Novel biospecific agents for the treatment of myelodysplastic syndromes

Levels of treatment for patients with myelodysplastic syndromes (MDS) fall within 3 broad categories: supportive care, low- and high-intensity therapy. Most approaches remain experimental, and supportive care remains the standard of treatment in MDS. In parallel with the growing knowledge of the multiple pathobiologic abnormalities in MDS, increasing numbers of low-intensity, biospecific agents that target these pathogenetic lesions have entered clinical trial testing. Although the term "biospecific" has been applied to many of these investigational drugs, they often exert pleiotropic effects, many of which remain to be identified. An ongoing challenge will be to more fully characterize the mechanisms of action of these drugs and to characterize biologic correlates of response. With these data in hand, it will be increasingly feasible to treat patients with combinations of biospecific drugs with non-overlapping actions and toxicities, a therapeutic approach that is likely required to effectively overcome the barriers posed by the biologic heterogeneity of MDS. This review focuses on recent therapeutic approaches using such biologic response modifiers to treat MDS.