An orally available, selective inhibitor of ALK (IC50 = 1.9 nM) that also inhibits F1174L, R1275Q, and L1196M mutants of ALK (IC50s = 1.0, 3.5, and 1.6 nM, respectively); inhibits the growth of tumors in mouse xenograft models of nonsmall cell lung cancer and anaplastic large-cell lymphoma.