Used as a potent inhibitor in targeted cancer therapies, particularly in the treatment of non-small cell lung cancer (NSCLC). It functions by selectively inhibiting mutant forms of the epidermal growth factor receptor (EGFR), including T790M and activating mutations, which are commonly associated with tumor progression and resistance to earlier-generation inhibitors. By covalently binding to the ATP-binding site of these mutant receptors, it blocks downstream signaling pathways involved in cell proliferation and survival. Its structural design allows improved selectivity for mutant EGFR over wild-type, reducing off-target effects and enhancing therapeutic efficacy. This compound is especially valuable in patients who have developed resistance to first-line EGFR inhibitors, offering a targeted option with favorable pharmacokinetic properties and central nervous system penetration, making it effective against brain metastases.