Dasatinib versus imatinib in Japanese patients with newly diagnosed chronic phase chronic myeloid leukemia: a subanalysis of the DASISION 5-year final report.

The international phase III DASISION trial demonstrated improved efficacy of dasatinib versus imatinib in treatment-naive patients with chronic myeloid leukemia in the chronic phase (CML-CP). We report efficacy and safety outcomes in a Japanese population from the final, 5-year follow-up of DASISION. At the end of the study, 77% (20/26) of dasatinib-treated and 61% (14/23) of imatinib-treated patients remained on initial therapy. Improved responses were observed in Japanese patients who received dasatinib versus imatinib (complete cytogenetic response: 96 vs 87%; major molecular response: 88 vs 74%; BCR-ABL1 ≤0.0032% International Scale [MR4.5]: 58 vs 52%). In patients who achieved BCR-ABL1 ≤10% at 3 months, 5-year progression-free survival and overall survival rates were high with dasatinib (96 and 96%) and imatinib (88 and 100%). The majority of adverse events were grade 1/2 in Japanese patients. Pleural effusion occurred more frequently in dasatinib-treated Japanese patients versus all patients (42 vs 28%), with no treatment discontinuations. Overall, in Japanese patients, dasatinib maintained its safety profile and had higher or comparable response and survival outcomes compared with imatinib or with all patients in DASISION. These findings demonstrate the long-term efficacy and tolerability of dasatinib and support frontline treatment of Japanese patients with CML-CP with dasatinib.