NCIt definition : A bispecific monoclonal antibody directed against the human epidermal growth factor
receptor ErbB3 (Her3) and the human insulin-like growth factor-1 receptor (IGF-1R),
with potential antineoplastic activity. The anti-IGF-1R targeting arm of Istiratumab
binds to IGF-1R on tumor cells thereby preventing the binding of the natural ligands
IGF-1, 2 and heregulin (HRG) to IGF-1R; the anti-ErbB3 therapeutic arm prevents the
binding of neuregulin (NRG) to ErbB3. This prevents the activation of the PI3K/AKT
signal transduction pathway and may result in both the induction of apoptosis and
a decrease in cellular proliferation in IGF-1R and ErbB3-overexpressing tumor cells.
IGF-1R, a receptor tyrosine kinase of the insulin receptor superfamily, and ErB3,
a member of the epidermal growth factor receptor (EGFR) family of receptor tyrosine
kinases, are frequently overexpressed in solid tumors.;