Patients with CML not achieving or losing a major cytogenetic response on whatever palliative treatment for CML, are at high risk to progress to accelerated phase and blast crisis. A new promising treatment with Imatinib (Glivec®), a tyrosine-kinase inhibitor, has been introduced recently. High rates of hematologic and cytogenetic responses can be achieved with Imatinib (Glivec®) at > = 300 mg/day in chronic phase CML patients that are refractory, resistant or intolerant to interferon-alpha. However, about 10 - 20% of these high risk patients will lose their response to Imatinib (Glivec®) within 1-2 years. Therefore, improvement of the treatment is warranted.~Since cytogenetic response rate is correlated to survival and the resistance to Imatinib (Glivec®) might be caused by mutations in the receptor, a more rapid decrease could lead to longer survival and/or less resistance development. In the initial 6 months of treatment, monotherapy with Imatinib (Glivec®) with a dose of 800 mg/day (high dose) should be more effective in the reduction of a high leukemic tumor burden, thereby allowing the residual normal progenitor and stem cells to expand. In addition, high dose Imatinib (Glivec®) should further improve the induction of a molecular response, as determined by quantitative reverse transcription polymerase chain reaction (RT-PCR), reducing the risk of relapse from residual malignant BCR-ABL positive cells.~This study will investigate the efficacy and tolerability of a short (6 months) high dose therapy followed by a standard dose compared to a continuous treatment with a standard dose of Imatinib (Glivec®).~In addition, the dynamics of the molecular and cytogenetic response will be investigated. Finally, the study will investigate the effect of this induction-maintenance concept on time-to-progression (TTP).
This study will investigate the efficacy and tolerability of a short (6 months) high dose therapy followed by a standard dose compared to a continuous treatment with a standard dose of imatinib (Glivec®) in pretreated Philadelphia chromosome- positive (Ph+)/BCR-ABL+ CML patients in chronic phase.