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Medline ® Abstract for Reference 77

of 'Clinical use of tyrosine kinase inhibitors for chronic myeloid leukemia'

Granulocyte-colony-stimulating factor (filgrastim) may overcome imatinib-induced neutropenia in patients with chronic-phase chronic myelogenous leukemia.
Quintas-Cardama A, Kantarjian H, O'Brien S, Garcia-Manero G, Rios MB, Talpaz M, Cortes J
Cancer. 2004;100(12):2592.
BACKGROUND: Imatinib mesylate administration has become standard treatment for patients with chronic myelogenous leukemia (CML). Although the safety profile of imatinib is favorable, Grade>or = 3 neutropenia (according to the National Cancer Institute Common Toxicity Criteria) occurs in 35-45% of patients with CML in chronic phase who receive standard-dose imatinib. Myelosuppression results in treatment interruptions, which may compromise responses to imatinib. The authors investigated the ability of granulocyte-colony-stimulating factor (filgrastim) to reverse imatinib-associated neutropenia, thereby allowing for more continuous imatinib administration.
METHODS: Thirteen patients with chronic-phase CML and Grade>or = 3, imatinib-induced neutropenia were treated with filgrastim. Treatment with filgrastim was initiated after a median of 22 months from the start of imatinib. Eleven patients received filgrastim 5 microg/kg 1-3 times weekly, and 2 patients received filgrastim 5 microg/kg daily; doses were titrated to maintain an absolute neutrophil count (ANC)>or = 10(9)/L.
RESULTS: Seven of 11 patients (64%) who began treatment with an ANC<1.5 x 10(9)/L had responses (i.e., their ANC improved to>or = 2 x 10(9)/L within 21 days); the other 4 patients experienced slower recovery but were able to continue receiving imatinib uninterrupted. Before filgrastim administration was initiated, patients did not receive imatinib (due to neutropenia-related treatment interruptions) for an average of 21% of the total time since the start of imatinib. This figure decreased to 6% after the start of filgrastim treatment (P = 0.0008). Before filgrastim treatment was initiated, only one patient had achieved a major (partial) cytogenetic response. After the start of filgrastim treatment, five patients had major cytogenetic responses (including two complete responses).
CONCLUSIONS: The authors concluded that filgrastim may overcome imatinib-associated neutropenia and allow improved delivery of imatinib. Some patients may experience improvements in their responses to therapy as a result.
Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.