 Eligible patients will have metastatic CRPC with no disease related symptoms and progression on ADT and will have progressed post-treatment with abiraterone. Patients will continue on ADT with LHRH agonist i.e. Zoladex, Trelstar, Eligard or Lupron or LHRH antagonist Degarelix if not surgically castrated throughout the duration of the study to inhibit endogenous testosterone production. Patients will be randomized 1:1 and stratified based on duration of prior abiraterone acetate therapy 6 months or less or greater than 6 months. Patients randomized to BAT Arm A will receive intramuscular injections with either testosterone cypionate or testosterone enanthate at a dose of 400 mg every 28 days. This dose was selected based on data demonstrating that it produces an initial supraphysiologic serum level of T i.e. 1500 ngdL or 3-10 times normal level with eugonadal levels achieved at the end of two weeks and near castrate levels after 28 days. Patients randomized to enzalutamide Arm B will receive daily oral dose of 160 mg. Each cycle is defined as 28 days. 