Lenalidomide and Cyclophosphamide in Treating Patients With Previously Treated Hormone-Refractory Prostate Cancer

PRIMARY OBJECTIVES: I. To determine the maximum tolerated dose (MTD) and the dose limiting toxicities (DLT) of lenalidomide administered in combination with oral cyclophosphamide. SECONDARY OBJECTIVES: I. To evaluate the objective prostate-specific antigen (PSA) response (50% decrease in PSA levels sustained for at least 4 weeks) as defined by PSA working group criteria; or a decrease in absolute PSA or a decrease in PSA velocity, increase in PSA doubling time, duration of any responses. II. To explore the anti-tumor activity of the combination of lenalidomide plus oral cyclophosphamide in patients with previously treated hormone refractory prostate cancer. III. To evaluate baseline and change of quality of life, particularly, bone pain and analgesic consumption, of the patients on this combination chemotherapy. TERTIARY OBJECTIVES: I. To determine whether related cytokines and biomarkers (serum levels of tumor necrosis factor-alpha, basic fibroblast growth factor, vascular endothelial growth factor \[VEGF\], T cell inhibitory activity, phytohemagglutinin \[PHA\] and interleukin \[IL\]-2, mononuclear cell isolation, VEGF, basic fibroblast growth factor \[bFGF\], IL-6) can help predict response to patients undergoing treatment with lenalidomide and cyclophosphamide. OUTLINE: This is a phase I, dose-escalation study of lenalidomide followed by a phase II study. Patients receive lenalidomide orally (PO) once daily (QD) on days 1-21 and cyclophosphamide PO QD on days 1-28. Treatment repeats every 28 days for at least 4 courses in the absence of disease progression or unacceptable toxicity. Treatment modifications may apply according to response. After completion of study treatment, patients are followed up periodically.