Used in the treatment of non-small cell lung cancer (NSCLC), particularly in patients with EGFR exon 19 deletion or exon 21 L858R substitution mutations. It acts as an irreversible inhibitor of the epidermal growth factor receptor (EGFR), blocking signaling pathways that drive tumor growth and proliferation. Dacomitinib is taken orally and has shown improved progression-free survival compared to earlier EGFR inhibitors in first-line therapy. Its use is limited to biomarker-selected patients due to higher toxicity in wild-type EGFR populations. Currently approved for clinical use in several countries as a targeted therapy option for advanced or metastatic NSCLC.