Monovalent antibody design and mechanism of action of onartuzumab, a MET antagonist with anti-tumor activity as a therapeutic agent

Proc Natl Acad Sci U S A. 2013 Aug 6;110(32):E2987-96. doi: 10.1073/pnas.1302725110. Epub 2013 Jul 23.


Binding of hepatocyte growth factor (HGF) to the receptor tyrosine kinase MET is implicated in the malignant process of multiple cancers, making disruption of this interaction a promising therapeutic strategy. However, targeting MET with bivalent antibodies can mimic HGF agonism via receptor dimerization. To address this limitation, we have developed onartuzumab, an Escherichia coli-derived, humanized, and affinity-matured monovalent monoclonal antibody against MET, generated using the knob-into-hole technology that enables the antibody to engage the receptor in a one-to-one fashion. Onartuzumab potently inhibits HGF binding and receptor phosphorylation and signaling and has antibody-like pharmacokinetics and antitumor activity. Biochemical data and a crystal structure of a ternary complex of onartuzumab antigen-binding fragment bound to a MET extracellular domain fragment, consisting of the MET Sema domain fused to the adjacent Plexins, Semaphorins, Integrins domain (MET Sema-PSI), and the HGF β-chain demonstrate that onartuzumab acts specifically by blocking HGF α-chain (but not β-chain) binding to MET. These data suggest a likely binding site of the HGF α-chain on MET, which when dimerized leads to MET signaling. Onartuzumab, therefore, represents the founding member of a class of therapeutic monovalent antibodies that overcomes limitations of antibody bivalency for targets impacted by antibody crosslinking.

Keywords: HGFR; MetMAb; OA5D5; scatter factor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Monoclonal / chemistry
  • Antibodies, Monoclonal / genetics
  • Antibodies, Monoclonal / metabolism
  • Antibodies, Monoclonal / pharmacology*
  • Antibodies, Monoclonal, Humanized / chemistry
  • Antibodies, Monoclonal, Humanized / genetics
  • Antibodies, Monoclonal, Humanized / pharmacology*
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Crystallography, X-Ray
  • Drug Design
  • Hepatocyte Growth Factor / chemistry
  • Hepatocyte Growth Factor / metabolism
  • Hepatocyte Growth Factor / pharmacology
  • Humans
  • Immunoglobulin Fab Fragments / chemistry
  • Immunoglobulin Fab Fragments / genetics
  • Immunoglobulin Fab Fragments / pharmacology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C3H
  • Mice, Nude
  • Mice, SCID
  • Mice, Transgenic
  • Models, Molecular
  • Molecular Sequence Data
  • Neoplasms / drug therapy*
  • Neoplasms / pathology
  • Protein Binding / drug effects
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins c-met / antagonists & inhibitors*
  • Proto-Oncogene Proteins c-met / chemistry
  • Proto-Oncogene Proteins c-met / metabolism
  • Sequence Homology, Amino Acid
  • Xenograft Model Antitumor Assays*


  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Agents
  • Immunoglobulin Fab Fragments
  • Hepatocyte Growth Factor
  • Proto-Oncogene Proteins c-met
  • onartuzumab

Associated data

  • PDB/4K3J