Imatinib mesylate may stop the growth of tumor cells by blocking the enzymes necessary for tumor cell growth. This phase II trial is studying how well imatinib mesylate works in treating patients with refractory metastatic and/or unresectable stomach or gastroesophageal junction cancer.

PRIMARY OBJECTIVES:

I. To determine the response rate, time to tumor progression, and overall survival in patients with metastatic gastric cancer treated with STI571 who have failed one chemotherapy regimen for metastatic disease.

II. To assess the toxicities of STI571 in these patients. III. To obtain preliminary data on molecular correlates to determine clinical efficacy and toxicity.

OUTLINE: This is a multicenter study. Patients are stratified according to risk (good risk [chemonaïve] vs poor risk [1 prior chemotherapy regimen]).

Patients receive oral imatinib mesylate twice daily on days 1-28. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.

Patients are followed for 30 days.

PROJECTED ACCRUAL: A total of 21-41 patients will be accrued for this study within 1-1.5 years.

Inclusion Criteria:

• Patients with metastatic and/or unresectable carcinoma of the stomach, who have measurable disease
• Life expectancy > 3 months
• Karnofsky Performance Status > 60%
• Absence of an active infection
• Granulocyte count of > 1,500/mm^3
• Hemoglobin (Hgb) >= 9 mg/dl
• Serum bilirubin =< 1.5 mg/dl, regardless of liver involvement secondary to tumor
• Platelets > 100,000/mm^3
• Serum glutamic oxaloacetic transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) < 2.5 x the institutional upper limit of normal
• Calculated creatinine clearance of > 60 ml/min
• Patients must have signed written informed consent
• Female patients of child-bearing potential must have a negative blood or urine pregnancy test within two weeks prior to initial study treatment
• Patients who have had prior chemotherapy or radiation therapy must have recovered from any toxicities prior to study entry
• Patients must have radiographic imaging to document measurable disease within 28 days prior to initial study therapy

Exclusion Criteria:

• Diagnosis of resectable carcinoma of the stomach
• Major surgery within four weeks of study entry
• Brain metastasis or known seizure disorder
• Fertile men and women not using an acceptable method of contraception
• Pregnant or lactating patients are excluded since STI571 may be harmful to the developing fetus and child
• Patients known to be HIV positive and receiving HAART are excluded because of possibly pharmacological interactions
• Active peptic ulceration or active gastrointestinal bleeding or any active bleeding disorders
• Use of therapeutic doses of coumadin (warfarin) as anticoagulation
• Medical, social, or psychological factors which would prevent the patient from completing the treatment protocol
• Patients with serious intercurrent illness which would preclude tolerance and completion of the protocol treatment

Adverse events were collected over a period of 2 years, 2 months.

"Other" adverse events include all grades and all attributions to treatment not included in "Serious" adverse events table.

In the first stage none of the 17 patients responded (CR/PR) to treatment. Due to budget constraints and recent reprioritizations, CTEP closed the study to accrual.