An orally bioavailable androgen receptor (AR) antagonist with potential antineoplastic activity. Upon administration, SHR3680 competitively binds to AR in target tissues, which both prevents androgen-induced receptor activation and facilitates the formation of inactive complexes that cannot be translocated to the nucleus. This prevents binding to and transcription of AR-responsive genes, inhibits the expression of genes that regulate prostate cancer cell proliferation, and may lead to an inhibition of cell growth of AR-expressing tumor cells. ARs are overexpressed in prostate cancer and play a key role in prostate cancer cell proliferation.