Predictive value of early molecular response in patients with chronic myeloid leukemia treated with first-line dasatinib.

Dasatinib is effective therapy for newly diagnosed patients with chronic myeloid leukemia, but not all patients respond well. We analyzed the outcome of patients treated with dasatinib as first-line therapy to identify patients who are more likely to fare poorly. The 8.6% of patients who at 3 months had a BCR-ABL1/ABL1 ratio > 10% had a significantly worse 2-year cumulative incidence of complete cytogenetic response (58.8% vs 96.6%, P < .001) and molecular responses than the remaining patients with a lower transcript levels. The predictive value of the 3-month transcript level could be improved using the dasatinib-specific transcript level cut-offs, namely, 2.2%, 0.92%, and 0.57% for complete cytogenetic response, 3 log and 4.5 log reductions in the transcript level, respectively. The study was registered at www.clinicaltrials.gov as #NCT01460693.