Predicting the hematopoietic response to recombinant human erythropoietin (Epoetin alfa) in the treatment of the anemia of cancer.

Recombinant human erythropoietin (Epoetin alfa) is effective in increasing hemoglobin concentration and hematocrit, and in significantly reducing transfusion requirements in the majority of patients with either the anemia of chronic renal failure or chemotherapy-induced anemia of cancer. Identification of factors that could enable the clinician to predict individual patient hematological responses to Epoetin alfa therapy would be of great value. Changes in levels of serum transferrin receptor protein, hemoglobin, ferritin and reticulocyte count, following a short course of Epoetin alfa therapy, were useful markers for predicting later hematopoietic responses to Epoetin alfa. In addition, recent data suggest that low baseline erythropoietin levels, in association with increases of either >0.5 g/dl in hemoglobin or >/=25% in circulating levels of transferrin receptor protein after 2 weeks of Epoetin alfa therapy, are highly predictive of a response (>/=2 g/dl increase in hemoglobin) to Epoetin alfa. Progress has clearly been made in the development of predictive models that can identify those patients most likely to respond to Epoetin alfa by monitoring several specific hematological parameters at baseline and early in therapy. Future studies will focus on nonhematological measures of response, such as transfusion requirement and quality of life benefit.