FDA018-ADC vs Investigator's Choice Chemotherapy to Treat Locally Advanced, Recurrent or Metastatic Triple-negative Breast Cancer

Inclusion Criteria:

1. Patients capable to give written informed consent;

2. Histologically or cytologically confirmed TNBC based on the most recent analyzedbiopsy or other pathology specimen. Triple negative is defined as <1% expression forestrogen receptor (ER) and progesterone receptor (PR) and negative for humanepidermal growth factor receptor 2 (HER2) by in-situ hybridization;

3. Prior exposure to a taxane in localized or advanced/metastatic setting, and recurredduring or after treatment;

4. Eligible for one of the chemotherapy options listed as ICC (eribulin, capecitabine,gemcitabine, or vinorelbine) as per investigator assessment;

5. Have measurable lesions defined in RECIST v.1.1, those with only skin or bonelesions cannot be included;

6. Expected survival≥3 months;

7. Eastern Cancer Cooperative Group (ECOG) performance status 0-1;

8. Adequate bone marrow, hepatic, and renal function;

9. All acute toxicity of previous anti-tumor treatment or surgery is relieved tobaseline severity or NCI CTCAE version 5.0≤1;

10. Subjects could provide tumor tissues or tissue specimens;

11. Patients of child bearing potential must agree to take contraception during thestudy and for 6 months after the last day of treatment.

Exclusion Criteria:

1. Patients with other malignancies, except cured basal or squamous cell skin cancer orin situ cancer of cervix; and patients with other malignancies must have atumor-free period of at least 5 years;

2. Have central nervous system metastasis with clinical symptoms;

3. Have history of clinical significant active chronic obstructive pulmonary disease,or other moderate-to-severe chronic respiratory illness present within 6 monthsprior to the first dose;

4. Suffering from active chronic inflammatory bowel disease (ulcerative colitis, Crohndisease), and history of intestinal obstruction, or Gl perforation;

5. Patients with Gilbert's disease or heterozygous for the UGT1A1*28 allele;

6. Participants known to be human immunodeficiency (HIV) positive, hepatitis Bpositive, or hepatitis C positive;

7. Patients who have received prior TROP-2-targeted therapy;

8. Patients who have received prior topoisomerase I inhibitor contained therapy;

9. Received other anti-tumor treatments (including chemotherapy, radiotherapy, targetedtherapy, immunotherapy, experimental treatment and so on) within 4 weeks prior tothe first dose;

10. Patients who have received live vaccines within 4 weeks prior to the first dose;

11. Patients who had undergone major surgery or severe trauma within 4 weeks prior tothe first dose;

12. Patients who had undergone systemic high-dose steroids within 2 weeks prior to thefirst dose;

13. Patients have history of psychotropic drug abuse, alcohol or drug abuse;

14. Women who are pregnant or lactating;

15. Other circumstances that is deemed not appropriate for the study by investigator.