A drug used to treat non-small cell lung cancer that has spread to other parts of the body. It is used in patients whose cancer has a mutated (changed) form of the anaplastic lymphoma kinase (ALK) gene or the ROS1 gene. It is also being studied in the treatment of other types of cancer. Crizotinib blocks the proteins made by the mutated ALK and ROS1 genes. Blocking these proteins may stop the growth and spread of cancer cells. Crizotinib may also prevent the growth of new blood vessels that tumors need to grow. It is a type of tyrosine kinase inhibitor and a type of antiangiogenesis agent.