Study on Sacituzumab Tirumotecan Alone and with Pembrolizumab Compared to Doctor's Choice Treatment for Advanced HR+/HER2- Breast Cancer

Inclusion Criteria

• Have advanced breast cancer that cannot be removed by surgery and is hormone receptor positive and HER2-negative.
• Cancer has worsened after one or more hormone therapies, including one with a CDK4/6 inhibitor.
• Eligible to receive chemotherapy.
• Have a good general health status, with a performance score of 0 or 1.
• Have adequate organ function.
• If HIV-positive, must have well-controlled HIV with medication.
• If Hepatitis B positive, must have been on antiviral therapy for at least 4 weeks with undetectable viral load.
• If previously infected with Hepatitis C, must have an undetectable viral load.

Exclusion Criteria

• Have breast cancer that can be treated with the aim of curing it.
• Cancer returned less than 6 months after finishing chemotherapy, making you eligible for second-line treatment.
• Have advanced cancer that is spreading quickly and could cause life-threatening issues.
• Have had chemotherapy for advanced breast cancer before.
• Have an active autoimmune disease needing treatment in the last 2 years.
• Have a history of lung disease requiring steroids or currently have lung disease.
• Have an active infection needing treatment.