Safety and Efficacy Study of Ipilimumab 3 mg/kg Versus Ipilimumab 10 mg/kg in Subjects With Metastatic Castration Resistant Prostate Cancer Who Are Chemotherapy Naive

rPFS was defined as the time from the date of randomization until the date of disease progression based on radiographic evidence and/or death from any cause, whichever occurs first. Radiographic disease progression is defined as: Confirmed bone disease progression according to criteria adapted from the Prostate Cancer Clinical Trials Working Group 2 (PCWG2), OR Non-bone disease progression according to the modified Response Evaluation Criteria In Solid Tumors (RECIST) 1.1. After termination of the study, collection of tumor assessments and other data to support the efficacy analyses was no longer required in patients who discontinued study treatment. As a result, the presented efficacy results are based on limited data. The number of participants with reported radiographic progression is shown.

The total number of participants with immune-related adverse events of any grade is reported for each arm.

OS was defined as the time from the date of randomization until the date of death. For those participants who have not died, OS was censored at the last date the participant was known to be alive. After termination of the study, collection of tumor assessments and other data to support the efficacy analyses was no longer required in patients who discontinued study treatment. As a result, the presented efficacy results are based on limited data. The total number of reported deaths is shown.

Prostate specific antigen progression-free survival (PSA PFS) was defined as the time from randomization to the earliest date of PSA progression or death, whichever occurs earlier. Participants who did not progress or die were censored at the last PSA assessment date. After termination of the study, collection of tumor assessments and other data to support the efficacy analyses was no longer required in patients who discontinued study treatment. As a result, the presented efficacy results are based on limited data. The number of participants with reported PSA progression is shown.

Pain progression was defined as an increase in BPI-SF pain Item #3 score of >= 2 point from baseline maintained over 2 consecutive periods. After termination of the study, collection of tumor assessments and other data to support the efficacy analyses was no longer required in patients who discontinued study treatment, and presented efficacy results are based on limited data. The number of participants with reported pain progression is shown.

PSA response rate was defined as the proportion of participants with a 50% or greater decrease from baseline to the lowest post-baseline PSA result (confirmed 3 weeks later) for each randomized arm. After termination of the study, collection of tumor assessments and other data to support the efficacy analyses was no longer required in patients who discontinued study treatment. As a result, the presented efficacy results are based on limited data. The number of participants showing PSA response is shown.