i. Prior progression despite therapy with either abiraterone acetate and/or enzalutamide ii. At least one of the following: 1) Liver metastases; 2) Bulky radiographic progression (≥2 cm short axis lymph nodes or ≥1 cm long axis visceral metastases) combined with low serum PSA (<10ng/mL); 3) High serum LDH (>1X upper limit of normal).