...● Age >= 18 years● Locally advanced or metastatic adenocarcinoma of the breast, not amenable to treatment with curative intent● Documented estrogen receptor-positive (ER+) tumor according to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) or European Society for Medical Oncology (ESMO) guidelines, assessed locally and defined as >= 1% of tumor cells stained positive based on the most recent tumor biopsy (or archived tumor sample)● Documented human epidermal growth factor receptor 2 (HER2)-negative tumor assessed locally● Availability of blood sample for circulating-tumor deoxyribonucleic acid (ctDNA) ESR1 mutation status determination by central testing prior to study treatment randomization● Patients who have bilateral breast cancers that are both ER+ and HER2-negative are eligible. ...

...- Documented ER-positive tumor and HER2-negative tumor, assessed locally...

...Documented estrogen receptor-positive (ER+) tumor and HER2-negative tumor, assessed locally 3....

...- Documented ER-positive tumor and HER2-negative tumor, assessed locally...

...- ER-positive tumor and HER2-negative breast cancer as per local laboratory testing...

...- Documented estrogen receptor (ER)-positive tumor in accordance to American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines (Allison et al.2020), assessed locally and defined as ≥1% of tumor cells stained positive on the basis of the most recent tumor biopsy...

...•Age >= 18 years of age•For women: postmenopausal or premenopausal/perimenopausal status:o Age >= 60 yearso Age = 12 months of amenorrhea without an alternative medical cause plus follicle-stimulating hormone and plasma estradiol levels within postmenopausal range by local laboratory assessment, in the absence of oral contraceptive pills, hormone replacement therapy, or gonadotropin releasing hormone agonist or antagonisto Documented bilateral oophorectomyo Premenopausal/perimenopausal willing to undergo and maintain treatment with approved LHRH-agonist therapy•For men: willing to undergo and maintain treatment with approved LHRH-agonist therapy•Locally advanced or metastatic adenocarcinoma of the breast, not amenable to treatment with curative intent•Disease progression after treatment with one or two lines of systemic therapy in the locally advanced or metastatic setting•Documented ER-positive tumor according to American Society of Clinical Oncology/College of American Pathologists guidelines•Documented HER2-negative tumor assessed locally•Confirmed availability of the most recently collected and representative tumor tissue specimen suitable for biomarker testing with de-identified associated pathology report is required. ...

...- Documented estrogen receptor (ER)-positive and HER2-negative breast tumor, as assessed locally on a primary disease specimen...

...- Documented estrogen receptor-positive (ER+), HER2-negative (HER2-) tumor assessed locally on the most recent tumor biopsy (or archived tumor sample)...

...- Estrogen receptor (ER)-positive tumor...

...- Documented estrogen receptor (ER)-positive tumor in accordance to ASCO/CAP guidelines (Allison et al....

The average ESR1 MAF decline on tx with GIR was greater in pts with a PR (–97%) vs PD (–54%, p = 0.025)...Data show that cTF and ESR1m ctDNA dynamics were associated with clinical response to GIR in ER+, HER2– aBC.

112 patients were evaluable for objective response rate in the giredestrant plus palbociclib group, and 108 were evaluable in the anastrozole plus palbociclib group. Objective response rates were similar between the two groups (56 [50·0%] of 112 [95% CI 40·4–59·6] with giredestrant plus palbociclib vs 53 [49·1%] of 108 [39·3–58·9] with anastrozole plus palbociclib...Giredestrant offers encouraging anti-proliferative and anti-tumour activity and was well tolerated, both as a single agent and in combination with palbociclib.