Low Antibody Dosing in Cancer Therapy: Targeted Cytotoxicity Combined with Anti-Tumour Immunostimulation

Overexpression of growth factor receptors and immunosuppressive molecules is a hallmark of many tumour cells, distinguishing them from normal tissue. This co-expression enables tumours both to exploit proliferative signalling and to evade immune surveillance. Here, we propose a strategy that employs a combination of monoclonal antibodies (mAbs) targeting two distinct antigens (Ags) at sub-cytotoxic doses. This approach aims to achieve a threshold cytotoxic density of immune complexes selectively on malignant cells expressing both target Ags, while sparing normal cells that express only one. Typically, the first target Ag may be a growth factor receptor, such as epidermal growth factor receptor (EGFR and HER1), epidermal growth factor receptor 2 (HER2), or vascular endothelial growth factor receptor 2 (VEGFR2), and the second, an immunoinhibitory molecule, such as programmed death-ligand 1 (PD-L1). Selective mAb-mediated tumour destruction is expected to enhance neoantigen (NeoAg) presentation to the immune system, while the blockade of PD-1/PD-L1 interactions should further stimulate anti-tumour immune responses. Notably, this strategy can be implemented using clinically approved therapeutic mAbs, potentially enabling rapid translation into clinical practice without extensive regulatory hurdles.