Efficacy of molecular response at 1 or 3 months after the initiation of dasatinib treatment can predict an improved response to dasatinib in imatinib-resistant or imatinib-intolerant Japanese patients with chronic myelogenous leukemia during the chronic phase

J Clin Exp Hematop. 2014;54(3):197-204. doi: 10.3960/jslrt.54.197.

Abstract

Dasatinib is a BCR-ABL kinase inhibitor with improved potency compared with imatinib, for which efficacy and safety in imatinib-resistant and imatinib-intolerant patients with chronic myelogenous leukemia (CML) have been established. Here, an open-label phase II study evaluated the efficacy and safety of dasatinib in 50 Japanese patients with imatinib-resistant or imatinib-intolerant CML during the chronic phase (CML-CP). Dasatinib was effective in imatinib-resistant and imatinib-intolerant patients. After 12 months of dasatinib therapy, 35 patients (70%) had achieved a major molecular response (MMR) and 16 patients (32%) had achieved a complete molecular response (CMR). Among the imatinib-resistant CML-CP cohort, 21 and 8 patients had achieved an MMR and a CMR after 12 months of dasatinib therapy, respectively. Among the imatinib-intolerant CML-CP cohort, 14 and 8 patients had achieved an MMR and a CMR after 12 months of dasatinib therapy, respectively. After 18 months of dasatinib therapy, 38 out of 50 patients (76.0%) had achieved an MMR and 19 patients (38.0%) had achieved a CMR. A lower level of BCR-ABL transcript at 1 or 3 months after the initiation of dasatinib treatment was more strongly correlated with the BCR-ABL transcript level at 12 and 18 months (p < 0.001) than a higher level of BCR-ABL. The T315I mutation was identified in two patients receiving dasatinib therapy. Dasatinib was generally well tolerated, with only 3 patients (5%) having treatment discontinuation as a result of adverse hematologic events (thrombocytopenia, anemia, neutropenia) and/or non-hematologic events at a 12-month follow-up evaluation. Dasatinib was a safe and effective treatment for Japanese patients with imatinib-resistant or imatinib-intolerant CML. In addition, the molecular response at 1 or 3 months predicted a response to dasatinib at 12 or 18 months.

Trial registration: ClinicalTrials.gov NCT00866736.

Publication types

  • Clinical Trial, Phase II
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Benzamides / pharmacology
  • Dasatinib
  • Drug Resistance, Neoplasm
  • Female
  • Genes, abl
  • Humans
  • Imatinib Mesylate
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics
  • Male
  • Middle Aged
  • Piperazines / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Thiazoles / therapeutic use*
  • Treatment Outcome
  • Young Adult

Substances

  • Benzamides
  • Piperazines
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Thiazoles
  • Imatinib Mesylate
  • Dasatinib

Associated data

  • ClinicalTrials.gov/NCT00866736