A PHASE II, RANDOMIZED, OPEN-LABEL, MULTICENTER STUDY EVALUATING THE EFFICACY AND SAFETY OF GDC-9545 COMPARED WITH PHYSICIAN'S CHOICE OF ENDOCRINE MONOTHERAPY IN PATIENTS WITH PREVIOUSLY TREATED ESTROGEN RECEPTOR-POSITIVE, HER2-NEGATIVE LOCALLY ADVANCED OR METASTATIC BREAST CANCER (WO42312, ACELERA)