New data from the largest study of CML patients (1106 patients included) ever conducted International Randomized IFN vs. ST1571 (IRIS) study, were presented today at the annual meeting of the American Society of Hematology (ASH). In the study, newly diagnosed patients with chronic-phase Philadelphia chromosome-positive (Ph+) chronic myeloid leukemia (CML) who achieved cytogenetic responses early had improved rates of progression-free survival compared to those who did not achieve early responses. Responses to imatinib were shown to be durable at 42 months.
"The IRIS study continues to show durable responses in patients treated with imatinib," said Pr Francois Guilhot, Head of Oncology Hematology and Cell Therapy Department, CHU La Miletrie, Poitiers, France. "For patients who achieved the highest responses at 12 months, the probability of remaining free of the leukaemia was very high."
Study Details
The landmark analysis showed that at 42 months, 84% of patients taking imatinib remained progression free, and only 6% progressed to the more advanced disease stages (accelerated phase and blast crisis). Overall survival (based on CML-related deaths) in patients treated with imatinib was 97% at 42 months. Patients taking imatinib as first treatment who achieved a complete cytogenetic response (CcyR) within 12 months of therapy had a 93% progression free survival rate at 42 months, compared with 74% in those without CcyR.
For patients who had achieved CcyR and a thousand-fold (3 log) or greater reduction in Bcr/Abl transcript level (called a molecular response) at 12 months,
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5-Dec-2004