Sacituzumab Govitecan Combined With Head Radiotherapy for Her2-negative Breast Cancer Brain Metastases

This study is a single-arm open phase II clinical trial. It aims to observe the effectiveness and safety of Sacituzumab Govitecan combined with head radiotherapy in the treatment of Her2-negative breast cancer brain metastases, and to search for a more effective treatment option for Her2-negative breast cancer brain metastases. Patients were treated with Sacituzumab Govitecan 10mg/kg every 21 days as a treatment cycle, which was infused intravenously on day 1 and day 8, and the treatment was continued until the disease progressed or unacceptable toxicity occurred. Radiotherapy was administered after the second infusion of Sacituzumab Govitecan, on day 9 after the start of this regimen. The radiotherapy regimen was: brain metastases at a dose of 60 Gy/20 doses. For lesions located adjacent to the brainstem and optic nerve, 54 Gy/20 doses were given. For patients with ≥5 lesions, whole-brain radiotherapy at 40 Gy/20 doses was synchronized with radiotherapy to localized brain metastases.

Inclusion criteria

• Have a definitive pathologic diagnosis of breast cancer with subtype Her2- (including IHC 0, IHC 1+ or IHC 2+ and ISH negative);
• Have a measurable intracranial lesion;
• Age ≥ 18 years;

Exclusion criteria

• Patients with cerebrospinal membrane metastases;
• Patients with acute/subacute hemorrhagic metastasis;
• Inadequate organ function: 1) Blood tests: ANC ≤ 1.5 x 10^9/L, PLT ≤ 90 x 10^9/L, Hb ≤ 90g/L; 2) Blood biochemistry tests: TBIL ≥ 1.5 times the upper limit of normal; 3) ALT and AST ≥ 2.5 times the upper limit of normal;
• Presence of serious and/or uncontrolled comorbidities that may affect participation: 1) allergy to study medications or adjuvant materials; 2) history of immunodeficiency, including HIV-positive or other acquired or congenital immunodeficiency diseases; 3) serious concomitant illnesses;
• Pregnant and lactating female patients; female patients of childbearing age who are unwilling to use effective contraception during the trial period;
• Patients who are unable to complete enhanced contrast MRI;
• Patients who have been treated with Sacituzumab Govitecan and are resistant to the drug;
• Any other condition that, in the opinion of the investigator, makes the patient ineligible for study participation.