Neoadjuvant Therapy Combined With Trastuzumab Rezetecan and Toripalimab for HR+/HER2-low Breast Cancer (NEOTORCH-BREAST 08)

Inclusion criteria

• Female patients aged 18-70 years old;
• ECOG score is 0-1 points;
• Histologically or pathologically confirmed invasive breast cancer, meeting the following criteria simultaneously: Invasive breast cancer staged as T1cN1-2M0 or T2-3N0-2M0; All patients must be pathohistologically confirmed as HR-positive/HER2-low. The interpretation of ER and PR status follows the 2020 ASCO/CAP Guidelines: expression ≥1% is defined as positive, and HR positivity is confirmed if either ER or PR is positive. The interpretation of HER2 status follows the 2023 ASCO/CAP Guidelines: HER2-low is defined as HER2 1+ or 2+ with negative FISH test results. Pathological testing for PD-L1 expression: The Combined Positive Score (CPS) is the percentage of PD-L1-positive cells (including tumor cells, lymphocytes, and macrophages) among the total number of tumor cells. The PD-L1 antibody clone used for detection at our center is 22C3. No prior anti-cancer treatment.
• Function levels of major organs must meet the required criteria
• For female patients who have not yet reached menopause or undergone surgical sterilization: during the treatment period and in the study treatment, the final use effective contraceptive methods for at least 6 months after a single administration.
• Voluntarily join this study, sign an informed consent form, have good compliance, and are willing to cooperate with follow-up.

Exclusion criteria

• Stage IV breast cancer.
• Inflammatory breast cancer.
• Previously received anti-tumor treatment or radiation therapy for any malignant tumor, excluding those that have been cured Malignant tumors such as cervical carcinoma in situ, basal cell carcinoma, or squamous cell carcinoma.
• Simultaneously undergoing anti-tumor treatment in other clinical trials, including but not limited to chemotherapy and endocrine therapy. Treatment, biological therapy, bone improvement drug therapy, or immune checkpoint inhibitor therapy, etc.
• The patient had undergone major surgical procedures unrelated to breast cancer within 4 weeks before the first administration of the study drug, or the patient has not fully recovered from such surgical procedures.
• Serious heart disease or discomfort.
• Uncontrolled active infections that require treatment; History of immunodeficiency, including HIV testing positive Sexual, or suffering from other acquired or congenital immunodeficiency diseases, or having a history of organ transplantation.
• Patients with chronic active hepatitis B or active hepatitis C
• Have received immunotherapy and experienced adverse immune events such as immune related pneumonia and myocarditis, which have been determined by researchers to potentially affect the safety of the experimental medication.
• Individuals with a known history of allergies to the components of this medication regimen.