A Single-arm, Open, Phase II Clinical Study of SBRT, Chemotherapy, and Ivonescimab Neoadjuvant Therapy for Luminal-type Breast Cancer
Studies have indicated that the improvement in pathological complete response (pCR) is significantly correlated with luminal breast cancer patients' overall survival (OS). Patients with luminal breast cancer have poor efficacy for neoadjuvant chemotherapy. The combination of neoadjuvant therapy with immunotherapy and chemotherapy has been demonstrated to enhance the pCR rate of luminal-type breast cancer patients, increasing it from 13-15% to approximately 24%. Therefore, how to further improve the pCR rate of luminal-type breast cancer became the main objective of this study. Stereotactic radiotherapy (SBRT) not only kills tumor cells directly, but also kills the distant unirradiated tumor cells by promoting the cross-initiation of tumor-specific CD8+ T cells, a phenomenon known as the abscopal effect. Our research team has recently discovered that the triple therapy model of SBRT + anti-vascular targeting + anti-PD-1 was safe and efficacious in lung cancer patients. Ivonescimab (AK112) is an anti-PD-1/VEGF-A bispecific antibody. In order to improve the pCR, a single-arm, open, phase II clinical study was proposed to explore the safety and efficacy of SBRT+AK112+chemotherapy, a neoadjuvant treatment modality, in the treatment of luminal breast cancer.
• This trial aims to enroll patients who treatment-naïve and voluntarily participate and provide written informed consent; Eligible participants must have histologically confirmed and HR+/HER2-negative breast cancer (HER2 immunohistochemistry 0, 1+, or 2+/FISH-); Patients must meet at least one of the following criteria: (1) tumor size \>2 cm, (2) axillary lymph node metastasis, or (3) intent for breast-conserving surgery, but tumor-to-breast volume ratio makes preservation challenging; Additional eligibility requirements include age ≥18 years, an ECOG performance status of 0-1, and baseline laboratory values within acceptable ranges: white blood cell count (WBC) ≥2.0×10⁹/L, absolute neutrophil count (ANC) ≥1.5×10⁹/L, platelet count (PLT) ≥100×10⁹/L, hemoglobin (Hb) ≥90 g/L. Liver function parameters must be within ≤1.5×upper limit of normal (ULN) for total bilirubin (TBIL) and ≤3×ULN for alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Renal function must be preserved, with serum creatinine (Cr) ≤1.5× ULN, or if Cr exceeds this limit, the creatinine clearance rate should be ≥50 mL/min (calculated using the Cockcroft-Gault formula). Coagulation parameters should meet the following thresholds: activated partial thromboplastin time (APTT)≤1.5×ULN and prothrombin time (PT) or international normalized ratio (INR) ≤1.5×ULN.