Tyrosine Kinase Inhibitors as Initial Therapy for Patients With Chronic Myeloid Leukemia in Accelerated Phase

Some patients with chronic myeloid leukemia (CML) present with accelerated phase (AP) features at the time of diagnosis. We analyzed the outcome of 51 consecutive patients with de novo CML-AP who received tyrosine kinase inhibitors (TKIs) as initial therapy. Patients with de novo CML-AP have excellent outcomes with TKIs as initial therapy, particularly with second-generation TKIs (2GTKI). Background: Accelerated phase CML most frequently represents a progression state in CML. However, some patients present with AP features at the time of diagnosis. There is limited information on the outcome of these patients who received TKIs as initial therapy. Patients and Methods: We analyzed the outcome of 51 consecutive patients with CML who presented with features of AP at the time of diagnosis, including blasts >= 15% (n = 6), basophils >= 20% (n = 22), platelets < 100 x 10(9)/L (n = 3), cytogenetic clonal evolution (n = 17), or more than 1 feature (n = 3). Patients received initial therapy with imatinib (n = 30), dasatinib (n = 5), or nilotinib (n = 16). Results: The rate of complete cytogenetic response for patients treated with imatinib was 80%, and with dasatinib or nilotinib was 90%. Major molecular response (MMR) (Breakpoint Cluster Region (BCR)-Abelson (ABL)/ABL <= 0.1%, International Scale [IS]) was achieved in 69% of patients including complete molecular response (BOR-ABL/ABL <= 0.0032% IS) in 49%. MMR rates for patients treated with imatinib were 63%, and with 2GTKIs, 76%. Overall survival at 36 months was 87% with imatinib and 95% with 2GTKIs. Conclusion: TKIs should be considered standard initial therapy for patients with AP at the time of diagnosis.