A Study of YM155 Plus Docetaxel as First-Line Treatment in Subjects With HER2 Negative Metastatic Breast Cancer

This is an outpatient study. All subjects enrolled in this study will receive a combined regimen of YM155 and docetaxel or docetaxel alone given during 21 day cycles. Each subject will be assessed at the end of each cycle to determine if the subject can continue to the next cycle. Each subject assigned to receive YM155 in combination with docetaxel will be eligible to continue receiving the combination regimen in this study until one of the discontinuation criteria is met. If a subject discontinues treatment with at least stable disease (SD) that subject will complete follow-up visits every 12 weeks for 2 years or until initiating another systemic anti-breast cancer treatment, exhibiting progressive disease (PD), or death. Each subject will be contacted by the study site every 12 weeks for survival following the End of Treatment Visit. The contacts will continue until death or for no more than 2 years.