MKI67 and breast cancer: Interim results from the first 46 patients in a WOO study of giredestrant (10 mg, 30 mg [the dose being studied in Phase 3 clinical trials], or 100 mg once daily for 14 days) administered to postmenopausal women with newly diagnosed ER+/HER2− breast cancer showed that, overall, giredestrant reduced tumor Ki67 expression by 79% [14], with no relationship between dose and effect size.