Combination strategies in myelodysplastic syndromes

The myelodysplastic syndromes (MDS) consist of an array of clonal hematological malignancies resulting from disorders of pluripotent hematopoietic stem cells. MDS is associated with a poor overall prognosis and patients are categorized as higher risk and lower risk on the basis of the International Prognostic Scoring System. Currently, lenalidomide, azacitidine, and decitabine are the only three FDA-approved drugs for MDS. Traditional therapies for MDS involve the administration of single agents providing either supportive measures or disease-modifying effects directed to slowing progression to acute myeloid leukemia (AML) and improving survival. Recently, however, there has been increasing evidence suggesting that the combination of drugs with different mechanisms of action offers substantial benefit in the form of diminished side effects, improved overall survival, and delayed progression to AML. Multiple studies indicate that when compared with traditional monotherapies, combining various medications with non-overlapping mechanisms of action and toxicities may result in significant benefit for patients with MDS. A variety of combination therapies with growth factors, DNA methytransferase inhibitors, histone deacetylase inhibitors, and immunosuppressant treatments provide encouraging data indicating that the successful future of MDS treatment rests in the combination of multiple treatments modalities to achieve improved clinical outcomes.