Safety and Efficacy Study of Enzalutamide Versus Bicalutamide in Men With Prostate Cancer

PFS was defined as time from randomization to earliest objective evidence of prostate specific-antigen (PSA) progression, radiographic progression, or death on study. PSA progression was defined as ≥ 25% increase in PSA with an absolute increase ≥ 2 ng/mL above the nadir and was to be confirmed by a second consecutive assessment. Radiographic progression in bone was based on The Prostate Cancer Clinical Trials Working Group (PCWG2) guidelines defined as at least 2 new lesions on bone scan. Radiographic progression in soft tissue on Computerized Tomography/Magnetic Resonance Imaging (CT/MRI) was based on Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1). CT/MRI and bone scans were read locally by the same radiologist (or nuclear medicine physician for interpretation of bone scans) whenever possible. Participants not known to have had a PFS event at the time of the analysis data cutoff were censored at the date of last assessment.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: Intent-to-treat population: all participants randomly assigned to study treatment.

Best overall soft tissue response is defined as partial response (PR) or complete response (CR) while on study treatment based on investigator assessment of target, nontarget, and new lesions using RECIST 1.1. Only participants in the metastatic population with measurable soft tissue disease (at least 1 target lesion identified per RECIST 1.1) at screening were included in the analysis. All percentages are based on number of participants with metastatic and measurable soft tissue disease at screening in each treatment group.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: All participants who were randomly assigned to study treatment and had metastatic and measurable soft tissue disease at screening.

Duration of radiographic PFS was defined as the time from randomization to the earliest objective evidence of radiographic disease progression or death on study and was to be evaluated for participants with metastatic disease at study entry. Radiographic disease progression in bone was based on PCWG2 guidelines defined as at least 2 new lesions on bone scan. Radiographic disease progression in soft tissue on CT/MRI was based on RECIST 1.1. CT/MRI and bone scans were read locally by the same radiologist (or nuclear medicine physician for interpretation of bone scans) whenever possible. Participants not known to have had radiographic progression at the time of analysis data cutoff were censored at the date of last radiographic assessment.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: All participants with metastatic disease at study entry and randomly assigned to study treatment.

PSA response was defined as a reduction in PSA of at least 50% from baseline at any post baseline assessment confirmed by a second PSA assessment at least 3 weeks later.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: Evaluable intent-to-treat population: all participants randomly assigned to study treatment and had a baseline and at least 1 post baseline PSA measurement.

An AE was any untoward medical occurrence in a participant who received study treatment without regard to possibility of causal relationship. An SAE was an AE resulting in any of following outcomes or deemed significant for any other reason: death, initial or prolonged inpatient hospitalization, life-threatening experience (immediate risk of dying), persistent or significant disability or incapacity, congenital anomaly. A treatment emergent AE defined as an event that emerged during treatment period (From first dose of study drug until end of open label phase \[up to maximum duration of 65 months\]) that was absent before treatment, or worsened during treatment period relative to pre-treatment state. AE included both serious and non- SAE. Treatment-related AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. An AE was considered related to study drug if event was assessed by investigator as probably or possibly related.

Time frame: From first dose of study drug until the end of open label phase (up to maximum duration of 65 months)

Population: Safety population included all participants who received at least 1 dose of study drug.

The FACT-P is a multidimensional, self-reported quality of life instrument consisting of 27 core items that assess patient function in 4 domains: physical, social/family, emotional, and functional well-being, and supplemented by 12 site-specific items to assess for prostate-related symptoms. Each item is rated on a 0 to 4 Likert-type scale, and then combined to produce subscale scores for each domain, as well as a global quality of life score (0 to 156) with higher scores representing better quality of life. Time to degradation of FACT-P was defined as the time from randomization to first assessment with at least a 10-point decrease from baseline in the global FACT-P score for each participant. Participants with no score degradation at the time of analysis data cutoff were censored at the date of last assessment showing no degradation.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: Intent-to-treat population: all participants randomly assigned to study treatment.

PSA progression was defined as ≥ 25% increase in PSA with an absolute increase ≥ 2 ng/mL above the nadir and was to be confirmed by a second consecutive assessment at least 3 weeks later. Participants not known to have had PSA progression were censored at the date of last PSA assessment.

Time frame: From randomization until the data cut-off date of 09 February 2015, median duration of treatment was 14.7 months in the enzalutamide arm and 8.4 months in the bicalutamide arm.

Population: Intent-to-treat population: all participants randomly assigned to study treatment.