Ensartinib is a potent and selective inhibitor of anaplastic lymphoma kinase (ALK; IC50 < 0.4 nM in a KINOMEscan kinase activity assay).1 It reduces ALK autophosphorylation and inhibits endogenous ALK phosphorylation and activation of downstream targets ERK and Akt in H3122 cells. Ensartinib reduces growth of H3122 lung cancer cells harboring gain-of-function ALK-fusion proteins (IC50 = 15 nM) but has no effect on cell growth driven by other mutant kinases or that of non-cancerous HepG2 cells. Ensartinib, at a dose of 25 mg/kg, reduces H3122 xenograft growth with no effect on body weight in nude mice. It is also brain-permeable to a concentration of 65 nM. Formulations containing ensartinib are being used to treat non-small cell lung cancer in Phase I/II clinical trials.2 WARNING This product is not for human or veterinary use.