Nilotinib vs. Dasatinib in Achieving MR4.5 for de novo Chronic Myeloid Leukemia: the Randomized JALSG CML212 Study.

Treatment-free remission (TFR) is a new therapeutic goal for chronic myeloid leukemia in chronic phase (CML-CP). Deep molecular response (DMR) is a prerequite condition for TFR. The Japan Adult Leukemia Study Group (JALSG) conducted a multicentral prospective randomized phase 3 CML212 study for de novo CML-CP to compare the cumulative achievement of MR4.5 (international scale [IS] BCR::ABL1≤0.0032%) by 18 months between nilotinib and dasatinib as a primary endpoint. A total of 454 patients were randomly assigned to the nilotinib 300 mg, bid arm or dasatinib 100 mg, qd arm (both, n=227). BCR::ABL1 mRNA levels were monitored every three months. Study treatment was stopped if the patients were judged as failure by the European LekemiaNet (ELN) 2009 criteria or showed intolerance. The cumulative achievement rates of MR4.5 by 18 months were 32.6% (95% confidence interval [CI]: 26.5-39.1%) in the nilotinib arm and 30.8% (95% CI: 24.9-37.3%) in the dasatinib arm with no significant difference (p=0.66). Also, the cumulative achievement rates of early molecular response (EMR), complete cytogenetic response (CCyR) and major molecular response (MMR), MR4.0 by 12, 18, 24, and 36 months were almost the same between the two arms. At 36 months, 66.5% and 65.0% patients continued nilotinib and dasatinib, respectively (p=0.76). There was no significant difference in progression-free survival (PFS) or overall survival (OS) between the two arms by log-rank tests (PFS, p=0.58; OS, p=0.64). These results suggest that nilotinib and dasatinib would be equally effective for de novo CML-CP patients with similar continuity. UMIN Clinical Trials Registry (#UMIN000007909).