Phase I/II study of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) in bone marrow failure.

We performed a Phase I/II study of the administration of recombinant human GM-CSF to patients suffering from severe bone marrow failure, either due to aplastic anemia or myelodysplastic syndrome. Doses ranging from 15 micrograms/m2 to 480 micrograms/m2 were administered as an intravenous infusion daily for 7 days. Temporary improvements were seen in granulocyte counts, monocyte counts and reticulocyte counts. There was no reduction in erythrocyte transfusion requirements and no effect was observed on platelet counts. There was only minimal toxicity consisting of transient low back discomfort, anorexia, myalgias/arthralgias, and low grade fever. Our data suggest that prolonged use of GM-CSF might benefit some patients with severe marrow failure.