EGFR-mutant NSCLC cells were treated with OT (osimertinib + trametinib) + XAV939 for 3 weeks. After drug washout, cell regrowth was monitored to assess dormancy. YAP activity was tracked using a fluorescent YAP reporter and nuclear localization assays. CRISPR/Cas9-mediated YAP1 knockout and CellTiter-Glo/apoptosis assays confirmed that XAV939 blocked YAP activation, increased apoptosis, and prevented dormant cell survival and regrowth. This evidence concerns the gene YAP1 and non-small cell lung carcinoma.