The purpose of this study is to evaluate the efficacy and safety of Ilaprazole 20 mg in patients with non-erosive reflux disease. This study intends to demonstrate the clinical superiority of Ilaprazole 20 mg to placebo administered once daily for 4 weeks.

This study is multicenter, randomized, parallel, double blind, placebo-controlled phase III study

Inclusion Criteria:

1. Male or female aged ≥ 19 years and ≤ 80 years

2. Diagnosed with non-erosive reflux disease meeting all of the following criteria:

   2-1) At least either heartburn or acid regurgitation has persisted for at least past 3 months before screening 2-2) Have experienced at least either heartburn or acid regurgitation of moderate or higher intensity on at least 2 days of 7 days prior to initiation of the investigational product 2-3) Esophageal mucosal breaks by LA Classification are not observed on upper gastrointestinal endoscopy at screening

3. Voluntarily provide written informed consent to participate in this study

Exclusion Criteria:

1. Esophageal stenosis, ulcerative stenosis, esophagogastric varices or Barrett esophagus confirmed by past upper gastrointestinal endoscopy within 1 year prior to screening

2. Active peptic ulcer or gastrointestinal bleeding confirmed by past upper gastrointestinal endoscopy at screening or within 4 weeks prior to screening

3. Abnormal value on laboratory test at screening:

   3-1) Total Bilirubin, Creatinine > Upper limit of normal (ULN) x 1.5 3-2) Alkaline Phosphatase, BUN > ULN x 2

4. Clinically significant abnormal findings on ECG (major arrhythmia, multifocal PVC, second-degree or higher AV block, etc.) within 3 months prior to screening

5. Have taken H2 receptor antagonists (H2RA), prostaglandin preparations, mucosal protective drugs, prokinetics, etc. within 2 weeks prior to initiation of the investigational product administration, or has taken PPIs within 4 weeks prior to initiation of the investigational product administration

6. Expected to continuously take nonsteroidal antiinflammatory drugs (NSAIDs) including aspirin or steroid preparations during the study

7. Surgical or medical condition that may significantly influence the absorption, distribution, metabolism or excretion of drug, including but not limited to: history of major gastrointestinal surgery such as gastrectomy, gastroenterostomy, colectomy, gastric bypass, gastric ligation or gastric banding; presence or history of active inflammatory bowel disease within 12 months prior to screening; has undergone critical surgery that may influence gastric acid secretion with exception of surgeries such as appendectomy, cholecystectomy, and hysterectomy

8. Zollinger-Ellison syndrome; past history of alcoholism or drug abuse

9. Past history of allergic symptoms (rash, fever, pruritus, etc.) or hypersensitivity to any ingredient of the Investigational product

10. Past history of treated or untreated malignancy, with or without local recurrence or metastasis, within 5 years prior to screening (with exception of local basal cell carcinoma of skin)

11. Pregnant or nursing women

12. Women of childbearing potential who do not use proper contraception during the study

13. Active liver disease; ALT or AST > ULN x 2 at screening; or history of hepatic encephalopathy, esophageal varix, or portacaval shunt

14. Receiving renal dialysis or history of kidney transplantation or presence of severe renal impairment (stage 4 or 5 chronic renal disease)

15. Participated in another clinical study and took an investigational product within 3 months prior to screening

16. Considered by the investigator to be ineligible to participate in this study for other reasons

IPD will not be shared to other researchers.