Abstract
BACKGROUND
The International Randomized study of Interferon‐alpha plus cytarabine (IFN‐α plus ara‐C) versus STI571 (imatinib mesylate) [IRIS trial] in patients with newly diagnosed Philadelphia chromosome (Ph)‐positive, chronic‐phase chronic myelogenous leukemia (CML) has not shown (to date) a survival advantage for imatinib. This was most likely because approximately 90% of patients receiving IFN‐α plus ara‐C changed to imatinib therapy after a median of 8 months into therapy.
METHODS
The authors analyzed the results with imatinib therapy in patients with newly diagnosed Ph‐positive CML in chronic phase and compared their outcome with patients who received IFN‐α regimens. A total of 187 patients with Ph‐positive CML in early chronic phase treated with imatinib were compared with a historic group of 650 similar patients treated with IFN‐α regimens from 1982 until 1997.
RESULTS
Patients who received imatinib were significantly older and had significantly more bone marrow basophilia and less leukocytosis. The complete cytogenetic response (Ph 0%) rates were better with imatinib (81% vs. 32%; P < 0.001), as were the survival rates (30‐month estimated survival rates 98% vs. 88%; P = 0.01). A multivariate analysis of the total study group of 837 patients identified imatinib therapy to be a significant independent favorable prognostic factor for survival (P = 0.01).
CONCLUSIONS
The current study is the first to indicate the survival advantage of imatinib compared with IFN‐α, the previous standard of care, in patients with early chronic‐phase CML. Cancer 2003;98:2636–42. © 2003 American Cancer Society.