Transplantation/Immune Reconstitution Funded Projects

Chronic lymphocytic leukemia (CLL) is a common B cell malignancy. While stem cell transplantation offers a potential cure for patients with resistant CLL, its widespread application is limited by transplant related morbidity and mortality. In view of these limitations, which are not exclusive to CLL, there has been much focus on cancer immunotherapy, using the immune system to battle cancer. There has been much development in harnessing T cells to attack cancer cells and indeed, this has drawn the largest share of attention.

The aim of this study is to engineer cord blood (CB) derived natural killer (NK) cells with a receptor tyrosine kinase-like orphan receptor 1 (ROR-1) chimeric antigen receptor (CAR) to enhance their cytotoxic activity against ROR-1 expressing CLL cells. This translates into killing more cancerous cells with targeted therapy with less toxicity compared to conventional therapy. ROR-1 was selected as the target antigen due to its overexpression on CLL cell surface and its lack of expression on mature normal B-cells and haematopoietic progenitor cells, potentially overcoming long-term complications of B-lymphopenia, as reported with CAR.CD19 T cell therapy.

The significance of our project lies in the selection of NK cells rather than T cells engineered to express ROR-1 CAR to improve the survival of cancer patients. Unlike T cells, NK cells from an allogeneic source do not increase the risk of graft-versus-host disease, providing a potential source of off-the-shelf cellular therapy for the treatment of patients with cancer.

Recent data support an important role for the immune system in the control of cancer. However, defects of the immune system have been described in CLL. Indeed, progressive dysfunction of the immune system often parallels disease progression. The aim of our study is to harness the innate immune system, specifically powerful immune cells called natural killer (NK) cells, in the control of CLL. We have developed a novel strategy to enhance NK cell function against CLL by genetic modification so that NK cells can recognize a molecule, ROR1, that is overexpressed on CLL cells but not on normal B cells. This strategy is advantageous as it will selectively target and kill CLL cells, while sparing normal B cells. Our preliminary data show that such ‘redirected ’ NK cells are much more efficient at recognizing CLL cells compared to their unmodified counterparts.

Defects of the immune system have been described in CLL patients that make them highly susceptible to infections. Progressive dysfunction of the immune system often parallels disease progression. This CLL Alliance proposal includes two clinical trials with companion laboratory studies which will be performed by scientific teams in Houston and London, aimed at improving the clinical outcome of patients with CLL.

In the first trial, immune cells (T-cells) will be harvested from patients with newly diagnosed CLL prior to the start of immunosuppressive chemotherapy. These cells will then be expanded and activated in our stem cell laboratory. The activated T-cells will then be infused back into the patients once the chemotherapy is completed. The hope is that the activated T-cells will reverse some of the immunological defects seen in CLL, thus reducing the risk of infections and potentially improve malignant disease control.

In the second trial, umbilical cord blood will be evaluated as a donor source of cells for CLL patients undergoing allogeneic stem cell transplantation who do not have an appropriately matched adult stem cell donor. A portion of the cord unit will be expanded and activated ex vivo (outside the body), and then will be trained to specifically kill CLL cells. These activated CLL-specific cells will be infused into the patient post-transplant. The hope is that the primary cord blood transplant and the subsequent activated T-cell infusion will eradicate the malignant CLL cells completely, leaving the patient with a normal immune system and long-term CLL-free survival.

Correlative laboratory studies will be performed to study the immune function of the patients before and after the T-cell therapy. We will determine how effective the activated T-cells are in fighting CLL and infections. Dr. John Gribben’s laboratory has recently demonstrated that CLL cells interact directly with immune cells and decrease the ability of these cells to mount an effective immune response. His group now has data that CLL cells can also affect healthy immune cells, so there is the potential that CLL cells can decrease responses after allogeneic transplantation. They have developed evaluation tools to be able to assess the impact of CLL on immune cell responses.

A more important assessment will be whether new treatments, including expansion of these cells or use of alternative stem cell donor sources such as cord blood cells, are able to prevent or reverse the defects induced by CLL cells. As part of the Alliance grant, the experiment shall be refined and automated for use in the two clinical trials.

Aim: Test the hypothesis that infusion of activated T-cells will influence immune reconstitution in patients receiving chemo-immunotherapy for CLL:
CLL in itself can cause disease related immunosuppression that is compounded by the immunosuppression induced by agents that are commonly used in the treatment of this disease. T-cells activated using CD3xCD28 microbeads may reverse some of these immune defects. In this study, we plan to give activated T-cell infusion to patients with CLL following treatment with fludarabine or alemtuzumab-based chemo-immunotherapy. A total of 8 patients have been enrolled in a multi-center clinical trial which will help us to determine the feasibility and safety of the infusion of autologous CD3 xCD28 bead-activated T-cells. The trial is a collaboration between Alliance members here at MD Anderson and at University of Pennsylvania, including Bruce Levine, Carl June, and Stephen Schuster.

Aim: Evaluate infusion of expanded umbilical cord blood (CB) T-cells following cord blood transplantation:
CB T-cells are an attractive source for adoptive immunotherapy and cellular therapy, but adult recipients of CB transplants often experience delays in hematological and immunologic reconstitution that increase the risk of infection. We propose to expand CB T-cells, using CD3xCD28 microbeads, to sufficient numbers which could contribute to the reconstitution of immunity and enhance anti-tumor activity. When incubated with peripheral blood T-cells, these microbeads can stimulate marked proliferation of antigen-specific T-cells. Validations for CB T-cell expansion are in progress.

Through our laboratory studies during the course of this grant, we were able to show that generating CLL-specific effectors from partially HLA-matched CB lymphocytes is feasible and practical. Further, we were able to demonstrate functional cytotoxic activity against untreated CLL cells, a distinct technological advancement in comparison to previous cell therapies that have sought to generate CLL-specific responses. These preclinical results support further exploration of this technique as a promising treatment modality in conjunction with CB transplantation.

Natural killer (NK) cells play a key role in the body’s innate immune system. First recognized over 30 years ago, NK cells have been shown to be able to recognize and kill tumor cells in the body, independent of extra signals from other cells. Because of this, NK cells have held great promise in the immune treatment of cancer, including CLL. However, patients with CLL often have reduced numbers of NK cells because of the disease or chemotherapy. Moreover, often times, NK cells are dysfunctional in patients with CLL.

The purpose of our work is to systematically characterize NK cell development as well as any qualitative defects in their function in patients with CLL. Extrapolating on work done by our group on normal NK cell function in humans, we will seek to understand how NK cells are affected by CLL. Secondly, we will investigate novel strategies to recover and enhance NK cell function as a novel means of therapy for patients with CLL.

These techniques may prove to be effective means to control infections in CLL patients as well as treat the underlying cancer. Especially in the setting of stem cell transplantation, NK cells potentially play a curative role the treatment of other blood cancers. Working in the CLL Global Research Foundation Alliance, we hope to move forward such therapies for patients with CLL in the future.

Chronic lymphocytic leukemia is associated with severe dysfunction in the overall immune system. Patients often suffer recurrent infections and other complications from this effect. Moreover, this process impairs a patient’s immune system’s ability to fight the CLL tumor cells, as well. This is important because established therapies such as rituximab (Rituxan) and alemtuzumab (Campath) work, in part, by enhancing immune function against the CLL. Additionally, emerging treatments such as lenalidomide (Revlimid) as well as allogeneic stem cell transplantation rely on the immune system, as well, to induce anti-CLL effects.

Natural killer cells are one type of immune cell that is important in fighting cancer. In the laboratory, we have begun to characterize how natural killer cells are impaired by CLL. We have translated these findings into the clinical setting by beginning to characterize the role of natural killer cells in fighting CLL in patients undergoing allogeneic stem cell transplant. Natural killer cell recovery after an allogeneic transplant may be crucial in eradicating residual CLL cells and promoting long-term disease-free survival. Our work may lead to novel trials to improve outcomes of patients with CLL follow allogeneic transplant to convey long-term, disease-free survival.

Allogeneic stem cell transplantation (SCT) is a potentially curative therapy for selected patients with chronic lymphocytic leukemia (CLL). However a significant proportion of patients – especially non-Caucasian patients – are unable to find a bone marrow donor for this life-saving treatment. Umbilical cord blood (CB) has emerged as an important donor source for these patients. CB can be procured quickly and requires less stringent “tissue type” matching when compared to unrelated bone marrow. Relapse following transplantation however remains a concern. One option to prevent relapse is to administer natural killer cells (NK) to CLL patients after transplant. NK cells made from adult blood have been given to leukemia patients after SCT with some good effects. However until now, CLL patients who received a CB transplant have not been able to be considered for NK cell therapy because the naïve NK cells in the CB unit are unable to kill tumor cells.

The central hypothesis of this proposal is that CB-derived NK cells can be manipulated in the laboratory to kill CLL. Furthermore we propose that NK cells can be expanded from CB to the numbers required for clinical use.  We aim to investigate the mechanism for the poor killing ability of CB NK cells and explore different techniques available in our laboratories to enable CB NK cells to kill CLL. The ultimate goal of this proposal is to optimize the conditions for the generation of CB-derived NK cells for a clinical trial that will study the effects of CB NK cells in CLL patients after CB transplant. Utilizing the unique expertise of each laboratory involved in this collaboration, the expansion and characterization of CB NK cells for clinical use will be performed at both the Baylor College of Medicine (Bollard) and MD Anderson Cancer Center (Shpall) sites.

No update is available at this time. Please check back soon.

Our project is based on the hypothesis that infusing patients with activated T-cells will influence quantitative and functional immune reconstitution in CLL patients following chemotherapy. This should result in reduced rate of infectious complications and may even delay the time to disease progression.

We are conducting a multi-center trial in conjunction with Drs. Chitra Hosing and EJ Shpall of MD Anderson Cancer Center and Dr. Stephen Schuster and Dr. Carl June at University of Pennsylvania.

The premise of the trial is to evaluate the efficacy of administering CD3/CD28 activated T-cells to CLL patients following treatment with fludarabine or alemtuzumab-based chemo-immunotherapy.

CD3 and CD28 are proteins found on T-cells that do not function properly in CLL patients. We are applying microbeads to CLL patients’ T-cells which contain antibodies that attach to CD3 and CD28 on T-cells to activate and expand them. By activating the T-cells, the microbeads turn on the anti-cancer and anti-infection activity and allow T-cells to multiply at an accelerated rate. Properly functioning CD3 and C28 on T-cells allows the immune system to better fight infection and cancer.

Patients enrolled in the trial will undergo apheresis to collect T-cells which will then be co-cultured with CD3/CD28 microbeads. Those subjects who achieve a complete or partial response to the chemo-immunotherapy based regimen will receive an infusion of their activated T-cells. Prior to, and multiple times after T-cell infusion, blood draws will be performed to assess immune reconstitution and immune function as compared to baseline.

No update is available at this time. Please check back soon.

CLL is characterized by the accumulation of monoclonal CD5+ B-lymphocytes and important immune abnormalities that are poorly studied if not totally neglected in CLL investigation. In particular, it is not known whether immune status influences response to therapy and whether immune function is ever recovered in CLL patients responding to therapy.

We hypothesize that immune function can alter response to therapy and its quality (e.g. MRD negativity achievement) in patients with CLL. Also, immune function might determine treatment outcome, as shown by the relationship between the graft-vs. CLL effect and treatment results in CLL patients having received an allograft.

Against this background, we plan to perform a multiparametric study and comparison of the immune status in patients with CLL: (1) untreated; (2) immediately prior to therapy; (3) after achieving response to (3a) chemo/chemo-immunotherapy, (3b) autologous stem cell transplantation, and (3c) allogeneic stem cell transplantation.

Immune function will be studied by both quantitative and functional parameters including: serum markers, B- and T-cell populations, T-regulatory cells, BAFF, APRIL. TK, VEGF, beta-2 microglobulin

A preliminary analysis of the study should allow us to fully describe immune status in patients with CLL in different clinical situations, particularly untreated and treated, and to identify parameters deserving further and more in depth investigation. In addition, throughout the study period, cells and serum samples will be frozen and preserved in order to refine the study as well as to study new, additional factors if deemed necessary.
Finally, patients’ samples will be made available to other USA/European Alliance institutions for other or additional investigations.

In the framework of the Transplantation/Immune Reconstitution Group of the U.S/European Alliance, we have focused on the analysis of the immune status in patients with CLL having undergone stem cell transplantation and who are in long lasting complete remission (CR). Up to now, we have collected samples from 16 patients who have a median follow-up of 5 years. From the raw data obtained in this population, one of the most striking findings is that beta-2 microglobulin (a very well known prognostic marker in CLL) seems to be an extremely powerful marker in patients with CLL who receive a transplant since it correlates with a variety of outcomes, including non-relapse mortality, progression-free and overall survival.

Moreover, we have also found that patients who are in CR, according to NCI criteria, still have abnormalities in T cell function, expansion of T CD8 + cells, and a high number of NK cells. Although these are preliminary results, studies by use of ELISPOT will be performed in order to determine cytokines that may be affected as a result of those abnormalities, and also to determine the potential relationship between these abnormalities and the presence or not of residual leukemic cells.