Trial Outcomes & Findings for A Study of Enzalutamide Re-treatment in Metastatic Castration-resistant Prostate Cancer After Docetaxel and/or Cabazitaxel Treatment (NCT NCT02441517)

Male participants from the United States were enrolled in this study.

Metastatic castration-resistant prostate cancer (mCRPC) patients who were previously treated with enzalutamide (for a minimum of 8 months), followed by docetaxel and/or cabazitaxel chemotherapy (for a minimum of 4 cycles) were enrolled in this study.

A Study of Enzalutamide Re-treatment in Metastatic Castration-resistant Prostate Cancer After Docetaxel and/or Cabazitaxel Treatment

Radiographic PFS (rPFS) was defined as the time from first dose to the radiographic disease progression (PD), or death on study, whichever occurred first. Radiological PD was defined by either soft tissue tumor progression defined by Response Evaluation Criteria In Solid Tumors (RECIST) 1.1, or bone progression defined by the Prostate Cancer Clinical Trials Working Group 2 (PCWG2). Bone progression per PCWG2 was defined as a minimum of two new lesions. Progression on bone scans at time points before or at week 9 required a confirmatory scan performed six or more weeks later, where it should have demonstrated at least 2 additional new lesions (PCWG2) compared to the week 9 scan. rPFS was analyzed using Kaplan-Meier methodology to account for censored outcomes (i.e., no observation of rPFS event within the study follow-up period).

Overall survival (OS) was defined as the date of death due to any cause minus the date of first dose + 1.

The time to PSA progression was defined as the PSA progression date minus the date of first dose + 1. PSA progression was defined as a ≥ 25% increase and an absolute increase of ≥ 2 ng/mL above the nadir (lowest PSA value observed postbaseline or the baseline value for participants who did not have a decline in PSA postbaseline values) in PSA levels, and which was confirmed by a second consecutive value obtained at least 3 or more weeks later (i.e., a confirmed rising trend) (PCWG2 criteria). The date of PSA progression was the first date the PSA progression was observed. Time to PSA progression was estimated via Kaplan-Meier methodology with censoring defined by the time of the last available PSA measure.

PSA response was defined for the three following categories: PSA30 response: a maximum decline of ≥ 30% from baseline at any post baseline time point; PSA50 response: a maximum decline of ≥ 50% from baseline at any post baseline time point; PSA90 response: a maximum decline of ≥ 90% from baseline at any post baseline time point.

Objective response was defined as the best overall response of complete response (CR) or partial response (PR) per RECIST 1.1. CR was defined as disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to \< 10 mm. PR was defined as at least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.

Time to start of other antineoplastic therapy was defined as the date of the first systemic antineoplastic therapy minus the date of the first dose of study drug + 1.

Safety was assessed by adverse events (AEs), which included abnormalities identified during a medical test (e.g. laboratory tests, vital signs, electrocardiogram, etc.) if the abnormality induced clinical signs or symptoms, needed active intervention, interruption or discontinuation of study medication or was clinically significant. A serious AE (SAE) was an event resulting in death, persistent or significant disability/incapacity or congenital anomaly or birth defect, was life-threatening, required or prolonged hospitalization or was considered medically important. Disease progression was not to be reported as an AE, and clinical signs and symptoms due to disease progression were collected as AEs.