Long-term therapy with recombinant human erythropoietin (rHu-EPO) in progressing multiple myeloma

Recombinant human erythropoietin (rHu-EPO) is an effective growth factor for erythroid progenitor cells in anemia provoked by several conditions, including bone marrow tumors such as multiple myeloma (MM). We studied a group of 54 patients with MM undergoing second-induction chemotherapy. Thirty of them were randomly assigned to receive rHu-EPO at an initial dosage of 150 units/kg body weight three times a week, increased to 300 units/kg from the sixth week to the end of the 24-week study. Hemoglobin (Hb) levels increased in 77.7% of these patients by the eighth week. In addition, five transfusion-dependent patients in treatment with the VMCP protocol completed the trial without requiring blood supplement after the third month, whereas seven control patients required frequent supplements. Monthly assessment of hematologic parameters demonstrated the ability of rHu-EPO to increase reticulocyte counts, whereas five patients became resistant to the second-induction chemotherapy in apparent concurrence with their rHu-EPO therapy. The response to rHu-EPO in four of the five MM patients receiving cytotoxic protocols combined with alpha-interferon (alpha-IFN) included an increase of serum IgM after the third month. This effect was not demonstrable in any other group, including three rHu-EPO-untreated patients undergoing alpha-IFN + VMCP combined therapy, as well as rHu-EPO-treated patients not receiving alpha-IFN. Our data suggest that alpha-IFN plus rHu-EPO treatment in MM patients is effective in restoring normal B cell function. These results may reflect in vivo the modulation of normal human B cells and lymphoblasts by rHu-EPO observed in vitro.