TAS0728 is a potent, selective, orally active, irreversible and covalent-binding HER2 inhibitor, with an IC50 of 13 nM. TAS0728 also shows IC50s of 4.9, 8.5, 31, 65, 33, 25 and 86 nM for BMX、HER4、BLK、EGFR、JAK3、SLK and LOK respectively. Furthermore, TAS0728 exhibits robust and sustained inhibition of the phosphorylation of HER2.IC50 & Target:IC50: 13 nM (HER2), 4.9 nM (BMX), 8.5 nM (HER4), 31 nM (BLK), 65 nM (EGFR), 33 nM (JAK3), 25 nM (SLK), 86 nM (LOK), 36 nM (Human HER2)In Vitro: TAS0728 is a covalent-binding inhibitor of HER2 kinase and exhibits high selectivity for HER2 kinase. It also shows inhibitory activity against BMX, HER4, BLK, EGFR, JAK3, SLK, and LOK.In Vivo: TAS0728 reveals the sustained and targeted inhibition of phosphorylation of HER2, HER3, AKT and ERK. TAS0728 also shows the ability of tumor regression and low toxicity.