Diffuse Gastric and Esophagogastric Junction Cancer S-1 Trial

This is an open-label, international, Phase 3 study evaluating the efficacy and safety of
the S-1/cisplatin regimen versus the 5-FU/cisplatin regimen in chemotherapy-naïve patients
with metastatic diffuse gastric carcinoma including carcinoma of the gastro-esophageal
junction. Patients will be randomly assigned to S-1/cisplatin (experimental regimen, Arm A)
or 5-FU/cisplatin (control regimen, Arm B).

Inclusion Criteria:

- Has given written Informed Consent

- Histologically confirmed, unresectable, metastatic diffuse gastric cancer including
carcinoma of the gastro-esophageal junction

- No prior chemotherapy for gastric cancer except adjuvant and/or neo-adjuvant
chemotherapy more than 12 months ago

- Life expectancy of at least 3 months

- Able to take medications orally

- ECOG performance status 0 to 1

- Adequate organ function (bone marrow, kidney and liver)

Exclusion Criteria:

- Certain type(s) of non-measurable lesion(s), if the only one(s).

- Certain serious illness or medical condition(s)

- Lost greater than or equal to 10% of body weight in the 3 months proceeding signing
the ICF

- Treatment with drugs interacting with S-1, 5-FU, or cisplatin.

- Pregnant or lactating female.

- Known hypersensitivity to fluoropyrimidines or cisplatin.

Other protocol-defined inclusion/exclusion criteria may apply