Nilotinib has a higher binding affinity and selectivity for the ABL kinase than does imatinib, which translates into 20- to 50-fold greater inhibitory activity than imatinib in imatinib-sensitive CML cells and 3- to 7-times the activity in imatinib-resistant cell lines with mutant ABL kinases [1-5]. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.