Alemtuzumab

Immunotherapy in chronic lymphocytic leukemia: advances and challenges

Chronic lymphocytic leukemia (CLL) is characterized as a clonal proliferation of mature B lymphocytes with distinct immunophenotypic traits, predominantly affecting the middle-aged and elderly population. This condition is marked by an accumulation of lymphocytes within the peripheral blood, bone marrow, spleen, and lymph nodes. The associated immune dysregulation predisposes CLL patients to a higher risk of secondary malignancies and infections, which significantly contribute to morbidity and mortality rates. The advent of immunotherapy has revolutionized the prognosis of CLL, advancing treatment modalities and offering substantial benefits to patient outcomes. This review endeavors to synthesize and scrutinize the efficacy, merits, and limitations of the current immunotherapeutic strategies for CLL. The aim is to inform the selection of optimal treatment regimens tailored to individual patient needs. Furthermore, the review juxtaposes various therapeutic combinations to elucidate the comparative advantages of each approach, with the ultimate objective of enhancing patient prognosis and quality of life.

Safety but limited efficacy of donor lymphocyte infusion for post-transplantation cyclophosphamide-treated patients

The therapeutic efficacy of donor lymphocyte infusions (DLIs) given after allogeneic hematopoietic cell transplantation (HCT) is limited by risk of graft-versus-host disease (GVHD). Post-transplantation cyclophosphamide (PTCy) effectively prevents severe GVHD, but there are limited data on outcomes of DLIs given to PTCy-treated patients. We reviewed 162 consecutive PTCy-treated patients transplanted between 2015-2022 within the Center for Immuno-Oncology at the National Cancer Institute. Of 38 DLIs given to 21 patients after 22 HCTs, few DLIs were associated with toxicities of acute GVHD (7.8%), cytokine release syndrome (CRS, 7.8%), or chronic GVHD (2.6%), and all occurred in those receiving serotherapy-containing pre-HCT conditioning (50% of HCTs). Seven DLIs resulted in complete response (18.4%), with 5 of these given after HCTs using serotherapy-containing conditioning. Excluding infectious indications, complete response to DLIs given after transplants with versus without serotherapy-containing pre-HCT conditioning were 30% and 4.3%, respectively. Two patients received DLI for infection and experienced complete resolution without GVHD or CRS, although the efficacy cannot be definitively attributable to the DLI. DLIs given to PTCy-treated patients had low toxicity but limited efficacy, although pre-HCT serotherapy may modulate both toxicity and response. Novel strategies are needed to enhance the therapeutic efficacy of post-transplant cellular therapies without aggravating GVHD.

The effect of probiotics on immune responses and their therapeutic application: A new treatment option for multiple sclerosis

Multiple sclerosis (MS) is known as a chronic inflammatory disease (CID) that affects the central nervous system and leads to nerve demyelination. However, the exact cause of MS is unknown, but immune system regulation and inhibiting the function of inflammatory pathways may have a beneficial effect on controlling and improving the disease. Studies show that probiotics can alter the gut microbiome, thereby improving and affecting the immune system and inflammatory responses in patients with MS. The results show that probiotics have a good effect on the recovery of patients with MS in humans and animals. The present study investigated the effect of probiotics and possible therapeutic mechanisms of probiotics on immune cells and inflammatory cytokines. This review article showed that probiotics could improve immune cells and inflammatory cytokines in patients with MS and can play an effective role in disease management and control.

Antibody engineering and its therapeutic applications

As a natural function, antibodies defend the host from infected cells and pathogens by recognizing their pathogenic determinants. Antibodies (Abs) gained wide acceptance with an enormous impact on human health and have predominantly captured the arena of bio-therapeutics and bio-diagnostics. The scope of Ab-based biologics is vast, and it is likely to solve many unmet clinical needs in future. The majority of attention is now devoted to developing innovative technologies for manufacturing and engineering Abs, better suited to satisfy human needs. The advent of Ab engineering technologies (AET) led to phenomenal developments leading to the generation of Abs-/Ab-derived molecules with desirable functional properties proportional to their expanding requirements. Evolution brought by AET, from the naturally occurring Ab forms to several advanced Ab formats and derivatives, was much needed as it is of great interest to the pharmaceutical industry. Thus, numerous advancements in AET have propelled success in therapeutic Ab development, along with the potential for ever-increasing improvements. Unique characteristics of Abs, such as its diversity, specificity, structural integrity and an array of possible applications, together inspire continuous innovation in the field. Overall, the AET could assist in conquer of several limitations of Abs in terms of their applicability in the field of therapeutics, diagnostics and research; AET has so far led to the production of next-generation Abs, which have revolutionized these arenas. Here in this review, we discuss the various distinguished engineering platforms for Ab development and the progress in modern therapeutics by the so-called "next-generation Abs."

The diverse landscape of dermatologic toxicities of non-immune checkpoint inhibitor monoclonal antibody-based cancer therapy

BACKGROUND

Since their first approval 25 years ago, monoclonal antibodies (mAbs) have become important targeted cancer therapeutics. However, dermatologic toxicities associated with non-immune checkpoint inhibitor (non-ICI) mAbs may complicate the course of cancer treatment. Data on the incidence and types of these reactions are limited.

METHODS

A comprehensive review was conducted on dermatologic toxicities associated with different classes of non-ICI mAbs approved for treatment of solid tumors and hematologic malignancies. The review included prospective Phase 1, 2, and 3 clinical trials; retrospective literature reviews; systematic reviews/meta-analyses; and case series/reports.

RESULTS

Dermatologic toxicities were associated with several types of non-ICI mAbs. Inflammatory reactions were the most common dermatologic toxicities, manifesting as maculopapular, urticarial, papulopustular/acneiform, and lichenoid/interface cutaneous adverse events (cAEs) with non-ICI mAbs. Immunobullous reactions were rare and a subset of non-ICI mAbs were associated with the development of vitiligo cAEs.

CONCLUSION

Dermatologic toxicities of non-ICI mAbs are diverse and mostly limited to inflammatory reactions. Awareness of the spectrum of the histopathologic patterns of cAE from non-ICI mAbs therapy is critical in the era of oncodermatology and oncodermatopathology.

New nonchemotherapy treatment options for cutaneous T-cell lymphomas

INTRODUCTION

The most common types of CTCL are mycosis fungoides (MF) and Sézary syndrome (SS). In both MF and SS, complete responses to treatment are uncommon. Recent developments and understanding of the biology of MF/SS have led to novel agents which may offer prolonged responses with less toxicity compared to conventional chemotherapy approaches.

AREAS COVERED

In this review, we discuss the efficacy and safety of new nonchemotherapy treatment options including antibody agents, small molecule inhibitors, fusion proteins, and CAR T-cell therapy. We also reflect on older immunomodulatory treatments including retinoids and histone deacetylase inhibitors.

EXPERT OPINION

Patients with MF/SS who require systemic therapy often progress through multiple agents sequentially, thus the need for additional novel agents in the treatment armamentarium. Antibody-based therapies such as alemtuzumab are highly effective in the blood compartment of disease, while brentuximab vedotin has shown higher activity in skin and lymph nodes. Checkpoint inhibitors may play a role in treating MF/SS but may induce hyperprogression, and engineered T cells and bispecific antibodies recruiting immune effectors are being developed and may show promise in the future.

Current Advances in Immunotherapy for Acute Leukemia: An Overview of Antibody, Chimeric Antigen Receptor, Immune Checkpoint, and Natural Killer

Recently, due to the application of hematopoietic stem cell transplantation and small molecule inhibitor, the survival of acute leukemia is prolonged. However, the 5 year survival rate remains low due to a high incidence of relapse. Immunotherapy is expected to improve the prognosis of patients with relapsed or refractory hematological malignancies because it does not rely on the cytotoxic mechanisms of conventional therapy. In this paper, the advances of immunotherapy in acute leukemia are reviewed from the aspects of Antibody including Unconjugated antibodies, Antibody-drug conjugate and Bispecific antibody, Chimeric Antigen Receptor (CARs), Immune checkpoint, Natural killer cells. The immunological features, mechanisms and limitation in clinic will be described.

Investigative drugs for the treatment of cutaneous T-cell lymphomas (CTCL): an update

Introduction: Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of skin-homing T-cell neoplasms, which represent approximately 75% of all primary cutaneous lymphomas. Mycosis fungoides and Sézary syndrome are the most common CTCL. Early stage disease follows a protracted course, carries a 5-year disease specific survival of 97% and can be treated with skin-directed therapies. Widespread, advanced disease has a 5-year OS of less than 25% and necessitates systemic treatment. Allogeneic stem cell transplantation is a potentially curative treatment option for advanced CTCL, however, transplant-related morbidity and mortality must be considered and a risk-benefit assessment performed on individual basis. Areas covered: Herein, we provide a review of investigative drugs in early-stage trials for the treatment of cutaneous CTCL, including topically applied immunomodulators such as replicating herpes virus or toll-like receptor 7/8 agonist resiquimod and systemic therapies with monoclonal antibodies, such as anti-CD47, recombinant cytotoxic interleukin 2 fusion protein anti-KIR3DL2 antibody and anti-miR-155 antibody. Expert Opinion: Among the reviewed drugs, resiquimod shows promising clinical efficacy with good tolerability in early CTCL. In refractory or relapsed disease, intratumoral anti-CD47-, anti-CCR4- and anti-KIR3DL2-antibodies show high response rates, however, latter two also show considerable toxicity. Larger trials are needed to better evaluate the discussed therapies.

Principles of alemtuzumab immunoablation in hematopoietic cell transplantation for non-malignant diseases in children: A review

Alemtuzumab is a humanized mAb targeted to CD52. Alemtuzumab is highly immunosuppressive with the ability to deplete T and B cells (in addition to other immune cell lines). A growing understanding of the PKs, dosing, and timing of administration of alemtuzumab has allowed for the study of its use as a conditioning agent for allogeneic HCT. The highly immunosuppressive properties of the drug are particularly appealing in the setting of non-malignant HCT, where GVHD provides no clinical benefit and relapse of malignancy is not applicable. In addition, the degree of immune suppression achieved with alemtuzumab has allowed for a reduction in the intensity of myeloablative cytotoxic agents included in some HCT conditioning regimens, allowing for fewer acute and late toxicities. This review paper will provide a comprehensive summary of the mechanism of action, PKs, dosing, and timing of alemtuzumab, a brief description of its use in various allogeneic HCT protocols for non-malignant conditions and a summary of the data regarding its use for GVHD therapy. The goal of this review was to provide an understanding as to how alemtuzumab might be safely incorporated into HCT conditioning regimens for children with non-malignant disease, allowing for expanded access to curative HCT therapy.

Alemtuzumab: a review of its use in patients with relapsing multiple sclerosis

Alemtuzumab (Lemtrada™) is a humanized therapeutic monoclonal antibody, which has been approved for use in patients with B-cell chronic lymphocytic leukaemia for several years, and has recently become approved in the EU and several other countries for use in adult patients with active relapsing-remitting multiple sclerosis. This article reviews the available pharmacological properties of intravenous infusions of alemtuzumab and its clinical efficacy and tolerability in adult patients with relapsing-remitting multiple sclerosis. Alemtuzumab is an effective treatment for patients with relapsing-remitting multiple sclerosis, and has a generally acceptable tolerability profile. In phase III trials, it was shown to be more effective than a current first-line treatment, subcutaneous interferon beta-1a, in decreasing relapse rate in treatment-naïve and previously treated patients and in decreasing disability progression in previously treated patients. Of note, these results appear to have extended into the long-term follow-up, despite no further treatment. There was an increased risk of autoimmunity and infection associated with alemtuzumab in these trials; while these adverse events were generally mild to moderate, some were severe. Alemtuzumab is a highly convenient treatment, requiring hospital attendance for an intravenous infusion for a handful of days on two consecutive years, with no treatment required in between; however, this convenience is counterbalanced by the need for regular monitoring for the increased risk of autoimmunity. More investigation is required before final conclusions can be drawn on the correct placement of alemtuzumab in multiple sclerosis treatment; however, it is of a certainty a welcome addition to the treatment options for these patients.

A comprehensive review and update on the biologic treatment of adult noninfectious uveitis: part II

INTRODUCTION

Treatment of adult, noninfectious uveitis remains a major challenge for ophthalmologists around the world, especially in regard to recalcitrant cases. It is reported to comprise approximately 10% of preventable blindness in the USA. The cause of uveitis can be idiopathic or associated with infectious and systemic disorders. The era of biologic medical therapies provides new options for patients with otherwise treatment-resistant inflammatory eye disease.

AREAS COVERED

This two-part review gives a comprehensive overview of the existing medical treatment options for patients with adult, noninfectious uveitis, as well as important advances for the treatment ocular inflammation. Part I covers classic immunomodulation and latest information on corticosteroid therapy. In part II, emerging therapies are discussed, including biologic response modifiers, experimental treatments and ongoing clinical studies for uveitis.

EXPERT OPINION

The hazard of chronic corticosteroid use in the treatment of adult, noninfectious uveitis is well documented. Corticosteroid-sparing therapies, which offer a very favorable risk-benefit profile when administered properly, should be substituted. Although nothing is currently approved for on-label use in this indication, many therapies, through either translation or novel basic science research, have the potential to fill the currently exposed gaps.

Pediatric relapsed or refractory leukemia: new pharmacotherapeutic developments and future directions

Over the past 50 years, numerous advances in treatment have produced dramatic increases in the cure rates of pediatric leukemias. Despite this progress, the majority of children with relapsed leukemia are not expected to survive. With current chemotherapy regimens, approximately 15 % of children with acute lymphoblastic leukemia and 45 % of children with acute myeloid leukemia will have refractory disease or experience a relapse. Advances in the treatment of pediatric relapsed leukemia have not mirrored the successes of upfront therapy, and newer treatments are desperately needed in order to improve survival in these challenging patients. Recent improvements in our knowledge of cancer biology have revealed an extensive number of targets that have the potential to be exploited for anticancer therapy. These advances have led to the development of a number of new treatments that are now being explored in children with relapsed or refractory leukemia. Novel agents seek to exploit the same molecular aberrations that contribute to leukemia development and resistance to therapy. Newer classes of drugs, including monoclonal antibodies, tyrosine kinase inhibitors and epigenetic modifiers are transforming the treatment of patients who are not cured with conventional therapies. As the side effects of many new agents are distinct from those seen with conventional chemotherapy, these treatments are often explored in combination with each other or combined with conventional treatment regimens. This review discusses the biological rationale for the most promising new agents and the results of recent studies conducted in pediatric patients with relapsed leukemia.

Low-dose alemtuzumab vs. standard policy for prevention of graft-versus-host disease in unrelated and related allogeneic stem cell transplantation-a matched pair analysis

Antibody-mediated in vivo T cell depletion is common prior to unrelated (URD) or mismatched allogeneic stem cell transplantation (alloSCT) and optional in HLA-identical sibling (FAM) alloSCT. While anti-thymocyte globulin (ATG) is the current standard, alemtuzumab is an alternative. The optimal dose of alemtuzumab has not been defined. This retrospective analysis compares low-dose alemtuzumab with ATG in URD alloSCT and with no antibody in FAM alloSCT. Twenty-eight patients treated with alemtuzumab (10 mg; HLA mismatch, 20 mg) were matched to 28 patients who have either received ATG (URD) or no antibody (noAB) according to disease, disease stage, age, transplant type and risk state. Both groups were compared for engraftment, outcome, disease-free (DFS) and overall survival (OS), graft-versus-host disease (GvHD), freedom from GvHD (ffGvHD) and transplant-related mortality (TRM). No significant differences were found between the groups for leukocyte engraftment, GvHD, ffGvHD, TRM, DFS and OS. There was a trend for reduction of cGvHD by alemtuzumab (p = 0.05). A transplant-type stratified subanalysis consolidated equivalency of alemtuzumab and ATG in URD-SCT and indicates possible superiority of low-dose alemtuzumab compared to noAB in FAM-SCT. Low-dose alemtuzumab, as part of conditioning regimen prior to alloSCT, is safe and comparable to standard ATG. Prospective trials, particularly comparing alemtuzumab vs. noAB in FAM alloSCT, should be conducted.

Treatment of steroid-resistant acute renal allograft rejection with alemtuzumab

Steroid-resistant renal allograft rejections are commonly treated with rabbit antithymocyte globulin (RATG), but alemtuzumab could be an effective, safe and more convenient alternative. Adult patients with steroid-resistant renal allograft rejection treated with alemtuzumab (15-30 mg s.c. on 2 subsequent days) from 2008 to 2012 (n = 11) were compared to patients treated with RATG (2.5-4.0 mg/kg bodyweight i.v. for 10-14 days; n = 20). We assessed treatment-failure (graft loss, lack of improvement of graft function or need for additional anti-rejection treatment), infections during the first 3 months after treatment and infusion-related side effects. In both groups, the median time-interval between rejection and transplantation was 2 weeks, and approximately 75% of rejections were classified as Banff-IIA or higher. Three alemtuzumab-treated patients (27%) experienced treatment failure, compared to eight RATG treated patients (40%, p = 0.70). There was no difference in the incidence of infections. There were mild infusion-related side-effects in three alemtuzumab-treated patients (27%), and more severe infusion-related side effects in 17 RATG-treated patients (85%, p = 0.013). Drug related costs of alemtuzumab-treatment were lower than of RATG-treatment (€1050 vs. €2024; p < 0.01). Alemtuzumab might be an effective therapy for steroid-resistant renal allograft rejections. In contrast to RATG, alemtuzumab is nearly devoid of infusion-related side-effects. These data warrant a prospective trial.

The role of biologic agents in the management of non-infectious uveitis

INTRODUCTION

Uveitis is an intriguing group of disorders characterized by inflammation of the uveal tract. Due to the potential grave consequences of the disease process, it is important to assess the various therapeutic options available for treating uveitis, and their outcomes.

AREAS COVERED

This review discusses the use of conventional agents in the management of uveitis, including discussion of the molecular and clinical properties of corticosteroids, antimetabolites, calcineurin inhibitors and alkylating agents and their side effects. In addition, it also discusses the molecular and clinical properties of novel biologic agents and their side effects. Moreover, recommendations as to when biologic agents should be employed are also discussed.

EXPERT OPINION

We recommend that in general (except in selected cases of Adamantiades-Behçet's disease) biologics should not be used as a first-line therapy for uveitis due to inconvenience, high cost, and potential immunosuppressive effects. However, many biologics are potent in inducing drug-free remission of uveitis and may be employed to manage recurrent diseases or diseases not responsive to conventional agents.

Evolving insights in the pathogenesis and therapy of cutaneous T-cell lymphoma (mycosis fungoides and Sezary syndrome)

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of malignancies derived from skin-homing T cells. The most common forms of CTCL are Mycosis Fungoides (MF) and Sezary Syndrome (SS). Accurate diagnosis remains a challenge due to the heterogeneity of presentation and the lack of highly characteristic immunophenotypical and genetic markers. Over the past decade molecular studies have improved our understanding of the biology of CTCL. The identification of gene expression differences between normal and malignant T-cells has led to promising new diagnostic and prognostic biomarkers that now need validation to be incorporated into clinical practice. These biomarkers may also provide insight into the mechanism of development of CTCL. Additionally, treatment options have expanded with the approval of new agents, such as histone deacetylase inhibitors. A better understanding of the cell biology, immunology and genetics underlying the development and progression of CTCL will allow the design of more rational treatment strategies for these malignancies. This review summarizes the clinical epidemiology, staging and natural history of MF and SS; discusses the immunopathogenesis of MF and the functional role of the malignant T-cells; and reviews the latest advances in MF and SS treatment.

Evolving concepts in the selection of immunosuppression regimen for liver transplant recipients

The introduction of calcineurin inhibitor (CNI) based immunosuppression has revolutionized the field of liver transplantation by dramatically reducing the incidence of acute cellular rejection and prolonging patient and allograft survival. However, the introduction of CNIs has also come at the price of increased patient morbidity, particularly with regard to the well-known nephrotoxic effects of the medications. In an effort to minimize the adverse effects, immunosuppression regimen have evolved to include the use of various induction agents and purine synthesis inhibitors to limit the dose of CNI necessary to achieve low acute cellular rejection rates. Careful assessments of risks and benefits are needed as these newer agents have their own side effect profiles. In addition, the impact of newer immunosuppression regimen on hepatitis C (HCV) recurrence has not been completely elucidated. This review will provide an overview of the most common immunosuppression regimen used in liver transplantation and discuss their impact on acute cellular rejection, patient and allograft survival, and HCV recurrence.

Relationship between pharmacokinetic profile of subcutaneously administered alemtuzumab and clinical response in patients with chronic lymphocytic leukemia

Alemtuzumab serum levels and clinical response after subcutaneous administration (10 mg 3 times/week for six weeks) have been explored in 29 chronic lymphocytic leukemia patients receiving the monoclonal antibody as consolidation. Serum concentrations after each administration gradually increased during the first week and more markedly during weeks 2 and 3, approaching the steady-state at week 6. Absorption continued slowly through the tissues for about 2-3 weeks after the last administration, starting to decrease thereafter. Difference between Responders and Non-responders was statistically significant: maximal concentration (Cmax) was 1.69 μg/mL vs. 0.44 μg/mL; concentration before subcutaneous administration (Cpre-dose) on day 15 was 0.7 vs. 0.21 μg/mL, area under curve (AUC0-12h) was 11.09 vs. 2.26 μgxh/mL for Responders and Non-responders, respectively. Higher systemic exposure to alemtuzumab correlated with a better clinical response and minimal residual disease. Results suggest that an adjusted schedule according to serum level could improve clinical outcome of patients receiving subcutaneous alemtuzumab.

New targets of therapy in T-cell lymphomas

T-cell lymphomas (TCL) are characterized by poor response to chemotherapy and generally poor outcome. While molecular profiling has identified distinct biological subsets and therapeutic targets in B-cell lymphomas, the molecular characterization of TCL has been slower. Surface markers expressed on malignant T-cells, such as CD2, CD3, CD4, CD25, and CD52 were the first TCL-specific therapeutic targets to be discovered. However, the presence of these receptors on normal T-cells means that monoclonal antibody (mAb)- or immunotoxin (IT)-based therapy in TCL inevitably results in variable degrees of immunosuppression. Thus, although some mAbs/IT have significant activity in selected subsets of TCL, more specific agents that target signaling pathways preferentially activated in malignant T-cells are needed. One such novel class of agents is represented by the histone deacetylase (HDAC) inhibitors. These molecules selectively induce apoptosis in a variety of transformed cells, including malignant T-cells, both in vitro and in vivo. Several HDAC inhibitors have been studied in TCL with promising results, and have recently been approved for clinical use. Immunomodulatory drugs, such as interferons and Toll Receptor (TLR) agonists have significant clinical activity in TCL, and are particularly important in the treatment of primary cutaneous subtypes (CTCL). Although most classical cytotoxic drugs have limited efficacy against TCL, agents that inhibit purine and pyrimidine metabolism, known as nucleoside analogues, and novel antifolate drugs, such as pralatrexate, are highly active in TCL. With improved molecular profiling of TCL novel pharmacological agents with activity in TCL are now being discovered at an increasingly rapid pace. Clinical trials are in progress and these agents are being integrated in combination therapies for TCL, both in the relapsed/refractory setting as well as front line.

Effective treatment of a peripheral T-cell lymphoma/lymphoepitheloid cell variant (Lennert's lymphoma) refractory to chemotherapy with the CD-52 antibody alemtuzumab

Lymphoepitheloid cell lymphoma (Lennert's lymphoma) is a rare malignant disease usually affecting patients at advanced age. Although classified as a "low-grade" lymphoma in the past, the clinical course is highly unfavorable and currently available chemotherapeutic regimens have given disappointing results. We present the case of a 74-year-old male suffering from disseminated Lennert's lymphoma. The patient underwent standard treatment approaches including chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP); fludarabin and cyclophosphamide; and ifosfamide, carboplatin and etoposide (ICE). Due to progressive disease with all these regimens, chemotherapy was discontinued. As cells stained highly positive for CD52, immunotherapy with alemtuzumab (Campath-1H) was started using a standard dosing regime of 30 mg every third day. Although the patient received prophylactic anti-infective medication, leucocytopenia with reactivation of cytomegalovirus (CMV) infection was observed and the administration of alemtuzumab had to be stopped temporarily. Re-assessment of disease 5 weeks after the start of alemtuzumab disclosed a significant reduction of all thoracic and abdominal lesions, and therapy with alemtuzumab was continued after normalization of the number of CMV copies and is currently ongoing. Our observations indicate clinical activity of alemtuzumab in the treatment of Lennert's lymphoma, including even bulky nodal disease, particularly for patients who have failed conventional therapies.

A comprehensive review of immunosuppression used for liver transplantation

Since liver transplantation was approved for the treatment of end stage liver disease, calcineurin inhibitors (CNI's) have played a critical role in the preservation of allograft function. Unfortunately, these medications cause a variety of Side effects such as diabetes, hypertension and nephrotoxicity which in turn result in significant morbidity and reduced quality of life. A variety of newer immunosuppressants have been evaluated over the last decade in an attempt to either substitute for CNI's or use with reduced dose CNI's while still preserving allograft function However, current data does not recommend complete cessation of CNI's due to unacceptably high rates of allograft rejection. As these medications have their own unique adverse effects, a careful assessment on their risks and benefits is essential, particularly when additive or synergistic effects with CNI's may occur. Furthermore, the impact of these newer medications on the risk of hepatitis C recurrence and progression remains to be elucidated. Controlled trials are urgently required to assist transplant physicians with choosing the optimum immunosuppressive regimen for their patients. This review will discuss commonly used immunosuppressants prescribed in liver transplantation, emerging therapties and where appropriate, the impact of these medications on the recurrence of hepatitis C after liver transplantation.

A Pilot Trial of Rituximab and Alemtuzumab Combination Therapy in Patients with Relapsed and/or Refractory Chronic Lymphocytic Leukemia (CLL)

The treatment of patients with chronic lymphocytic leukemia (CLL) who fail purine analogues is sub optimal. CLL lymphocytes express two antigens, namely CD 20 and CD 52, for which monoclonal antibodies are readily available. Rituximab is a chimeric monoclonal antibody targeted against CD 20, which has some activity in refractory CLL, with primary effect on nodal disease. Alemtuzumab is a humanized anti-CD 52 antibody that is approved for the treatment of CLL in patients who fail alkylating agents and purine analogues. Alemtuzumab has better activity in the peripheral blood and the bone marrow compared to nodal disease. We investigated whether combining both antibodies is safe in refractory CLL. Both antibodies were given to a total of 12 patients divided into 3 cohorts with escalating alemtuzumab doses (3 mg, 10 mg, and 30 mg). The combination was proven to be safe, not toxic, feasible, and active. One patient attained PR by NCI criteria while all other patients had stable disease lasting a median of 101.5 days. All patients normalized their peripheral lymphocytosis within a median of 23.5 days. No treatment-related mortality was identified. No CMV reactivation occurred. Additional studies are needed to investigate the clinical significance of such a combination in this patient population, and whether this combination can be administered safely with systemic chemotherapy. These studies are currently underway.

Eradication of Minimal Residual Disease with Alemtuzumab in B-Cell Chronic Lymphocytic Leukemia (B-CLL) Patients: The Need for a Standard Method of Detection and the Potential Impact of Bone Marrow Clearance on Disease Outcome

The introduction of new therapeutic agents, such as fludarabine phosphate (Fludara) and alemtuzumab (MabCampath, Campath), has made it possible to treat B-cell chronic lymphocytic leukemia (B-CLL) more effectively, compared with alkylating agents. However, although an increasing number of patients are able to achieve complete remission (CR), relapse is almost inevitable, because of the re-emergence of the malignant clone from small numbers of residual malignant cells. This phenomenon has introduced a need for a more sensitive assessment of low-level disease which, in turn, has encouraged the development of therapies aimed at the eradication of all residual disease in CR patients. The eradication of residual disease is associated with improved remission durability and has great potential in offering the possibility of cure. Alemtuzumab is the foundation of many eradication-based treatment approaches because of its ability to achieve clinical remissions and to successfully purge minimal residual disease (MRD) from both blood and bone marrow in B-CLL patients. This article describes and compares polymerase chain reaction (PCR) and flow cytometric methodologies for the assessment of MRD, and presents data demonstrating that alemtuzumab can eliminate residual malignant cells from blood and bone marrow (whether assessed by PCR or flow cytometry) at the highest levels of sensitivity currently available. The ability to clear MRD from bone marrow in patients achieving clinical CR using alemtuzumab is a significant step forward in the treatment of B-CLL, and supports treatment strategies in which alemtuzumab is used in combination with other agents. Purging of MRD from both blood and bone marrow also enables patients to proceed to autologous hematopoietic stem cell transplantation, a strategy that is able to achieve long-term remission.

Update on Targeted Therapy—Focus on Monoclonal Antibodies

Monoclonal antibodies represent a diverse class of therapeutic agents frequently used in the treatment of various malignancies. Monoclonal antibodies have a common structure with varying amounts of human and nonhuman components. These agents have been developed to identify and to interact with specific cellular targets or signaling pathways, leading to cell death by various mechanisms. Adverse effects associated with monoclonal antibodies are related to their structure (human vs nonhuman content) and to their cellular targets. Pharmacists should be familiar with this class of therapeutic agents to provide effective management and to monitor patients receiving monoclonal antibody therapy.

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.

Blastomycosis in solid organ transplant recipients

BACKGROUND

Blastomyces dermatitidis, the etiologic agent of blastomycosis, causes severe disease and substantial mortality in those immunocompromised by acquired immunodeficiency syndrome or malignancy. In solid organ transplant recipients, the epidemiology, clinical features, and outcomes have not been fully described.

METHODS

We conducted a retrospective case-series at the University of Wisconsin Hospital and Clinics. Case patients were solid organ transplant recipients with blastomycosis.

RESULTS

From 1986 to 2004, we identified 11 cases of post-transplant blastomycosis with 64% occurring between 2000 and 2004. Onset of infection occurred a median of 26 months post transplantation with near equal distribution before and after the first year of transplantation. Rejection did not precede any case of post-transplant blastomycosis. Opportunistic co-infections were common, occurring in 36% of patients. Pneumonia was the most common clinical presentation and was frequently complicated by acute respiratory distress syndrome (ARDS). Extrapulmonary disease predominantly involved the skin and spared the central nervous system. The overall mortality rate was 36%; however, this increased to 67% in those with ARDS. None of the surviving patients relapsed or received routine secondary antifungal prophylaxis.

CONCLUSION

Blastomycosis is an uncommon infection following solid organ transplantation that is frequently complicated by ARDS, dissemination, and opportunistic co-infection. After cure, post-transplant blastomycosis may not require lifelong antifungal suppression.

Drugs, their targets and the nature and number of drug targets

What is a drug target? And how many such targets are there? Here, we consider the nature of drug targets, and by classifying known drug substances on the basis of the discussed principles we provide an estimation of the total number of current drug targets.

Engineering of therapeutic antibodies to minimize immunogenicity and optimize function

One of the first difficulties in developing monoclonal antibody therapeutics was the recognition that human anti-mouse antibody (HAMA) response limited the administration of murine antibodies. Creative science has lead to a number of ways to counter the immunogenicity of non-human antibodies, primarily through chimeric, humanized, de-immunized, and most recently, human-sequence therapeutic antibodies. Once therapeutic antibodies of low or no immunogenicity were available, the creativity then turned to engineering both the antigen-binding domains (e.g., affinity maturation, stability) and altering the effector functions (e.g. antibody-dependent cellular cytotoxicity, complement-dependent cellular cytotoxicity, and clearance rate).

Activity of alemtuzumab in patients with CD52-positive acute leukemia

BACKGROUND

Alemtuzumab is a humanized monoclonal antibody directed against the cell surface antigen CD52 and has demonstrated activity in chronic lymphocytic leukemia and other CD52-positive lymphoproliferative disorders. Because CD52 also is expressed on acute leukemic blasts, the authors investigated the safety and efficacy of alemtuzumab in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL).

METHODS

Fifteen patients with CD52-positive (> or = 20%), recurrent or refractory acute leukemia (9 patients with AML and 6 patients with ALL) received alemtuzumab at a dose of 30 mg intravenously given 3 times a week (dose escalation during Week 1) for a total of 4 to 12 weeks.

RESULTS

The median age of the patients was 39 years (range, 18-71 years). Patients had received a median of 3 prior therapies (range, 1-5 prior therapies). Two patients (13%) achieved a bone marrow complete response and 1 patient achieved a substantial reduction in bone marrow blasts. No complete remissions were observed. Ten patients developed disease progression while on study. Alemtuzumab was myelosuppressive in nearly all patients. Infusion-related toxicities were common, but usually did not exceed Grade 2 (according to the National Cancer Institute Common Toxicity Criteria). Infectious episodes occurred in 13 patients (87%) and included pneumonia (6 patients), bacteremia (11 patients), fungemia (2 patients), and cytomegalovirus reactivation (2 patients).

CONCLUSIONS

Single-agent alemtuzumab was found to have limited activity in recurrent or refractory acute leukemia. An evaluation in patients with a better prognosis, in combination with other agents or as part of consolidation therapy, is warranted.

Biologic therapies for inflammatory eye disease

The era of biologic medical therapies provides new options for patients with treatment-resistant inflammatory eye disease. In this review, the authors summarize current published experience in a rapidly progressing clinical field, including the use of biologics, such as the tumour necrosis factor blockers, daclizumab and rituximab, and related agents, interferons and intravenous immunoglobulin, for the treatment of uveitis, scleritis and orbital inflammation. Reports of dramatic recoveries in patients with recalcitrant ocular inflammation who have received such therapies must be balanced against the high cost of biologics and the potential for serious, and at times unanticipated, complications of this treatment.

High concentrations of therapeutic IgG1 antibodies are needed to compensate for inhibition of antibody-dependent cellular cytotoxicity by excess endogenous immunoglobulin G

A common feature of human IgG1 antibodies used for cancer treatment is that their anti-tumour efficacy requires high serum trough levels and continued therapy for several months. Treatment cycles, thereby, consume several grams of IgG1 translating into significant drug needs and costs. The basis for the low in vivo efficacy, which is in contrast to high in vitro antibody-dependent cellular cytotoxicity (ADCC), is not well understood. Here, we have explored factors contributing to this discrepancy using adecatumumab (MT201), a fully human monoclonal IgG1 against epithelial cell adhesion molecule (Ep-CAM) and trastuzumab (Herceptin), a humanized IgG1 with specificity for the human epithelial growth factor receptor type 2 (HER-2) antigen. We found that physiological levels of human sera strongly inhibited ADCC of both IgG1 antibodies. Effects showed some dependence on the density of Ep-CAM and HER-2 targets, the tumour cell line tested and on effector cell and serum donors. Removal of IgG by affinity chromatography abolished the inhibitory effect of a serum pool. Inhibition of ADCC was fully restored by adding back the IgG fraction or by an equal amount of IgG from a commercial source. We further demonstrate that CD56-positive lymphocytes within human PBMC contributed >90% to ADCC and that normal serum levels of IgG effectively competed for in vitro binding of an IgG1 antibody to low-affinity Fcgamma receptor type III (CD16), as is present on natural killer (NK) cells. Competition of serum IgG for binding of therapeutic IgG1 to NK cell may be one important reason why high antibody doses are required in the clinic for treatment of cancer by an ADCC-based mechanism.

Sustained remission from angioimmunoblastic T-cell lymphoma induced by alemtuzumab

BACKGROUND

A 73-year-old woman presented with acute lower back pain, fever, chills and arthralgias. She had previously had a positive protein derivative test with a negative chest X-ray; her medical history was also remarkable for a mitral valve prolapse. Initial symptoms resolved spontaneously without therapy, but fever recurred with associated arthralgias, myalgias, diffuse and worsening lymphadenopathy, splenomegaly, and bilateral pulmonary infiltrates.

INVESTIGATIONS

Physical examination, blood and urine cultures, MRI of the spine, echocardiogram, extensive serologies, serum and urine protein electrophoresis, immunofixation electrophoresis, bone-marrow aspiration and biopsy with flow cytometry, cytogenetics, and gene rearrangement studies, CT scan of the chest, abdomen and pelvis, whole-body PET, and lymph-node biopsy for histological examination, immunohistochemistry, and gene rearrangement studies.

DIAGNOSIS

Angioimmunoblastic T-cell lymphoma.

MANAGEMENT

Steroids (prednisone, methylprednisolone), levofloxacin, isoniazid with pyridoxine, ciclosporin A, methotrexate, alemtuzumab, broad-spectrum antibiotics, Pneumocystis carinii prophylaxis, vancomycin, and clindamycin.

Therapy of chronic lymphocytic leukemia with purine analogs and monoclonal antibodies

B-cell chronic lymphocytic leukemia (CLL) is a clonal hematopoietic disorder characterized by proliferation and accumulation of small lymphocytes. It is the most common form of leukemia in North America and Europe. The management of CLL is determined by the stage and activity of the disease. Several randomized studies indicate that cytotoxic therapy based on alkylating agents in the indolent phase of disease, does not prolong the survival time of CLL patients. Chlorambucil, with or without steroids, has been for many years the drug of choice in previously untreated patients with this leukemia. Alternative treatment approaches, including new purine nucleoside analogs (PNA), such as fludarabine and 2-chlorodeoxyadenosine (cladribine) have also shown activity in CLL. The randomized studies have indicated a higher overall response, complete remission rates and longer response duration in patients treated initially with PNA than with chlorambucil or cyclophosphamide based combination regimens. These agents alone or in combinations, seem to be the treatment of choice for patients failing standard therapies. The monoclonal antibodies directed against CD52 antigen (alemtuzumab, Campath-1H) and CD20 antigen (rituximab) demonstrate also significant activity in CLL patients. These agents have significant single-agent activity, distinct mechanism of action and generally, favorable toxicity profiles. Both antibodies achieved the most promising results in the treatment of patients with relapsed or refractory CLL. More recently the effect of alemtuzumab in previously untreated patients has been also investigated and results are very encouraging. A multicenter prospective randomized study comparing alemtuzumab and chlorambucil as first line therapies are ongoing and preliminary results show acceptable toxicity profile of monoclonal antibody.

Immunosuppression in liver transplantation: beyond calcineurin inhibitors

Although calcineurin inhibitors (CNIs) remain the mainstay of immunosuppression in liver transplantation (LTX), their long-term toxicity significantly contributes to morbidity and mortality. The elucidation of mechanisms of alloimmunity and leukocyte migration have provided novel targets for immunosuppression development. The toxicities of these agents differ from that of the CNI and act additively or synergistically. CNI avoidance protocols in LTX have not been achieved routinely; however, pilot trials have begun to delineate the limitations and promises of such approaches. CNI-sparing protocols appear to be much more promising in balancing the early need for minimizing rejection while tapering doses and minimizing long-term toxicity.

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.

Monoclonal antibodies in the treatment of autoimmune cytopenias

In recent years, clinical studies have been undertaken with selected monoclonal antibodies (MoAbs) in the treatment of several hematological diseases, especially in malignant disorders. However, some clinical observations indicate that MoAbs may be an important alternative for the conventional therapy of some autoimmune disorders. Two MoAbs directed against CD20 antigen (rituximab, Rituxan, Mabthera) and CD52 antigen (alemtuzumab, Campath-1H) seem to be especially useful for this purpose. Autoimmune cytopenias have been investigated in the last few years with positive preliminary results. Rituximab seems to be an effective and safe agent for the treatment of immune thrombocytopenias, autoimmune hemolytic anemia, cold agglutinin disease and pure red cell aplasia. Although the case series are small, rituximab seems to be an effective and safe agent for the treatment of these diseases. Clinical experience with alemtuzumab in patients with autoimmune cytopenias is even more limited than with rituximab. However, preliminary results indicate that further studies with this MoAb are warranted. A longer follow-up and the studies on larger number of patients are needed to determine the real value of these new approaches in autoimmune cytopenias. Recent experiences with the use of MoAbs in treatment of these diseases are the subject of this review.

Therapeutic potential of antisense nucleic acid molecules

Elucidation of many disease-related signal transduction and gene expression pathways has provided unparalleled opportunities for the development of targeted therapeutics. The types of molecules in development are increasingly varied and include small-molecule enzyme inhibitors, humanized antibodies to cell surface receptors, and antisense nucleic acids for silencing the expression of specific genes. This Perspective reviews the basis for various antisense strategies for modulating gene expression, including RNA interference, and discusses the prospects for their clinical use.