Abstract
BackgroundNilotinib is a second-generation tyrosine kinase inhibitor that exhibits significant efficacy as first- or second-line treatment in patients with chronic myeloid leukemia (CML). We conducted a multicenter Phase II Clinical Trial to evaluate the safety and efficacy of nilotinib among Japanese patients with imatinib-resistant or -intolerant CML-chronic phase (CP) or accelerated phase (AP).ResultsWe analyzed 49 patients (33 imatinib-resistant and 16 imatinib-intolerant) treated with nilotinib 400 mg twice daily. The major molecular response (MMR) rate was 47.8% at 12 months among 35 patients who did not demonstrate an MMR at study entry. Somatic BCR-ABL1 mutations (Y253H, I418V, and exon 8/9 35-bp insertion [35INS]) were detected in 3 patients at 12 months or upon discontinuation of nilotinib. Although 75.5% of patients were still being treated at 12 months, nilotinib treatment was discontinued because of progressing disease in 1 patient, insufficient effect in 2, and adverse events in 9. There was no statistically significant correlation between MMR and trough concentrations of nilotinib. Similarly, no correlation was observed between trough concentrations and adverse events, except for pruritus and hypokalemia. Hyperbilirubinemia was frequently observed (all grades, 51.0%; grades 2–4, 29%; grades 3–4, 4.1%). Hyperbilirubinemia higher than grade 2 was significantly associated with the uridine diphosphate glucuronosyltransferase (UGT)1A9 I399C/C genotype (P = 0.0086; Odds Ratio, 21.2; 95% Confidence Interval 2.2–208.0).ConclusionsNilotinib was efficacious and well tolerated by patients with imatinib-resistant or -intolerant CML-CP/AP. Hyperbilirubinemia may be predicted before nilotinib treatment, and may be controlled by reducing the daily dose of nilotinib in patients with UGT1A9 polymorphisms.Trial registrationclinicaltrials.gov: UMIN000002201
Highlights
Nilotinib is a second-generation tyrosine kinase inhibitor that exhibits significant efficacy as first- or second-line treatment in patients with chronic myeloid leukemia (CML)
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-chronic phase (CP) or -accelerated phase (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 uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) and UGT1A9
The present study revealed that nilotinib therapy was effective in Japanese patients with CML-CP/AP who have developed imatinib resistance or intolerance
Summary
Nilotinib is a second-generation tyrosine kinase inhibitor that exhibits significant efficacy as first- or second-line treatment in patients with chronic myeloid leukemia (CML). We conducted a multicenter Phase II Clinical Trial to evaluate the safety and efficacy of nilotinib among Japanese patients with imatinib-resistant or -intolerant CML-chronic phase (CP) or accelerated phase (AP). Point mutations in BCR-ABL1 are a major cause of imatinib-resistance, nilotinib is effective in patients with known point mutations in this oncogene, with the exception of the T315I mutation [3]. The frequency or profile of BCR-ABL1 point mutations has not been determined in daily practice when treating Japanese patients with imatinib-resistant CML in chronic phase (CP) or accelerated phase (AP). We are not aware of any studies that have examined a correlation between hyperbilirubinemia and the UGT1A9 I399C > T polymorphism
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