Category: Research Publications

Integrin αvβ3 Presents a Possible Therapeutic Target for Patients with T-cell Lymphomas

lecBy Leandro Cerchietti, MD

Malignant T-cell proliferation, survival, and drug resistance are dependent on a combination of external stimuli delivered by the micro-environment. Previous research has shown that the transmembrane receptor integrin αvβ3 plays a crucial role in mediating the interaction of T-cell lymphoma (TCL) cells with external signals. Integrin αvβ3 ligands include extracellular matrix-associated signaling proteins and soluble factors such as thyroid hormones (TH). Having previously shown that TH stimulate the proliferation of TCL through complimentary intracellular pathways involving the αvβ3 integrin, we hypothesized that targeting integrin αvβ3 could represent a novel strategy in treating TCL patients in an abstract presented during ASH.

In determining whether αVβ3 integrin is of therapeutic benefit for TCL, xenografts were developed in SCID mice using CUTLL1 cells transfected with si-control, si-αV and si-β3, and monitored tumor growth and angiogenesis. CUTLL1 was found to transfect with si-αV and si-β3 developed significant smaller tumors than si-control. The translational impact of this strategy was determined through the effect of cilengitide, a selective αVβ3 integrin inhibitor in phase 3 for glioma, in pre-clinical models of PTCL-NOS,  ALCL-ALK+ and  ALCL-ALK-. Similarly to si-αV and si-β3 treated mice, the anti-lymphoma effect of cilengitide correlated with lower levels of angiogenesis and NFkB activation.

This allowed us to elucidate the mechanisms by which integrin αvβ3 activation increases TCL proliferation through the activation of pro-survival pathways in malignant T-cells, while promoting angiogenesis. In the course of our research we also found that the genetic and pharmacological targeting of integrin αvβ3 induces an anti-lymphoma effect in TCL, including ALCL-ALK + and ALCL-ALK- PDT models obtained from treatment refractory patients. Both of these findings present potentially new therapeutic targets for the treatment of patients with T-cell lymphoma.

Circulating Memory T-cell Isolated from Hodgkin Lymphoma Patients Display Evidence of Exhaustion and Chronic Activation

Picture2By Jia Ruan, MD, PhD

Although Hodgkin Reed-Sternberg (HRS) cells comprise only a small number of tumor cells, their number is outweighed by their relative importance as the orchestrators of an inflammatory microenvironment that allows for the growth of Hodgkin Lymphoma (HL). The peritumoral CD4 and CD8 cells in patients with HL, display high expression of the receptor programmed death-1 (PD-1). PD-1 is involved in the functional impairment and “exhaustion” of T-cells. Recent data confirms that the effects of HL-mediated immune suppression may stretch beyond the tumor microenvironment, with reports of high levels of inflammatory cytokines and chemokines in patients with both newly diagnosed and relapsed HL.

In results presented from an abstract presented during the 2014 American Society of Hematology conference (ASH), we found that HL patients have evidence of chronic activation/exhaustion in their central memory and effector T-cells. Informed consent was requested for correlative blood testing was obtained from patients with both newly diagnosed and relapsed HL. For patients with progressive disease persistence of this phenotype is worthy of further investigation as to whether immune dysfunction results from or is caused by resistance to therapy. An answer to this question may provide the rationale for an immune targeted therapy in patients with relapsed or resistance HL.

Chemotherapy Free Novel Combination of Lenalidomide and Rituximab Displays Promising Results as Initial Therapy for Patients with Mantle Cell Lymphoma

Ruan FaceBy Jia Ruan, MD, PhD

Yesterdays results presented at ASH 2014 provides the first demonstrated feasibility and efficacy of a chemotherapy-free, biologic approach using lenalidomide and rituximab as an initial therapy for mantle cell lymphoma (MCL).  These findings present an important chemotherapy-free alternative initial treatment for MCL, as current conventional upfront chemoimmunotherapies are generally not curative.

During this multi-center phase II study patients were administered lenalidomide at 20 mg in days 1-21 of a 28-day cycle for a total of 12 cycles, with doses escalated to 25 mg when tolerated. Rituximab was administered weekly x 4 during first cycle and then once every other cycle for a total of 9 doses.  The induction phase was followed by a maintenance phase, which at the 13th cycle, lenalidomide was administered at 15 mg on days 1-21 of a 28 day cycle, while rituximab maintenance was employed once every other cycle until disease progression.

Of the 38 patients with previously untreated MCL the median age was 65 years (range 42-86), with a male to female ratio of 2.5:1. Treatment was generally well tolerated with mild to moderate side effects. The overall response rate in patients was 84.2%, complete response rate was over 50%, with median time to objective response being 2.8 months. The median progression-free survival has not been reached, and the 2 year progression free survival rate is estimated to be 83.9%.

This study demonstrated that a high proportion of MCL patients can achieve durable remissions while maintaining a high quality of life. The data gathered from this trial justifies further evaluations of the lenalidomide and rituximab regimen both alone and in combination with other treatment approaches to MCL.