Lenalidomide is the first drug to consistently induce transfusion independence and complete cytogenetic remissions in MDS patients with deletion of 5q. However, recently concerns were raised whether lenalidomide treatment may increase the risk of leukemic transformation. The selective activity of lenalidomide against the deletion 5q clone may allow pre-existing aberrant clones to expand if the dominant deletion 5q clone is eradicated in a circumstance in which few normal stem cells remain. This conditional selection of pre-existing clones (
Disclosures: Göhring:Celgene Corporation: cytogenetic reference lab for Celgene MDS-004 study. Giagounidis:Celgene Corporation: Speakers Bureau. Aul:Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees. Büsche:Celgene Corporation: histology reference lab for Celgene MDS-004 study. Kreipe:Celgene Corporation: histology reference lab for Celgene MDS-004 study. Hellström-Lindberg:Celgene Corporation: Consultancy, Research Funding. Knight:Celgene Corporation: Employment. Schlegelberger:Celgene Corporation: cytogenetic reference lab for Celgene MDS-004 study.