Utidelone Capsule Plus Capecitabine (CAP) for Metastatic Breast Cancer

Inclusion Criteria:

1. Voluntarily participate in this study, sign an informed consent form, have goodcompliance, and are willing to follow-up.

2. Female, aged ≥ 18 and ≤ 70 years, with an ECOG score of 0-1 and an expected survivaltime of ≥ 12 weeks.

3. The pathological and/or cytological diagnosis (based on the latest biopsy results)is HER2 negative recurrent or metastatic breast cancer, regardless of hormonereceptor status (ER/PR positive or negative, but the hormone receptor status needsto be determined);

4. All patients have received at least paclitaxel and/or anthracycline as a treatmentoption;

5. All patients with prior treatment ≤ 3 lines (for those who progress during theneoadjuvant/adjuvant period or within 12 months after the end of the last treatment,it is considered as the first line, and no progress is counted as the number oflines); For HR+/HER2- breast cancer patients, they also need to have received thefirst line systemic CDK4/6 inhibitor+endocrine therapy before the diseaseprogresses.

6. According to RECIST 1.1 standard, there is at least one measurable extracraniallesion present.

7. Within one week before enrollment, the blood routine examination was basicallynormal (no blood transfusion within two weeks, no use of drugs to increase whiteblood cells or platelets): Neutrophil count (ANC) ≥ 1.5 × 109/L; Platelet count (PLT) ≥ 90 × 109/L; Hemoglobin ≥ 9.0 g/dL.

8. Within one week before enrollment, the blood biochemistry test was basically normal (based on the normal values of each research center laboratory): Total bilirubin (TBIL) ≤ 1.5 x Upper limit of normal value (ULN) SGPT/ALT ≤ 3 × ULN (livermetastasis patients ≤ 5 × ULN); SGOT/AST ≤ 3 × ULN (liver metastasis patients ≤ 5 ×ULN); The creatinine clearance rate (Ccr) is ≥ 50 ml/min (Cockcroft Gault formula).

9. No major organ dysfunction

10. Women with fertility must agree to use effective contraceptive methods during thestudy period and within 6 months after the last study medication. Women withfertility must have a negative blood or urine pregnancy test before enrollment.

Exclusion Criteria:

1. Other malignant tumors within the 5 years prior to enrollment, excluding curedcervical carcinoma in situ, basal cell carcinoma of the skin, papillary thyroidcarcinoma without lymph node metastasis, or squamous cell carcinoma of the skin.

2. Those who meet the following conditions:

3. Received systemic anti-tumor therapy within 2 weeks prior to enrollment,including but not limited to endocrine therapy, small molecule targetedtherapy, anti-tumor traditional Chinese medicine, etc;

4. Within the 4 weeks prior to enrollment, chemotherapy, targeted biologicaltherapy or immunotherapy, other clinical investigational drugs, radiationtherapy, or major organ surgery (excluding biopsy) or significant trauma havebeen received, or elective surgery is required during the trial period. Thosewho have undergone major surgeries;

5. Received nitroso urea or mitomycin C within 6 weeks prior to enrollment;

6. Individuals who have previously received treatment with Utidelone injection.

7. Peripheral neuropathy CTCAE 5.0 grade evaluation ≥ 2.

8. Those who have received treatment with capecitabine or other drugs with an activeingredient of 5-fluorouracil (excluding those who relapse after more than 12 monthsof treatment).

9. Pregnant and lactating patients.

10. Adverse reactions from previous anti-tumor treatments have not yet recovered toCTCAE 5.0 grade ≤1 (excluding toxicity judged by researchers to have no safety riskfor hair loss).

11. Accompanied by meningeal metastasis; Accompanied by uncontrollable brain metastases (researchers have determined that new asymptomatic brain metastases or those knownto have stable brain metastases after treatment can be enrolled); Or uncontrollablebone metastasis, which refers to patients who have or have recently been at risk offractures or have obvious symptoms or other critical situations.

12. Uncontrollable pleural effusion, pericardial effusion, or abdominal effusion.

13. Individuals with active infections who currently require systematic anti infectiontreatment.

14. Have a history of immunodeficiency, including HIV antibody testing positive, or haveother acquired or congenital immunodeficiency diseases, or have a history of organtransplantation.

15. Individuals with active hepatitis B or hepatitis C; Known active syphilis infection.

16. Have a history of severe cardiovascular and cerebrovascular diseases, including butnot limited to: Serious cardiac rhythm or conduction abnormalities, such as ventricular arrhythmiasrequiring clinical intervention, grade II-III atrioventricular block, etc; At rest,the average QTcF obtained from three 12 lead electrocardiogram examinationsis>470ms; Acute coronary syndrome, congestive heart failure, aortic dissection,stroke, or other Grade 3 or higher cardiovascular events occurring within 6 monthsprior to the first administration; Hypertension that cannot be controlledclinically. Other researchers have identified high-risk heart diseases.

17. Uncontrolled diabetes patients.

18. Patients with active gastrointestinal ulcers.

19. Have a clear history of neurological or psychiatric disorders, including epilepsy ordementia.

20. Participate in another clinical trial or use other investigational treatmentssimultaneously.

21. Individuals known to be allergic to the investigational drug or any of itsexcipients.

22. The researchers believe that the subjects have a history of other serious systemicdiseases or other reasons that make them unsuitable to participate in this trial.