A significant issue to consider for these results is that the subtype refractory anemia with excess blasts in transformation is likely to represent patients with overt AML, while refractory anemia and refractory anemia with excess blasts represent MDS. The optimum therapy for patients with refractory anemia/refractory anemia with excess blasts without MFD is unknown. Some of these patients require no therapy for years and have indolent diseases. Because failure rates after HSCT are lower in this group, strong consideration should be given for such treatment, especially when a 5/6 or 6/6 HLA-MFD is available. However, alternative forms of HSCT, utilizing matched unrelated donor cord blood, should be considered when treatment is required, as is usually the case in patients with severe cytopenias.[28,31]
For patients with clinically significant cytopenias, supportive care, including transfusions and prophylactic antibiotics, can be considered, but have not been proven to be curative; however, it is important that supportive care be utilized in these patients awaiting transplant. In addition, the use of hematopoietic growth factors can improve the hematopoietic status, but there is some concern that such treatment could accelerate conversion to AML. Steroid therapy has also been used, including glucocorticoids and androgens, with mixed results. Treatments directed toward scavenging free oxygen radicals with amifostine [39,40] or the use of differentiation-promoting retinoids, DNA methylation inhibitors (e.g., azacytidine and decitabine), and histone deacetylase inhibitors, have all shown some positive responses. Azacytidine has been FDA-approved for the treatment of MDS in adults based on randomized studies. Agents, such as lenalidomide, an analog of thalidomide, have been tested based on findings that demonstrated increased activity in the bone marrow of patients with MDS. Lenalidomide has shown most efficacy in patients with 5q- syndrome and is now FDA-approved for use in this group. Immunosuppression with antithymocyte globulin and/or cyclosporine has also been reported.[43,44]
Treatment Options Under Clinical Evaluation
The following are examples of national and/or institutional clinical trials that are currently being conducted.
- The use of a variety of inhibitors of DNA methylation and histone deacetylase inhibitors, as well as other therapies designed to induce differentiation, are being studied in both young and older adults with MDS.[45,46,47]