This study shows results of a five year follow up of a large group of patients who received Imatinib (Glivec). The results are very encouraging:
N Engl J Med 2006; 355: 2408-2417
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Abstract Five year follow up data of patients with chronic myeloid leukaemia (CML) who received imatinib as initial therapy, have been reported in the New England Journal of Medicine.
The data come from the ‘International Randomised Study of Interferon and STI571’ (IRIS), which compared imatinib with interferon alpha plus cytarabine in the chronic phase of CML. (The latter regimen was considered standard therapy for patients with CML not planning to undergo allogeneic haematopoietic stem-cell transplantation, before the advent of imatinib). At a median follow-up of 19 months, this study had shown superiority of imatinib in all standard indicators of the disease. Five years after the last of 1106 patients had started treatment, and with a median of 60 months of follow-up, 382 of 553 patients (69%) in the imatinib group and 16 of 553 patients (3%) in the group on interferon alpha plus cytarabine continued with their initially assigned treatment. Of those on interferon plus cytarabine, 359 (65%) had crossed over to imatinib, whilst 14 patients (3%) in the imatinib group had switched to the alternative treatment. This report focuses on the 553 patients who received imatinib as a primary treatment, followed up until treatment was stopped, death, loss to follow-up, or withdrawal of consent.
At a median follow up of 60 months:
• The estimated overall survival of patients who received imatinib as initial therapy was 89%
• Cumulative best rates of complete cytogenetic response were 69% by 12 months and 87% by 60 months.
• An estimated 7% of patients progressed to accelerated-phase CML or blast crisis.
• Patients who had a complete cytogenetic response or in whom levels of BCR-ABL transcripts had fallen by at least 3 log had a significantly lower risk of disease progression than did patients without a complete cytogenetic response (p < 0.001).
• Grade 3 or 4 adverse events diminished over time, and there was no clinically significant change in the profile of adverse events.
The authors conclude “After 5 years of follow-up, continuous treatment of chronic-phase CML with imatinib as initial therapy was found to induce durable responses in a high proportion of patients.” They note that the 5-year estimated overall survival rate for patients on imatinib as initial therapy (89%) was higher than that reported in any previously published prospective study of the treatment of CML; previous randomised studies of interferon alpha plus cytarabine have