ABT-869 is multi-targeted inhibitor of all members of the VEGF and PDGF receptor families (e.g., KDR, IC₅₀ value of 4 nM), but has much less activity (IC₅₀ values >1 µM) against unrelated receptor tyrosine kinases, soluble tyrosine kinases or serine/threonine kinases. The kinase inhibition profile of ABT-869 is evident in cellular assays of RTK phosphorylation (IC₅₀ values of 2, 4 and 7 nM for PDGFRβ, KDR and CSF-1R, respectively) and VEGF-stimulated proliferation (0.2 nM IC₅₀ for human endothelial cells).