Strategies for overcoming inherent and acquired resistance to EGFR inhibitors by targeting downstream effectors in the RAS/PI3K pathway.

Abstract

Mutations in K-Ras are observed in approximately 40% of colon tumours. This has significant implications for predicting likelihood of response to the antibody-based EGFR inhibitors, cetuximab and panitumumab, with K-Ras mutant patients now clearly shown to be inherently resistant to these agents. Alternative treatment strategies for K-Ras mutant patients are therefore urgently needed. Farnesyltransferase inhibitors, developed to inhibit K-Ras, have to-date been largely unsuccessful. However, a number of agents which target signaling components in the MAPK and PI3K pathways downstream of mutant K-Ras are currently being evaluated in clinical trials and will be discussed. A further clinical co..