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Coinciding with the 2004 American Society of Hematology's annual meeting, the following is a full-text review article that provides the latest on CLL from the research community.

Some highlights include:

"CD38 or ZAP-70 as compared to VH (mutations) in all series described, indicate that these markers may not be as reliable as initially thought for routine diagnostics."

"The VH mutation status, 17p deletion, 11q deletion, age, leukocyte count and LDH were identified as independent prognostic factors...(The) four subgroups of CLL with markedly differing survival probabilities can be defined by the VH mutation status, 11q deletion and 17p deletion."

"(V)irtually all CLL patients who are treated (with fludarabine) become fludarabine-refractory."

"(O)verall survival was inferior for (unfavorable) subgroups...despite the fact that comparable treatment(s) were used for patients...suggests that response to therapy may be different in genetic subgroups."

"Allogeneic transplants...result in survival curves plateaus of about 40%. Unfortunately, (a sizable minority) of patients died from procedure-related causes."

Although autologous SCT are generally not curative, they "resulted in significantly longer overall survival as compared to conventional chemotherapy." 

^"(Campath can) eliminate CLL disease with p53 mutations or deletion(, which are not) responsive to rituximab therapy."

"Most promising of (the new trials) includes...flavopiridol...where promising early results have been observed."

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Chronic Lymphocytic Leukemia

Abstract

Chronic lymphocytic leukemia (CLL) is one of the most commonly diagnosed leukemias managed by practicing hematologists. For many years patients with CLL have been viewed as similar, with a long natural history and only marginally effective therapies that rarely yielded complete responses. Recently, several important observations related to the biologic significance of V_H mutational status and associated ZAP-70 overexpression, disrupted p53 function, and chromosomal aberrations have led to the ability to identify patients at high risk for early disease progression and inferior survival. Concurrent with these investigations, several treatments including the nucleoside analogues, monoclonal antibodies rituximab and alemtuzumab have been introduced. Combination of these therapies in clinical trials has led to high complete and overall response rates when applied as initial therapy for symptomatic CLL. Thus, the complexity of initial risk stratification of CLL and treatment has increased significantly. Furthermore, when these initial therapies do not work, approach of the CLL patient with fludarabine-refractory disease can be quite challenging. This session will describe the natural history of a CLL patient with emphasis on important decision junctures at different time points in the disease.

In Section I, Dr. Stephan Stilgenbauer focuses on the discussion that occurs with CLL patients at their initial evaluation. Ongoing and future efforts examining early intervention strategies in high risk CLL are reviewed.

In Section II, Drs. Ian Flinn and Jesus G. Berdeja focus on the discussion of CLL patients when symptomatic disease has developed. This includes an updated review of monotherapy trials with nucleoside analogs and recent trials that have combined these with monoclonal antibodies and/or alternative chemotherapy agents.

In Section III, Dr. John Byrd focuses on the discussion that occurs with CLL patients whose disease is refractory to fludarabine.

http://www.asheducationbook.org/cgi/content/full/2004/1/163

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This is an excellent review article by a number of top CLL researchers, led by Michael Keating.  I've posted the abstract; the full text article is available for free (registration may be necessary) by clicking the link below the article. 

Biology and Treatment of Chronic Lymphocytic Leukemia

Abstract

Major advances have occurred in our understanding of the biology, immunology, and opportunities for treatment of chronic lymphocytic leukemia (CLL) in recent times. Surface antigen analysis has helped us define classical CLL and differentiate it from variants such as marginal zone leukemia, mantle cell leukemia, and prolymphocytic leukemia. An important observation has been that the B-cells in indolent types of CLL, which do not require therapy, have undergone somatic hypermutation and function as memory B-lymphocytes whereas those more likely to progress have not undergone this process.

Section I by Dr. Nicholas Chiorazzi encompasses emerging elements of the new biology of CLL and will address the types of somatic hypermutation that occur in CLL cells and their correlation with other parameters such as telomere length and ZAP70 status. In addition he addresses the concept of which cells are proliferating in CLL and how we can quantitate the proliferative thrust using novel methods. The interaction between these parameters is also explored.

Section II by Dr. Thomas Kipps focuses on immune biology and immunotherapy of CLL and discusses new animal models in CLL, which can be exploited to increase understanding of the disease and create new opportunities for testing the interaction of the CLL cells with a variety of elements of the immune system. It is obvious that immunotherapy is emerging as a major therapeutic modality in chronic lymphocytic leukemia. Dr. Kipps addresses the present understanding of the immune status of CLL and the role of passive immunotherapy with monoclonal antibodies such as rituximab, alemtuzumab, and emerging new antibodies. In addition the interaction between the CLL cells and the immune system, which has been exploited in gene therapy with transfection of CLL cells by CD40 ligand, is discussed.

In Section III, Dr. Michael Keating examines the question "Do we have the tools to cure CLL?" and focuses on the fact that we now have three distinct modalities, which are able to achieve high quality remissions with polymerase chain reaction (PCR) negativity for the immunoglobulin heavy chain in CLL. These modalities include initial chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab, the use of alemtuzumab for marrow cytoreduction in minimal residual disease and allogeneic bone marrow transplants. The emergence of non-ablative marrow transplants in CLL has led to the broadening of the range of opportunities to treat older patients. The addition of rituximab to the chemotherapy preparative regimens appears to be a significant advance.

The combination of our increased understanding of the biology, immune status, and therapy of CLL provides for the first time the opportunity for curative strategies.

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Another good article, this time on using the immune system to fight cancers.  The problem with CLL is, of course, that by definition, CLL patients have an impaired immune system.  That makes using the immune system to defeat CLL is more difficult than it may be in other cancers.  Not impossible, just more difficult.

Immunotherapy of Hematologic Malignancy

Abstract

Over the past few years, improved understanding of the molecular basis of interactions between antigen presenting cells and effector cells and advances in informatics have both led to the identification of many candidate antigens that are targets for immunotherapy. However, while immunotherapy has successfully eradicated relapsed hematologic malignancy after allogeneic transplant as well as virally induced tumors, limitations have been identified in extending immunotherapy to a wider range of hematologic malignancies. This review provides an overview of three immunotherapy strategies and how they may be improved.

In Section I, Dr. Stevenson reviews the clinical experience with genetic vaccines delivered through naked DNA alone or viral vectors, which are showing promise in clinical trials in lymphoma and myeloma patients. She describes efforts to manipulate constructs genetically to enhance immunogenicity and to add additional elements to generate a more sustained immune response.

In Section II, Dr. Molldrem describes clinical experience with peptide vaccines, with a particular focus on myeloid tissue-restricted proteins as GVL target antigens in CML and AML. Proteinase 3 and other azurophil granule proteins may be particularly good targets for both autologous and allogeneic T-cell responses. The potency of peptide vaccines may potentially be increased by genetically modifying peptides to enhance T-cell receptor affinity.

Finally, in Section III, Dr. Heslop reviews clinical experience with adoptive immunotherapy with T cells. Transferred T cells have clinical benefit in treating relapsed malignancy post transplant, and Epstein-Barr virus associated tumors. However, T cells have been less successful in treating other hematologic malignancies due to inadequate persistence or expansion of adoptively transferred cells and the presence of tumor evasion mechanisms. An improved understanding of the interactions of antigen presenting cells with T cells should optimize efforts to manufacture effector T cells, while manipulation of lymphocyte homeostasis in vivo and development of gene therapy approaches may enhance the persistence and function of adoptively transferred T cells.

http://www.asheducationbook.org/cgi/content/full/2003/1/331

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Our next article is from 2002, and is an excellent overview of CLL.

Chronic Lymphocytic Leukemia

Abstract

This update of early stage B-cell chronic lymphocytic leukemia (B-CLL) embraces current information on the diagnosis, biology, and intervention required to more fully develop algorithms for management of this disease. Emphasis on early stage is based on the rapid advancement in our understanding of the disease parameters and our increasing ability to predict for a given early stage patient whether there is a need for more aggressive management.

In Section I, Dr. Terry Hamblin addresses the nature of the disease, accurate diagnostic procedures, evidence for an early "preclinical" phase, the use of newer prognostic features to distinguish who will be likely to progress or not, and whether it is best to watch or treat early stage disease.

In Section II, Dr. Neil Kay and colleagues address the biologic aspects of the disease and how they may relate to disease progression. Review of the newer insights into gene expression, recurring genetic defects, role of cytokines/autocrine pathways, and the interaction of the CLL B cell with the microenvironment are emphasized. The relationship of these events to both trigger disease progression and as opportunities for future therapeutic intervention even in early stage disease is also considered.

In Section III, Dr. John Byrd and colleagues review the historical and now current approaches to management of the previously untreated progressive B-CLL patient. They discuss what decision tree could be used in the initial decision to treat a given patient. The use of single agents versus newer combination approaches such as chemoimmunotherapy are discussed here. In addition, the place of marrow transplant and some of the newer antibodies available for treatment of B-CLL are considered. Finally, a challenge to utilize our growing knowledge of the biology of B-CLL in the early stage B-CLL is proffered.

http://www.asheducationbook.org/cgi/content/full/2002/1/193

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This paper is a good introduction to mutational status, CD38, and survival 

 

VH mutation status, CD38 expression level, genomic aberrations, and survival in chronic lymphocytic leukemia  New!

 

Alexander Kröber, Till Seiler, Axel Benner, Lars Bullinger, Elsbeth Brückle, Peter Lichter, Hartmut Döhner, and Stephan Stilgenbauer

From Abteilung Innere Medizin III, University of Ulm, Germany; Zentrale Einheit Biostatistik and Abteilung Organisation komplexer Genome, Deutsches Krebsforschungszentrum, Heidelberg, Germany.

 

Abstract

 

In chronic lymphocytic leukemia (CLL), biologic risk factors such as immunoglobulin variable heavy chain gene (VH) mutation status, CD38 expression level, and genomic aberrations have recently been identified, but the relative prognostic impact of the individual parameters is unknown. In the current study, we analyzed VH mutation status by polymerase chain reaction and sequencing (n = 300), genomic aberrations by fluorescence in situ hybridization (+3q, 6q, +8q, 11q, +12q, 13q, t(14q), 17p) (n = 300), and CD38 expression by triple-color FACS (CD5, CD19, CD38) (n = 157) in a unicentric CLL cohort.

 

The prognostic influence of VH mutation rate and CD38 expression level was tested by maximally selected log-rank statistics. A corrected P value (Pcor) for a cutoff level allowing the best separation of 2 subgroups with different survival probabilities was identified at 97% VH homology (95% confidence interval [CI], 96%-98% homology, Pcor <.001) and at 7% CD38 expression (95% CI, 20%-71% expression, Pcor = .02).

 

In univariate analyses, unmutated VH genes and high CD38 expression levels predicted for shorter survival times. The overall incidence of genomic aberrations was similar in the VH unmutated and VH mutated subgroups. High-risk genomic aberrations such as 17p and 11q occurred almost exclusively in the VH unmutated subgroup, whereas favorable aberrations such as 13q and 13q as single abnormalities were overrepresented in the VH mutated subgroup.

 

In multivariate analysis, unmutated VH, 17p deletion, 11q deletion, age, WBC, and LDH were identified as independent prognostic factors, indicating a complementary role of VH mutation status and genomic aberrations to predict outcome in CLL. (Blood. 2002;100:1410-1416)

 

© 2002 by The American Society of Hematology.

 

Read the full-text article at:

 

http://www.bloodjournal.org/cgi/content/full/100/4/1410?ck=nck

 

This is a heavily-cited paper.  The full text is available as noted below.  The paper discusses the gene profiles of mutated and unmuated CLL cells.  This article sheds more light on the type of cell which became malignant CLL.

Gene Expression Profiling of B Cell Chronic Lymphocytic Leukemia Reveals a Homogeneous Phenotype Related to Memory B Cells New!

¹ Institute for Cancer Genetics, Departments of Pathology and Genetics & Development, Columbia University, New York, NY 10032
² IBM T.J. Watson Research Center, Yorktown Heights, New York, NY 10598
³ Department of Adult Oncology Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, MA 02115
⁴ Department of Pathology, New York University Medical Center, New York, NY 10016
⁵ Ematologia 1, Department of Hematology, Ospedale Maggiore, I.R.C.C.S., Milan 20122, Italy
⁶ First Genetic Trust, Inc., Lyndhurst, NJ 07071

Abstract:

B cell–derived chronic lymphocytic leukemia (B-CLL) represents a common malignancy whose cell derivation and pathogenesis are unknown. Recent studies have shown that >50% of CLLs display hypermutated immunoglobulin variable region (IgV) sequences and a more favorable prognosis, suggesting that they may represent a distinct subset of CLLs which have transited through germinal centers (GCs), the physiologic site of IgV hypermutation.

To further investigate the phenotype of CLLs, their cellular derivation and their relationship to normal B cells, we have analyzed their gene expression profiles using oligonucleotide-based DNA chip microarrays representative of 12,000 genes. The results show that CLLs display a common and characteristic gene expression profile that is largely independent of their IgV genotype. Nevertheless, a restricted number of genes (<30) have been identified whose differential expression can distinguish IgV mutated versus unmutated cases and identify them in independent panels of cases.

Comparison of CLL profiles with those of purified normal B cell subpopulations indicates that the common CLL profile is more related to memory B cells than to those derived from naive B cells, CD5⁺ B cells, and GC centroblasts and centrocytes. Finally, this analysis has identified a subset of genes specifically expressed by CLL cells of potential pathogenetic and clinical relevance.

http://www.jem.org/cgi/content/full/194/11/1625

Stanford Researchers Claim Major Progress in Curbing GvHD: New!

New Marrow Transplant Method Developed At Stanford May Eliminate
Fatal Side Effects
12/6/2004

Source: Stanford University

Bone marrow transplantation can cure lymphomas and leukemia, but in
about half of the cases transplanted immune cells wind up attacking
the patient's body, as well as the cancer.

In response to this problem, researchers at the Stanford University
School of Medicine have developed a technique that can virtually
eliminate this life-threatening complication, known as graft-versus-
host disease, without compromising the transplanted cells'
effectiveness against cancer.

The therapy entails adjusting the patient's level of a specific type
of immune cell, the regulatory T cells, before the transplant is
done. The method was first developed in mice by Samuel Strober, MD,
professor of medicine (immunology and rheumatology), who has been
studying these types of cells for more than 25 years. Robert Lowsky,
MD, assistant professor of medicine (bone marrow transplantation),
has adapted this strategy for humans along with Strober, and will
present the results of tests Dec. 6 at the annual American Society of
Hematology meeting in San Diego.

In two clinical trials funded by the National Institutes of Health,
Lowsky, Strober and other colleagues found that only one of the 37
patients who received the treatment developed graft-versus-host
disease. "You would have expected something in the order of 30 to 60
percent incidence of severe graft-versus-host disease in these
patients, according to conventional methods," said Strober.

Studies of the new method found there was no increase in the rate of
infections in the treated patients. The studies also found that the
majority of patients who were in partial remission went into complete
remission, and those who were in complete remission didn't relapse.

"It looks like there is a potent anti-tumor effect from our method
despite the incidence of graft-versus-host disease being dramatically
lowered," said Lowsky.

Also at the conference, Strober will conduct a session in which he
reviews the checkered history of regulatory T cells. For years
immunologists were polarized into groups who believed in the cells,
once known as suppressor T cells, and those who doubted their
existence. But with the development of more advanced techniques for
distinguishing between the different types of immune system cells,
the existence of the regulatory T cells has been confirmed. The
latest research suggests that the regulatory T cells act as the
immune system's peacekeepers, signaling to other T cells when to hold
off from attacking an intruder.

"The news going into this meeting is that the field of regulatory T
cells has not only come out of the clouded period that it was in, but
is now being accepted and adapted into clinical trials as a
conceptual framework for achieving certain desirable outcomes, for
example in the area of bone marrow transplantation," said Strober.

Always a proponent of the existence of regulatory T cells, Strober
worked out over the years a strategy using irradiation and antibodies
to increase the relative amount of regulatory T cells in the immune
tissues of host mice from about 1 percent of the total T cells to
more than 90 percent. By increasing the relative amount of these
cells, he found that he could retain the desired effect of killing
cancerous cells following bone marrow transplantation, but eliminate
the attack on host tissues. "It allows you to throw out the one
effect but not the other," he said.

Lowsky said he and Strober have now taken Strober's animal model and
translated it to the clinical setting for people. Although they have
not yet gathered conclusive evidence that this cellular process
worked the same in humans as it did in mice-that would require doing
direct examinations of cells from patients' spleens or lymph nodes-
Lowsky said their evaluations of the blood and marrow samples suggest
that is the case.

Now that the method is proving to be a viable therapy for humans, the
team will be testing it with other cancer centers.

Others involved in the clinical trial are Robert Negrin, MD,
professor of medicine; Yinping Liu, MD, a staff research associate
and Judith Shizuru, MD, PhD, associate professor of medicine, all in
the bone marrow transplantation division, and Tsuyoshi Takahashi, MD,
a research fellow in Strober's lab.

Here's the abstract from the 2004 ASH Meeting:

Non-Myeloablative Conditioning of Total Lymphoid Irradiation (TLI) and Anti-Thymocyte Globulin (ATG) Protects Against Acute GVHD Following Allogeneic Hematopoietic Cell Transplantation (HCT) but Retains Anti-Tumor Activity. Session Type: Oral Session

Robert Lowsky, Tsuyoshi Takahashi, Yin Ping, Judith Shizuru, Robert S. Negrin, Samuel Strober. Medicine, Stanford University School of Medicine, Stanford, CA, USA

Separation of GVHD from graft versus tumor (GVT) reactions is critical in improving outcomes for HCT. Murine models of transplantation showed that after conditioning with repeated low doses of irradiation targeted to lymphoid tissues (TLI) are combined with ATG, regulatory natural killer (NK) T cells become the predominant T cell subset. Secretion of high levels of IL-4 by the host NK T cells protects against aGVHD following HCT. Yet tumor killing activity mediated by donor CD8⁺ T cells via a direct cytolytic pathway involving perforin remains intact. Thus, regulatory T cells can separate GVHD from graft anti-tumor activity. We adapted the murine protocol to a clinical regimen of TLI (10 doses of 80 cGy/dose) and rabbit ATG (5 doses of 1.5 mg/kg/dose) with post-grafting immunosuppression of mycophenylate mofetil (MMF) and cyclosporin (CSP) to determine if the regimen separates aGVHD from GVT reactions in humans. In a completed phase I and an ongoing phase II study 37 patients with extensively pretreated hemato-lymphoid malignancies (22 with lymphoma, 4 with lymphocytic leukemia and 11 with AML) received related (23) or unrelated (14) HLA matched G-CSF mobilized HCT. Twenty nine patients (78%) had advanced stage disease, 12 had received prior autologous transplants, 18 were in a partial remission (PR) at the time of allogeneic transplant, 2 had progressive disease (PD) and 17 were in complete remission (CR). All patients had initial multilineage donor hematopoietic cell engraftment within 56 days post transplantation. The median follow-up (F/U) for all patients is 262 days with 27 of 37 patients alive. Thirty six of 37 patients had grade 0 aGVHD and 1 patient had grade III aGVHD that responded to steroid therapy. Thirty-five patients were alive at day 100 and considered at risk for cGVHD. Six of the 35 developed denovo extensive cGVHD, and one developed extensive cGVHD following aGVHD. Twenty-eight patients had either no or limited cGVHD. Of the 18 patients transplanted in PR, 11 achieved a CR and have not relapsed, 2 did not clear their tumor, 2 are too early to evaluate and 3 died from non-relapse causes. Eleven of 16 patients transplanted in CR continue in CR and of the 5 that relapsed all had advanced stage disease. Evaluation of sorted CD4⁺ T cells obtained 1-6 months after HCT from fully chimeric recipients conditioned with TLI/ATG showed a statistically significant increase in IL-4 secretion following in vitro stimulation, and a statistically significant decrease in the proliferation response to allogeneic stimulator cells in the mixed leukocyte reaction (MLR) as compared to normal controls or to patients given non-myeloablative TBI conditioning. Sorted CD8⁺ T cells obtained from TLI/ATG conditioned patients retained vigorous cytolytic activity in the cell mediated lympholysis (CML) assay. In conclusion, TLI/ATG conditioning resulted in a markedly reduced incidence of aGVHD but with retained GVT reactions as the majority of patients with PR converted to CR and did not relapse. We show evidence that as in the pre-clinical model the low incidence of GVHD is associated with increased IL-4 secretion by chimeric donor T cells and a reduced proliferative response to alloantigens but retained anti-tumor activity.
Abstract #433 appears in Blood, Volume 104, issue 11, November 16, 2004
Keywords: Hematopoietic cell transplantation|NK-T cells|Graft-versus-host disease (GVHD)

Monday, December 6, 2004, 01:30 PM

Simultaneous Session: Immunological Approaches to Allogeneic Mismatched and Unrelated Transplantation (1:30 PM-3:00 PM)