Recombinant human erythropoietin in patients with myelodysplastic syndromes.

As anemia is frequently the main problem in myelodysplastic syndromes (MDS), we studied the efficacy of human erythropoietin (rhEpo) in stimulating the erythroid lineage in 14 patients, starting with 40 U/kg three times a week and doubling the dose every 6 weeks until a response was observed. The highest doses administered were 80 (n = 1), 160 (n = 4), 320 (n = 8) and 640 U/kg (n = 1). One patient (refractory anemia with an excess of blasts, RAEB) showed an increase of hemoglobin, white blood cells and platelets with 80 U/kg rhEpo. However, this patient developed acute leukemia while on therapy. Two other patients (RAEB and RAEB in transformation) also transformed to acute leukemia. In the other 11 patients no response was observed. There was no correlation between in vitro culture data and in vivo responsiveness. The treatment was well tolerated and no nonhematological side effects were observed. From this study we conclude that rhEpo, even when given at high doses, has a low response rate in patients with MDS. Further investigation is needed in order to clarify whether rhEpo increases the potential risk of transformation to acute leukemia.