Hemopoietins in Clinical Oncology

Abstract

Despite major advances in supportive care, neutropenic infections and thrombopenic bleedings remain major lethal treatment- and disease-related complications in patients with malignancy. Moreover, complications of platelet (Plt) and erythrocyte transfusion therapy have become a cause of great concern and shortages of homologous blood products are a constant problem. Suggestions that the application of recombinant human hemopoietins may provide an alternative treatment modality in this patient population is currently being evaluated in clinical trials. Erythropoietin (EPO) has been shown to be effective in the treatment of anemia in patients with bone marrow, infiltrating low-grade non-Hodgkin's lymphoma, multiple myeloma, and in some patients with myelodysplastic syndrome. Preliminary data suggest that subcutaneous administration of EPO results in a higher slope of increasing erythropoietic parameters compared to intravenous administration. Protective effects on normal erythropoiesis have been attributed to EPO in patients receiving chemotherapy. The finding of EPO receptors on megakaryocytes supports the clinical observation of increased Plt production associated with decreased bleeding and transfusion frequencies in a substantial number of patients receiving EPO. Clinical trials with granulocyte-macrophage (GM-CSF) and granulocyte colony stimulating factor (G-CSF) have reached phase III trials. Both factors show high efficacy to shorten or improve neutropenia related to chemotherapy, bone marrow transplant, or underlying disease. Mechanisms responsible for mucosa protection and improved healing of mucositis observed with both factors remain undetermined yet phase I/II evaluation of IL-3 shows multilineage hemopoietic responses including myeloid, erythroid, and megakaryocyte lineages. Possible anti-cancer effects of hemopoietins achieved by direct action or by increased chemotherapy intensity are currently under investigation.