The mechanism of action of lenalidomide has not been fully characterized; its activity is attributed to anti-neoplastic, immunomodulatory and antiangiogenic properties. Inhibits secretion of pro-inflammatory cytokines and increases the secretion of anti-inflammatory cytokines from the peripheral mononuclear blood cells. Inhibits the growth of Namalwa (human B cell lymphoma) and KG-1(human myeloblastic) cells with deletion of chromosome 5. Inhibits growth of multiple myeloma cells, by inducing cell cycle arrest and apoptosis. Lenalidomide also inhibits the expression of cyclooxygenase-2 (COX-2) in-vitro.