High BCR-ABL/GUS(IS) levels at diagnosis of chronic phase CML are associated with unfavorable responses to standard-dose imatinib

Abstract Purpose: The approval of second-generation tyrosine kinase inhibitors (TKIs) for the first-line treatment of chronic myeloid leukemia (CML) has generated an unmet need for baseline molecular parameters associated with inadequate imatinib responses. Experimental Design: We correlated BCR–ABL/GUSIS and BCR–ABL/ABL transcripts at diagnosis with the outcome—defined by the 2013 European LeukemiaNet recommendations—of 272 patients newly diagnosed with CML receiving imatinib 400 mg/daily. Applying receiver-operating characteristic curves, we defined BCR–ABL/GUSIS and BCR–ABL/ABL levels associated with lower probabilities of optimal response, failure-free (FFS), event-free (EFS), transform…