An Asian Study to Evaluate Efficacy and Safety of Oral Enzalutamide in Progressive Metastatic Prostate Cancer Participants

The time to Prostate Specific Antigen (PSA) progression was defined as the time from randomization to the PSA progression. The PSA progression was defined according to the consensus guidelines of Prostate Cancer Clinical Trials Working Group 2 (PCWG2).For participants with PSA decline at Week 13, the PSA progression date was defined as a ≥ 25% increase and an absolute increase of ≥ 2 ng/mL above the nadir, which would be confirmed by a second consecutive value obtained 3 or more weeks later. For participants with no PSA decline at Week 13, the PSA progression date was defined as the date when a ≥ 25% increase and an absolute increase of ≥ 2 ng/mL above the baseline was documented, which was confirmed by a second consecutive value 3 or more weeks later. Time to PSA progression was estimated using the Kaplan-Meier method. Participants without confirmed PSA progression were censored.

Duration of overall survival was defined as the time from the randomization to deaths from any cause. For participants who were alive at the time of the data analysis, overall survival time was censored to the last know date the participants were known to be alive.

Duration of Radiographic Progression-free Survival (rPFS) was defined as the time from randomization to the rPFS event (deaths from any cause and radiographic disease progression). Radiographic disease progression is defined by RECIST 1.1 for soft tissue disease, or PCWG2 for bone lesions. If a participant met the criteria for more than 1 censoring rule, they were censored with the earliest censoring date. The radiographic progression date was the first date when progression definition was met, not confirmed.

Time to first skeletal-related event (SRE) was defined as the time from randomization to the first skeletal-related event, defined as radiation therapy or surgery to bone, pathologic bone fracture, spinal cord compression, or change of anti-neoplastic therapy to treat bone pain. Participants who have not had a SRE at the time of the analysis were censored at their last assessment indicating no evidence of SRE.

Time to initiation of cytotoxic chemotherapy was defined as the time from randomization to initiation of cytotoxic chemotherapy. It included only therapies for prostate cancer. When multiple cytotoxic chemotherapies were initiated, the first chemotherapy was used to determine the time to event. Participants who did not start cytotoxic chemotherapy at the time of analysis data cutoff were censored at the date of their last assessment indicating no evidence of cytotoxic chemotherapy usage.

Best PSA response was defined as as ≥50% reductions in PSA level from baseline to the lowest post-baseline PSA result as determined by the central laboratory, with a consecutive assessment conducted at least 3 weeks later to confirm the PSA response. Only participants who had both baseline and post-baseline assessments were included in the analysis.

Participants with measurable soft tissue disease at screening visit (i.e., at least one target lesion per Response Evaluation Criteria in Solid Tumors, version 1.1 (RECIST 1.1) who have an objective response (complete response (CR) or partial response (PR)) during the study were included in the best overall soft tissue response assessment. The best overall soft tissue response was based on the investigator assessment using RECIST 1.1. CR was defined as complete resolution of all attributable clinical symptoms and physical findings. PR was defined as partial resolution of at Least some of the clinical symptoms and physical findings.

N is the number of participants with available data at this time point.

N is the number of participants with available data at this time point.

An AE was defined as any untoward medical occurrence, temporally associated with use of medicinal product, whether considered related to medicinal product. AE could therefore be any unfavorable & unintended sign, symptom, or disease temporally associated with use of a medicinal product. An AE was considered serious if, results in death; is life-threatening; results in persistent disability; results in congenital anomaly; requires inpatient hospitalization; or leads to prolongation of hospitalization; other medically important events. TEAE was defined as AE occurring from time of study drug administration on Day 1 until follow-up visit (28 days after last dose, or one day before date of initiation of cytotoxic chemotherapy or an investigational agent, whichever comes first). AEs were graded using National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03, where Grade 1 = Mild; Grade 2 = Moderate; Grade 3 = Severe; Grade 4 = Life-threatening; Grade 5 = Fatal.