The goals of the present study were as follows: 1) to determine the major molecular response rate (MMR) at 12 months of twice daily (BID) treatment with 400 mg nilotinib in patients with imatinib-resistant/intolerant CML-CP or -AP; 2) to evaluate molecular responses associated with BCR-ABL1 mutation status or plasma concentrations of nilotinib; and 3) to evaluate the safety of administering 400 mg nilotinib BID, including hyperbilirubinemia development, based on plasma concentrations of nilotinib or polymorphisms of UGT1A1 and UGT1A9. The gene discussed is UGT1A9; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.