ES009: A Potential Best-in-Class Antibody Targeting LILRB2


ES009 is a potential best-in-class monoclonal antibody targeting LILRB2 designed to reprogram inhibitory myeloid cells to create an immune favorable TME. LILRB2 is an inhibitory receptor that suppresses myeloid cell activation. Blocking LILRB2 reverses immunosuppression by reprograming tumor-associated macrophages (TAMs) from M2 (pro-tumor) to M1 (anti-tumor) phenotype, leading to immune responses including myeloid cell activation and pro-inflammatory cytokine release. 

In preclinical studies, ES009 demonstrated potent ligand blockade and effective reprogramming of TAMs from M2 to M1, leading to pro-inflammatory cytokine release from macrophages as well as T cell proliferation and activation. 


Mechanism of Action

  • LILRB2 is a critical inhibitory receptor expressed on myeloid cells (including monocytes, dendritic cells, macrophages and neutrophils), mediated by functional ligands such as HLA-G which are mainly expressed on tumor cells
  • LILRB2 blocking promotes macrophage switch from pro-tumor M2 to anti-tumor M1 phenotype and activates pro-inflammatory response in the TME
  • LILRB2-mediated immune suppression is regarded as one mechanism of anti-PD-(L)1 resistance 


Key Differentiation

  • Distinct epitope with multiple-ligand HLA-G and HLA-A2 blocking
  • High binding affinity and specificity against human LILRB2
  • Higher pro-inflammatory cytokine release in M2-T co-culture
  • Promotes T cell proliferation and activation