Radium-223 Dichloride and Abiraterone Acetate Compared to Placebo and Abiraterone Acetate for Men With Cancer of the Prostate When Medical or Surgical Castration Does Not Work and When the Cancer Has Spread to the Bone, Has Not Been Treated With Chemotherapy and is Causing no or Only Mild Symptoms

This study is a phase III multinational, multicenter,randomized, double blind, placebo controlled, study with a randomization allocation ratio of 1:1 (radium-223 dichloride plus abiraterone acetate plus prednisone/prednisolone: placebo plus abiraterone acetate plus prednisone/prednisolone). Until the final overall survival (OS) analysis, the study period consisted of screening / randomization, treatment, active follow-up with clinic visits, active follow-up without clinic visits, and longterm follow-up phases. Up until this point, subjects received study treatment (radium-223 dichloride or placebo in addition to abiraterone acetate plus prednisone / prednisolone for the first 6 cycles followed by abiraterone acetate plus prednisone / prednisolone thereafter) until an on-study SSE occurred (or other withdrawal criteria were met). After the final OS analysis (after implementation of Amendment 7), in order to reduce the burden to study subjects, evaluation of efficacy and exploratory endpoints will be discontinued, except for symptomatic skeletal event (SSE) and OS. Subjects who are discontinued from study treatment will initiate the long-term follow-up period; therefore, active follow-up periods will no longer be applicable. Subjects who are in active follow-up at the time of Amendment 7 is implemented should have the end of active follow-up completed (protocol driven decision) and should be directly transitioned into the extended safety follow-up study. Long term follow-up will continue until the subject dies, is lost to follow-up, withdraws informed consent, actively objects to collection of further data , or is transitioned to the extended safety follow-up study. Subjects will be followed for safety for up to 7 years, which eventually will be completed in this study or in the extended safety follow-up study.