Purity >98% by HPLC. Naquotinib is a potent, irreversible, third-generation, mutant-selective, epidermal growth factor receptor (EGFR) inhibitor that displays antineoplastic activity. Naquotinib 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.