⁃ Subjects are eligible to be included in the study only if all of the following criteria apply:

• Male or female who is 18 years of age or older on the day of signing the informed consent form.

• Subjects with metastatic triple-negative breast cancer, with clear clinical data records; specific reference to the American Society of Clinical Oncology - College of American Pathologists (ASCO/CAP) guidelines.

• Have received less than or equal to 1 line of chemotherapy for metastatic breast cancer;

• Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 as assessed within 10 days before the start of study treatment;

• Subjects must have at least one measurable lesion present; specific reference to the Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1) guidelines;

• Subjects may have previously received treatment with anthracyclines (e.g., doxorubicin, epirubicin) and/or taxanes (e.g., paclitaxel, docetaxel) as follows: a) The subject has used anthracyclines and/or taxanes during adjuvant and/or neoadjuvant therapy before breast cancer recurrence. b) The subject has experienced treatment failure during or after chemotherapy based on anthracyclines and/or taxanes. c) According to the investigator's judgment, the Subject is not suitable for anthracyclines and/or taxanes-based chemotherapy as a first-line treatment option.

• Female subjects are not pregnant, not lactating, and agree to use necessary contraceptive measures.

• Subjects are able to sign an informed consent form to participate in the study.

• Have appropriate organ function, as detailed in Table 1; all screening laboratory tests should be completed within 10 days before the start of study treatment.