Efficacy and safety of tyrosine kinase inhibitors for newly diagnosed chronic-phase chronic myeloid leukemia over a 5-year period: results from the Japanese registry obtained by the New TARGET system.

We report the results of a multicenter observational study using the New TARGET system, in which the effectiveness and safety of tyrosine kinase inhibitors (TKIs) were evaluated in newly diagnosed chronic-phase chronic myeloid leukemia (CML) patients. A total of 506 patients were enrolled between April 2010 and March 2013. Median age was 56 (range 18-92) years; 35% of patients were females. As the first-line therapy, 139 (27.9%), 169 (33.9%) and 144 (28.9%) patients were treated with imatinib, nilotinib, and dasatinib, respectively. Five-year progression-free survival (PFS) and overall survival (OS) were 93.8% and 94.5%, respectively. The OS curve was significantly superior for patients treated with second-generation TKIs than imatinib (P = 0.0068), and an early molecular response (EMR) at 3 months (BCR-ABL1 < 10%) was detected in 328 of 377 patients evaluated for molecular response. The PFS curve was significantly superior for patients with EMR than without (P < 0.0001). Although 12 patients experienced vascular adverse events, no new safety issues were observed in patients with adverse events. The results of this observational study demonstrated that treating newly diagnosed CML-CP patients with TKI results in satisfactory and reliable outcomes.