 - Progression of disease after one prior chemotherapy regimen which must have been taxane-based for CRPC. Progression is defined as at least one of the following: A minimum of three consecutive serum PSA measurements obtained 14 days apart and all within 3 months, with progressively increasing values for two consecutive measurements. The latest value must be obtained within the screening period and must be 5 ngmL; or progression of measurable disease, as defined by RECIST; or progression of bone disease, as defined by the appearance of one or more new bone lesions 