A Study to Check the Safety of Dexlansoprazole and Learn if it Can Treat Symptomatic Nonerosive Gastroesophageal Reflux Disease in Children 2 to 11 Years Old

Inclusion Criteria:

1. In the opinion of the investigator, the participant (as age appropriate) and/orparent(s)/legal guardian is capable of understanding and complying with protocolrequirements.

2. Prior to any study-specific procedures being performed, the appropriate informedconsent and the assent form(s) (as applicable) must be signed and dated by parent(s)or legal guardian and by the participant respectively, if appropriate.

3. Has a medical history of symptoms of GERD for at least 3 months prior to Screening.

4. Has met the eDiary qualification criteria as assessed by the PGSDD, defined ashurting or burning in the stomach, chest, or throat on at least 3 of any 7consecutive days during the Screening Period.

5. Has no evidence of erosive esophagitis (EE) according to the Los Angeles (LA)Classification of Esophagitis and, in the investigator's clinical judgment, thesymptoms are suggestive of acid-related disease. A 24-hour pH-metry (with or withoutimpedance) may be performed during Screening or within 6 months prior to Screeningfor similar symptoms as those identified during Screening if, in the investigator'sjudgment, this procedure would aid in the determination of whether the participant'ssymptoms are acid-related. An endoscopy performed within 1 week prior to signingscreening informed consent and assent form (as applicable) is an acceptablereplacement for the screening endoscopy if nonerosive GERD is confirmed,protocol-required biopsies were collected, and endoscopic pictures were obtained.

6. Is male or female and age 2 to 11 years, inclusive, at the time of screeninginformed consent.

Exclusion Criteria:

1. Has evidence of cardiovascular, pulmonary, central nervous system, hepatic,hematopoietic, renal, or metabolic disorder, severe allergy, asthma, or allergicskin rash that suggests any uncontrolled, clinically significant underlying diseaseor condition (other than the disease being studied), which may impact the ability ofthe participant to participate or potentially confound the study results.

2. Has a coexisting disease affecting the esophagus (eg, esophageal varices,scleroderma, viral or fungal infection, or esophageal stricture), history ofradiation therapy or cryotherapy to the esophagus, caustic or physiochemical traumasuch as sclerotherapy to the esophagus.

3. Has any findings in his/her medical history, physical examination, or safetyclinical laboratory tests giving reasonable suspicion of underlying disease thatmight interfere with the conduct of the trial.

4. Has a history of hypersensitivity or allergies to dexlansoprazole or any componentof the formulation of dexlansoprazole capsules, or any proton pump inhibitor (PPI) (including lansoprazole, omeprazole, rabeprazole, pantoprazole, or esomeprazole) orantacids.

5. Is required to take excluded medications or it is anticipated that the participantwill require treatment with at least 1 of the disallowed concomitant medicationsduring the study evaluation period.

6. Has a condition that may require inpatient surgery during the course of the study.

7. Has a known history of Barrett's esophagus with dysplastic changes in the esophagus.

8. Has a known history of eosinophilic esophagitis (EoE) or histologic findingssuggestive of EoE (≥15 eosinophils per high-powered field [HPF]).

9. Has history of celiac disease, tests positive for tissue transglutaminase (tTG),antibody or confirmed disease by histology.

10. Has history of inflammatory bowel disease, or irritable bowel syndrome.

11. Has active gastric or duodenal ulcers within 4 weeks prior to Day -1. If present >4weeks prior to Day -1, ulcers must not be present upon screening endoscopy.

12. Requires dilatation of esophageal strictures and/or strictures preventing passage ofthe endoscope during the screening endoscopy. Schatzki's ring (a ring of mucosaltissue near the lower esophageal sphincter) is acceptable.

13. A female participant who has reached menarche by Day -1.

14. Is known to be positive for the human immunodeficiency virus (HIV).

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

16. Has a history of gastric, duodenal, or esophageal surgery except simple oversew ofan ulcer. A history of gastric tube and/or percutaneous endoscopic gastrostomy (PEG)placement is allowed.

17. Had an acute upper gastrointestinal hemorrhage within 4 weeks prior to endoscopy.

18. Has donated or lost >10% of the total blood volume, undergone plasmapheresis, or hashad a transfusion of any blood product within 90 days prior to the first dose ofstudy drug.

19. Has a known history of alcohol abuse or illegal drug use within the past 12 monthsprior to the first dose of study drug.

20. Has any screening abnormal laboratory value that suggests a clinically significantunderlying disease or condition that may prevent the participant from entering thestudy; or the participant has: creatinine >1.5 mg/dL, alanine aminotransferase (ALT)and/or aspartate aminotransferase (AST) >2 times the upper limit of normal (×ULN),or total bilirubin >2.0 milligrams per deciliter (mg/dL) with AST/ALT elevated abovethe limits of normal values.

21. Is an immediate family member, study site employee, or is in a dependentrelationship with a study site employee who is involved in the conduct of this studyor may consent and assent (as applicable) under duress. Students of theinstitution/research facility who are under the supervision of, or in a subordinaterole to, the investigator are also ineligible.

22. The participant, in the opinion of the investigator, is unlikely to comply with theprotocol or is unsuitable for any other reason.

23. Has participated in another clinical study (not including screening for StudyTAK-390MR_205 [NCT02615184]) and/or has received any investigational compound within 30 days prior to Screening.