Iressa insights

Ever since Iressa gefitinib received accelerated approval in 2003 for non-small cell lung cancer, AstraZeneca plc has been trying to find a way to identify the 10% of patients who respond to the drug, which targets the epidermal growth factor (EGF) receptor (HER1). The anecdotal populations that seem to respond - women, non-smokers, Asians and patients with adenocarcinomas - don't provide much guidance. What's needed are biomarkers.

Last week, researchers reported in the Proceedings of the National Academy of Sciencesa novel molecular resistance marker to Iressa that is not based solely on in vitro data but also on patient samples. The marker seems to be associated with both primary and acquired Iressa resistance. Previously, only one study had identified in vivo a mutation correlating with Iressa resistance, and that mutation correlates only with acquired, not with primary, resistance to the drug...