Evaluation of Long-Term Outcomes, Cytogenetic and Molecular Responses with Imatinib Mesylate in Early and Late Chronic-Phase Chronic Myeloid Leukemia: A Report from a Single Institute

Abstract

Here we compare the management and survival outcomes of chronic myeloid leukemia (CML) patients who had early or late imatinib mesylate (IM) therapy. The cytogenetic and molecular responses of 189 CML patients were analyzed. Of this group, 121 patients were classified as the early chronic phase (ECP) group and started IM within 12 months of diagnosis. The other 68 patients were classified as the late chronic phase (LCP) group who had been treated with interferon (IFN)-alpha-2 and crossed over to IM more than 12 months after diagnosis. The overall rates of complete cytogenetic response (CCyR) and major molecular response (MMR) at last follow-up were 83.6 and 78.1% in the ECP and LCP groups, respectively. The CCyR rates were 89.3 (for ECP patients) versus 73.5% (for LCP patients; p < 0.0001). At last follow-up, 82.4% ECP and 64.2% LCP patients had achieved an MMR (p < 0.0001). No significant differences were noted between the two groups with regard to survival outcomes. Our experience reveals that IM is an effective rescue therapy in most CML LCP patients who are intolerant or in whom IFN-alpha therapy fails. Such therapeutic options should be considered in LCP patients, particularly in countries where IM may not be available.