• Signed Informed Consent Form (ICF) prior to participation in any study-related activities.

• Patients aged ≥19 years at the time of signing ICF.

• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

• Life expectancy of ≥ 12 weeks.

• Histologically confirmed TNBC per American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) criteria based on local testing on the most recent analyzed biopsy. Triple-negative is defined as \<1% expression for estrogen receptor (ER) and progesterone receptor (PgR) and negative for human epidermal growth factor receptor 2 (HER2) (0-1+ by IHC or 2+ and negative by in situ hybridization \[ISH) test\].

• Metastatic disease documented by computerized tomography (CT) scan or magnetic resonance imaging (MRI) that is not amenable to resection with curative intent.

• Refractory to at least one, and no more than two, prior standard of care chemotherapy regimens for unresectable locally advanced or MBC. PARP inhibitor could have been counted as prior chemotherapy for purposes of study eligibility.

• All patients must have been previously treated with taxanes regardless of disease stage (adjuvant, neoadjuvant, or advanced), unless contraindicated for a given patient.

• Measurable or non-measurable, but evaluable disease, as per RECIST v.1.1. Patients with bone-only metastases are also eligible.

⁃ Brain MRI must be done for patients with suspicion of brain metastases and patient must have stable central nervous system (CNS) disease for at least 4 weeks after local therapy, without neurological symptoms, and off anticonvulsants and steroids (no more than 10mg/day prednisone or its equivalent) for at least 2 weeks before first dose of study treatment.

⁃ Meet the following organ function requirements:

∙ Hemoglobin ≥ 9 g/dL

‣ ANC ≥ 1500/mm3

‣ Platelets ≥ 100,000/μL

‣ Bilirubin ≤ 1.5 X IULN or ≤ 3X IULN for patients with documented Gilbert's syndrome

‣ AST and ALT ≤ 2.5 X IULN or ≤ 5 X IULN if known liver metastases

‣ Serum albumin \> 3 g/dL

‣ Creatinine clearance ≥ 60 mL/min or ≥ 30 mL/min as assessed by the Cockcroft-Gault equation

‣ INR/PT and PTT or aPTT ≤ 1.5 X IULN unless patient is currently receiving therapeutic anticoagulant therapy

⁃ Resolution of all acute AEs of prior anti-cancer therapy to grade 1 as determined by the NCI-CTCAE v.5.0 (except for alopecia or other toxicities not considered a safety risk for the patient at investigator discretion).

⁃ Male patients and female patients of childbearing potential who engage in heterosexual intercourse must agree to use institution specified method(s) of contraception during treatment with sacituzumab govitecan and for 6months after the last dose.

∙ Required contraception for female of childbearing potential patients using hormonally based method, intrauterine device (IUD), bilateral tubal occlusion, female condom with spermicide should during study period and continue until 6 months after the last dose of latest administered study drug

‣ Required contraception for male patients using abstinence, male condom with spermicide, vasectomy should during study period and continue until 6 months after the last dose of latest administered study drug

⁃ Patients must have completed all prior cancer treatments at least 2 weeks prior to 1st infusion of study drug including chemotherapy (includes also endocrine treatment), radiotherapy, and major surgery.

∙ Prior anticancer biologic agent must have been completed at least 4 weeks prior to 1st infusion of study drug.