A Study to Evaluate the Efficacy and Safety of BLI5100 in Patients With Non-Erosive Reflux Disease

Inclusion Criteria:

1. Aged ≥18 years at the time of signing informed consent;

2. Have experienced heartburn (burning sensation, pain at posterior bony thorax) for atleast 6 months prior to Screening;

3. Have documented history of symptomatic GERD;

4. Have no mucosal break(s) on the upper GI endoscopy performed during Screening;

5. Have reported heartburn on ≥4 days during any consecutive 7-day period of theScreening Period as recorded in the eDiary;

6. Able to understand and comply with the protocol requirements;

7. Willing and able to provide written informed consent at Screening;

8. A female of reproductive potential defined as a non-post-menopausal female who hasnot had a bilateral oophorectomy or medically documented ovarian failure; or If afemale of childbearing potential, agrees to use an acceptable form of birth controland avoid egg donation from the Screening Visit until 6 months after the last doseof study drug.

9. If a male, agrees to use an acceptable form of birth control from the ScreeningVisit until 3 months after the last dose of study drug.

10. If a male, agrees to abstain from sperm donation through 3 months afteradministration of the last dose of study drug.

Exclusion Criteria:

1. Unable to undergo an upper GI endoscopy;

2. Presence of esophageal stricture, gastroesophageal varix (including postsclerotherapy or ligation), untreated Barrett's esophagus, gastric bleeding,infection, tumor, or gastric or duodenal ulcer on the upper GI endoscopy; o Note: Patients with diagnosis of Schatzki's ring (mucosal tissue ring around loweresophageal sphincter) are eligible to participate.

3. Diagnosed with erosive gastroesophageal reflux disease, acute upper GI bleeding,gastric ulcer or duodenal ulcer, or acute gastritis within 2 months prior to theupper GI endoscopy;

4. Alarm symptoms such as odynophagia, severe dysphagia, upper GI bleeding, weightloss, anemia, or hematochezia within 4 weeks prior to Screening, unless the presumedmalignancy is ruled out;

5. History or suspicion of functional upper gastrointestinal disorders, such as:

• Functional heartburn, as described in the Rome IV criteria, or

• Functional dyspepsia, as described in the Rome IV criteria.

6. History of a connective tissue disorder associated with GI symptoms (eg, sclerodermaor systemic lupus erythematous) or inflammatory bowel disease, or documented historyof delayed gastric emptying;

7. History of acid-suppressive, esophageal, or gastric surgery; o Note: This is not applicable to appendectomy, cholecystectomy, or endoscopicexcision of benign tumor.

8. History of malignancy within the past 5 years (with the exception of resected basalcell or squamous cell carcinoma of the skin); o Note: This is not applicable to patients who had complete response or pathologicalcomplete response and whose tumor had not recurred for at least 5 years from thedate of last treatment, or patients whose tumor had been removed by endoscopicresection without any findings indicating recurrence of the tumor within 3 years.

9. History of an allergic disease, or hypersensitivity or intolerance to the activeingredient or excipients of the study drug;

10. History of alcoholism, chronic opiate use, or substance addiction in the 12 monthsbefore Screening or a positive urine drug screen for opiates or substances of abuse;

• Note: Patients on prescribed opioids are eligible to participate if they havebeen on a stable dose for >3 months prior to Screening.

• Note: Retesting of a positive urine drug screen requires Medical Monitorapproval. Positive urine drug screen for all drugs will require verification ofprescription for the positive tested substance.

11. Presence of manic-depression, anxiety disorder, panic disorder, somatoform disorder,personality disorder, or other psychological disorder; o Note: A diagnosis of manic-depression, anxiety disorder, panic disorder,somatoform disorder, personality disorder, or other psychological disorder is notexclusionary, as long as the patient is asymptomatic and well-controlled on stabletreatment (ie, stable dose for >6 months prior to Screening), including non-medicaltherapy.

12. Current use of antipsychotics, antidepressants, anxiolytics, or prescriptionsleeping medications, with the exception of a stable dose for >6 months prior toScreening;

13. Use of any gastric acid-suppressive agents, including PPIs, within 2 weeks prior tothe upper GI endoscopy at Screening;

14. Use of 2 or more commercial doses of reflux esophagitis-related medications (including H2 blockers, prostaglandins, mucosal protective agents, prokinetics, andantacids) within 1 week prior to the upper GI endoscopy at Screening;

15. Requirement of persistent (>3 times per week for >30 days) use of non-steroidalanti-inflammatory drugs (NSAIDs) during the course of the study; o Note: Low-dose (≤100 mg/day) aspirin is allowed provided that it has been used forprophylaxis prior to study participation.

16. If a female, is pregnant, breastfeeding, or planning to become pregnant during thestudy or within 6 months after the last dose of study drug;

17. Positive test result for human immunodeficiency virus, hepatitis B surface antigen,or hepatitis C virus at Screening;

18. Positive test result for H. pylori at Screening or diagnosis and treatment of H.pylori within 4 to 6 weeks prior to Randomization; o Note: Patients who test positive for H. pylori at Screening will be offeredtreatment according to local standard of care and may be re-screened for eligibilityfollowing completion of treatment.

19. Abnormal laboratory results with clinical relevance at Screening as follows:

• Aspartate aminotransferase (AST), alanine aminotransferase (ALT), or alkalinephosphatase level of ≥2 × upper limit of normal (ULN);

• Total bilirubin level of ≥2 × ULN, unless Gilbert's syndrome is confirmed whendirect bilirubin is ≤0.3 mg/dL;

• Estimated glomerular filtration rate <30 mL/min; or

• Serum magnesium <lower limit of normal.

20. Abnormal ECG of clinical significance (eg, major arrhythmia, multifocal prematureventricular contractions, or 2° atrioventricular block anomaly);

21. Presence of any gastric acid hypersecretory conditions, such as Zollinger-Ellisonsyndrome;

22. Involvement in another clinical study within 4 weeks of initiation of study drug; or

23. Any other clinically relevant condition that would confound study endpoints oradversely affect patient compliance with the study procedures in the medicaljudgment of the Investigator or Medical Monitor based on previous medical history orfindings on Screening assessments .