Low-Dose Dasatinib (50 mg Daily) Frontline Therapy in Newly Diagnosed Chronic Phase Chronic Myeloid Leukemia: 5-Year Follow-Up Results

Dasatinib 50 mg daily was given to 83 patients with newly diagnosed Ph-positive CML in chronic phase. The cumulative incidence of major molecular and deep molecular responses at 5 years were 95% and 82%, respectively. Only 5% had CML resistance at 5 years. The 5-year overall survival was 96%. Grade 3 to 4 pleural effusions were noted in 2%. Background: Dasatinib is a BCR::ABL1 tyrosine kinase inhibitor approved as frontline therapy at a 100 mg daily for chronic myeloid leukemia in chronic phase (CML-CP). The use of a lower dose of dasatinib (50 mg daily) has demon-strated better tolerance and improved outcomes compared with the standard dose. Here, we report the updated results in a large cohort with a 5-year follow-up. Patients and Methods: Patients with newly diagnosed CML-CP were eligible. Entry and response-outcome criteria were standard. Dasatinib was given as 50 mg orally daily. Results: Eighty-three patients were included. At 3 months, 78 (96%) patients achieved BCR::ABL1 transcripts (IS) <10%, and at 12 months, 65 (81%) patients achieved BCR::ABL1 transcript (IS) <0.1%. The cumulative incidence of complete cytogenetic, major molecular, and deep molecular responses at 5 years were 98%, 95%, and 82%, respectively. Rates of failures due to resistance (n = 4; 5%) and toxicity (n = 4; 5%) were low. The 5-year overall survival was 96% and event-free survival 90%. No transformations to accelerated or blastic phase were observed. Grade 3 to 4 pleural effusions developed in 2% of patients. Conclusion: Dasatinib 50 mg daily is an effective and safe treatment for newly diagnosed CML-CP.