This study will be conducted in three parts. Part A is a dose-escalation study to determine two safe and tolerable doses of ASN001 for men with metastatic castration resistant prostate cancer. Part A will also characterize the pharmacokinetics and pharmacodynamics of the ASN001 through blood sampling. Subjects in Part B will receive one of two doses identified in Part A to determine which one is more effective, and collect additional pharmacokinetic data. Part C is an extension for subjects completing either Part A or B.