An orally bioavailable, small molecule inhibitor of the N-terminal domain (NTD) of the androgen receptor (AR), with potential antineoplastic activity. Upon oral administration, AR inhibitor EPI-506 specifically binds to the NTD of AR, thereby inhibiting both AR activation and the AR-mediated signaling pathway. This inhibits cell growth in AR-overexpressing tumor cells. AR is overexpressed in prostate cancers and is involved in proliferation, survival and chemoresistance of tumor cells.