Pelitinib (EKB-569; WAY-EKB 569) is a potent irreversible EGFR inhibitor with IC50 of 38.5 nM.
Pelitinib displays much higher inhibitory activity against EGFR, compared with the closely related c-erbB-2, as well as other kinases such as Src, Cdk4, c-Met, Raf, and MEK/ERK, with IC50 ranging from 282 nM for Src to >20 M for Cdk4. Consistently, Pelitinib treatment significantly inhibits the autophosphorylation of EGFR but not c-Met in A431 cells . Pelitinib potently inhibits the proliferation of normal human keratinocytes (NHEK), as well as A431 and MDA-468 tumor cells with IC50 of 61 nM, 125 nM, and 260 nM, respectively, while displaying little activity against MCF-7 cells with IC50 of 3.6 M. Pelitinib inhibits EGF-induced phosphorylation of EGFR in A431 and NHEK cells with IC50 of 20-80 nM, as well as the phosphorylation of STAT3 with IC50 of 30-70 nM. Pelitinib at 75-500 nM also specifically inhibits the activation of AKT and ERK1/2, without affecting NF-B pathway. In NHEK cells, Pelitinib also potently inhibits TGF- mediated EGFR activation with IC50 of 56 nM, as well as activation of STAT3 and ERK1/2 with IC50 of 60 nM and 62 nM, respectively