EGF816 (S-enantiomer), also known as Nazartinib S-enantiomer, is primarily investigated for its application in the treatment of non-small cell lung cancer (NSCLC). It functions as a potent and selective epidermal growth factor receptor (EGFR) inhibitor, specifically targeting mutant forms of EGFR that are often associated with resistance to first-generation EGFR inhibitors. This makes it particularly useful in patients who have developed resistance to earlier treatments, such as those with the EGFR T790M mutation. The compound is designed to improve therapeutic outcomes by effectively blocking the signaling pathways that promote tumor growth and survival. Clinical trials have focused on its efficacy and safety profile, aiming to establish it as a viable option for advanced or metastatic NSCLC cases. Additionally, its S-enantiomer form is emphasized for its enhanced pharmacological properties, contributing to better bioavailability and reduced side effects compared to racemic mixtures.