Study to Evaluate the Safety and Efficacy of CJ-12420 in Patients With Gastric Ulcer

CJ-12420 50 mg tablets will be orally administered, once daily, for up to 8 weeks. For subjects whose gastric ulcer is not endoscopically healed(S1 or S2 stage) at Week 4, subjects will receive additional 4 weeks treatment of CJ-12420 50 mg.

CJ-12420 100 mg tablets will be orally administered, once daily, for up to 8 weeks. For subjects whose gastric ulcer is not endoscopically healed(S1 or S2 stage) at Week 4, subjects will receive additional 4 weeks treatment of CJ-12420 100 mg.

Lansoprazole 30 mg capsule will be orally administered, once daily, for up to 8 weeks. For subjects whose gastric ulcer is not endoscopically healed(S1 or S2 stage) at Week 4, subjects will receive additional 4 weeks treatment of Lansoprazole 30 mg.