DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed gastric or gastroesophageal junction (GEJ)* adenocarcinoma

  • Metastatic or unresectable disease
  • Siewert's classification I, II, or III NOTE: *The GEJ is defined as within 5 cm (proximal or distal) of the anatomical cardia. Tumors centered more than 5 cm proximal to the anatomical cardia are considered esophageal tumors.
• No ulcerated, non-healing tumors or tumors that have developed a malignant fistula
• No esophageal tumors
• No known or active brain metastases

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• Karnofsky 60-100% OR
• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 75,000/mm^3
• No bleeding diathesis or coagulopathy

Hepatic

• Bilirubin ≤ 1.5 mg/dL
• AST and ALT ≤ 3 times upper limit of normal (ULN) (5 times ULN if liver metastases are present)
• PT (INR) ≤ 1.5*
• PTT ≤ 3 seconds above ULN* NOTE: *In the absence of anticoagulation therapy

Renal

• Creatinine ≤ 1.5 mg/dL
• Proteinuria < 1+ OR
• Protein < 500 mg/24-hour urine collection

Cardiovascular

• No acute ischemia or significant conduction abnormality by EKG
• No clinically significant cardiovascular disease
• No uncontrolled hypertension (blood pressure > 160/90 mm Hg on medication)
• No myocardial infarction within the past 6 months
• No unstable angina within the past 6 months
• No transient ischemic attack within the past 6 months
• No cerebrovascular accident within the past 6 months
• No other arterial thromboembolic event within the past 6 months
• No New York Heart Association class II-IV congestive heart failure
• No serious cardiac dysrhythmia requiring medication
• No peripheral vascular disease (grade II or greater)
• No history of stroke

Other

• No CNS disease within the past 5 years (e.g., uncontrolled seizures)
• No other concurrent uncontrolled illness
• No ongoing or active infection requiring parental antibiotics on Day 0 of study
• No serious, non-healing wound
• No serious wound healing by secondary intention
• No ulcer
• No bone fracture
• No psychiatric illness or social situation that would preclude study compliance
• No significant traumatic injury within the past 28 days
• No other neoplastic disease within the past 3 years except basal cell skin cancer, carcinoma in situ of the cervix, or nonmetastatic prostate cancer
• No known hypersensitivity to Chinese hamster ovary cell products or other recombinant human antibodies
• No other medical condition that would preclude study participation

• Not pregnant or nursing

  • No nursing during and for 4 months after study participation
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 4 months after study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• More than 8 weeks since prior immunotherapy and recovered
• No other concurrent biologic or immunologic agents
• No other concurrent bevacizumab

Chemotherapy

• No prior chemotherapy for metastatic disease
• No prior cisplatin or irinotecan
• Prior neoadjuvant and/or adjuvant chemotherapy or chemoradiotherapy allowed
• More than 3 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered
• No other concurrent chemotherapy

Endocrine therapy

• Not specified

Radiotherapy

• See Chemotherapy
• More than 3 weeks since prior radiotherapy and recovered
• No concurrent radiotherapy

Surgery

• More than 28 days since prior major surgical procedure or open biopsy
• More than 7 days since prior fine needle aspirations or core biopsies
• No concurrent major surgery

Other

• No other concurrent investigational agents
• No other concurrent anticancer therapy
• No concurrent chronic daily aspirin (> 325 mg/day)
• No concurrent nonsteroidal anti-inflammatory medications that would inhibit platelet function at doses used to treat chronic inflammatory diseases

• Full-dose anticoagulants allowed, provided the following criteria are met:

  • INR in range (i.e., 2-3) while on a stable dose of warfarin or low molecular weight heparin
  • No active bleeding or pathologic condition that would confer a high risk of bleeding (e.g., tumor involving major blood vessels or known varices)
• No concurrent thrombolytic agents

• No concurrent vitamins, antioxidants, herbal preparations, or supplements

  • Single tablet multivitamin allowed