Growth factor priming in therapy of acute myelogenous leukemia.

Treatment of acute myelogenous leukemia (AML) incorporates the use of growth factors towards several objectives, including abbreviating the time of neutropenia, reducing susceptibility to infections, reducing length of hospitalization, and increasing susceptibility of the blasts to chemotherapy drugs, or priming. Priming is defined as the driving of leukemia cells into cell cycle in order to increase response to S-phase-specific drugs such as cytarabine (Ara-C). Growth factors that have been used in priming include both filgrastim (G-CSF) and sagramostim (GM-CSF). Priming has often been applied in the treatment of older patients, who do not respond as well to standard treatment regimens, and whose disease was transformed from a myelodysplastic syndrome (MDS), or preleukemia. Recent, large randomized trials have demonstrated that although subgroups of patients may benefit, there does not appear to be any improvement in the complete remission rate sustained by inclusion of growth factor priming as part of the initial therapy of acute myelogenous leukemia.