A Randomized Phase IIa Efficacy and Safety Study of Radium-223 Dichloride With Abiraterone Acetate or Enzalutamide in Metastatic Castration-resistant Prostate Cancer (CRPC)

Radium-223 dichloride (Xofigo, BAY88-8223) 50 kBq/kg (55 kBq/kg after implementation of NIST \[National Institute of Standards and Technology\] update) every 4 weeks x 6 doses intravenous slow bolus

Abiraterone acetate 1000 mg (4 x 250 mg tablets) taken orally once daily for up to two years following last dose of radium-223 dichloride

Prednisone 5 mg capsule taken orally twice daily for up to two years following last dose of radium-223 dichloride

Enzalutamide 160 mg (four 40 mg capsules) taken orally once daily for up to two years following last dose of radium-223 dichloride