An orally available inhibitor of the receptor tyrosine kinase anaplastic lymphoma kinase (ALK) with antineoplastic activity. Upon administration, ALK inhibitor RO5424802 binds to and inhibits ALK kinase, which leads to a disruption of ALK-mediated signaling and eventually inhibits tumor cell growth in ALK-overexpressing tumor cells. ALK belongs to the insulin receptor superfamily and plays an important role in nervous system development. ALK dysregulation and gene rearrangements are associated with a series of tumors. Additionally, ALK mutations are associated with acquired resistance to small molecule tyrosine kinase inhibitors.