Phase III Study to Evaluate the Safety, Efficacy, and Impact on Quality of Life of Capivasertib Alongside Standard-of-care Endocrine Treatment in Patients With HR+/HER2- Advanced Breast Cancer and Progression on Prior Endocrine-based Treatment

This Phase III study is testing whether capivasertib, a targeted therapy drug, added to standard hormone-blocking treatment improves outcomes for patients with hormone receptor-positive, HER2-negative advanced breast cancer whose cancer progressed on prior hormone therapy. **You may be eligible if...** - You are 18 or older (male or female) - You have hormone receptor-positive (HR+), HER2-negative advanced or metastatic breast cancer - Your cancer progressed while on a prior endocrine (hormone-blocking) treatment - Pre-menopausal women must be willing to use a GnRH agonist (a hormone-suppressing injection) throughout the study **You may NOT be eligible if...** - You have not previously received endocrine therapy for advanced disease - You have certain genetic mutations, serious organ problems, or other conditions that would make this treatment unsafe - You are pregnant or unable to use effective contraception Talk to your doctor to see if this trial is right for you.