Alemtuzumab in the Treatment of Chronic Lymphocytic Leukemia

Therapeutic anti-NLGP monoclonal antibody for carcinoembryonic antigen expressing tumors is nontoxic to Swiss and BALB/c mice

A murine monoclonal antibody (mAb), 1C8 was developed against a novel glycoprotein NLGP and its unique property to recognize carcinoembryonic antigen (CEA) was reported. Utilizing this CEA recognizing property, 1C8 is successful to restrict the growth of CEA(+) murine and human cancers both in vitro and in vivo. Here, we have thoroughly evaluated the toxicity profile of this mAb 1C8 on different physiological systems of both tumor-free and tumor-bearing Swiss and BALB/c mice. Effective concentration (25 μg/mice) of 1C8 caused no behavioral changes in animals and no death was recorded. Moreover, little increase in the body and organ weights in all mice groups was noted. MAb 1C8 showed no adverse effect on the hematological system, but little hematostimulation was noticed, as evidenced by increased hemoglobin content, leukocyte count and lymphocyte numbers. Liver enzymes like alkaline phosphatase, SGOT, SGPT and nephrological products like urea and creatinine assessment confirmed no abnormalities in both hepatic and renal functions. Number of T cells, B cells, NK cells, macrophages and dendritic cells was upregulated in vivo by mAb treatment with significant downregulation of regulatory T cells. During this treatment serum levels of type 1 cytokines were upregulated over type 2 cytokines. This mAb 1C8 also did not induce any significant increase in antibody titer following treatment. Accumulated evidences from Swiss and BALB/c mice strongly suggest that this mAb 1C8 is completely safe, thus, can be recommended for further clinical trial for the therapy of CEA(+) tumors.

The impact of the host on fungal infections

Outcomes of fungal infections in immunocompromised individuals depend on a complex interplay between host and pathogen factors, as well as treatment modalities. Problems occur when host responses to an infection are either too weak to effectively help eradicate the pathogen, or when they become too strong and are associated with host damage rather than protection. Immune reconstitution syndrome (IRS) can be generally defined as a restoration of host immunity in a previously immunosuppressed patient that becomes dysregulated and overly robust, resulting in host damage and sometimes death. IRS associated with opportunistic mycoses presents as new or worsening clinical symptoms or radiographic signs consistent with an inflammatory process that occur during receipt of an appropriate antifungal, and that cannot be explained by a newly acquired infection. Because there are currently no established tests or biomarkers for IRS, it can be difficult to distinguish from progression of the original infection, although culture and biomarkers for the fungal pathogen or infection are typically negative during diagnostic workup. IRS was originally characterized in human immunodeficiency virus-infected patients receiving antiretroviral therapy, but has subsequently been described in solid-organ transplant recipients, neutropenic patients, women in the postpartum period, and recipients of tumor necrosis factor-α inhibitor therapy. In each of these cases, recovery of the host's immunity during treatment of an initial infection results in a powerful proinflammatory environment that overshoots and leads to host damage. Optimal management of IRS has not been established at present, but often involves treatment with a corticosteroid or other anti-inflammatory compounds. This article uses a number of patient cases to explore the intricacies of diagnosing and managing a patient with IRS, as well as the other extreme, namely patients who are so immunocompromised without immune recovery that they essentially become breeding grounds for a wide range of opportunistic pathogens, often simultaneously.

Cytotoxic effect of R-etodolac (SDX-101) in combination with purine analogs or monoclonal antibodies on ex vivo B-cell chronic lymphocytic leukemia cells

R-etodolac (SDX-101) is an isoform of the non-steroidal anti-inflammatory drug, etodolac, and is currently being tested in phase II clinical trials for the treatment of refractory B-cell chronic lymphocytic leukemia (B-CLL). The aim of this study was to evaluate the cytotoxicity of SDX-101 combined with agents proven to be effective as first-line treatment of B-CLL: the purine nucleoside analogs, fludarabine (FA) and cladribine (2-CdA), and the monoclonal antibodies, anti-CD52 (alemtuzumab; ALT) and anti-CD20 (rituximab; RIT). The cytotoxicity and specific pro-apoptotic effects of the study drugs on B-CLL cells were assessed in vitro in samples from overall 37 untreated patients. The combinations of SDX-101 with 2-CdA, FA or RIT exerted additive effects in B-CLL cells, with the following combination indices (CI): 0.89 for SDX-101 + 2-CdA, 0.95 for SDX-101 + RIT, and 1.17 for SDX-101 + FA. The main mechanism of these interactions was caspase-mediated apoptosis. The SDX-101 plus ALT combination resulted in only sub-additive cytotoxicity (CI = 1.25). In conclusion, these data obtained in vitro indicate that addition of 2-CdA, FA or RIT to SDX-101 significantly enhance cytotoxicity in B-CLL cells.

Skin lesions in chronic lymphocytic leukemia

Cutaneous lesions occur in up to 25% of patients with chronic lymphocytic leukemia (CLL). These can be caused by either cutaneous seeding by leukemic cells (leukemia cutis, LC) and other malignant diseases or nonmalignant disorders. Skin infiltration with B-lymphocyte CLL manifests as solitary, grouped, or generalized papules, plaques, nodules, or large tumors. Prognosis in CLL patients with LC is rather good and many authors claim that it does not significantly affect patients' survival. However, prognosis is poor in patients in whom LC shows blastic transformation (Richter's syndrome) and when leukemic infiltrations in the skin appear after the diagnosis of CLL. Secondary cutaneous malignancies are also frequent complications in patients with CLL. A higher risk was seen in skin cancer, for which eightfold higher occurrence has been stated. There are some suggestions that alkylating agents and purine analogs may be associated with an increased incidence of secondary malignancies in CLL. Nonspecific, secondary cutaneous lesions are frequently observed in CLL patients. The most common secondary cutaneous changes seen in CLL are those of infectious or hemorrhagic origin. Other secondary lesions present as vasculitis, purpura, generalized pruritus, exfoliative erythroderma, and paraneoplastic pemphigus. An exaggerated reaction to an insect bite and insect bite-like reactions have been also observed.

Acute leukemia immunohistochemistry: a systematic diagnostic approach

CONTEXT

The diagnosis and classification of leukemia is becoming increasingly complex. Current classification schemes incorporate morphologic features, immunophenotype, molecular genetics, and clinical data to specifically categorize leukemias into various subtypes. Although sophisticated methodologies are frequently used to detect characteristic features conferring diagnostic, prognostic, or therapeutic implications, a thorough microscopic examination remains essential to the pathologic evaluation. Detailed blast immunophenotyping can be performed with lineage- and maturation-specific markers. Although no one marker is pathognomonic for one malignancy, a well-chosen panel of antibodies can efficiently aid the diagnosis and classification of acute leukemias.

OBJECTIVE

To review important developments from recent and historical literature. General immunohistochemical staining patterns of the most commonly encountered lymphoid and myeloid leukemias are emphasized. The goal is to discuss the immunostaining of acute leukemias when flow cytometry and genetic studies are not available.

DATA SOURCES

A comprehensive review was performed of the relevant literature indexed in PubMed (National Library of Medicine) and referenced medical texts. Additional references were identified in the reviewed manuscripts.

CONCLUSIONS

Immunophenotyping of blasts using an immunohistochemical approach to lymphoid and myeloid malignancies is presented. Initial and subsequent additional antibody panels are suggested to confirm or exclude each possibility in the differential diagnosis and a general strategy for diagnostic evaluation is discussed. Although the use of immunohistochemistry alone is limited and evaluation by flow cytometry and genetic studies is highly recommended, unavoidable situations requiring analysis of formalin-fixed tissue specimens arise. When performed in an optimized laboratory and combined with a careful morphologic examination, the immunohistochemical approach represents a useful laboratory tool for classifying various leukemias.

Emerging drugs for rarer chronic lymphoid leukemias

BACKGROUND

Rarer indolent lymphoid leukemias include well defined mature B-cell and T-cell neoplasm with widely varying natural history and specific morphological, immunophenotypic and molecular characteristics. Among these are prolymphocytic leukemia (PLL), hairy cell leukemia (HCL) and its variants, large granular lymphocyte leukemia (LGLL) and adult T-cell leukemia/lymphoma (ATLL).

OBJECTIVE

To present current therapies and emerging drugs potentially useful in the treatment of rarer chronic lymphoid leukemias.

METHODS

After searching MEDLINE, PubMed and the Current Contents database, and conference proceedings from the previous 3 years of the American Society of Hematology (ASH), the European Society of Hematology (EHA) and the American Society of Clinical Oncology (ASCO) were searched manually; articles written in English and additional relevant publications were then selected.

RESULTS/CONCLUSION

New drugs including monoclonal antibodies (mAbs), new purine analogs, small molecules targeting specific molecular targets and other agents are included. Future research should focus on the novel therapeutic strategies based on the molecular pathogenic mechanisms and the development of new targeted therapies for each distinct chronic lymphoid leukemia.

Recent progress in the management of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a clonal disease characterized by proliferation and accumulation of small CD5-positive B cells. More than 50% of patients are asymptomatic at diagnosis and usually require no treatment. However, treatment is needed in the advanced and progressive disease. Chlorambucil with or without steroids has been the drug of choice for many years in previously untreated patients with CLL. The purine nucleoside analogs (PNAs), fludarabine (FA), cladribine (2-CdA-chlorodeoxyadenosine) and pentostatin (DCF, 2'-deoxycoformycin) also have been introduced for treatment of CLL. Significantly higher overall response (OR) and complete response (CR) and longer progression free survival (PFS) in patients with CLL treated with FA or 2-CdA have been confirmed in randomized, multicenter trials and more recently in meta-analysis. However, the median survival time did not differ between patients treated with PNA and alkylating agents. Combination therapies with PNAs and cyclophosphamide and especially with cyclophosphamide and rituximab are more active than monotherapy in terms of OR, CR and PFS. Several reports have shown significant activity of alemtuzumab in previously untreated and pretreated patients even when refractory to FA. Alemtuzumab also can be used in CLL as a preparative regimen before stem cell transplantation (SCT) and to eliminate minimal residual disease (MRD). Recently, several new agents have shown promise in treating CLL, including new monoclonal antibodies, agents targeting bcl-2 family of proteins, antisense oligonucleotides and other agents. Moreover, autologous and allogenic hematopoietic cell transplantations are increasingly considered for treatment of patients with CLL. In this review current therapeutic strategies in CLL are presented.

Alemtuzumab (Campath-1H) in the treatment of chronic lymphocytic leukemia

Alemtuzumab (Campath-1H) is a humanized IgG1 monoclonal antibody that targets the human CD52 antigen. CD52 is expressed by a variety of lymphoid neoplasms and most human mononuclear cell subsets. In 2001, alemtuzumab was approved for marketing in the United States and Europe for use in patients with fludarabine-refractory chronic lymphocytic leukemia (CLL). In heavily pretreated patients with CLL, the overall response rate (ORR) is approximately 35%, and in previously untreated patients the ORR is greater than 80%, with a recent randomized study suggesting it is superior to alkylator-based therapy. Importantly, alemtuzumab is effective in patients with high-risk del(17p13.1) and del(11q22.3) CLL. Alemtuzumab combination studies with fludarabine and/or monoclonal antibodies such as rituximab have demonstrated promising results. Alemtuzumab is also being studied in CLL patients as consolidation therapy for treatment of minimal residual disease, in preparation for stem cell transplantation and to prevent acute and chronic graft versus host disease. Alemtuzumab is frequently associated with acute 'first-dose' reactions when administered intravenously, but is much better tolerated when administered subcutaneously without loss of therapeutic efficacy. Additional potential adverse events associated with alemtuzumab administration include myelosuppression as well as profound cellular immune dysfunction with the associated risk of viral reactivation and other opportunistic infections. Additional studies detailing the mechanism of action of alemtuzumab as well as new strategies for prevention of opportunistic infections will aid in the future therapeutic development of this agent.

Role of monoclonal antibodies in tumor-specific immunity

Monoclonal antibodies, considered to be 'magic bullets' 20 years ago, may finally be realizing their full potential, particularly in the area of oncology, where > 10 monoclonal antibodies are approved for treatment. Monoclonal antibodies are being used to modulate tumor-specific immunity through several approaches: antibodies that direct cytotoxicity against the tumor through cellular or complement-mediated pathways; antibodies that directly modulate immune regulation; antibodies that alter tolerance to tumor antigens; and antibodies that act as antigen mimetics through the anti-idiotype network. Therapeutic progress in these areas is reviewed as well as the potential to combine these approaches with standard therapies.

Economic Evaluation of Third-Line Treatment with Alemtuzumab for Chronic Lymphocytic Leukaemia

OBJECTIVE

The objective of this study was to compare the potential economic efficiency of third-line treatment of chronic lymphocytic leukaemia (CLL) with alemtuzumab versus fludarabine, cyclophosphamide and rituximab (FCR).

METHODS

The target population for this study were patients with CLL who were able to tolerate third-line treatment with either FCR or alemtuzumab. The perspective used was that of the New Zealand Pharmaceutical Management Agency (PHARMAC)/District Health Board. Health outcomes considered were survival time from commencement of treatment and quality-adjusted life-years (QALYs) gained. Average costs and outcomes and incremental cost per patient treated, per survival month and per QALY gained, were calculated. All costs were presented in 2006 New Zealand dollars.

RESULTS

Base-case direct medical costs for alemtuzumab per treatment regimen per patient were $NZ15 303 lower than those for FCR. The average direct medical cost per survival month gained for alemtuzumab was $NZ3144 and for FCR was $NZ4101, and the average direct medical cost per QALY gained was $NZ46,016 and for FCR was $NZ60,012.

CONCLUSION

Third-line treatment of eligible patients with alemtuzumab was found to be $NZ15,303 less costly than FCR per patient.

Antibody therapy in non-Hodgkin's lymphoma: the role of rituximab, 90Y-ibritumomab tiuxetan, and alemtuzumab

Targeting cancer cells with monoclonal antibodies has become an indispensable part of modern treatment against hematologic malignancies. The excitement of the first successful experimental results could be confirmed by large multicenter trials, thus paving the way for new approaches in first-line, relapse, and maintenance therapy. Three antibodies--rituximab, 90Y-ibritumomab tiuxetan, and alemtuzumab--are in clinical use worldwide and are reviewed in this chapter with a focus on practical information and fundamental principles of antibody-based therapy.

Neurologic complications of bone marrow, stem cell, and organ transplantation in patients with cancer

Bone marrow and peripheral blood stem cell transplantation are part of the standard of care for a variety of oncologic and non-oncologic disorders and are associated with a large spectrum of neurologic complications. These complications may arise at any time during and after the transplantation process, especially in subjects requiring chronic immunosuppression, and are most frequently related to infections, cerebrovascular or metabolic events, and toxicity from radiation or chemotherapy. Due to the unique circumstances and treatments surrounding each step in the transplantation process, there is a higher incidence of some neurologic complications during discrete time periods. Being aware of the temporal relationship of the neurologic disorder within the transplantation process can therefore facilitate diagnosis and institution of appropriate therapy. Neurologic complications after solid organ transplantation are often due to similar mechanisms as in patients after bone marrow and stem cell transplantation although there are several complications unique to these patients such as transmission of infectious agents by the donated organ. For these patients, the clinician needs to have a high index of suspicion that the neurologic problem is related to the transplant.

Current treatment options in hairy cell leukemia and hairy cell leukemia variant

Hairy cell leukemia (HCL) is a chronic B-cell lymphoproliferative disorder characterized by splenomegaly, pancytopenia and circulating lymphocytes displaying prominent cytoplasmic projections. HCL has usually an indolent course and the patients with asymptomatic disease do not require therapy. Treatment of progressive symptomatic HCL includes a variety of pharmacological approaches such as interferon-alpha (IFN-alpha), pentostatin (DCF) and cladribine (2-CdA), which have significantly improved the disease prognosis. 2-CdA and DCF seem to induce a similar high response rate and a long overall survival. They are also active in relapsed patients. More recently high activity of anti-CD20 monoclonal antibody (rituximab) and anti-CD25 (LMB-2) and anti-CD22 (BL-22) immunotoxins have increased the number of therapeutic options for HCL. Splenectomy may be still indicated in patients with massive, symptomatic splenomegaly or results in severe cytopenia. IFN-alpha may have a place in patients with very severe cytopenia, in HCL in pregnancy and in patients who have failed prior therapy with purine nucleoside analogs. HCL variant (HCL-V) is a distinct clinico-pathological entity which seems to be resistant to IFN-alpha and purine nucleoside analogs - DCF and 2-CdA. However, preliminary observations suggest that monoclonal antibodies - rituximab and BL-22 immunotoxin are highly active in this disorder even refractory to 2-CdA. In this review current therapeutic strategies in HCL and HCL-V are presented.

Adverse effects of the humanized antibodies used as cancer therapeutics

PURPOSE OF REVIEW

Humanized monoclonal antibodies represent a recent and very significant addition to the anticancer armamentarium. With improved therapeutic strategies due to these agents, however, there are also various, sometimes unexpected, side effects.

RECENT FINDINGS

Most of the monoclonal antibodies used in oncology share a risk of infusion-related manifestations, including the possibility of anaphylaxis; these reactions usually appear early on during the first administration. Hematological toxicity is also frequent, especially if the antibodies are associated with chemotherapy; the resulting neutropenia--and with some agents lymphopenia--is associated with an increased risk of infection. Cardiac failure and pulmonary complications have been reported with some of these agents, especially in patients with prior cardiac or pulmonary comorbidities.

SUMMARY

Although consideration of these side effects is important in terms of prevention and therapy, overall they are relatively uncommon, making therapy with monoclonal antibodies quite safe in comparison with other therapeutic modalities used in cancer patients.

B CELL IMMUNOBIOLOGY IN DISEASE: Evolving Concepts from the Clinic

The pathogenic roles of B cells in autoimmune diseases occur through several mechanistic pathways that include autoantibodies, immune complexes, dendritic and T cell activation, cytokine synthesis, chemokine-mediated functions, and ectopic neolymphogenesis. Each of these pathways participate to different degrees in autoimmune diseases. The use of B cell-targeted and B cell subset-targeted therapies in humans is illuminating the mechanisms at work in a variety of human autoimmune diseases. In this review, we highlight some of these recent findings that provide insights into both murine models of autoimmunity and human autoimmune diseases.

Exogenous administration of immunomodulatory therapies in hematopoietic cell transplantation: an infectious diseases perspective

PURPOSE OF REVIEW

In contrast to the recipient of a solid organ transplantation, the immunological competence of recipients of hematopoietic cell transplantation does not correlate well with the administration of non-corticosteroid immunosuppressive agents. This apparent paradox reflects the unique and dynamic conglomeration of factors that affect immune reconstitution after hematopoietic cell transplantation. The following is the second part of a review of the recent primary literature regarding exogenous immunomodulatory influences as they pertain to infections in the setting of hematopoietic cell transplantation.

RECENT FINDINGS

The main themes of published primary research from 2004 to the present include the influence of exogenously administered immunomodulatory agents on infectious complications after hematopoietic cell transplantation.

SUMMARY

The use of immunomodulatory agents such as monoclonal antibodies directed against lymphocyte antigens in the treatment of hematopoietic malignancy has greatly expanded during the past decade. Separate trials of the potential utility of these agents, particularly in the reduction of graft-versus-host disease, in the setting of hematopoietic cell transplantation have yielded encouraging results. Given the infancy of these new approaches, it is not possible to make definitive statements regarding the relative risk of serious infection with each therapy. It is clear that a reduction in regimen-related non-infectious complications or mortality does not necessarily ensure a reduction in clinically significant infections. Improvements in early diagnostic and therapeutic options for these infections now bring us to an era of understanding pathogens such as cytomegalovirus as probes of the functional reconstitution of immunity.

Therapy of chronic lymphocytic leukaemia with purine nucleoside analogues: facts and controversies

Chronic lymphocytic leukaemia (CLL) is a neoplastic disease of unknown aetiology characterised by an absolute lymphocytosis in peripheral blood and bone marrow. The disease is diagnosed most commonly in the elderly with the median age at diagnosis being about 65 years. The purine nucleoside analogues (PNAs) fludarabine, cladribine (2-chlorodeoxyadenosine) and pentostatin (2'-deoxycoformycin) are highly active in CLL, both in previously treated and in refractory or relapsed patients. These three agents share similar chemical structures and mechanisms of action such as induction of apoptosis. However, they also exhibit significant differences, especially in their interactions with enzymes involved in adenosine and deoxyadenosine metabolism. Recent randomised studies suggest that fludarabine and cladribine have similar activity in CLL. However, clinical observations indicate the existence of cross-resistance between fludarabine and cladribine. Patients who received PNAs as their initial therapy and achieved long-lasting response can be successfully retreated with the same agent. PNAs administered in combination with other chemotherapeutic agents and/or monoclonal antibodies may produce higher response rates, including complete response (CR) or molecular CR, compared with PNAs alone or other treatment regimens. Management decisions are more difficult in elderly patients because of the apparent increase in toxicity of PNAs in this population. In elderly patients, we recommend chlorambucil as the first-line treatment, with PNAs in lower doses in refractory or relapsed patients. Myelosuppression and infections, including opportunistic varieties, are the most frequent adverse effects in patients with CLL treated with PNAs. Therefore, some investigators recommend routine antibacterial and antiviral prophylaxis during and after PNA treatment. This review presents current results and treatment strategies with the use of PNAs in CLL, especially in elderly patients.