Novartis Oncology (previously Novartis) is developing nazartinib (formerly EGF 816), a third generation mutant-selective tyrosine kinase inhibitor (TKI) of epidermal growth factor receptor (EGFR), for the treatment of solid malignancies, with a focus on non-small cell lung cancer. Nazartinib is a covalent mutant-selective EGFR inhibitor, with Ki and Kinact of 31 nM and 0.222 min−1 on EGFR(L858R/790M) mutant, respectively. Upon oral administration, nazartinib covalently binds to and inhibits the activity of mutant forms of EGFR, including the T790M EGFR mutant, thereby preventing EGFR-mediated signaling. This may both induce cell death and inhibit tumor growth in EGFR-overexpressing tumor cells. EGFR, a receptor tyrosine kinase mutated in many tumor cell types, plays a key role in tumor cell proliferation and tumor vascularization. EGF816 preferentially inhibits mutated forms of EGFR including T790M, a secondarily acquired resistance mutation, and may have therapeutic benefits in tumors with T790M-mediated resistance when compared to other EGFR tyrosine kinase inhibitors. As this agent is selective towards mutant forms of EGFR, its toxicity profile may be reduced as compared to non-selective EGFR inhibitors which also inhibit wild-type EGFR.