• Membrane protein of endothelial cells
  • Internalization capability
  • TGF-beta receptor pathway
  • Overexpression in tumor microvasculature cells
  • In healthy adult tissues, ENG expression is detectable only in kidney and placenta.
  • Optimal accessibility from blood
  • Associated to angiogenesis and neovascularization in different types of cancer


  • OMTX003 anti-ENG human mAb A5 and mE12 IgG1s bind in a concentration-dependent manner to human and murine ENG, respectively, at subnanomolar and nanomolar E50 values
  • OMTX003 anti-ENG human mAb A5 is rapidly internalized within cells. (75% after 60min)
  • OMTX003 anti-ENG human mAb A5 binds primate ENG
  • HUVEC apoptosis increases in response to human mAb OMTX005 A5
  • Angiogenesis is reduced in response to human mAb OMTX005 A5


Natural cytoysins, Tubulysins:

  • Isolated from Myxobacteria
  • Very strong cytotoxic activity (nM to pM range)
  • Tubulin polymerization inhibitors that block formation of mitotic spindles
  • Stable in lysosome enriched cell fraction



Synthetic Cytolysins

  • Synthetic Tetrapeptidic analogues of the natural class Tubulysins
  • Low MW: 780 g/mol
  • Not a substrate of Multiple Drug Resistance proteins
  • Highly cytotoxic
  • Anti-angiogenic
  • Easy to conjugate
  • Achievable by total synthesis in sufficient amount for preclinical and clinical development
  • Functional group for linker technology can be modified
  • Several linker technologies applicable
  • Robust IP position
  • Different combinations of cytolysins and linkers were evaluated in vitro as well as in vivo models and TAM558 was selected as the optimal structure for highest activity and stability


TAM558, a selected cytolysin-linker has been conjugated to OMTX003 human anti-ENG antibodies to generate OMTX703.

OMTX703 shows 100% tumor growth inhibition in preclinical models for Ewing sarcoma of MD Anderson Cancer Center.