Biomarker Analysis of Castration-resistant Prostate Cancer Undergoing Treatment With Docetaxel Followed by Enzalutamide

This study is a prospective biomarker study of patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing sequential treatment with docetaxel followed by enzalutamide. In this study, all participants will receive standard of care treatment with docetaxel 75 mg/m2 every 3 weeks up to 10 cycles and after progression, patients will receive enzalutamide 160 mg daily until limiting toxicity or disease progression. The participants will undergo serial pre- and post-therapy blood collection for biomarker analysis as part of the primary objective of the study.