Palazestrant (OP-1250), a Complete Estrogen Receptor Antagonist, Inhibits Wild-Type and Mutant ER-Positive Breast Cancer Models as Monotherapy and in Combination

The authors described palazestrant (OP-1250), a novel, orally bioavailable complete estrogen receptor (ER) antagonist and selective ER degrader. OP-1250, like fulvestrant, had no agonist activity on the ER and completely blocked estrogen-induced transcriptional activity.