New therapeutic modalities for the clinical use of rhGM-CSF in patients with malignancies

Data from several clinical trials in patients with solid tumors clearly demonstrate that recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) is able to shorten the time period of neutropenia after chemotherapy and to reduce neutropenia-related morbidity such as infections, time in hospital, etc. A placebo-controlled, double-blind multicenter trial including 81 patients with acute lymphoblastic leukemia and non-Hodgkin's lymphoma demonstrates the efficacy of rhGM-CSF to enhance engraftment (neutrophils greater than 0.5 x 10(3)/mm3) after autologous bone marrow transplantation (p less than 0.001) and to reduce the frequency of bacterial infections (34% vs. 56%). In addition, GM-CSF is able to shift the cell cycle of myeloid leukemic cells from the G0 to S phase in vitro and in vivo, which results in an increased sensitivity to cell-cycling-dependent cytostatic agents. Dose intensification of chemotherapy in patients with soft tissue sarcoma and metastatic breast cancer is possible due to adjuvant treatment with GM-CSF and results in a higher frequency of remissions. Further controlled clinical studies are warranted to support these results.