Pelitinib (also known as EKB-569), a 3-cyanoquinoline, is a potent, and irreversible inhibitor of epidermal growth factor receptor (EGF-R) tyrosine kinase that inhibits the activity of EGF-R with the half maximal inhibition concentration IC50 value of 38.5 nM in vitro [1].

Pelitinib has been found to exert a potent anti-proliferative activity against tumor cells overexpressing EGF-R, including NHEK, A431 and MDA-468 cells, with IC50 values of 61 nM, 125 nM and 260 nM respectively; while it has also been found to potently inhibit EGF-induced phosphorylated EGF-R (pEGF-R) in A431 and NHEK cells with IC50 values ranging from 20 nM to 80 nM [2].

References:
[1] Torrance CJ, Jackson PE, Montgomery E, Kinzler KW, Vogelstein B, Wissner A, Nunes M, Frost P, Discafani CM. Combinatorial chemoprevention of intestinal neoplasia. Nat Med. 2000 Sep;6(9):1024-8.
[2] Nunes M, Shi C, Greenberger LM. Phosphorylation of extracellular signal-regulated kinase 1 and 2, protein kinase B, and signal transducer and activator of transcription 3 are differently inhibited by an epidermal growth factor receptor inhibitor, EKB-569, in tumor cells and normal human keratinocytes. Mol Cancer Ther. 2004 Jan;3(1):21-7.