Results of dasatinib therapy in patients with early chronic-phase chronic myeloid leukemia

Purpose: Dasatinib is effective therapy for chronic myeloid leukemia (CML) after imatinib failure. In this study, we investigate the efficacy of dasatinib as initial therapy for patients with CML in early chronic phase. Patients and Methods: Patients with newly diagnosed CML in early chronic phase were randomly assigned to receive dasatinib 100 mg once daily or 50 mg twice daily as initial therapy. Results: Among 50 patients observed for at least 3 months, 49 patients (98%) achieved a complete cytogenetic response (CCyR), and 41 patients (82%) achieved a major molecular response (MMR). Responses occurred rapidly, with 94% of patients achieving CCyR by 6 months. There was no difference in response rate by treatment arm. The projected event-free survival rate at 24 months is 88%, and all patients are alive after a median follow-up time of 24 months. Grade ≥ 3 neutropenia and thrombocytopenia occurred in 21% and 10% of patients, respectively. Nonhematologic toxicity was usually grade 1 to 2. There was no significant difference in toxicity between the two arms, and the actual median dose at 12 months was 100 mg (range, 20 to 100 mg). Conclusion: Dasatinib is an effective agent for the initial management of CML in early chronic phase, producing high rates of CCyR and MMR.