Prostate Cancer Biomarker Enrichment and Treatment Selection Wednesday, December 20, 2017 IND.234 - Prostate Cancer Biomarker Enrichment and Treatment Selection (PC_BETS) Study - Master Screening Protocol has been centrally activated with participation limited to invited centres. Eligibility: Patients (>=18 years old, ECOG PS 0-1) must have histologically confirmed mCRPC with no evidence of small cell/neuroendocrine differentiation. Patients must consent to undergo genomic screening. Clinically/radiologically documented disease (measurable or non-measurable). Evidence of biochemical and/or radiological disease progression in the setting of surgical or medical castration. Patients must have received prior hormonal treatment with at least one of abiraterone acetate, enzalutamide, ARN-509 TAK-700 and TOK-001. Prior anti-androgen therapy must have been discontinued >=28 days (>=42 days for bicalutamide) prior to registration. Maximum of one prior regimen of cytotoxic chemotherapy permitted. Prior immunotherapy, vaccines and oncolytic viruses permitted. Prior/concurrent CDK or mTOR inhibitors, strontium-89, systemic corticosteriods equivalent to prednisone >10 mg daily not allowed. Objectives: Primary Objective - To centrally genotype cfDNA from patients with mCRPC progressing after a "next-generation" AR-pathway inhibitor in order to facilitate accrual to targeted therapy trials and then to assess the clinical benefit rate (CBR), of each Study Drug. Secondary Objectives - To determine the effect of each Study Drug on PSA decline and time to PSA progression. To determine objective response as determined by RECIST 1.1 criteria. To evaluate the safety and toxicity profile of each Study Drug in mCRPC patients. Tertiary Objectives - To obtain cfDNA and non-malignant DNA from peripheral blood clinically annotated with patient disease characteristics and follow-up data to identify potential predictive and prognostic factors and relationship between cfDNA results with clinical presentation. For more information please contact the study coordinator: Scott Wilkes