Efficacy and Safety of Dalpiciclib in Hormone Receptor-positive Advanced Breast Cancer

This study is testing whether a drug called dalpiciclib, combined with hormone-blocking therapy, can help treat hormone receptor-positive (HR+) breast cancer that has spread or come back and cannot be removed with surgery. **You may be eligible if...** - You are 18 or older - You have HR-positive breast cancer that has spread to other parts of the body or returned after treatment - Your cancer cannot be cured by surgery or radiation - You are male or female (women can be pre- or post-menopausal) - You are in good enough health to participate (able to carry out daily activities) - You have a negative pregnancy test if you can become pregnant, and are willing to use birth control **You may NOT be eligible if...** - You have a serious uncontrolled illness (like uncontrolled high blood pressure, active infection including hepatitis B/C or HIV, or major organ damage) - You still have significant side effects (grade 3 or higher) from previous cancer treatment - You are allergic to dalpiciclib or similar drugs - You are currently pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.