This is randomized, multicenter, parallel-group, double-blind trial that investigates the efficacy and safety of E3810 10mg twice daily over a period of 52 weeks. The non-recurrence rate as endoscopically confirmed at 52 weeks shall be the primary end point, and this shall be examined through a randomized, multicenter, parallel-group, double-blind trial that investigates the efficacy and safety of E3810 10mg twice daily over a period of 52 weeks.