Daily treatment of chronic-phase chronic myeloid leukemia (CML-CP) with 50 mg dasatinib has been shown to be safe and effective in a recent follow-up report of a phase 2 clinical trial, with results presented in Cancer.
In this pilot study (ClinicalTrials.gov Identifier: NCT02689440), 83 patients with newly diagnosed Philadelphia chromosome-positive CML-CP received 50 mg dasatinib per day. Patients were evaluated at multiple time points for molecular response in terms of BCR-ABL1 transcript levels, complete cytogenetic response as measured by fluorescence in situ hybridization, and toxicity.
Follow-up occurred at a median of 24 months in 81 evaluable patients, with a minimum follow-up time of 12 months.
At the 3-month evaluation, 96% of patients had BCR-ABL1 transcript levels at or below 10% and 77% had transcript levels at or below 1%.
The 12-month cumulative major molecular response rate (MMR) was 81%. The cumulative rate of molecular response with a 4.5-log reduction (MR4.5) was 49% at 12 months. At 30 months, the cumulative MMR reached 91%, and the cumulative MR4.5 was 70%. The cumulative complete cytogenetic response rate was 77% at 6 months, 95% at 12 months, and 98% at 18 months.
The 2-year rates for overall and event-free survival were both 100%.
Pleural effusions occurred with 6% of the patients in this study. A total of 25% of patients required dose interruptions, but the researchers reported that the therapy was generally well tolerated.
“In this update, low-dose dasatinib continued to demonstrate faster and deeper molecular responses in comparison with standard-dose dasatinib and imatinib,” stated the researchers. They also noted the lack of new safety signals during this follow-up and suggested that dasatinib given at 50 mg per day may be an appropriate option for initial CML-CP treatment.
- Naqvi K, Jabbour E, Skinner J, et al. Long-term follow-up of lower dose dasatinib (50 mg daily) as frontline therapy in newly diagnosed chronic-phase chronic myeloid leukemia [published online September 25, 2019]. Cancer. doi:10.1002/cncr.32504