Overall survival and progression-free survival were similar at 5 years in chronic myeloid leukemia patients receiving dasatinib or imatinib, but those given dasatinib had higher major molecular response rates and complete cytogenic response rates without a higher rate of adverse events, based on an extension study of previously published data from the DASISION trial.

The DASISION phase III clinical trial included 519 patients with newly diagnosed and treatment-naive chronic myeloid leukemia. Participants were randomly assigned to receive either 100 mg of dasatinib daily (259 patients) or 400 mg of imatinib daily (260 patients). Dosage was altered on a per-patient basis if adverse events or suboptimal responses were observed. The median average daily dose was 99 mg for dasatinib and 400 mg for imatinib after 5 years.

“Initial results showed that dasatinib had met its primary end point of superior efficacy compared with imatinib and had an acceptable safety profile, leading to its approval for first-line use,” reported Dr. Jorge Cortes of the University of Texas MD Anderson Cancer Center, Houston, and his associates (J Clin Oncol. 2016 May 23. doi: 10.1200/JCO.2015.64.8899). Given the faster and deeper molecular responses seen in patients taking dasatinib, “dasatinib should continue to be considered a standard first-line therapy for patients with newly diagnosed” chronic myeloid leukemia, they wrote.

In DASISION (Dasatinib Versus Imatinib Study in Treatment-Naive Chronic Myeloid Leukemia Patients), complete cytogenic response, major molecular response, overall survival, and progression-free survival were measured.

The major molecular response rate was significantly higher for patients receiving dasatinib, compared with patients receiving imatinib (76% vs. 64%, P = .0022).

The rate of complete cytogenic response was 28% for dasatinib and 26% for imatinib.

The 5-year overall survival for patients receiving dasatinib was 91% and was not significantly different than the overall survival rate for patients receiving imatinib (90%, P = .1192). Five-year progression-free survival was 85% for patients receiving dasatinib and 86% for patients receiving imatinib.

Grade 3 or 4 adverse events were seen in 15% of patients receiving dasatinib and 11% of patients receiving imatinib. After 5 years, 26 patients had died in each experimental group.

This study was supported by Bristol-Myers Squibb. Eleven investigators reported serving in advisory roles or receiving financial compensation from multiple companies. One investigator had no disclosures to report.

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