This is a clinical research study of T900607-sodium to determine if it is effective and safe in treating gastric cancer and adenocarcinoma of the esophagus. Patients will be treated on a weekly basis with an intravenous injection of the study drug.

Inclusion Criteria

• Histologically or cytologically confirmed diagnosis of gastric cancer or adenocarcinoma of the esophagus

• Subjects must have received 1-2 regimens of prior chemotherapy

• At least 18 years of age

• Bidimensionally measurable disease amenable to CT scanning. At least one lesion must be least 1 X 1 cm in size.

• Karnofsky performance status of at least 70%

• Estimated life expectancy of at least 12 weeks

• Females of childbearing potential must have a negative pregnancy test and agree to use an effective contraceptive

• Subject must be able to comply with study procedures and follow-up examinations.

• Signed written informed consent

• Lab Values (obtained ≤ 7 days prior to study enrollment):

  • ANC at least 1.5x10e9/L, * Platelet count at least 100x10e9/L,
  • Creatinine within 2 times upper limit of normal * AST and ALT within 5 times upper limit of normal
  • Bilirubin within 1.5 times upper limit of normal
  • Albumin great than 2.5 g/dL

Exclusion Criteria

• Severe, concurrent disease, infection or co-morbidity that, in the judgment of the investigator, would make the subject inappropriate for enrollment
• NYHA Class III/IV cardiac disease, left ventricular ejection fraction (LVEF) of <50%, or acute anginal symptoms
• Patients who have received any investigational agent within 4 weeks of enrollment
• Patients who are pregnant or breast-feeding
• History of prior malignancy other than gastric cancer or adenocarcinoma of the esophagus within the last 5 years, except for adequately treated basal cell or squamous cell skin cancer or carcinoma in situ of the cervix
• History of central nervous system metastases or carcinomatous meningitis
• Major surgery within 4 weeks of enrollment