Inclusion Criteria

DISEASE CHARACTERISTICS:

- Diagnosis of gastric or gastroesophageal junction adenocarcinoma

- Metastatic or unresectable disease

- Progressive disease after receiving 1 prior chemotherapy regimen for metastatic
disease comprising 1 of the following:

- Fluorouracil

- Cisplatin and irinotecan

- Capecitabine

- Taxanes

- Measurable disease

- No esophageal cancer

- No brain metastases

PATIENT CHARACTERISTICS:

Age

- Over 18

Performance status

- ECOG 0-2 OR

- Karnofsky 60-100%

Life expectancy

- At least 3 months

Hematopoietic

- Absolute neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin normal

- AST and ALT ≤ 2.5 times upper limit of normal

Renal

- Creatinine ≤ 1.5 mg/dL

Cardiovascular

- No symptomatic congestive heart failure

- No unstable angina pectoris

- No cardiac arrhythmia

- No acute ischemia by EKG

- No significant conduction abnormality by EKG, including either of the following:

- Bifasicular block, defined as left anterior hemiblock in the presence of right
bundle branch block

- Second or third degree atrioventricular block

- No history of cardiac or cerebrovascular disease due to hypotension and tachycardia

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception before, during, and for 6 months
after study participation

- No ongoing or active infection

- No other uncontrolled illness

- No peripheral neuropathy ≥ grade 2 within the past 2 weeks

- No allergy to boron or mannitol

PRIOR CONCURRENT THERAPY:

Biologic therapy

- More than 4 weeks since prior immunotherapy

Chemotherapy

- More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) and recovered

Endocrine therapy

- Not specified

Radiotherapy

- More than 4 weeks since prior radiotherapy and recovered

Surgery

- More than 2 weeks since prior major surgery

Other

- No concurrent highly active anti-retroviral therapy for HIV-positive patients

- No other concurrent investigational agents