Key Inclusion Criteria:

1. Male or female patients, 18 to 65 years of age.
2. If female, not of childbearing potential by reason of surgery, radiation or menopause, or of childbearing potential, but using an approved method of contraception since the last menstrual period, for example, intrauterine device (IUD), implant, double barrier method, or oral contraceptives for at least one cycle. Females of childbearing potential must have a negative urine pregnancy test before medication is dispensed.
3. Patients must report a minimum three-month history of GERD symptoms. GERD symptoms are defined as heartburn with or without regurgitation or other associated GERD symptoms.
4. Patients must have at least 4 days with heartburn per week in each of the 2 weeks prior to Screening.
5. Patients must have no esophagitis, with no proton pump inhibitors (PPIs, prescription or OTC), H2 blockers (prescription or OTC) or prokinetics within 14 days, prior to the endoscopy.

Key Exclusion Criteria:

1. Evidence of significant hepatic, renal, respiratory, endocrine, hematologic, neurologic, psychiatric or cardiovascular system abnormalities, unless the Sponsor and Investigator agree that the nature and severity of any abnormality is unlikely to interfere with the conduct of the study, the interpretation of study results, or the health of the patient during the study.
2. Females must not be pregnant, lactating or have a positive urine eta human chorionic gonadotropin (B-hCG) laboratory result.
3. Patients with a history of allergy or sensitivity to proton pump inhibitors or to their inactive ingredients.
4. Patients with known gastric ulcer, duodenal ulcer, infectious or inflammatory conditions of the small or large intestine, malabsorption syndromes, obstruction, a history of gastrointestinal malignancy, or prior gastric or intestinal surgery (including vagotomy).
5. Patients who have a history of Barrett's esophagus, esophageal stricture, or pyloric stenosis.
6. Patients with a history of endoscopically-proven esophagitis any time in the past.
7. Patients who have taken proton pump inhibitors (PPIs, prescription or OTC), H2 blockers (prescription or OTC) or prokinetics within 14 days, prior to Screening endoscopy, or any of these medications within 7 days prior to the single-blind placebo run-in period.