RIPTACs were optimized for oral bioavailability, and tumor ternary complex formation in prostate cancer cell line-derived xenograft models. RIPTAC therapeutics display nanomolar in vitro potency in AR:RIPTAC:EP ternary complex formation, which results in abrogation of the EP function and antiproliferative activity in prostate cancer cell lines, but not in AR-knockout control cells. Taken together, our in vitro mechanistic data and in vivo PD/efficacy observations in multiple prostate cancer models support further investigation of prostate cancer RIPTAC therapeutics as a novel heterobifunctional therapeutic modality in mCRPC.