Clinical impact of subclonal EGFR T790M mutations in advanced-stage EGFR-mutant non-small-cell lung cancers

A recent clinical trial shows that a proportion of lung cancer patients carrying the EGFR T790M mutation develop resistance to osimertinib. In this study, the authors show that T790M subclonality is associated with worse clinical outcome likely through co-occurring PIK3CA alterations, which can be targeted by PI3K pathway inhibitors.