Serplulimab Plus Chemotherapy for Early-stage HR+/HER2- Breast Cancer

In recent years, significant progress has been made in the immunotherapy of breast cancer, and PD1/PDL1 inhibitors have achieved good results in the treatment of triple-negative breast cancer. There have also been many attempts to apply them in HR+/HER2- breast cancer. In the I-SPY2 study, Pembrolizumab combined with chemotherapy increased the pCR rate of HR+/HER2- breast cancer from 13% in the chemotherapy alone group to 30%. In the KEYNOTE756 study, Pembrolizumab in combination with chemotherapy increased the pCR rate by 8.5% (24.3% vs. 15.6%) compared to the chemotherapy-only arm in HR+/HER2- breast cancer. pCR rates in the Nivolumab arm of the CheckMate 7FL study were 24.5% compared with 13.8% in the control arm. While further long-term follow-up data are still needed to confirm patient benefit, it still provides a new treatment option for HR+/HER2- breast cancer patients.

The neoadjuvant treatment options commonly used for HR+/HER2- breast cancer are mainly anthracycline sequential or combined with paclitaxel chemotherapy regimens. Several clinical studies have confirmed that albumin paclitaxel is more effective than solvent-based paclitaxel, and therefore, albumin paclitaxel in combination with epirubicin has also become a commonly used chemotherapy regimen in clinical practice.

The aim of this study was to explore the efficacy and safety of the Serplulimab combined with nab-paclitaxel and epirubicin in the neoadjuvant treatment of HR+/HER2- breast cancer

Inclusion criteria

Patients must meet all of the following criteria to be eligible:

Age: ≥18 years old.

Clinical-pathological confirmation:

cT2-cT4 breast cancer, or cT1c with axillary lymph node metastasis.

Histopathologically confirmed HR+/HER2- invasive breast cancer:

ER and/or PR positive (IHC nuclear staining ≥1%).

HER2-negative (IHC 0 or 1+ without FISH testing, or IHC 2+ with FISH-negative amplification).

Ki67 ≥20%.

Clinically measurable lesions:

Measurable lesions confirmed by ultrasound, mammography, or MRI (optional) within 1 month prior to randomization.

Adequate organ and bone marrow function (within 1 month prior to chemotherapy):

Absolute neutrophil count (ANC) ≥2.0 × 10^9/L.

Hemoglobin ≥90 g/L.

Platelet count ≥100 × 10^9/L.

Total bilirubin <1.5 × ULN (upper limit of normal).

Creatinine <1.5 × ULN.

AST/ALT <1.5 × ULN.

Cardiac function: Left ventricular ejection fraction (LVEF) ≥55% by echocardiography.

Reproductive status: Women of childbearing potential must have a negative serum pregnancy test within 14 days prior to randomization.

ECOG performance status: ≤1.

Informed consent: Signed written informed consent.

Exclusion criteria

Patients meeting any of the following criteria will be excluded:

Evidence of metastatic breast cancer:

Prior systemic therapy: Chemotherapy, endocrine therapy, targeted therapy, or radiotherapy for the current breast cancer.

Second primary malignancy, except: Adequately treated non-melanoma skin cancer.

Prior immunotherapy: Treatment with anti-PD-1, anti-PD-L1, anti-PD-L2, or other immune checkpoint inhibitors.

Immune-related conditions:

Diagnosed immunodeficiency or active autoimmune disease.

Severe cardiopulmonary disease: Uncontrolled or clinically significant.

Active hepatitis B or C.

Pregnancy or lactation: Pregnant or breastfeeding women.

Other contraindications: Severe uncontrolled comorbidities deemed by investigators to contraindicate chemotherapy or PD-1 inhibitor therapy.