XL-184+Abiraterone in Post-Chemo CRPC

This research study is a Phase I clinical trial. Phase I clinical trials test the safety of an investigational drug. Phase I studies also try to define the appropriate dose of the investigational drug to use for further studies. "Investigational" means that the drug is still being studied and that research doctors are trying to find out more about it. It also means that the FDA (U.S. Food and Drug Administration) may not have approved this drug for use in participants, including people with your type of cancer. In this research study, we are testing the safety of XL184 at different dose levels. XL184 is a new study drug, which is taken by mouth. Laboratory studies have shown that XL184 may prevent tumor growth by stopping the formation of blood vessels inside the tumor and also shrink tumors. This drug has been used in early-stage studies and is also currently being studied in other trials. Information from those other research studies suggests that XL184 may help to slow or stop tumor growth including prostate cancer. We will also be taking blood and urine tests to look at how your body processes the drug.