Patients are randomized to one of two treatment groups: enzalutamide or enzalutamide, abiraterone and prednisone. Treatment will continue until disease progression or unacceptable toxicity. Patients are followed for clinical outcomes for a maximum of 5 years post study treatment. The primary and secondary objectives are described below.
To compare the overall survival of patients with progressive metastatic castration-resistant prostate cancer (CRPC) treated with either enzalutamide only or enzalutamide with abiraterone (abiraterone acetate) and prednisone
- To assess the grade 3 or higher toxicity profile and compare safety by treatment arm.
- To assess and compare post-treatment prostate-specific antigen (PSA) declines by treatment arm.
- To compare radiographic progression free survival defined by Prostate Cancer Working Group 2 (PCWG2), and objective response rate, by treatment arm.
- To test for radiographic progression free survival (rPFS) treatment interaction in predicting overall survival.
- To assess pre- and post-treatment measures of tumor burden and bone activity using sodium fluoride (NaF) positron emission tomography (PET)/computed tomography (CT) and technetium (Tc) methylene diphosphonate (MDP) bone scintigraphy and correlate these measures with overall survival.
- To develop and validate prognostic and predictive models of overall survival that include baseline clinical and molecular markers.