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/or
parent(s)/legal guardian is capable of understanding and complying with protocol
requirements.

2. Prior to any study-specific procedures being performed, the appropriate informed
consent 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 as
hurting or burning in the stomach, chest, or throat on at least 3 of any 7
consecutive 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, the
symptoms are suggestive of acid-related disease. A 24-hour pH-metry (with or without
impedance) may be performed during Screening or within 6 months prior to Screening
for similar symptoms as those identified during Screening if, in the investigator's
judgment, this procedure would aid in the determination of whether the participant's
symptoms are acid-related. An endoscopy performed within 1 week prior to signing
screening informed consent and assent form (as applicable) is an acceptable
replacement 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 screening
informed consent.

Exclusion Criteria:

1. Has evidence of cardiovascular, pulmonary, central nervous system, hepatic,
hematopoietic, renal, or metabolic disorder, severe allergy, asthma, or allergic
skin rash that suggests any uncontrolled, clinically significant underlying disease
or condition (other than the disease being studied), which may impact the ability of
the 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 of
radiation therapy or cryotherapy to the esophagus, caustic or physiochemical trauma
such as sclerotherapy to the esophagus.

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

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

5. Is required to take excluded medications or it is anticipated that the participant
will require treatment with at least 1 of the disallowed concomitant medications
during 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 findings
suggestive 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 >4
weeks prior to Day -1, ulcers must not be present upon screening endoscopy.

12. Requires dilatation of esophageal strictures and/or strictures preventing passage of
the endoscope during the screening endoscopy. Schatzki's ring (a ring of mucosal
tissue 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 other
hypersecretory condition.

16. Has a history of gastric, duodenal, or esophageal surgery except simple oversew of
an 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 has
had a transfusion of any blood product within 90 days prior to the first dose of
study drug.

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

20. Has any screening abnormal laboratory value that suggests a clinically significant
underlying disease or condition that may prevent the participant from entering the
study; 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 above
the limits of normal values.

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

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

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