Effect of recombinant human granulocyte-macrophage colony stimulating factor on progenitor cells in patients with advanced malignancies.

Haemopoietic progenitor cell levels were determined in the blood and marrow of 37 patients with advanced malignancies undergoing a phase I/II clinical trial of 0.3-30 micrograms/kg/d recombinant human granulocyte-macrophage colony stimulating factor (rGM-CSF). After injection of rGM-CSF, the absolute number of circulating progenitor cells fell initially but after 4 d of infusion a dose-dependent increase was observed in progenitor cells of all lineages with a slight bias favouring granulocyte-macrophage progenitors. A mean 8.4-fold increase in GM-CFC and a 3.3-fold increase in BFU-E were observed at a dose level of 20 micrograms/kg/d of rGM-CSF. Patients with malignant lymphoma showed a greater response than other patients at the same dose level and the CFU-E rise correlated with the haematocrit. This study suggests that GM-CSF may be of value in elevating circulating progenitor cells for subsequent autografting.