Study on Giredestrant vs. Doctor's Choice of Hormone Therapy for Advanced or Metastatic Breast Cancer

Inclusion Criteria

• Women who are postmenopausal or premenopausal/perimenopausal.
• Premenopausal or perimenopausal women and men must agree to use LHRH agonist therapy during the study.
• Have advanced breast cancer that cannot be cured with surgery.
• Cancer must be estrogen receptor-positive and HER2-negative.
• Cancer has worsened after one or two previous treatments for advanced cancer.
• Have measurable cancer or bone-only disease with at least one bone lesion that can be tracked by scans.
• Be in good overall health with an ECOG performance status of 0 or 1.
• Have good organ function.

Exclusion Criteria

• Have previously been treated with a selective estrogen receptor degrader (SERD), except for fulvestrant, if it was stopped at least 28 days before joining the study.
• Have taken any experimental treatments within 28 days before joining the study.
• Have advanced cancer that has spread to vital organs and is causing severe symptoms.
• Have uncontrolled or symptomatic cancer spread to the brain or spinal cord.
• Have active heart disease or a history of heart problems.
• Are pregnant or breastfeeding.