DISEASE CHARACTERISTICS:

• Patients must meet 1 of the following criteria:

  • Treatment-naïve with newly diagnosed Her2/neu non-overexpressing (non amplified) metastatic (stage IV) breast cancer
  • HER2/neu-negative breast cancer with metastasis diagnosed 6 or more months after completing primary systemic treatment (i.e., neoadjuvant or adjuvant chemotherapy)
• Measurable disease as defined by RECIST criteria OR evaluable disease
• No CNS or brain metastases

PATIENT CHARACTERISTICS:

• Inclusion Criteria

  • Pre- or postmenopausal
  • ECOG performance status 0-1
  • Life expectancy > 3 months
  • Female or male patients must be surgically sterilized or willing to use an acceptable method of birth control for the duration of the study
  • Neutrophils ≥ 1.5 x 10^9/L
  • Platelets ≥ 100 x 10^9/L
  • Hemoglobin ≥ 9.0 g/dL
  • Serum creatinine ≤ 1.5 mg/dL
  • Bilirubin ≤ upper limit of normal (ULN), except when caused by metastatic disease
  • ALT/AST ≤ 2.5 times ULN, except when caused by metastatic disease
  • Urine protein:creatinine (UPC) ratio < 1.0 at screening

• Exclusion Criteria

  • Pregnant (positive pregnancy test) or lactating
  • History of gastrointestinal bleeding within the past 3 months
  • Inadequately controlled hypertension (i.e., systolic BP > 150 mm Hg and/or diastolic BP > 100 mm Hg while on antihypertensive medications)
  • Prior history of hypertensive crisis or hypertensive encephalopathy
  • Peripheral neuropathy > grade 1
  • Clinical AIDS or known positive HIV serology
  • No concurrent clinically evident malignancy except for inactive nonmelanoma skin cancer, inactive cervical cancer, or other cancer for which the patient has been disease-free for 5 years
  • Unstable angina
  • New York Heart Association class II-IV congestive heart failure
  • History of myocardial infarction within the past 6 months
  • History of stroke within the past 6 months
  • Clinically significant peripheral vascular disease
  • Evidence of bleeding diathesis or coagulopathy
  • History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 6 months
  • Serious nonhealing wound, ulcer, or bone fracture
  • Serious medical or psychiatric illness that would render chemotherapy unsafe
  • Significant traumatic injury within the past 28 days

PRIOR CONCURRENT THERAPY:

• Exclusion Criteria

  • Previous chemotherapy for metastatic breast cancer
  • Previous treatment with gemcitabine hydrochloride
  • Chemotherapy within 4 weeks prior to study enrollment
  • Radiation therapy or evidence of acute effects of radiation therapy within 2 weeks prior to study enrollment
  • Any major surgery or open biopsy within 4 weeks prior to study enrollment
  • Minor surgical procedures (i.e., fine needle aspirations or core biopsies) within 7 days prior to study enrollment
  • Participation in another experimental drug study (other than a bevacizumab clinical trial for cancer) within 4 weeks prior to study enrollment
  • Anticipation of need for major surgical procedure during the course of the study
  • Concurrent irradiation
  • Other concurrent chemotherapy, immunotherapy, or anti-tumor hormonal therapy