Phase III Study of NPO-11 in Patients Undergoing Therapeutic Upper Gastrointestinal Endoscopy

Inclusion Criteria: inpatients or outpatients of either sex who require therapeutic upper gastrointestinal endoscopy (EMR or ESD) and meet the criteria (1)-(4) below will be enrolled in the study. Patients have to provide written informed consent for voluntary participation in the study. The criteria (2) and (3) will be confirmed by the endoscopic observation just before starting the intended treatment. 1. Patients with an early gastric cancer located in the lower third of the stomach, who require therapeutic upper gastrointestinal endoscopy (EMR or ESD) (except for those with an intended treatment by using a scope of \<9 mm in diameter) 2. Differentiated -type intramucosal gastric cancer or the suspected lesion, ≤ 2 cm in size, no ulcer finding 3. Patients with a single intended lesion for the treatment 4. Patients who are older than 20 years at the time of consent Exclusion Criteria: Patients who meet any of the following criteria will be excluded from the study beforehand. The criteria (3) to (5) will be confirmed by the endoscopic observation just before starting the intended treatment. 1. Patients with a history of surgery to the upper gastrointestinal tract 2. Patients who require emergency endoscopy 3. Patients with severe gastric stenosis or deformation which makes observation of gastric peristalsis difficult 4. Patients who require emergency endoscopic treatment except for the intended lesion 5. Patients with a lesion extended to the pyloric ring 6. Patients with an ongoing cancer treatment (chemotherapy or radiotherapy) 7. Patients with pacemaker 8. Patients with known bleeding tendency or Patients with difficulty of antithrombogenic agents withdrawal 9. Patients with a history of shock or hypersensitivity to l-menthol or peppermint oil 10. Patients with contraindications to glucagon 11. Patients with contraindications to benzodiazepines, pethidine hydrochloride, and epinephrine 12. Pregnant or lactating women, women of childbearing potential, or women who plan to become pregnant during the study 13. Patients who have received other investigational drugs within four months before consent or who are participating in other clinical studies 14. Patients otherwise ineligible for participation in the study in the investigator's opinion