Fractionated Docetaxel and Radium 223 in Metastatic Castration-Resistant Prostate Cancer

The objective of this study is to determine the maximum safe dose of Ra-223 in combination with fractionated (split doses) docetaxel when given to subjects and to determine the best administering dose. The study will look at side effects that may happen while taking the combination treatment. A total of approximately 18 subjects will take part in the dose escalation part of the study and an additional 25 subjects will participate in the expansion cohort. This study will be conducted across four centers in the United States.