“Dasatinib, a potent Bcr‐Abl tyrosine kinase inhibitor, is approved for the treatment of chronic‐phase chronic myeloid leukemia (CML‐CP) in the frontline and salvage settings. Notable side effects include pleural effusions and myelosuppression,” the researchers reported in Cancer. Previous studies found that dasatinib 50 mg was better tolerated than dasatinib 100 mg. Here, investigators sought to determine whether 50 mg was still the optimal dose.
The study included 83 patients with newly diagnosed CML-CP. Patients received daily dasatinib 50 mg. Patients were followed for at least 12 months; at final follow-up, 81 patients were eligible for analysis (the two patients excluded from the final findings exited the study in less than three months). The researchers evaluated the rates of BCR-ABL1 transcript levels per International standard; at three months,96% of patients had levels ≤ 10%, and 77% had levels ≤ 1%. At six months, 77% of patients had a complete cytogenic response, and by 12 months, this grew to 95%. The cumulative rate for a major molecular response at 12 months was 81%; rates for molecular responses with a 4.0-log reduction and 4.5-log reduction were 55% and 49%, respectively. A total of 21 (25%) patients had treatment interruptions (median [range] 13 [four–64] days). Of the five (6%) patients who developed pleural effusions, four (80%) were given a lower dose of dasatinib. The two (2%) patients who achieved neither a cytogenic nor molecular response were removed from the trial. After a median 24 months of follow-up, no cases transformed to an accelerated or blastic phase. Overall survival and event-free rates were 100% at two years.
“These updated results continue to support 50 mg of dasatinib daily as an effective and safe dose for early CML‐CP,” the authors concluded.