The resistance is growing.

A mutation in EGFR T790M is a known cause of resistance to older EGFR-TKIs and is a common indication for switching to osimertinib. A novel report shows that loss of this T790M mutation may in turn cause resistance to osimertinib. Plus, a coinciding study indicates that EGFR-TKI induced clonal variation in T790M-dependent and independent pathways within the same patient likely explain mixed responses to therapy. | Oxnard, JAMA Oncol 2018 & Piotrowska, J Clin Oncol 2018