A Study Evaluating the Efficacy and Safety of Adjuvant Giredestrant Compared With Physician's Choice of Adjuvant Endocrine Monotherapy in Participants With Estrogen Receptor-Positive, HER2-Negative Early Breast Cancer (lidERA Breast Cancer)

Exclusion Criteria

• •Pregnant or breastfeeding, or intending to become pregnant during the study or within 10 days after the final dose of giredestrant, or within the time period specified per local prescribing guidelines after the final dose of the endocrine therapy of physician's choice
• •Received treatment with investigational therapy within 28 days prior to initiation of study treatment or is currently enrolled in any other type of medical research judged by the sponsor not to be scientifically or medically compatible with this study
• •Receiving or planning to receive a CDK4/6 inhibitor as (neo)adjuvant therapy. A short course of up to 12 weeks of neoadjuvant or adjuvant treatment with CDK4/6 inhibitor therapy prior to randomization is allowed.
• •Active cardiac disease or history of cardiac dysfunction
• •Diagnosed with Stage IV breast cancer
• •A history of any prior (ipsilateral and/or contralateral) invasive breast cancer or ductal carcinoma in situ (DCIS). Participants with a history of contralateral DCIS treated by only local regional therapy at any time may be eligible.
• •A history of any other malignancy within 3 years prior to screening, except for appropriately treated carcinoma in situ of the cervix, nonmelanoma skin carcinoma, or Stage I uterine cancer
• •Any prior endocrine treatment with selective ER modulators (e.g., tamoxifen), degraders, or aromatase inhibitors. A short course of neoadjuvant or adjuvant endocrine therapy (up to 12 weeks) is allowed.
• •Clinically significant liver disease consistent with Child-Pugh Class B or C, including active hepatitis (e.g., hepatitis B virus \[HBV\] or hepatitis C virus \[HCV\]), current alcohol abuse, cirrhosis, or positive test for viral hepatitis
• •Treatment with strong CYP3A4 inhibitors or inducers within 14 days or 5 drug elimination half-lives (whichever is longer) prior to initiation of study treatment
• •Known allergy or hypersensitivity to any of the study drugs or any of their excipients
• •Pre- and perimenopausal participants or male participants who have a known hypersensitivity to LHRH agonists
• •A documented history of hemorrhagic diathesis, coagulopathy, or thromboembolism
• •Renal dysfunction that requires dialysis
• •A major surgical procedure unrelated to breast cancer within 28 days prior to randomization
• •A serious infection requiring oral or IV antibiotics within 14 days prior to screening or other clinically significant infection (e.g., COVID-19) within 14 days prior to screening
• •Any serious medical condition or abnormality in clinical laboratory tests that, in the investigator's judgment, precludes an individual's safe participation in and completion of the study
• •Unable or unwilling to comply with the requirements of the protocol in the opinion of the investigator