Is Real-World Evidence on Acquired Resistance to Osimertinib Relevant Clinically?

Osimertinib is the standard therapy for patients with treatment-naive advanced NSCLC, where the tumors carry EGFR mutation,1 and for those with advanced NSCLC whose tumors have progressed on first- or second-generation EGFR inhibitors and carry EGFR T790M mutations.2 Acquired resistance to osimertinib has been reported, and this resistance may be EGFR on-target or EGFR off-target (selected review by Blaquier et al.3). Most reports on acquired resistance to osimertinib have adopted a retrospective design and involved small sample sizes.