This study evaluates PGE2 production, COX-2 enzyme activity and PCNA expression in Barrett's
metaplastic tissue. All patients will have a baseline endoscopy with multiple biopsies. The
patients will then be receive four dosing regimens (esomeprazole, esomeprazole and aspirin,
esomeprazole and rofecoxib, or rofecoxib alone) consecutively each for a 10 day dosing
period, whilst undergoing further follow up endoscopies and multiple biopsies.