Dasatinib Compared with Imatinib In Newly Diagnosed Chronic Myelogenous Leukemia In Chronic Phase (CML-CP):Results of Japanese Subset Analysis In DASISION Trial.

Dasatinib is a highly potent BCR-ABL kinase inhibitor. The previous report from the global DASISION trial showed dasatinib 100 mg once daily resulted in significantly higher and faster rates of complete cytogenetic response (CCyR) and major molecular response (MMR) compared with imatinib; both treatment arms were well-tolerated (N Engl J Med. 2010;362:2260-70). The objective of this subset analysis was to assess the efficacy and safety of dasatinib compared with imatinib in the Japanese population.

Forty-nine Japanese patients (total 519 pts) with newly diagnosed CML-CP were randomly assigned to receive dasatinib 100 mg QD or imatinib 400 mg QD. Confirmed CCyR (cCCyR; CCyR on 2 consecutive assessments at least 28 days apart) was the primary efficacy endpoint with MMR as an important secondary endpoint. The safety profiles were also evaluated.

Minimum follow-up time and median treatment duration were 12 months and 15 months, respectively. Twenty-six patients with median age 56 (range, 21–70) years were treated with dasatinib and 23 patients with median age 52 (range, 22–77) years were treated with imatinib. Overall 89% of patients receiving dasatinib and 83% of patients receiving imatinib continue to receive treatment. The cCCyR rate by 12 months (primary endpoint), CCyR rate by 12 months and MMR rate at any time in dasatinib arm were higher than those in imatinib for Japanese patients (96% vs 70%, 96% vs 78%, and 73% vs 48%, respectively). Grade 3/4 cytopenias in dasatinib arm and imatinib arm were as follows: anemia (8% vs 4%), neutropenia (27% vs 39%), and thrombocytopenia (8% vs 9%). Non-hematologic and drug-related adverse events occurring in ≥10% of patients are shown as Table. No deaths were reported in either group. Drug-related serious adverse events were rarely reported and all events were not severe (Grade 1–2, including vomiting, hypoxia and cardiomyopathy in dasatinib arm).

Dasatinib showed higher rates of cCCyR and MMR compared with imatinib. Both treatments were well tolerated. Given the predictive value of 12 months cCCyR, dasatinib may improve long-term outcomes in Japanese patients with newly diagnosed CML-CP.

Ueda:Bristol-Myers K.K.: Employment. Seriu:Bristol-Myers K.K.: Employment. Bradley-Garelik:Bristol-Myers Squibb: Employment. Zhu:Bristol-Myers Squibb: Employment.