Alvarado Y, Kantarjian H, O'Brien S, Faderl S, Borthakur G, Burger J, Wierda W, Garcia-Manero G, Shan J, Cortes J
Significance of suboptimal response to imatinib, as defined by the European LeukemiaNet, in the long-term outcome of patients with early chronic myeloid leukemia in chronic phase. [JOURNAL ARTICLE]
Cancer 2009 Jun 10.
BACKGROUND:: The European LeukemiaNet recommendations for chronic myeloid leukemia (CML) defined a group of patients with suboptimal response to imatinib. The significance of this response was not well defined.
METHODS:: The significance of having had a suboptimal response during imatinib therapy among 281 patients with CML treated with standard-dose (n = 73) or high-dose (n = 208) imatinib was investigated.
RESULTS:: Rates of suboptimal response at 6, 12, and 18 months were 4%, 8%, and 40%, respectively, and were not influenced by Sokal risk score. Patients with a suboptimal response at 6 months had a significantly lower probability of eventually achieving a complete cytogenetic response (CCyR) compared with those with an optimal response (30% vs 97%; P < .001), and their event-free survival (EFS) and transformation-free survival (TFS) were found to be similar to those with criteria for failure at this time point. Suboptimal response at 12 months defined a group with a similar TFS as those with optimal response, but with worse EFS. In contrast, patients with a suboptimal response at 18 months had outcomes that were similar to those patients with an optimal response. A multivariate analysis confirmed the significance of response category after adjusting for pretreatment characteristics and imatinib dose.
CONCLUSIONS:: The results of the current study suggested that suboptimal response was a heterogeneous category, and some patients had an outcome that mirrored that of patients with failed therapy. Interventions aimed at improving this outcome are required. Cancer 2009. (c) 2009 American Cancer Society.
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