Enzalutamide is an androgen receptor antagonist drug developed by the pharmaceutical company Medivation for the treatment of metastatic castration-resistant prostate cancer. Enzalutamide has approximately fivefold higher binding affinity for the androgen receptor (AR) compared to the antiandrogen bicalutamide. As opposed to bicalutamide, enzalutamide does not promote translocation of AR to the nucleus and in addition prevents binding of AR to DNA and AR to coactivator proteins. When LNCaP cells (a prostate cancer cell line) engineered to express elevated levels of AR (as found in patients with advanced prostate cancer) were treated with enzalutamide, the expression of androgen dependent genes PSA and TMPRSS2 was down regulated in contrast to bicalutamide where the expression was upregulated. In VCaP cells which over express androgen receptors, enzalutamide induced apoptosis whereas bicalutamide did not.