Role of iron in optimizing responses of anemic cancer patients to erythropoietin.

Approximately 50% of cancer patients develop anemia. In the past, the only available treatment option for these patients was transfusion. Since the late 1980s, recombinant human erythropoietin (rHuEPO, epoetin alfa [Epogen, Procrit]) has provided a treatment alternative. Controlled clinical trials have shown that rHuEPO increases hemoglobin and hematocrit levels and reduces the need for transfusions in patients with cancer-related anemia. These controlled trials have suggested (as larger, uncontrolled studies) that the improvements in hemoglobin are associated with increases in energy level, functional status, and overall quality of life. However, only about 50% of patients respond adequately to usual doses of rHuEPO. In the chronic renal failure population, functional iron deficiency is the most common cause of inadequate response to rHuEPO. It has been hypothesized that functional iron deficiency may also occur in cancer patients receiving rHuEPO and may account for the lack of response in up to half of those patients. Studies in renal failure patients have shown that administration of intravenous iron can correct functional iron deficiency more effectively than oral iron and may improve response to rHuEPO. Intravenous iron also reduces the total amount of rHuEPO needed to normalize hematocrit and hemoglobin levels, thereby reducing treatment costs. Ongoing clinical trials are evaluating whether IV iron can also improve rHuEPO responsiveness in patients with cancer-related anemia.