ZD6474 (Zactima) and Metronomic Chemotherapy in Advanced Breast Cancer

The purpose of this research study is to determine the safety and tolerability of the combination of Zactima with metronomic chemotherapy. Zactima is an oral anti-angiogenesis drug, which means it fights cancer by cutting off a tumor's blood supply. Thus, the drug starves the tumor by preventing the delivery of nutrients and oxygen. Metronomic chemotherapy is low dose oral chemotherapy pills which are taken daily. Unlike traditional chemotherapy, metronomic chemotherapy is thought to fight cancer like Zactima, by cutting off the blood supply to tumors. Because the dose is very low, the side effects are generally mild and very different from those with higher dose chemotherapy given by vein.

* Each study cycle is 28 days long. Participants will take the study drug, Zactima, by mouth once a day. The dose of Zactima the participant will receive will be determined by the time when they enroll on the study. They will also take the metronomic chemotherapy by mouth. This consists of two drugs: cyclophosphamide and methotrexate. Cyclophosphamide is taken every day and methotrexate is taken on days 1 and 2 of each week. * A physical exam will be performed on Day 1 of each cycle. Vital signs, including height, weight, blood pressure, and temperature will be done on Day 1 of each cycle, as well as at week 3 of Cycles 1 and 2. * Electrocardiograms will be performed at various points to assess heart function. This will be done at week 1, 3, 5, 7, and 9, and then every 3 months for the rest of the study. * Routine blood tests will be done on Day 1 of each cycle, as well as at week 3 for the first two cycles. Urine tests will be done on Day 1 of each cycle. * An ultrasound will be done at Brigham and Women's Hospital in the Department of Vascular Medicine at week 3 and week 7. * Participants will have scans done to assess their tumor every 2 cycles (8 weeks). These may include a CT scan, MRI, PET scan, x-rays, and/or bone scans.