Alemtuzumab therapy in B-cell lymphoproliferative disorders

Loss of the GPI-anchor in B-lymphoblastic leukemia by epigenetic downregulation of PIGH expression

Adult B-lymphoblastic leukemia (B-ALL) is a hematological malignancy characterized by genetic heterogeneity. Despite successful remission induction with classical chemotherapeutics and novel targeted agents, enduring remission is often hampered by disease relapse due to outgrowth of a pre-existing subclone resistant against the treatment. In this study, we show that small glycophosphatidylinositol (GPI)-anchor deficient CD52-negative B-cell populations are frequently present already at diagnosis in B-ALL patients, but not in patients suffering from other B-cell malignancies. We demonstrate that the GPI-anchor negative phenotype results from loss of mRNA expression of the PIGH gene, which is involved in the first step of GPI-anchor synthesis. Loss of PIGH mRNA expression within these B-ALL cells follows epigenetic silencing rather than gene mutation or deletion. The coinciding loss of CD52 membrane expression may contribute to the development of resistance to alemtuzumab (ALM) treatment in B-ALL patients resulting in the outgrowth of CD52-negative escape variants. Additional treatment with 5-aza-2'-deoxycytidine may restore expression of CD52 and revert ALM resistance.

Sensitizing protective tumor microenvironments to antibody-mediated therapy

Therapy-resistant microenvironments represent a major barrier toward effective elimination of disseminated malignancies. Here, we show that select microenvironments can underlie resistance to antibody-based therapy. Using a humanized model of treatment refractory B cell leukemia, we find that infiltration of leukemia cells into the bone marrow rewires the tumor microenvironment to inhibit engulfment of antibody-targeted tumor cells. Resistance to macrophage-mediated killing can be overcome by combination regimens involving therapeutic antibodies and chemotherapy. Specifically, the nitrogen mustard cyclophosphamide induces an acute secretory activating phenotype (ASAP), releasing CCL4, IL8, VEGF, and TNFα from treated tumor cells. These factors induce macrophage infiltration and phagocytic activity in the bone marrow. Thus, the acute induction of stress-related cytokines can effectively target cancer cells for removal by the innate immune system. This synergistic chemoimmunotherapeutic regimen represents a potent strategy for using conventional anticancer agents to alter the tumor microenvironment and promote the efficacy of targeted therapeutics.

Autoimmunity associated with immunotherapy of cancer

In this age of promise of new therapies for cancer, immunotherapy is emerging as an exciting treatment option for patients. Vaccines and cytokines are being tested extensively in clinical trials, and strategies using monoclonal antibodies and cell transfer are mediating dramatic regression of tumors in patients with certain malignancies. However, although initially advocated as being more specific for cancer and having fewer side effects than conventional therapies, it is becoming increasingly clear that many immunotherapies can lead to immune reactions against normal tissues. Immunotoxicities resulting from treatment can range from relatively minor conditions, such as skin depigmentation, to severe toxicities against crucial organ systems, such as liver, bowel, and lung. Treatment-related toxicity has correlated with better responses in some cases, and it is probable that serious adverse events from immune-mediated reactions will increase in frequency and severity as immunotherapeutic approaches become more effective. This review introduces immunotherapeutic approaches to cancer treatment, provides details of toxicities arising from therapy, and discusses future potential ways to avoid or circumvent these side effects.

High incidence of tuberculosis after alemtuzumab treatment in Hong Kong Chinese patients

Twenty-seven patients received the anti-CD52 monoclonal antibody alemtuzumab for hematologic malignancies and autoimmune cytopenias in a tuberculosis-endemic area. Seven patients developed mycobacterium tuberculosis (TB) infections (median: 4, 1-24, months from alemtuzumab). The actuarial 1- and 2-year incidence of TB was 31% and 45%. All patients had severe depression of lymphocyte counts subsequent to alemtuzumab treatment, and tuberculosis was extra-pulmonary in three cases. All seven patients had received prior chemotherapy/immunosuppression and tuberculosis had not occurred until alemtuzumab was administered. Patients receiving alemtuzumab in areas endemic for tuberculosis should have careful initial evaluation of TB exposure, so that prophylactic antibiotics might be administered. Tuberculosis reactivation should be considered for unexplained fever and symptoms after alemtuzumab treatment.

Nursing guidelines for managing infections in patients with chronic lymphocytic leukemia

Infections are a primary cause of death in patients with chronic lymphocytic leukemia (CLL). Such individuals are particularly susceptible to infectious complications stemming from immune deficits associated with the primary disease process and with immunosuppression secondary to treatment. Although the recent availability of new treatment modalities and more aggressive therapies are improving outcomes for patients with CLL, standardized approaches are needed so that nurses can monitor for and manage infections. The aim is overall reduction in morbidity and mortality, as well as improvement in quality of life. The current pharmacologic therapies for CLL are alkylating agents, purine nucleoside analogs, monoclonal antibodies, and combinations of those therapies, which may present their own unique risks for and different spectra of infectious events. This article provides an overview of the known risks for developing infections in CLL, as well as nursing guidelines for monitoring and managing patients with CLL.

The natural history of fludarabine-refractory chronic lymphocytic leukemia patients who fail alemtuzumab or have bulky lymphadenopathy

The natural history and outcome of salvage treatment for patients with fludarabine-refractory chronic lymphocytic leukemia who are either refractory to alemtuzumab ("double-refractory") or ineligible for alemtuzumab due to bulky lymphadenopathy ("bulky fludarabine-refractory") have not been described. We present the outcomes of 99 such patients (double-refractory n = 58, bulky fludarabine-refractory n = 41) undergoing their first salvage treatment at our center. Patients received a variety of salvage regimens including monoclonal antibodies (n = 15), single-agent cytotoxic drugs (n = 14), purine analogue combination regimens (n = 21), intensive combination chemotherapy (n = 36), allogeneic stem cell transplantation (SCT; n = 4), or other therapies (n = 9). Overall response to first salvage therapy other than SCT was 23%, with no complete responses. All four patients who underwent SCT as first salvage achieved complete remission. Early death (within 8 weeks of commencing first salvage) occurred in 13% of patients, and 54% of patients experienced a major infection during therapy. Overall survival was 9 months, with hemoglobin < 11 g/dL (hazard ratio 2.3), hepatomegaly (hazard ratio 2.4), and performance status > or = 2 (hazard ratio 1.9) being significant independent predictors of inferior survival.

Fully human antibody exhibits pan-human leukocyte antigen-DR recognition and high in vitro/vivo efficacy against human leukocyte antigen-DR-positive lymphomas

HD8, a fully human monoclonal antibody specific for human leukocyte antigen-DR (HLA-DR), was generated by using the transchromosome mouse that bears the human immunoglobulin genes. HD8 could bind to all 13 tested HLA-DR-positive cell lines and 35 B-cells from healthy donors. Epitope mapping revealed that while the antibody recognizes the most polymorphic region of the HLA-DRB chain, its critical epitope residues are conserved in the major alleles. Indeed, HD8 could recognize 99.2% of HLA-DRB alleles. Since its essential epitope residues are also largely conserved in HLA-DP and HLA-DQ, HD8 could recognize 100% and 66% of the HLA-DP and HLA-DQ alleles tested, respectively. HD8 exerted strong antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro, and significantly extended the life span of immunocompromised mice inoculated with non-Hodgkin lymphoma cell lines. The HD8 antibody may be highly useful in HLA-DR-targeted immunotherapy as it is likely to evoke similarly strong responses in individuals carrying different HLA-DR alleles.

Alemtuzumab (Campath® 1-H)

Alemtuzumab is an exciting targeted therapy for patients with CD52-sensitive malignancies. The drug is being used in a variety of hematologic malignancies in different dosing schedules and different routes of administration. The Cancer and Leukemia Group B is conducting a study using alemtuzumab as consolidation treatment for patients with B-CLL. The group also is conducting a phase I and II dose-escalation study using alemtuzumab during intensification therapy in adults with untreated acute lymphoblastic leukemia. A national pharmaceutical protocol is actively accruing participants for a trial in which alemtuzumab is used in combination with fludarabine for relapsed and refractory B-CLL. The SQ route of administration is gaining popularity because it is highly effective with fewer side effects than IV infusions. Nurses administering alemtuzumab are in a unique position to ensure patient safety and tolerance of the therapy. By understanding the mechanism of action and the potential complications associated with alemtuzumab, nurses will be better able to provide optimal care to patients as the use of targeted monoclonal therapy continues to progress.

Recent advances in chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a low-grade B-lineage lymphoid malignancy. Based on recent findings, the disease appears to be more heterogeneous than previously thought. Many cases may require no treatment at all unless patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is noncurative and is directed at reducing the symptoms. Recently described molecular risk features may help delineate at initial diagnosis which patients will have a more aggressive course. Newer treatment regimens incorporating purine nucleoside analogs and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to increased survival. Reduced intensity conditioning regimens have made the potentially curative modality of allogeneic transplantation more widely available. All of these recent treatments have significant risks of infectious complications, which must be carefully weighed against the risks posed by the underlying disease, and many low-risk asymptomatic patients do not require any treatment. A proposed risk-based treatment algorithm will be discussed.

Chronic Lymphocytic Leukemia: Recent Advances in Diagnosis and Treatment

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy but may have more heterogeneity than previously thought. Many cases require no treatment at all because of an indolent course, while other patients become symptomatic or develop signs of rapid progression. Treatment is usually noncurative and is directed at reducing the symptoms. Some molecular risk features may help delineate, at initial diagnosis, which patients will have a more aggressive course. Newer CLL treatment regimens incorporating purine nucleoside analogues and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to better survival times. Reduced intensity allogeneic transplant conditioning regimens have made the potentially curative modality more widely available. All these treatments have significant risks for infectious complications, which must be carefully weighed against the risks posed by the underlying disease. A proposed risk-based treatment algorithm is discussed.

Engineered antibodies act as targeted therapies in cancer treatment

Over the last two decades cancer cure rates have not gone up as expected, and the effectiveness of chemotherapy has reached a plateau. This has prompted a search for targeted therapies with higher efficacy and lesser toxicities. Monoclonal antibodies against cancer cells offer targeted therapies with little or no toxicities against normal tissues. In this review we will discuss the concepts behind the development of monoclonal antibodies in cancer and their present status in the clinic. Specifically, we will discuss the clinical use of Rituximab (RituxanO), Trastuzumab (HerceptinO) and Bevacizumab (AvastinO) in various cancers and the key clinical trials that have led to their incorporation in cancer therapeutics.

Selective targeting of antibody-conjugated nanoparticles to leukemic cells and primary T-lymphocytes

In the present study, surface-modified nanoparticles based on biodegradable material were used for antibody coupling in order to get a selective drug carrier systems. Gelatin nanoparticles were prepared by a desolvation process. Sulfhydryl groups were introduced which enabled the linkage of NeutrAvidin (NAv). Antibodies specific for the CD3 antigen on lymphocytic cells were conjugated to the nanoparticles surface. The binding of biotinylated anti-CD3 antibody was achieved by NAv-biotin-complex formation. Cellular binding and uptake were determined by flow cytometry and confocal laser scanning microscopy (CLSM). Cell-type-specific targeting of anti-CD3-conjugated nanoparticles into CD3-positive human T-cell leukemia cells and primary T-lymphocytes could be shown. Celluar uptake and effective internalization of antibody-conjugated nanoparticles into CD3 expressing cells were demonstrated. Uptake rates of about 84% into T-cell leukemia cells were observed. To confirm selectivity of T-cell targeting, competition experiments were carried out adding excessive free anti-CD3 prior to nanoparticle incubation leading to significantly reduced cellular uptake of antibody-conjugated nanoparticles. Further analysis on the mechanism of uptake confirmed a receptor-mediated endocytotic process. Protein-based nanoparticles conjugated with an antibody against a specific cellular antigen hold promise as selective drug delivery systems for specific cell types.

Giant cell tumors of the bone: Molecular profiling and expression analysis of Ephrin A1 receptor, Claudin 7, CD52, FGFR3 and AMFR

Giant cell tumors (GCTs) of the bone are osteolytic neoplasms with variable degrees of aggressiveness. The aim of this study was the molecular characterization of GCT tissue. We established gene expression profiles and discovered a number of genes that have not been described in GCTs before. RNA was prepared from 7 cryopreserved GCTs (primary tumors n = 5, relapses n = 2) and was hybridized to Affymetrix HG U133A microarrays. Paraffin-embedded samples were used for immunohistochemical validation (primary tumors n = 16, relapses n = 6). Gene ontology revealed that the majority of genes, found to be differentially expressed between primary and recurrent GCTs, were associated with receptor tyrosine kinase activity. We selected one upregulated gene (Claudin 7) and four downregulated genes (CD52, Ephrin A1 receptor, autocrine motility factor receptor [AMFR] and fibroblast growth factor receptor 3 [FGFR3] for further analysis using immunohistochemistry. Immunohistochemical analysis of CD52, AMFR, and Ephrin A1 receptor revealed expression profiles concordant with the microarray data, also with regard to differences between primary tumors and relapses.

Fatal thrombocytopaenia temporally related to the administration of alemtuzumab (MabCampath) for refractory CLL despite early discontinuation of therapy

Alemtuzumab (Campath 1H -MabCampath), initially used for prophylaxis of graft versus host disease in allogenic transplantaion, is now increasingly used for refractory chronic lymphatic leukaemia (CLL). Its efficacy has been well documented in this--the commonest form of leukaemia. Alemtuzumab is associated with severe immunosuppression, allergic reactions and thrombocytopenia. Data sheet and information supplied by the manufacturer confirm the rare occurrence of serious immune thrombocytopenia, recommending discontinuation of therapy when platelet counts fall below 50x10(9)/l. We report a patient with refractory CLL in which relentless progressive cytopenia occurred despite the discontinuation of alemtuzumab therapy while the platelet count was over 97x10(9)/l. Marrow biopsy showed increased megakaryocytes, the patient bleed uncontrollably and died of cerebral haemorrhage with a platelet count <10x10(9)/l. Data on the predictive factors underlying this complication are few and deserve further study as this drug is increasingly used the treatment of CLL.

Advances in the diagnosis and treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy, which is often not treated until patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is non-curative and is directed at reducing the symptoms from an increasing disease burden. Newer treatment regimens incorporating purine nucleoside analogs have increased the rate of successful remission induction in CLL patients. Recent combination chemoimmunotherapy regimens have produced frequent complete molecular remissions, and early evidence suggests this may result in an improved long-term survival. Allogeneic hematopoietic cell transplantation is the only curative therapy for CLL but is infrequently used due to the older age of most patients, although reduced intensity conditioning regimens have reduced the toxicity of allogeneic transplantation. This review will summarize recent advances in the management of CLL, including prognostic factors, combination chemotherapy including nucleoside analogs and monoclonal antibodies, and reduced intensity allogeneic transplant conditioning regimens.

Alemtuzumab in the Treatment of Chronic Lymphocytic Leukemia

Alemtuzumab is a humanized therapeutic monoclonal antibody (MAb) that recognizes the CD52 antigen, expressed on normal and neoplastic lymphocytes, monocytes, and natural killer cells. In 2001, alemtuzumab was approved in the US and Europe to treat B-cell chronic lymphocytic leukemia (CLL) that had been treated previously with alkylating agents and was refractory to fludarabine. In heavily pretreated patients this MAb is able to produce response rates of about 40%, and in symptomatic, previously untreated patients response rates of more than 80% can be achieved. Alemtuzumab can also be used in patients with CLL as a preparative regimen for stem cell transplantation (SCT) and to prevent graft versus host disease. Moreover its in vivo use before or after SCT may also potentially result in depletion of residual leukemia cells, especially in the autologous setting. Adverse events associated with alemtuzumab include acute first-dose reaction, hematologic toxicity, and infectious complications. Usually they are predictable, manageable, and acceptable in the context of CLL. However, in a significant percentage of patients, cytomegalovirus reactivation occurs during alemtuzumab therapy, and routine weekly monitoring with the polymerase chain reaction methodology is indicated. Moreover, antiviral and antibacterial prophylaxis is mandatory.

Antibody-targeted therapy: a paradigm of innovative treatment strategies in indolent and aggressive B-cell non-Hodgkin lymphoma

PURPOSE OF REVIEW

This review outlines the principles of treatment of indolent and aggressive B-cell lymphoma based on current knowledge on the classification of hematologic malignancies and the rationale to implement new antibody-targeted immunotherapeutic approaches.

RECENT FINDINGS

An update is provided on the use of antibody-targeted therapies in clinical trials, with emphasis on new, emerging strategies of immunotherapy in B-cell non-Hodgkin lymphoma.

SUMMARY

The success of immune-mediated therapies has encouraged studies on antibody-targeted therapy in B-cell non-Hodgkin lymphoma. Promising new approaches combine classical dose-intense chemotherapy with "tumor-specific" antibody targeting during several phases of the disease. The safety and efficacy of anti-CD20 in the treatment of indolent and aggressive B-cell non-Hodgkin lymphoma at any stage of disease, either as a single agent or as part of multimodality regimes, as an unconjugated antibody or as radioimmunoconjugate have changed dramatically our treatment strategies. Increasing insights into basic molecular biology and immunology of B-cell non-Hodgkin lymphoma may identify subgroups of patients categorized in current classification systems who may benefit from tailored approaches with new modality antibody-targeted therapy in near future.

Alemtuzumab-induced remission of both severe paraneoplastic pemphigus and leukaemic bone marrow infiltration in a case of treatment-resistant B-cell chronic lymphocytic leukaemia

BACKGROUND

Alemtuzumab (MabCampath; ILEX Pharmaceuticals, Geneva, Switzerland) is a humanised monoclonal antibody directed against CD52. It belongs to a new group of monoclonal antibodies with anti-neoplastic effects used in chronic lymphocytic leukaemia (CLL) either as first-line treatment or in those cases resistant to alkylating drugs. Paraneoplastic pemphigus (PNP) is a severe mucocutaneus disease mostly associated with B-cell lymphoproliferative disorders. Independent of the course of the underlying malignancy, this disease is often resistant to conventional immunosuppressive treatment and may lead to death as a result of infectious complications.

CASE PRESENTATION

We report a case where an ongoing long-term remission of PNP has been induced by alemtuzumab in a patient with an underlying B-CLL. A 68-yr-old male with a 4-yr history of B-CLL presented with a widespread blistering eruption on the extremities and trunk and a severe stomatitis. The diagnosis of PNP relied on the clinical, histological and direct immunofluorescence findings. Despite intensive treatment strategies with various immunosuppressive drugs and antibiotics, blisters continued to develop and the patient was deteriorating. When treated with alemtuzumab the mucocutaneous lesions healed almost completely within a few weeks and the patients' general condition improved significantly. After 12 wk of treatment with alemtuzumab, the CLL infiltration of the bone marrow previously quantified at 75-80% remitted completely. Twelve months later, the patient was still in remission with only a small residual ulceration on the lip and one on the penis.

CONCLUSIONS

Based on this case report we recommend treatment with alemtuzumab to severe cases of PNP in CLL. However, further follow-up of this case is needed in order to assess the long-term effect of alemtuzumab treatment in PNP.

Emerging antibody-targeted therapy in leukemia and lymphoma: current concepts and clinical implications

The success of immune-mediated therapies has encouraged studies on passive and active immunotherapy in leukemia and lymphoma. This review outlines the impact of increasing insights from basic immunology studies on the potentiation of effective immune responses and the identification of new antigens as targets for antibody (Ab)-targeted therapies. The principles of treatment in leukemia and lymphoma based on current knowledge on the classification of hematologic malignancies are reviewed, and discussed in the context of a rationale to implement new Ab-targeted immunotherapeutic approaches. An update is provided on the use of Ab-targeted therapies in clinical trials with emphasis on new emerging strategies to further expand the successful field of immunotherapy in leukemia and lymphoma.