Novel targeted therapies for mantle cell lymphoma

Mantle cell lymphoma (MCL) is an aggressive B-cell malignancy characterized by short median survival despite intensive therapies. The clinical behavior of MCL most likely relates to the complex pathophysiology of the disease which includes its genetic hallmark, the chromosomal translocation t(11;14) resulting in aberrant expression of cyclin D1, alteration in the DNA damage response, and constitutive activation of key antiapoptotic pathways such as phosphatidyl-inositol 3-kinase (PI3K)/Akt and nuclear factor-kB (NF-kB). Together, these changes result in cell cycle dysregulation and give rise to profound genetic instability. Given this complex pathophysiology, the limited number of options for patients with relapsed/refractory MCL, and the difficulty in achieving long-lasting remissions with conventional approaches, it is essential to explore new treatment options targeting the pathophysiology of MCL. We have recently reported that milatuzumab, a fully humanized anti-CD74 monoclonal antibody (mAb), in combination with anti-CD20 mAbs has significant preclinical and clinical activity in MCL. Here we discuss these results, provide additional insights into milatuzumab-mediated MCL cell death, and report preliminary data on the activity of other targeted biologic agents including PCI-32765, CAL-101 and mammalian target of rapamycin (mTOR) inhibitors currently undergoing evaluation at our institution and others.