〈Cases Reports〉Achievement of complete molecular response by the switch from imatinib to dasatinib in a patient with chronic myeloid leukemia in chronic phase

publisher[Abstract] The prognosis of chronic myeloid leukemia (CML) in chronic phase (CP) have been greatly improved by a tyrosine kinase inhibitor (TKI),imatinib. However, some patients show resistance or intolerance to imatinib. For such patients, more potent 2^nd generation TKIs, nilotinib and dasatinib, were developed, and have been shown to be effective for imatinib resistant/intolerant cases. We here report a case with CML-CP, who had been treated with interferon (IFN) and hydroxycarbamide (HU) since 1999. Although complete hematologic response was achieved by IFN+HU, any cytogenetic response was not obtained. So, we changed IFN + HU to imatinib from 2002. She achieved complete cytogenetic response and major molecular response at 18 and 44 months from the start of imatinib, respectively. However, minimum residual disease (MRD) was still detected by thenested PCR at 94 months. In addition, she complained of side effects of imatinib, general fatigue and muscle clumps. So, we changed imatinib to dasatinib. Without any side effect of dasatinib, MRD became undetectable twelve months after the switch to dasatinib. This case suggests that the switch from imatinib to 2^nd TKI would be a useful option for CML-CP patients with MRD and/or side effects in terms of both efficacy and quality of life