A SERD (IC50 = 0.138 nM for ERα downregulation); selective for ERα compared to other nuclear hormone receptors (IC50s = 0.0008, 0.54, 0.92, and 30 μM for ERα, PR, GR, and AR, respectively); decreases ERα activity (IC50 = 0.282 nM for PR antagonism); reduces proliferation of MCF-7 breast cancer cells (IC50 = 0.0398 nM); inhibits MCF-7 xenograft growth in mice in a dose-dependent manner,