Treatment of Low-Risk Myelodysplastic Syndrome: Hematopoietic Growth Factors Erythropoietins and Thrombopoietins

The use of erythropoietic growth factors has become standard of care in many countries for lower risk myelodysplastic syndrome (MDS) patients. Throughout a large number of clinical trials, therapy with erythropoietic agents has consistently shown improvement of anemia and reduction of transfusion dependence. There is currently no evidence of safety issues of erythropoietins in MDS, including thrombosis, polycythemia, and progressive disease. Large retrospective comparative analyses have shown no increase in mortality in erythropoietin (EPO)-treated MDS patients. Doses of up to 80,000 IU/wk have successfully been employed and the addition of granulocyte colony-stimulating factor (G-CSF) can benefit previously unresponsive patients. Although several other combination therapies have been tested, apart from G-CSF, none has gained wide clinical acceptance. Thrombopoietic agents can alleviate thrombocytopenia and bleeding symptoms in lower risk MDS patients. However, concerns regarding a higher rate of transformation to acute myeloid leukemia and the fear of increased bone marrow fibrosis during treatment have hampered their clinical development.