Is There a Difference Between on Target Resistance and Off Target Resistance?

Ross: Would somebody who progressed after a year and a half make you nervous that maybe something else is going on? Justin: We need to draw a distinction between clear evidence of benefit and then the development of resistance. Ross: I'm curious how you approach patients who are non-smokers and yet on next generation sequencing don't have anything. What about RNA sequencing, other assays and when you do that what do you find?