This is a randomized, multicenter, open-label, two-arm, Phase II study to evaluate the efficacy, safety, and pharmacokinetics of giredestrant versus anastrozole (in the window-of-opportunity phase) and giredestrant plus palbociclib compared with anastrozole plus palbociclib (in the neoadjuvant phase) in postmenopausal women with untreated, estrogen receptor (ER)-positive, human epidermal growth factor receptor-2 (HER2)-negative, early breast cancer.
The study consists of a screening period of up to 28 days, a window-of-opportunity phase for 14 days, followed by a neoadjuvant treatment phase for 16 weeks (four 28-day cycles), surgery, and an end of study visit (28 days after the final dose of study treatment).