Theliatinib (Xiliertinib) tartrate is a potent, ATP-competitive, orally active and highly selective EGFR inhibitor with a K i of 0.05 nM and an IC 50 of 3 nM. Theliatinib has an IC 50 of 22 nM for EGFR T790M/L858R mutant. Theliatinib shows >50-fold selectivity for EGFR than other kinases. Theliatinib (tartrate) is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.