Background:

AST1306 is a novel inhibitor of EGFR and HER2 (IC50 = 0.5 nM and 3 nM respectively)

EGFR (epidermal growth factor receptor) is a cell-surface receptor tyrosine kinase. The receptor activation leads to dimerization and tyrosine autophosphorylation. It induces a cascade of downstream cellular responses such as modification in gene expression, cell proliferation and cytoskeletal rearrangement etc. HER2 is a member of the epidermal growth factor and is associated with breast and ovarian cancers.

AST1306 selectively blocked EGFR and HER2 kinase activities in a cell-free assay. The tyrosine kinase activity of EGFR mutant T790M/L858R was also inhibited by AST1306 in intact cell and cell-free assays. In addition, AST1306 attenuated the EGFR and HER2 phosphorylation and downstream substrates. [1]

In ErbB2-overexpressing xenograft and FVB-2/Nneu transgenic mouse model, AST1306 potently inhibited tumor growth. In SK-OV-3 xenograft model, AST1306 caused a quick and long-lasting (≥24h) inhibition of EGFR and HER2. [1]

Reference:
1. Xie H, Lin L, Tong L et al.  AST1306, a novel irreversible inhibitor of the epidermal growth factor receptor 1 and 2, exhibits antitumor activity both in vitro and in vivo. PLoS One. 2011;6(7):e21487.