 The purpose of this study is to evaluate whether the combination of fulvestrant and ZACTIMA, versus fulvestrant plus placebo, results in a significant decrease in the bone marker, urinary N-Telopeptide NTx in postmenopausal women with bone only, or bone predominant, hormone receptor-positive metastatic breast cancer. A significant decrease will be defined as a 30 reduction in urinary NTx level from baseline. 