Neoadjuvant Adebrelimab and Chemotherapy in High-rish ER+/HER2- BC

Inclusion Criteria:

• pathologically diagnosed as unilateral primary invasive breast cancer with a)cT1c-T2N1-3 or cT3-4N0-3, b) Tumor Grade 3 or Grade 2 with PR- or Ki67 > 20%;

• IHC ER expression ≥1%; IHC HER2 0 or 1+; IHC HER2 2+ and no amplification in FISHtest;

• At least one measurable lesion according to RECIST 1.1;

• Available core needle biopsy samples for PD-L1 status testing;

• ECOG 0 or 1 within 10 days prior to initiation of treatment;

• Not currently pregnant or breastfeeding, agree to strict contraception duringtreatment and at least 6 months after last dose;

• Intact hematologic, liver, renal and heart functions;

• Signed written informed consent.

Exclusion Criteria:

• Bilateral invasive breast cancer or Stage IV breast cancer;

• Severe heart disease;

• Diagnosed as immune deficiency or receiving systemic steroid therapy or any form ofimmuno-suppressive therapy within 7 days prior to the first dose of treatment;

• Had active autoimmune diseases requiring systemic therapy within the past 2 years;

• Severe systemic infections or other serious medical conditions;

• Other malignant tumors in the past 5 years, except for cured carcinoma in situ ofthe cervix and skin cancer without melanoma;

• History of HIV infection;

• Active HBV or HCV infection;

• Known allergies or intolerance to the therapeutic drug or its excipients;

• History of application of any immunotherapy targeting PD-1/PD-L1/T cell receptors;

• Judged by the investigator to be unsuitable to participate in this study.