This study is a prospective, multi-cohort, multicenter, open-label exploratory clinical trial. The primary study objective is to evaluate the pathologic complete response (PCR) of treatment of HR+/HER2-low breast cancer with neoadjuvant therapy combined with Trastuzumab Rezetecan and Toripalimab , including the incidences and types of adverse events. The secondary endpoints include event-free survival (EFS), residual cancer burden (RCB), and objective response rate (ORR).
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
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.
Parallel
Neoadjuvant therapy combined with Trastuzumab Rezetecan and Toripalimab
DrugTrastuzumab Rezetecan administered intravenously at a dose of 4.8mg/kg every 3 weeks for a total of 24 weeks with Toripalimab intravenous infusion of 240mg. During postoperative adjuvant therapy, Toripalimab used as before till a total of 1 year.
Neoadjuvant Chemotherapy in Combination with Toripalimab
DrugEpirubicin (or Liposomal Doxorubicin)+Cyclophosphamide, intravenous infusion of 100 mg/m2. Epirubicin (or 35 mg/m2 liposomal doxorubicin)+600 mg/m2 cyclophosphamide, starting from the first day of the week, for a total of 12 weeks. Paclitaxel, administered intravenously at a dose of 260 mg/m2 every 3 weeks for a total of 12 weeks. During neoadjuvant chemotherapy and postoperative adjuvant therapy, use of Toripalimab: intravenous infusion of 240 mg, once every 3 weeks, combined with preoperative neoadjuvant and postoperative adjuvant therapy for a total of 1 year.
Neoadjuvant Chemotherapy
DrugEpirubicin (or Liposomal Doxorubicin)+Cyclophosphamide, intravenous infusion of 100 mg/m2. Epirubicin (or 35 mg/m2 liposomal doxorubicin)+600 mg/m2 cyclophosphamide, starting from the first day of the week, for a total of 12 weeks. Paclitaxel, administered intravenously at a dose of 260 mg/m2 every 3 weeks for a total of 12 weeks.
pathologic complete response（PCR）
Event free survival (EFS)
objective response rate (ORR)
Residual Cancer Burden (RCB)
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