PD-1 + VEGFA

Class

PD-1/VEGF bispecific antibody (IgG4 Fab-PD-1 arm + anti-VEGFA nanobody)

Pathway

blocks PD-1/PD-L1-PD-L2 immune checkpoint interaction while simultaneously inhibiting VEGF-driven angiogenesis; VEGFA binding enhances PD-1 engagement/internalization

PD-1 is an inhibitory receptor on T cells that, when engaged by its ligands PD-L1 and PD-L2 on tumor or immune cells, dampens T-cell activity—a checkpoint that tumors exploit to evade immune attack. VEGFA is a signaling protein that drives angiogenesis, the formation of new blood vessels; tumors secrete VEGFA to build a vascular supply, and VEGFA also has direct immunosuppressive effects on T cells and antigen-presenting cells. This bispecific antibody format combines a PD-1-blocking arm with a VEGFA-neutralizing arm in a single molecule, addressing both an immune-evasion pathway and the tumor vasculature/immunosuppressive microenvironment simultaneously. The rationale for pairing these two mechanisms is that anti-angiogenic activity can normalize aberrant tumor blood vessels and reduce VEGFA's suppressive effect on immune cells, potentially making checkpoint blockade more effective, while checkpoint blockade independently restores antitumor T-cell activity. A bispecific design may also favor binding within the tumor microenvironment, where both targets are locally abundant, compared with giving two separate drugs. This combined mechanism is broadly relevant across solid tumors in which immune evasion and pathological blood vessel growth occur together, reflecting a wider strategy of pairing checkpoint inhibition with anti-angiogenic activity within one therapeutic agent.