To Compare the Gastrointestinal Safety of a 14-Day Oral Dosing Regimen of ATB-346 to Sodium Naproxen in Healthy Subjects

Exclusion Criteria

• •1\. Subject with abnormal baseline laboratory values deemed to be clinically significant by the Investigator 2. Ongoing use of any prescription or over-the-counter medications, or natural/herbal or vitamin preparations, that in the opinion of the Investigator would interfere with the study objectives, or impact subject safety (with the exception of systemic contraceptives and hormone replacement therapy) 3. Use of investigational drugs up to thirty (30) days before screening 4. Use of the following medications within two weeks prior to randomization:
• •1. NSAIDs, Aspirin, aspirin-containing products or naproxen-containing medications, NSAID-containing products
• •2. Proton pump inhibitors
• •3. H-2 blockers
• •4. Anti-platelet agents
• •5. Anti-coagulants
• •6. Antimicrobials
• •7. Other gastroprotective agents such as antacids, misoprostol, or bismuth-containing products 5. Subject-reported past history of gastrointestinal ulcer or gastrointestinal bleeding, or any clinically significant gastrointestinal disease.
• •6\. Positive for Helicobacter pylori urea breath test at the screening visit 7. Clinically significant gastrointestinal, hepatic or renal disease, or any other conditions known to significantly impact or interfere with absorption, distribution, metabolism or elimination of the investigational drug(s) 8. Clinically significant past or present diseases or illnesses that, in the opinion of the investigator, would interfere with the study objectives or integrity or with the subject's safety.
• •9\. Subject with seated pulse rates \<50 beats per minute (bpm) or \>100 bpm at screening 10. Seated blood pressure \<100/60 mm Hg or \>140/90 mm Hg at screening 11. Known hypersensitivities to naproxen, other non-steroidal anti-inflammatory (NSAID) agents, related products (including excipients and formulations) 12. Known hypersensitivities to drugs used for sedation during endoscopy 13. Severe hypersensitivity (including angioedema) to any drugs 14. Use of medications with known drug-drug interactions including potent enzyme-modifying drugs, potent inhibitors and/or inducers of CYP enzymes (such as fluoxetine, barbiturates or St. John's Wort) in the previous thirty (30) days before randomization 15. Female who is pregnant or breastfeeding 16. Positive test for HIV antigen/antibody combination, hepatitis B surface antigen (HBsAg), or anti-Hepatitis C virus tests 17. Positive urine drug test at screening 18. Positive urine alcohol test prior to the screening endoscopy 19. Any clinically significant illness up to thirty (30) days before screening