Study of Eribulin in Combination With Anti-PD-1 Antibody in Patients With Metastatic Triple-Negative Breast Cancer

Inclusion Criteria:

1. The patients sign the written informed consent.
2. Women aged 18-75.
3. The pathologic diagnosis of unresectable recurrent or metastatic triple-negativebreast cancer ［ER-negative(IHC<1%), PR-negative(IHC<1%), HER2-negative（IHC-/+ or IHC++and FISH/CISH-）］. Patients with at least one measuring lesion that was conformed toRECIST v1.1 standard.
4. PD-1/PD-L1positive or TMB≥5.
5. Prior therapy (adjuvant/neoadjuvant/advanced) must have included an anthracyclineand/or a taxane in any combination or order and either in the early or metastaticdisease setting unless contraindicated for a given patient.
6. Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 1.
7. The results of patient's blood tests are as follows: • Hb≥90g/L; • Plt≥100^9/L; • Serum albumin ≥3g/dL;• Neutrophils≥1.5^9/L; TSH≤ normalupper limit (ULN);• ALT and AST ≤1.5 ULN (liver metastases ≤3 ULN); • TBIL ≤ULN (totalbilirubin ≤1.5 ULN in Gilbert's syndrome or liver metastasis subjects);• ALT and AST ≤1.5 ULN (liver metastases ≤3 ULN);• AKP≤ 2.5 ULN; • Renal function within 7 daysbefore the first administration: serum creatinine ≤1.5 ULN or creatinine clearance ≥60mL/min
8. Female subjects of childbearing potential must have a negative serum pregnancy testwithin 7 days before the first dose and must be willing to use very efficient barriermethods of contraception for the course of the study through 6 months after the lastdose of study treatment.

Exclusion Criteria:

1. The subjects had a central nervous system metastases with clinical symptoms.
2. Subjects with treatment history of PD-1 / PD-L1 inhibitors;
3. Peripheral neuropathy ≥ grade 2; Cardiac dysfunction, hyperthyroidism orhypothyroidism, type 1 diabetes, active hepatitis and tuberculosis; Autoimmunediseases requiring systemic treatment, and a history of pneumonia (requiringcorticosteroid treatment) or interstitial lung disease.
4. Pregnant or lactating women.
5. Other clinical trials of drugs were used in the first four weeks before the firstdose.
6. The subjects had any history of autoimmune disease or any use of systemicglucocorticoid or immunosuppressive medications.
7. Hereditary or acquired bleeding and thrombotic tendencies (such as hemophilia,coagulation dysfunction, thrombocytopenia, hypersplenism, etc.).
8. Congenital or acquired immune deficiency (such as HIV infection);
9. Receive live vaccine within 4 weeks before or during the study period;
10. Patients who are allergic to or contraindicated to the experimental drugs.
11. Other malignant tumors in the past, except cervical cancer and non melanoma skincancer, which have survived for 5 years without disease.
12. Subjects with any other diseases that are unfit for the treatment.