In particular, ceritinib effectively inhibits ALK harboring L1196M...mutations, and a co-crystal of ceritinib bound to ALK provides structural bases for this increased potency….These data demonstrate that ceritinib is active against cancers derived from patients with acquired resistance to crizotinib and is more potent than crizotinib against ALK-rearranged cancers harboring the L1196M and G1269A resistance mutations.