This study tests a drug called sacituzumab govitecan for patients with HER2-negative breast cancer that has spread to the brain. HER2-negative means the cancer does not have a protein called HER2 on its surface. Sacituzumab govitecan is a special medicine that combines a monoclonal antibody (sacituzumab) with a chemotherapy drug (govitecan). It targets cancer cells by attaching to Trop-2 receptors on their surface to deliver chemotherapy directly to them.

Patients in this study will receive the medication through an intravenous (IV) drip for 1-3 hours on days 1 and 8 of each 21-day cycle, continuing for up to 2 years unless the disease worsens or side effects become too severe. After finishing the study treatment, patients will have follow-up visits every 3 months for the first year and every 6 months for the second year.

• Study lasts up to 2 years, with regular follow-ups.
• Patients receive treatment via IV on a schedule.
• Potential risks include side effects from the medication.