Apatinib Combined With cdk4/6i in First-line Treatment for HR+/HER2- SNF4 Subtype Breast Cancer

Inclusion Criteria:

• Inclusion Criteria:

• Patients need to meet all of the following conditions

• Patients must be ≥18 and ≤ 75 years of age;

• Pathologically confirmed breast cancer is HR+/HER2- breast cancer (IHC ER >10%, or/and PR>10%, HER 0 OR +, if HER2++, FISH negative);

• SNF4 subtype definition: SNF4 subtype confirmed by digital pathology of H&Esections;

• Locally advanced breast cancer (radical local therapy is not possible) ormetastatic breast cancer (without using adjuvant CDK4/6 inhibitors in the past,or one year after adjuvant CDK4/6 inhibitor therapy has ended);

• No prior therapy (chemotherapy, targeted therapy, etc.) for advanced ormetastatic breast cancer;

• Patients with at least one measurable lesion that has not previously receivedradiation therapy and can be evaluated repeatedly according to RECIST 1.1;

• The functions of the main organs are basically normal, and the followingconditions are met:

1. Blood routine examination standards should meet: HB≥90g/L (no bloodtransfusion within 14 days); ANC≥1.5×109/L; PLT≥75×109/L;
2. Biochemical examination shall meet the following standards: TBIL≤1.5×ULN (upper limit of normal value); ALT and AST≤3 x ULN; In case of livermetastasis, ALT and AST≤5×ULN; Serum Cr ≤1.5×ULN, endogenous creatinineclearance > 50ml/min (Cockcroft-Gault formula);

• ECOG performance status 0 or 1; The expected survival is more than 3 months;

• Fertile female is required to use a medically approved contraceptive duringstudy treatment and for at least 3 months after the last use of the study drug;

• Patients voluntarily join the study, sign the informed consent, have goodcompliance, and cooperate with follow-up.

Exclusion Criteria:

• Patients with any of the following conditions were excluded from the study

• Patients with central nervous system metastasis out of control (symptoms needto use glucocorticoids or mannitol).

• A history of clinically significant or uncontrolled heart disease, includingcongestive heart failure, angina pectoris, myocardial infarction within thelast 6 months, or ventricular arrhythmia;

• Radiotherapy, chemotherapy, surgery, other targeted therapy, and immunotherapyfor advanced HR+/HER2- breast cancer within 4 weeks before the firstadministration of drugs used in this study.

• Pregnant or lactating patients;

• Other malignancies within the previous 3 years, excluding cured skin basal cellcarcinoma and cervical carcinoma in situ;

• Significant comorbid medical conditions, including mental illnesses that theinvestigator or sponsor believes would adversely affect the patient'sparticipation in the study;

• Allergic physique, or known allergic history of the drug components of thisprogram; Or allergic to other monoclonal antibodies;

• The investigator does not consider the patient suitable for participation inany other circumstances of the study.