• Time to progression every 8 weeks [ Designated as safety issue: No ]
• Overall survival [ Designated as safety issue: No ]

• Time to progression every 8 weeks
• Overall survival

RATIONALE: Imatinib mesylate may stop the growth of tumor cells by blocking the enzymes necessary for tumor cell growth.

PURPOSE: 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.

OBJECTIVES:

• Determine the response rate and time to tumor progression in patients with refractory metastatic and/or unresectable adenocarcinoma of the stomach treated with imatinib mesylate.
• Determine the overall survival of patients treated with this drug.
• Determine the toxic effects of this drug in these patients.

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.

• Esophageal Cancer
• Gastric Cancer

DISEASE CHARACTERISTICS:

• Diagnosis of metastatic and/or unresectable adenocarcinoma of the stomach or gastroesophageal junction
• Measurable disease by radiographic imaging
• No brain metastasis

PATIENT CHARACTERISTICS:

Age

• Over 18

Performance status

• Karnofsky 70-100%

Life expectancy

• More than 3 months

Hematopoietic

• Granulocyte count greater than 1,500/mm^3
• Platelet count greater than 100,000/mm^3
• Hemoglobin at least 9 g/dL
• No active bleeding disorder

Hepatic

• Bilirubin no greater than 1.5 mg/dL
• SGOT/SGPT less than 2.5 times upper limit of normal

Renal

• Creatinine clearance greater than 60 mL/min

Gastrointestinal

• No active peptic ulceration
• No active gastrointestinal bleeding

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception during and for 3 months after study completion
• No active infection
• No known seizure disorder
• No medical, social, or psychological factors that would preclude completion of study treatment
• No serious concurrent illness that would preclude tolerance and completion of study treatment

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• Recovered from prior chemotherapy

Endocrine therapy

• Not specified

Radiotherapy

• Recovered from prior radiotherapy

Surgery

• More than 4 weeks since prior major surgery

Other

• No concurrent therapeutic warfarin for anticoagulation
• No concurrent highly active antiretroviral therapy for HIV-positive patients
• No concurrent grapefruit juice