Crizotinib (trade name Xalkori, Pfizer, Inc.) is an anti cancer drug approved for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors are anaplastic lymphoma kinase (ALK)-positive as detected by an FDA-approved test. Crizotinib is an inhibitor of receptor tyrosine kinases including ALK, Hepatocyte Growth Factor Receptor (HGFR, c-Met), ROS1 (c-ros), and Recepteur d’Origine Nantais (RON). Common adverse reactions in clinical trials with crizotinib, occurring at an incidence of 25% or higher, included visual disorders, nausea, diarrhea, vomiting, constipation, edema, elevated transaminases, and fatigue. Crizotinib is currently under investigational study for use in treatment of Uveal Melanoma.

(S)-crizotinib was discovered as an attractive chemical entity for further pre-clinical evaluation, and small-molecule inhibitors of MTH1 as a promising novel class of anticancer agents.