Three novel cytolysin molecules were designed and synthesized, to be conjugated to Oncomatryx human mAbs in a novel precision drug.

High microtubule polymerization inhibition and cytotoxic activity of the novel cytolysins were confirmed.

Natural 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
  • Derivatives accesible 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

Nigrin b – A chain

 Nigrin b

  • Plant toxin from Sambucus nigra (bark)
  • Member of Type 2 RIP family
  • Heterodimer derived from a unique precursor through post-translational processing
  • B chain function: Binding to cell membrane carbohydrates and internalization
  • A chain function: 28S rRNA N-glycosidase activity that inhibits E2F binding to ribosome
  • Similar RIP activity as Ricin in cell-free extracts
  • Much lower Toxicity than Ricin to intact cells and animals
  • Different Intracellular Pathway after internalization
  • Different surface receptors


recNigrin b – A chain

  • Oncomatryx has cloned, expressed in bacteria and purified the recombinant A chain of Nigrin b, responsible for the RIP activity of this plant toxin
  • recNigrin b- A chain lacks B chain, the lectin domain that is responsible for the cell internalization and immunogenicity of this toxin
  • RIP activity of recNigrin b- A chain is maintained.
  • Immunogenicity of recNigrin b- A chain is much lower than Nigrin b, whose immunogenicity is already much lower than other RIPs (Lavelle)
  • In silico – predicted immunogenicity of recNigrin b-Achain is lower than commercial therapeutic antibodies as Rituximab
  • Robust IP position


Rabbit Lysate HeLa CellsMouse LD50
IC50 (pM) IC50 (pM) (μg/kg)
Ricin 100 0.67 3.00
Nigrin-b 30 27,600.00 12,000.00












By continuing to use the site, you agree to the use of cookies. Continue, scroll or accept. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.