SEQUENTIAL ADMINISTRATION OF RECOMBINANT HUMAN GRANULOCYTE-MACROPHAGE COLONY-STIMULATING FACTOR AND HUMAN ERYTHROPOIETIN FOR TREATMENT OF MYELODYSPLASTIC SYNDROMES

Treatment of myelodysplastic syndromes (MDS) with recombinant human erythropoietin (Epo) is successful in only 10% to 25% of patients. We performed a pilot study in 10 anaemic patients with MDS to examine whether sequentially applied recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) and Epo improves haemoglobin levels and/or reduces red blood cell transfusion requirements. Morphological diagnoses of patients were refractory anaemia (RA) in 3 cases, RA with ring sideroblasts in 3 cases and RA with excess blasts in 4 cases. GM-CSF was given subcutaneously at a dose of 150 mu g/m(2)/d during the initial 10 days. From day 11, Epo was administered by subcutaneous injections for 8 weeks at a dose of 100 U/kg/d and subsequently at an escalated dose of 200 U/kg/d in 3 patients. Changes in reticulocyte counts, haemoglobin levels, RBC support and ferrokinetic parameters were compared with pretreatment values. Two out of 8 evaluable patients showed a rise in haemoglobin levels at week 8 and 10, respectively, and lost their transfusion dependency for a period of 13 and 27 weeks. In 1 patient, haemoglobin level increased only after dose escalation of Epo (200 U/kg/d). Leukocyte counts remained uneffected by treatment with Epo, while 1 patient showed a 4-fold increase in platelet numbers. Toxicity was mild. Two patients died of pneumonia and global heart failure, respectively, unrelated to growth factor therapy. Based on this pilot study, we conclude that sequential treatment with GM-CSF and Epo does not increase erythroid responses in anaemic patients with MDS. Because of the delayed increase in haemoglobin in both responders, we surmise that the beneficial effects were induced by Epo alone.