Definition

An orally bioavailable selective estrogen receptor degrader/downregulator (SERD), with potential antineoplastic activity. Upon oral administration, bexirestrant specifically targets and binds to both wild-type and mutant forms of the estrogen receptor (ER; ERalpha), including the somatic mutations Y537S and D538G. This induces a conformational change that results in ER degradation. This prevents ER-mediated signaling and inhibits both the growth and survival of ER-expressing cancer cells. Somatic mutations in the ER gene ESR1, especially Y537S and D538G, have been associated with acquired antiestrogen drug resistance.