PURPOSE: This Food and Drug Administration (FDA) approval report describes the data and analyses leading to the approval by the FDA of nilotinib (Tasigna, AMN-107; Novartis Pharmaceuticals Corporation), an inhibitor of Bcr-Abl tyrosine kinase, for the treatment of chronic-phase (CP) and accelerated-phase (AP) chronic myelogenous leukemia (CML) resistant to or intolerant of imatinib. EXPERIMENTAL DESIGN: The FDA approval of the efficacy and safety of nilotinib was based on the results of an ongoing single-arm, open-label, phase 2 clinical trial. The primary end point for CML-CP was unconfirmed major cytogenetic response. The efficacy end point for CML-AP was confirmed hematologic response. RESULTS: The major cytogenetic response rate in 232 evaluable CP patients was 40% (95% confidence interval, 33%, 46%). The hematologic response rate in 105 evaluable AP patients was 26% (95% confidence interval, 18%, 35%). The median duration of response has not been reached for both CML-CP and CML-AP responding patients. In CML-CP patients, the common serious drug-related adverse reactions were thrombocytopenia and neutropenia. In CML-AP patients, the common serious drug-related adverse reactions were thrombocytopenia, neutropenia, pneumonia, febrile neutropenia, leukopenia, intracranial hemorrhage, elevated lipase, and pyrexia. Nilotinib prolongs the QT interval and sudden deaths have been reported; these risks and appropriate risk minimization strategies are described in a boxed warning on the labeling. CONCLUSIONS: On October 29, 2007, the U.S. FDA granted accelerated approval to nilotinib (Tasigna) for use in the treatment of CP and AP Philadelphia chromosome positive CML in adult patients resistant to or intolerant of prior therapy that included imatinib.