Breast Cancer Clinical Trials

• Age ≥18 years;

• Locally advanced breast cancer (unable to undergo radical local treatment) or recurrent metastatic breast cancer;

• Previously received ADCs;

• The most recent pathology results will be considered for enrollment according to local testing of ER, PR and HER2. Participants with any hormone receptor (HR) status will be allowed on study.

• Prior endocrine therapy: Participants with HR-positive breast cancer must have received prior CDK4/6 inhibitor;

• Participants must have measurable disease per RECIST 1.1.

• The functions of the main organs are basically normal and meet the following conditions:

• I. Blood routine examination criteria shall meet: HB ≥90 g/L (no blood transfusion within 14 days); The ANC acuity 1.5 x 10\^9 / L; PLT acuity 75 x 10\^9 / L; II. Biochemical tests should meet the following criteria: TBIL ≤1.5×ULN (upper limit of normal value); ALT and AST ≤3×ULN; If liver metastases were present, ALT and AST≤ 5×ULN; Serum Cr ≤1.5×ULN, endogenous creatinine clearance \> 50 ml/min (Cockcroft-Gault formula); III. LVEF≥50%

• They have not received radiotherapy, molecular targeted therapy, or surgery within 3 weeks before the start of the study, and have recovered from the acute toxicity of previous treatment (if surgery was performed, the wound has healed completely); No peripheral neuropathy or grade I peripheral neurotoxicity; Participants may have discontinued all CDK4/6 inhibitor at least 14 days prior to study treatment initiation. Prior endocrine therapy does not require washout.

• ECOG score ≤2, and life expectancy ≥3 months;

⁃ Fertile female subjects were required to use a medically approved contraceptive method during the study treatment period and for at least 3 months after the last use of the study drug;

⁃ Subjects volunteered to join the study, signed informed consent, had good compliance, and cooperated with follow-up.