Breast Cancer Clinical Trials

• Female patients aged 18 to 70 years (calculated on the date of informed consent signing).

• Karnofsky Performance Status (KPS) score ≥ 70, or KPS = 60 primarily attributable to neurological symptoms.

• HER2-negative status confirmed by pathology from Jiangsu Provincial Hospital's Pathology Department. HER2 immunohistochemistry (IHC) must be (-) or (1+). Patients with HER2 IHC (2+) must have a negative result on confirmatory fluorescence in situ hybridization (FISH) testing.

• Presence of brain metastases confirmed by contrast-enhanced cranial MRI prior to enrollment. At least one measurable intracranial lesion is required according to RANO-BM criteria.

• If prior anti-tumor therapy (excluding treatments specifically targeting intracranial metastases) has been administered, a washout period of at least 2 weeks is required. Any prior treatment-related toxicities must have resolved to ≤ Grade 2 (CTCAE v3.0; excluding alopecia and hematological toxicities). Concurrent use of bisphosphonates, mannitol, corticosteroids, etc., is permitted during the study. Corticosteroid dosage must have been stable for at least one week prior to enrollment (e.g., dexamethasone ≤ 16 mg/day or equivalent).

• Life expectancy of at least 3 months.

• Adequate organ and hematological function, meeting the following criteria:

‣ Hematology (without transfusion or growth factor support within 14 days):

• Hemoglobin (Hb) ≥ 80 g/L.

∙ Absolute neutrophil count (ANC) ≥ 1.0 × 10⁹/L.

∙ Platelet count (PLT) ≥ 50 × 10⁹/L.

⁃ Biochemistry:

• Total bilirubin (TBIL) \< 1.5 × upper limit of normal (ULN), or ≤ 3 × ULN in patients with liver metastases.

∙ Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 × ULN, or ≤ 5 × ULN in patients with liver metastases.

∙ Serum creatinine (Cr) ≤ 1.5 × ULN or calculated creatinine clearance ≥ 60 mL/min (Cockcroft-Gault formula).

∙ Magnesium ≥ lower limit of normal (LLN).

• Women of childbearing potential must be surgically sterile, postmenopausal, or agree to use highly effective contraception (e.g., oral contraceptives, intrauterine device, sexual abstinence, or barrier methods with spermicide) during the study and for 6 months after the final dose. A negative serum pregnancy test within 7 days prior to enrollment is required for all non-sterile, premenopausal women (positive results must be ruled out as false-positive by ultrasound). Patients must not be breastfeeding.

• Voluntary participation with written informed consent.