Inclusion Criteria:

- Histologically or cytologically confirmed stage IV breast cancer

- Patients without pathologic or cytologic confirmation of metastatic disease must
have unequivocal evidence of metastasis by physical exam or radiologic study

- Must meet 1 of the following criteria:

- Received 1 or 2 prior conventional chemotherapy regimens for metastatic disease

- Relapsed within 1 year after adjuvant chemotherapy and no prior chemotherapy for
metastatic disease

- At least 1 unidimensionally measurable lesion, meeting 1 of the following criteria:

- At least 20 mm by conventional techniques

- At least 10 mm by spiral CT scan

- No CNS metastases by CT scan or MRI within the past 6 weeks

- No prior or concurrent primary CNS tumor on physical exam

- Disease progression after bone marrow or peripheral blood stem cell transplantation
allowed

- HER2-positive tumors allowed if previously treated with trastuzumab (Herceptin)

- Hormone receptor status:

- Not specified

- Male or female

- Performance status - ECOG 0-2

- Performance status - Karnofsky 60-100%

- More than 3 months

- Absolute neutrophil count at least 1,500/mm^3

- Hemoglobin at least 9 g/dL

- Platelet count at least 100,000/mm^3

- No prior bleeding diathesis or coagulopathy

- Bilirubin no greater than 1.5 times upper limit of normal (ULN)

- AST/ALT no greater than 2.5 times ULN

- INR no greater than 1.5

- Creatinine less than 2 mg/dL

- Urine protein no greater than +1 by dipstick

- Urine protein less than 500 mg by 24-hour urine collection

- LVEF at least 50%

- No prior stroke

- No New York Heart Association class II-IV congestive heart failure

- No serious cardiac arrhythmia requiring medication, including atrial fibrillation
requiring systemic anticoagulation

- No grade II or greater peripheral vascular disease within the past year

- No clinically significant peripheral artery disease

- No deep vein thrombosis or embolism within the past 5 years

- No arterial thromboembolic event within the past 6 months, including any of the
following:

- Transient ischemic attack

- Cerebrovascular accident

- Unstable angina

- Myocardial infarction

- No other significant cardiovascular disease

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No evidence of seizures not controlled with standard medical therapy

- No prior allergic reactions attributed to compounds of similar chemical or biologic
composition to bevacizumab or other agents used in the study

- Prior mild infusion reaction to trastuzumab allowed

- No serious non-healing wound, ulcer, or bone fracture

- No significant traumatic injury within the past 4 weeks

- No other concurrent illness (such as active infection) that would require active
treatment or preclude study

- No psychiatric illness or social situation that would preclude study

- See Disease Characteristics

- No prior bevacizumab

- No other prior experimental angiogenesis inhibitors

- At least 2 weeks since prior trastuzumab and recovered

- Concurrent epoetin alfa or filgrastim (G-CSF) allowed

- See Disease Characteristics

- At least 2 weeks since prior chemotherapy and recovered

- No prior vinorelbine

- No more than 2 prior conventional chemotherapy regimens for metastatic breast cancer

- Prior hormonal therapy allowed

- At least 1 week since prior radiotherapy and recovered

- No concurrent radiotherapy

- At least 4 weeks since prior major surgical procedure or open biopsy

- At least 1 week since prior fine-needle aspiration except in the breast

- No concurrent major surgical procedure

- Recovered from the toxic effects of any prior therapy

- At least 10 days since prior oral or parenteral anticoagulants (e.g., heparin or
warfarin) except to maintain the patency of permanent, indwelling central venous
catheter

- At least 10 days since prior thrombolytic agents

- No chronic aspirin therapy greater than 325 mg per day or non-steroidal
anti-inflammatory medications that inhibit platelet function

- No concurrent COX-2 inhibitors that inhibit platelet function

- No other concurrent investigational or commercial agents or therapies for the
malignancy

- No concurrent antiretroviral therapy for HIV-positive patients

- No concurrent ketoconazole, zidovudine, or macrolide antibiotics

- No concurrent oral or parenteral anticoagulants except to maintain patency of
permanent, indwelling central venous catheter

- No concurrent thrombolytic agent

- Concurrent bisphosphonates allowed

- Concurrent celecoxib or rofecoxib allowed