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