The purpose of the first study part is to investigate the safety and tolerability of ASP9521 in patients with Castrate Resistant Prostate Cancer. This will be done at different doses, starting at the lowest dose up to higher doses to find the maximum dose that is tolerated.~The second part will investigate the safety and tolerability and evaluate initial anti-tumor activity of ASP9521. This will be done at multiple doses which are identified in part 1 to potentially be effective. The number of patients in part 2 will be higher number compared to part I.~The third part of the study will investigate the effect of food on the drug in patients; this will be a crossover design fed to fasted and vice versa.
The study has three parts. Part 1 is a dose escalation to investigate the safety and tolerability of ASP9521. Part 2 will evaluate the safety and tolerability and initial anti-tumor activity of ASP9521. Part 3 of the study will be a Food Effect study.