An orally available antagonist of the glucocorticoid receptor (GR), with potential antineoplastic activity. Upon administration, relacorilant competitively binds to and blocks GRs. This inhibits the activity of GRs, and prevents both the translocation of the ligand-GR complexes to the nucleus and gene expression of GR-associated genes. This decreases the negative effects that result from excess levels of endogenous glucocorticoids, like those seen when tumors overproduce glucocorticoids. In addition, by binding to GRs and preventing their activity, inhibition with CORT125134 also inhibits the proliferation of GR-overexpressing cancer cells. GRs are overexpressed in certain tumor cell types and promote tumor cell proliferation.