Lenalidomide + Plerixafor in Previously Treated Chronic Lymphocytic Leukemia (CLL)

In research studies, lenalidomide (also called Revlimid) has shown some response in chronic lymphocytic leukemia (CLL); however, responses are usually partial responses that occur after several months of taking the study drug. It is thought that by adding the drug plerixafor (also called Mozobil) responses may be improved and/or occur sooner. The main purpose of this study is to determine the dose of plerixafor that is safe to use in combination with lenalidomide. The study will also look at the response rates of the combination of lenalidomide and plerixafor and the effect the study drugs have on CLL cells.