Efficacy of Dexlansoprazole MR on Heartburn Control in Participants Previously Receiving Twice Daily Proton Pump Inhibitor Therapy

Inclusion Criteria:

1. Prior to any study-specific procedures being performed, the participant voluntarilysigns an Investigational Review Board-approved informed consent form (ICF) and anyprivacy statement/authorization form required (eg, The Health Insurance Portabilityand Accountability Act (HIPAA) authorization)

2. Has a history of gastroesophageal reflux disease symptom, including heartburn, priorto therapy, who are currently being treated with twice daily proton pump inhibitors,excluding Dexilant (dexlansoprazole).

3. Taking a stable dose of any twice daily proton pump inhibitors for less than or equalto 1 year and greater than 8 weeks prior to Screening.

4. Participant is well-controlled on their current twice daily proton pump inhibitors.

5. Females cannot be nursing and must have a negative urine pregnancy test at Day -1 orbe of non-childbearing potential. If females are of child bearing potential, must havea negative serum human chorionic gonadotropin (hCG) pregnancy test during Screeningand on an acceptable form of contraception, or have had bilateral tubal ligation ifperformed a minimum of 90 days prior to Day 1.

Exclusion Criteria:

1. Has a history of co-existing diseases affecting the esophagus, history of radiationtherapy or cryotherapy to the esophagus, caustic or physiochemical trauma such assclerotherapy to the esophagus.

2. Has active gastric or duodenal ulcers during the 30 days prior to Screening.

3. Has acute upper gastrointestinal hemorrhage during the 30 days prior to Screening.

4. Has current or historical evidence of Zollinger-Ellison syndrome or otherhypersecretory condition.

5. Has known hypersensitivity to any proton pump inhibitor or any component ofdexlansoprazole MR.

6. Use of any Histamine type-2 receptor antagonist or antacids during Screening oranticipated use during the study treatment period.

7. Use of the following medications 7 days prior to Screening or anticipated use duringthe study:

• Sucralfate.

• Misoprostol.

• Systemic corticosteroids.

• Prokinetics (to include metoclopramide, cisapride, tegaserod).

• Bisphosphonates during the 6 months prior to Screening or anticipated use duringthe study.

• Chronic use (> 12 doses per month) of nonsteroidal anti-inflammatory drugs

• Drugs with significant anticholinergic effects such as tricyclic antidepressantsor drugs with central nervous system effects that could mask perception ofsymptoms.

• Any investigational drug(s) within 30 days of Screening.

8. Has received blood products within the 3 months prior to Screening.

9. History of alcohol abuse or illegal drug use or drug addiction in the 12 months priorto Screening.

10. Evidence of uncontrolled, clinically significant neurologic, cardiovascular,pulmonary, hepatic, renal, metabolic, gastrointestinal, or endocrine disease or otherabnormality, which may impact the ability of the participant to participate orpotentially confound the study results.

11. Atypical manifestations of gastroesophageal reflux disease.

12. Has abnormal screening laboratory values that suggest a clinically significantunderlying disease or condition.

13. Cancer within 5 years prior to Screening.

14. Is known to have acquired immunodeficiency syndrome.

15. Has any condition that is likely to require inpatient surgery during the course of thestudy.

16. Surgery of the acute upper gastrointestinal tract, including bariatric.

17. Is in the opinion of the investigator unable to comply with the requirements of thestudy or are unsuitable for any reason.