ALK and neuroblastoma: TSR-011 has potency at nanomolar concentrations against wild-type ALK in vitro and in ALK-dependent cellular models, as well as in ALK-dependent tumour growth inhibitory activity in mouse models.12,14 In addition, TSR-011 is ~200-fold more potent than crizotinib against the L1196M ALK gatekeeper mutant form and is also about 10-fold more potent than crizotinib against the R1275Q mutant,14 which is one of the most common activating mutations in neuroblastoma.15