Nazartinib is a selective inhibitor of epidermal growth factor receptor (EGFR) with activity against both activating mutations and the T790M resistance mutation commonly found in non-small cell lung cancer (NSCLC). It is primarily developed for the treatment of patients with EGFR-mutated NSCLC who have progressed on first- or second-generation EGFR inhibitors due to the emergence of resistance. The compound shows strong central nervous system (CNS) penetration, making it particularly effective in controlling brain metastases, which are a common complication in advanced EGFR-mutant lung cancer. Its targeted mechanism allows for sustained inhibition of mutant EGFR signaling while sparing wild-type EGFR, potentially reducing skin and gastrointestinal toxicities commonly seen with broader EGFR inhibitors. Nazartinib has been evaluated in clinical trials to assess its efficacy and safety as a monotherapy and in combination with other agents. It represents a potential therapeutic option for patients with limited treatment alternatives, especially those with CNS involvement. Ongoing research continues to explore optimal dosing, long-term outcomes, and combination strategies to improve patient response and delay resistance.