Alternatives to conventional or myeloablative chemotherapy in myelodysplastic syndrome

At present, the only 2 treatments that can prolong survival in patients with myelodysplastic syndrome (MDS) are allogeneic stem cell transplantation and intensive chemotherapy. Alternatives to myeloablative or conventional chemotherapy include: (1) supportive therapy, (2) stimulation of normal residual hematopoietic progenitors, and (3) manipulation of myelodysplastic hematopoiesis. These alternative therapeutic strategies can be accomplished using various therapeutic tools. Supportive therapy remains the mainstay in the management of MDS patients and desferrioxamine should be administered to individuals who have a regular need for blood transfusion. The only hematopoietic growth factors that can be useful in the treatment of selected MDS patients are recombinant human erythropoietin (rhEpo) and granulocyte colony-stimulating factor (G-CSF). Overall, 15% to 20% of patients with MDS respond to rhEpo treatment. Factors predicting response include serum erythropoietin levels <100 to 200 mU/mL, low-risk MDS, and no or low need for transfusion. G-CSF alone should be used only for short-term treatments during severe infection episodes that do not respond to conventional therapy. About 40% of MDS patients respond to a combined treatment of rhEpo plus G-CSF with amelioration of anemia. Cytoprotective antiapoptotic agents such as amifostine, alone or in combination, may improve blood values in occasional MDS patients. MDS patients with immunologically mediated myelosuppression may respond favorably to antithymocyte globulin or cyclosporin A (CyA). Although rhEpo and CyA may be used in individual patients who appear likely to respond, the remaining therapeutic tools must be considered strictly experimental; phase III clinical trials are required to establish whether they can be useful in the treatment of MDS patients. More generally, because of the current uncertainties concerning MDS treatment, participation of patients in clinical trials should be always encouraged.