Immune Therapy in HR-positive/HER2-negative Metastatic Breast Cancer(ENIGMA)-BCTOP-L-M02

Inclusion Criteria

• •Females ≥18 years and ≤ 75 years old;
• •Histologically confirmed HR + / HER2- invasive breast cancer (specific definition: immunohistochemical detection of ER\> 10% tumor cell positive is defined as ER positive, PR\> 10% tumor cell positive is defined as PR positive, ER and / or PR Positive is defined as HR positive; HER2 0-1 + or HER2 is ++ but negative followed by FISH detection, no amplification, defined as HER2 negative);
• •Subtype of similarity network fusion-2 (SNF-2) confirmed by the Department of Pathology and Key Laboratory of Breast Cancer of Fudan University Affiliated Cancer Hospital
• •Locally advanced breast cancer (incapable of radical local treatment) or recurrent metastatic breast cancer;
• •Measurable disease according to Response Evaluation Criteria in Solid Tumors v1.1 (RECIST v1.1); or unmeasurable lytic or mixed (osteolytic + osteoblastic) bone lesions in the absence of measurable lesions;
• •Has adequate bone marrow function: absolute neutrophil count \> 1.5x10ˆ9 /L; platelet count \> 75x10ˆ9 /L, hemoglobin \> 9g/dL;
• •Patients had received no previous chemotherapy or targeted therapy for metastatic disease
• •Has adequate liver function and kidney function: serum creatinine
• •ECOG score ≤ 2 and life expectancy ≥ 3 months;
• •Participants voluntarily joined the study, has signed informed consent before any trial related activities are conducted, has good compliance and has agreed to follow-up.