Mechanism of Action of Amivantamab-Lazertinib in EGFR-Mutated NSCLC and the Biology of Resistance Prevention

Dr. Gumbleton explains the mechanism of action of amivantamab-lazertinib for clinicians treating patients with EGFR-mutated NSCLC. Lazertinib is a highly selective, CNS-penetrant, third-generation EGFR TKI that blocks downstream mitogenic signaling from the mutant EGFR kinase, preventing cancer cell survival and proliferation. Amivantamab is an EGFR-MET bispecific antibody that operates through multiple distinct mechanisms: it blocks EGFR ligand binding and receptor signaling; facilitates immune cell-directed tumor killing through antibody-dependent cellular cytotoxicity (ADCC); causes EGFR internalization and receptor degradation; and simultaneously binds and blocks MET, the dominant bypass resistance mechanism for EGFR-driven NSCLC.

Dr. Gumbleton highlights MET amplification as underappreciated in its frequency and importance, noting that although published thresholds for defining MET amplification may be set too high, biologically meaningful MET dysregulation occurs frequently in patients progressing on single-agent EGFR TKI therapy. Preemptive MET blockade with amivantamab prevents acquisition of this resistance mechanism, explaining the distinctly different post-progression resistance profiles between the 2 intensified regimens. Biopsy data at progression demonstrate that MET amplification is common after osimertinib or osimertinib-chemotherapy, but not after amivantamab-lazertinib, consistent with upfront MET targeting.

Dr. Riess adds that the mechanistic dual EGFR targeting, wild-type EGFR inhibition from amivantamab plus mutant EGFR inhibition from lazertinib, directly produces the amivantamab-lazertinib adverse effect profile: EGFR-mediated toxicities drive dermatologic adverse events (rash, paronychia, pruritus), whereas MET inhibition contributes to peripheral edema and hypoalbuminemia. Understanding this mechanistic link helps clinicians anticipate and manage specific adverse events before they escalate and allows for dose reduction or interruption as effective interventions.