Successful treatment with nilotinib after imatinib failure in a CML patient with a four-way Ph chromosome translocation and point mutations in BCR/ABL gene
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- Okada, M., Satake, A., Kaida, K. et al. Int J Hematol (2011) 93: 243. doi:10.1007/s12185-011-0769-z
Chronic myelogenous leukemia (CML) is characterized by Philadelphia (Ph) chromosome with a chimeric gene BCR–ABL created by reciprocal t(9:22) (q34;q11) translocation. Variant Ph chromosome translocations involving chromosomes other than 9 and 22 are found in 5–10% of CML cases. We here report a CML patient who carries a four-way Ph chromosome translocation, t(9;22;15;19) (q34;q11;q15;q13). The patient was diagnosed in 1997 and initially treated with hydroxyurea. In 2002, treatment with imatinib, a selective BCR–ABL tyrosine kinase inhibitor (TKI), was started but Ph-positive chromosomes remained at the levels of 42–65%, indicating imatinib failure. In 2006, the point mutations of F359I and L387M were detected in BCR/ABL gene, which may be related to imatinib failure. Treatment with nilotinib, a TKI with high target specificity, was then started which resulted in durable major molecular response. Administration of nilotinib offered an effective treatment in a CML patient with variant Ph chromosome translocations and BCR–ABL point mutations after imatinib failure.