer within 3 years prior to screening. * Subject has participated in a previous Dexlansoprazole study. * Subjects who, in the opinion of the investigator, are unable to comply with the requirements of the study or are unsuitable for any reason.