DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed adenocarcinoma of the breast

  • Stage IV disease
• Measurable disease, defined as ≥ 1 unidimensionally measurable lesion > 20 mm by conventional techniques or > 10 mm by spiral CT scan

• No known brain metastases

  • Patients with neurological symptoms must undergo a CT scan/MRI of the brain to exclude brain metastasis
• Hormone receptor status not specified

PATIENT CHARACTERISTICS:

• Menopausal status not specified
• ECOG performance status 0-2
• Life expectancy > 6 months
• Hemoglobin ≥ 9.0 g/dL
• ANC ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Total bilirubin ≤ 1.5 times upper limit of normal (ULN)
• ALT and AST ≤ 2.5 times ULN (≤ 5 times ULN if liver involvement)
• Creatinine ≤ 1.5 times ULN
• INR < 1.5 OR PT/PTT normal
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 12 weeks after completion of study treatment
• No HIV positivity
• No chronic hepatitis B or C infection

• No concurrent uncontrolled illness including, but not limited to, any of the following:

  • Ongoing or active infection > CTCAE grade 2
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Myocardial infarction within the past 6 months
  • Cardiac ventricular arrhythmias requiring antiarrhythmic therapy
  • Psychiatric illness/social situation that would limit compliance with study requirements
• No uncontrolled hypertension, defined as systolic blood pressure (BP) > 150 mm Hg or diastolic BP > 90 mm Hg despite optimal medical management
• No thrombolic or embolic events (e.g., cerebrovascular accident, including transient ischemic attacks) within the past 6 months
• No pulmonary hemorrhage/bleeding event ≥ CTCAE grade 2 within the past 4 weeks
• No other hemorrhage/bleeding event ≥ CTCAE grade 3 within the past 4 weeks
• No serious non-healing wound, ulcer, or bone fracture
• No evidence or history of bleeding diathesis or coagulopathy
• No condition that impairs the ability to swallow whole pills
• No malabsorption problems
• No known or suspected allergy to sorafenib tosylate or any other agent given in the study
• No significant traumatic injury within the past 4 weeks

PRIOR CONCURRENT THERAPY:

• Prior adjuvant therapy for metastatic disease allowed
• No more than 2 lines of prior chemotherapy for metastatic disease (including trastuzumab [Herceptin®]-containing regimens for patients with HER2+ tumors)
• Prior hormonal therapy allowed
• Prior bevacizumab administered within the past 4 weeks allowed
• More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C) and recovered
• More than 4 weeks since prior radiotherapy and recovered
• More than 4 weeks since prior major surgery or open biopsy
• No prior sunitinib malate
• No concurrent St. John's wort or rifampin
• No other concurrent investigational agents
• Concurrent anticoagulation therapy (e.g., warfarin or heparin) allowed