Inclusion Criteria:

• Histologically or cytologically confirmed metastatic breast adenocarcinoma
• No HER2 overexpression or gene amplification
• Absent or low ER or PR expression
• No previous therapy for metastatic breast cancer is allowed
• Age 18-75 years
• Measurable disease as defined by the presence of at least one measurable lesion (except bone metastases, ascites or pleural effusions)
• Performance status (WHO) 0-2
• Adequate liver (serum bilirubin <1.5 times the upper normal limit, AST and ALT <2.5 times the upper normal limit in the absence of demonstrable liver metastases, or <5 times the upper normal limit in the presence of liver metastases)
• adequate renal function (serum creatinine <1.5 times the upper normal limit)
• bone marrow (neutrophils ≥ 1.5x 109 /L, and platelets ≥ 100x 109 /L)
• No radiation of measurable disease (except brain metastases)
• No progressive brain metastases according to clinical or radiological criteria
• No brain metastases without prior radiation therapy
• Written informed consent

Exclusion Criteria:

• Active infection
• History of significant cardiac disease (unstable angina, congestive heart failure, myocardial infarction within the previous 6 months, ventricular arrhythmias)
• History of stroke
• Anticoagulation therapy (except of low dose aspirin <325mg)
• Other invasive malignancy except nonmelanoma skin cancer
• Psychiatric illness or social situation that would preclude study compliance
• Pregnant or lactating women