Recombinant human granulocyte-macrophage colony-stimulating factor plus erythropoietin for the treatment of cytopenias in patients with myelodysplastic syndromes.

In vitro studies have indicated that granulocyte-macrophage colony-stimulating factor (GM-CSF) synergizes with erythropoietin (EPO) for the production of erythroid precursors in patients with myelodysplastic syndrome (MDS). We performed a clinical trial to evaluate whether the combination of these growth factors was effective in relieving the cytopenias associated with MDS. 31 anaemic patients with low and intermediate-risk primary MDS were enrolled in a 12-week study. Therapy was initiated with GM-CSF at 1 microgram/kg/d.s.c., and then adjusted to either normalize or double the absolute neutrophil count. EPO was given subcutaneously on alternate days starting from day 2. The EPO dose was initiated at 150 U/kg and increased to 300 U/kg if after 6 weeks there was no or suboptimal erythroid response. 26 patients completed the study treatment. All evaluable cases had a neutrophil response. Clinically significant erythroid responses with increases of haemoglobin levels of at least 1 g/dl and/or reduction of transfusion needs were seen in 9/26 (34.6%), five patients improving their response after dose escalation of EPO. Treatment had no apparent effect on mean platelet counts, a single case displaying a trilineage response. An elevated bone marrow erythroid infiltration and low concentrations of circulating tumour necrosis factor-alpha were the only predictors of haemoglobin response both in univariate and in multivariate analysis. We conclude that the combination GM-CSF + EPO can abrogate neutropenia and substantially relieve transfusion requirements in a large proportion of patients with low and intermediate risk MDS. However, in vivo synergy between these growth factors for the production of erythroid precursors is not supported by our data.