Despite therapeutic advancements in the treatment of chronic myeloid leukemia (CML), patients who transform to blast phase (CML-BP) have a poor outcome, especially if they have previously received a tyrosine kinase inhibitor (TKI), according to findings that will be presented at the American Society of Hematology (ASH) 58th Annual Meeting & Exposition in San Diego, California.1

The introduction of TKIs has dramatically improved outcomes for patients with CML and reduced the risk of transformation to CML-BP, though some patients become resistant to therapy and progress to CML-BP, and some present with CML-BP at diagnosis. Researchers evaluated for clinical characteristics, prognostic factors, and outcomes of patients with CML-BP treated with a TKI at some point during the course of their disease.

For the single-center study, investigators analyzed data from 498 patients diagnosed with CML-BP, of which 302 presented to MD Anderson Cancer Center in Houston, Texas, already in blast phase, 84 presented in accelerated phase and later progressed, and 112 presented in chronic phase and progressed to blast phase. A total of 84% of patients had received 1 or more TKIs by the time of transformation.

Median overall survival was 12 months overall, 10 months for the 67% with myeloid immunophenotype, and 17 months for the 29% with lymphoid phenotype.

After adjusting for confounding factors, researchers found that age of 56 years or higher (hazard ratio [HR], 1.73; P < .001), prior TKI (HR, 1.53; P = .02), LDH level of 888 or higher (HR, 1.56; P = .002) and myeloid phenotype (HR, 1.67; P < .001) were significantly associated with inferior overall survival. Myeloid phenotype and prior TKI therapy were associated with inferior failure-free survival.

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Future research should focus on identifying novel treatment options for this small population of patients with CML who have a poor prognosis.

Reference

  1. Jain P, Kantarjian HM, Jabbour E, et al. Factors affecting survival outcomes in patients with blast phase CML (CML-BP) in the tyrosine kinase inhibitor (TKI) era: A cohort study of 498 patients. Paper presented at: American Society of Hematology (ASH) 58th Annual Meeting & Exposition; December 3-6, 2016; San Diego, CA.