Definition

An orally available, small molecule antagonist of estrogen receptor alpha (ERalpha; ERa; ESR1; nuclear receptor subfamily 3, group A, member 1; NR3A1) and a selective ER degrader (SERD), with potential antineoplastic activity. Upon oral administration, palazestrant competes with the endogenous activating estrogenic ligand 17-beta estradiol for binding in the ligand binding pocket of ERalpha, thereby inhibiting the activity of ERalpha. Palazestrant blocks estrogen-driven transcriptional activity and induces degradation of ERalpha. This inhibits the growth and survival of ERalpha-expressing cancer cells. ERalpha, a nuclear hormone receptor, is often overexpressed and/or mutated in a variety of cancer cell types. It plays a key role in tumor cell proliferation and survival.