Used primarily in the treatment of non-small cell lung cancer (NSCLC), especially in patients with specific epidermal growth factor receptor (EGFR) mutations. It functions as a tyrosine kinase inhibitor, blocking signals involved in the growth and spread of cancer cells. Gefitinib is taken orally and is preferred in cases where chemotherapy is less effective or not well tolerated. It has shown improved progression-free survival and response rates in EGFR-positive patients, making it a key option in targeted cancer therapy.