RESPONSE TO RECOMBINANT-HUMAN-ERYTHROPOIETIN IN PATIENTS WITH MYELODYSPLASTIC SYNDROMES

Recombinant human erythropoietin (rhEPO) at pharmacological doses was used to improve anemia and reduce the transfusional requirements of 43 patients with myelodysplastic syndrome (MDS), rhEPO was given by s,c, injection three times per week for 12 weeks, The EPO dose was started at 150 IU/kg and was increased to 300 IU/kg if after 6 weeks there wa s no or suboptimal erythroid response, Responses were defined as being a complete response (CR), partial response (PR), or no response (NR), A CR was considered a rise in untransfused hemoglobin concentrations of at least 2 g/dl or a 100% decrease in RBC transfusion requirements over the treatment period, A PR was defined as an increase in untransf used hemoglobin values of 1-2 g/dl or a decrease in RBC transfusion re quirements equal to or greater than 50%, NR was defined as responses l ess than a PR, Patients who responded to therapy were continued on rhE PO at the same dose for 6 additional months, An objective response (CR and PR) was observed in 7 of 42 (16.7%) assessable cases after 6 week s of treatment at the dose of 150 IU/kg, Dose escalation (300 IU/kg) i n nonresponders resulted in another six patients attaining a rise in h emoglobin concentrations, The final response rate was 13 of 41 (31.7%) ; 4 patients became transfusion independent, Therapy was tolerated wel l, with no relevant side effects, MDS progression was seen in one case , An elevated bone marrow erythroid infiltration (erythroid index) and detectable pretreatment circulating erythroid progenitors (burst-form ing units-erythroid) were the best predictors of hemoglobin response w hen we controlled for other variables, These data suggest that rhEPO h as a role in the treatment of certain patients with MDS, particularly in those with a high erythroid index and detectable circulating erythr oid burst-forming units.