GLL398

GLL398 is an Oral Selective Estrogen Receptor Downregulator. GLL398 strongly binds to ERα in a fluorescence resonance energy transfer binding assay (IC50 =1.14 nM) and potently degrades ERα in MCF-7 breast cancer cells (IC50 = 0.21 μM). Most importantly, the introduction of the boronic acid group confers superior oral bioavailability of GLL398 (AUC = 36.9 μg·h/mL) in rats as compared to GW7604 (AUC = 3.35 μg·h/mL). The strikingly favorable pharmacokinetic property of GLL398 makes it a promising oral SERD suitable for clinical evaluation.