EKB-569 (Pelitinib), an irreversible EGFR tyrosine kinase inhibitor has shown potential therapeutic efficiency in solid tumors. In SCC-4 and SCC-9 cells, Pelitinib inhibited IR-induced NF-kB, telomerase activity and hTERT transactivation. Ionizing radiation-induced telomerase activity is regulated at the transcriptional level by triggering TERT promoter activation. 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. The ABCG2 multidrug transporter confers resistance to gefitinib and pelitinib. In breast and ovarian cancer cells, although ErbB phosphorylation was reduced by pelitinib and canertinib, activation of the AKT/mTOR pathway remained essentially unaltered in drug-resistant cells.
In vivo
A single oral dose of 10 mg/kg Pelitinib potently inhibits the EGFR phosphorylation in A431 xenografts with over-expressed EGFR, by 90% within 1 hour, and by >50% after 24 hours.In the cy/+ rats with overexpression, activation and apical mislocalization of EGFR, the administration of EKB-569 by gavage was less effective probably because of lower bioavailability. EKB-569 is as effective as first-generation EGFR tyrosine kinase inhibitors in reducing cyst formation and preserving renal function. Treatment of BPK mice with EKB-569 alone resulted in a marked reduction of kidney weight/body weight ratios.