Resistance mechanisms were diverse, including EGFR amplification, RTK/RAS pathway alterations, and rare events such as gene fusion and small-cell lung cancer transformation.<h4>Conclusions</h4>Mobocertinib demonstrated clinically meaningful activity, regardless of previous exposure to amivantamab, in EGFR exon 20 insertion-positive NSCLC subjects. This evidence concerns the gene EGFR and non-small cell lung carcinoma.