Lenalidomide is an immunomodulatory drug that was developed by modification of the first-generation immunomodulatory drug thalidomide in a drug discovery program. Lenalidomide more potently regulates cellular immune and cytokine responses, while lacking the side-effect profile of thalidomide. The promising activity seen in multiple myeloma and myelodysplastic syndrome has led to its approval by the U.S. Food and Drug Administration in these conditions. The clinical results that we have seen so far, which demonstrate significant efficacy with a tolerable toxicity profile, provide a strong basis for the use of lenalidomide in other malignancies. Combination therapy with lenalidomide could enhance this agent's antineoplastic role; this is likely the position it will occupy in the armamentarium against cancer. Copyright (c) 2007 Prous Science. All rights reserved.