Disposition of basiliximab, an interleukin-2 receptor monoclonal antibody, in recipients of mismatched cadaver renal allografts

Unique Reduced-Intensity Conditioning Haploidentical Peripheral Blood Stem Cell Transplantation Protocol for Patients with Hematologic Malignancy

Reduced-intensity conditioning (RIC) haploidentical (haplo-) hematopoietic stem cell transplantation (HSCT) requires more hematopoietic progenitor and stem cells (HPSCs) to promote engraftment and immune reconstitution and needs a stronger graft-versus-leukemia effect. Peripheral blood stem cells (PBSCs) offer advantages over bone marrow; however, the use of higher-dose non-T cell-depleted (non-TCD) in vitro PBSCs may increase the occurrence of severe graft-versus-host disease (GVHD). This prospective, single-arm clinical study was performed to investigate using high-dose non-TCD in vitro PBSCs as the graft source, using fludarabine/Ara-C/busulfan (FAB) as the conditioning regimen, using rabbit antithymocyte globulin to remove T cells in vivo, and enhancing GVHD prophylaxis with an IL-2 receptor antagonist in RIC-haplo-HSCT in patients with hematologic malignancies age 50 to 70 years or <50 years with comorbidities (Hematopoietic Cell Transplantation Comorbidity Index score ≥2) classified as intermediate to high risk. The primary endpoint was day 100 acute GVHD (aGVHD). A total of 47 patients were enrolled; the median age was 52 years (range, 30 to 68 years), the median duration of follow-up was 34 months (range, 2 to 99 months), and the medium-infused doses of mononuclear cells, CD34⁺ cells, and CD3⁺ cells were 15.93 × 10⁸/kg, 8.68 × 10⁶/kg, and 5.57 × 10⁸/kg, respectively. The cumulative incidence of grade II-IV aGVHD at day 100 was 30.3% (95% confidence interval [CI], 15.9% to 44.8%), and that of grade III-IV aGVHD was 10.2% (95% CI, .6% to 19.8%). The 2-year cumulative incidence of chronic GVHD (cGVHD) was 34.9% (95% CI, 19.0% to 50.8%). The 2-year cumulative incidences of localized and extensive cGVHD were 26.1% (95% CI, 11.80% to 40.40%) and 8.7% (95% CI, 3.26% to 20.65%), respectively. The 2-year cumulative incidence of relapse was 17.3% (95% CI, 5.1% to 29.5%), the 2-year overall survival rate was 71.2% (95% CI, 57.9% to 84.5%), and the 2-year disease-free survival rate was 66.2% (95% CI, 52.1% to 80.3%). The incidence of aGVHD was not high, and the overall efficacy was good. This study demonstrates that this unique RIC-haplo-PBSC transplantation protocol was effective in treating hematologic malignancies. Nonetheless, larger prospective multicenter clinical trials and experimental studies should be performed to further confirm our findings.

CD4+CD25+ T regulatory cells in renal transplantation

The immune response to an allograft activates lymphocytes with the capacity to cause rejection. Activation of CD4+CD25+Foxp3+T regulatory cells (Treg) can down-regulate allograft rejection and can induce immune tolerance to the allograft. Treg represent <10% of peripheral CD4+T cells and do not markedly increase in tolerant hosts. CD4+CD25+Foxp3+T cells include both resting and activated Treg that can be distinguished by several markers, many of which are also expressed by effector T cells. More detailed characterization of Treg to identify increased activated antigen-specific Treg may allow reduction of non-specific immunosuppression. Natural thymus derived resting Treg (tTreg) are CD4+CD25+Foxp3+T cells and only partially inhibit alloantigen presenting cell activation of effector cells. Cytokines produced by activated effector cells activate these tTreg to more potent alloantigen-activated Treg that may promote a state of operational tolerance. Activated Treg can be distinguished by several molecules they are induced to express, or whose expression they have suppressed. These include CD45RA/RO, cytokine receptors, chemokine receptors that alter pathways of migration and transcription factors, cytokines and suppression mediating molecules. As the total Treg population does not increase in operational tolerance, it is the activated Treg which may be the most informative to monitor. Here we review the methods used to monitor peripheral Treg, the effect of immunosuppressive regimens on Treg, and correlations with clinical outcomes such as graft survival and rejection. Experimental therapies involving ex vivo Treg expansion and administration in renal transplantation are not reviewed.

A New Generation of Cell Therapies Employing Regulatory T Cells (Treg) to Induce Immune Tolerance in Pediatric Transplantation

Kidney transplantation is the most common solid organ transplant and the preferred treatment for pediatric patients with end-stage renal disease, but it is still not a definitive solution due to immune graft rejection. Regulatory T cells (Treg) and their control over effector T cells is a crucial and intrinsic tolerance mechanism in limiting excessive immune responses. In the case of transplants, Treg are important for the survival of the transplanted organ, and their dysregulation could increase the risk of rejection in transplanted children. Chronic immunosuppression to prevent rejection, for which Treg are especially sensitive, have a detrimental effect on Treg counts, decreasing the Treg/T-effector balance. Cell therapy with Treg cells is a promising approach to restore this imbalance, promoting tolerance and thus increasing graft survival. However, the strategies used to date that employ peripheral blood as a Treg source have shown limited efficacy. Moreover, it is not possible to use this approach in pediatric patients due to the limited volume of blood that can be extracted from children. Here, we outline our innovative strategy that employs the thymus removed during pediatric cardiac surgeries as a source of therapeutic Treg that could make this therapy accessible to transplanted children. The advantageous properties and the massive amount of Treg cells obtained from pediatric thymic tissue (thyTreg) opens a new possibility for Treg therapies to prevent rejection in pediatric kidney transplants. We are recruiting patients in a clinical trial to prevent rejection in heart-transplanted children through the infusion of autologous thyTreg cells (NCT04924491). If its efficacy is confirmed, thyTreg therapy may establish a new paradigm in preventing organ rejection in pediatric transplants, and their allogeneic use would extend its application to other solid organ transplantation.

Standard induction with basiliximab versus no induction in low immunological risk kidney transplant recipients: study protocol for a randomized controlled trial

BACKGROUND

Induction therapy with IL-2 receptor antagonist (IL2-RA) is recommended as a first-line agent in low immunological risk kidney transplant recipients. However, the role of IL2-RA in the setting of tacrolimus-based immunosuppression has not been fully investigated.

AIMS

To compare different induction therapeutic strategies with 2 doses of basiliximab vs. no induction in low immunologic risk kidney transplant recipients as per KFSHRC protocol.

METHODS

Prospective, randomized, double blind, non-inferiority, controlled clinical trial EXPECTED OUTCOMES: 1. Primary outcomes: Biopsy-proven acute rejection within first year following transplant 2.

SECONDARY OUTCOMES

a. Patient and graft survival at 1 year b. eGFR at 6 months and at 12 months c. Emergence of de novo donor-specific antibodies (DSAs) TRIAL REGISTRATION: The study has been prospectively registered at clinicaltrials.gov (NTC: 04404127). Registered on 27 May 2020.

Model-informed precision dosing to optimise immunosuppressive therapy in renal transplantation

Immunosuppressive therapy is pivotal for sustained allograft and patient survival after renal transplantation. However, optimally balanced immunosuppressive therapy is challenged by between-patient and within-patient pharmacokinetic (PK) variability. This could warrant the application of personalised dosing strategies to optimise individual patient outcomes. Pharmacometrics, the science that investigates the xenobiotic-biotic interplay using computer-aided mathematical modelling, provides options to describe and quantify this PK variability and enables identification of patient characteristics affecting immunosuppressant PK and treatment outcomes. Here, we review and critically appraise the available pharmacometric model-informed dosing solutions for the typical immunosuppressants in modern renal transplantation, to guide their initial and subsequent dosing.

Implications for body weight extremes in solid organ transplantation

The pharmacokinetic profiles of medications are altered in overweight and underweight patients, but few studies have described these differences in patients with body mass index extremes. As solid organ transplant programs expand their candidate selection criteria to accommodate a growing population of patients with weight extremes, it has become imperative to understand and evaluate the impact weight extremes have on the pharmacokinetics of life-sustaining immunosuppression in this population. This review will describe pharmacokinetic and dosing considerations for weight extremes in solid organ transplant recipients, including changes following bariatric surgeries, non-pharmacologic and pharmacologic management strategies for weight loss and gain, and potential drug-drug interactions with popular weight management products.

Basiliximab impairs regulatory T cell (TREG) function and could affect the short-term graft acceptance in children with heart transplantation

CD25, the alpha chain of the IL-2 receptor, is expressed on activated effector T cells that mediate immune graft damage. Induction immunosuppression is commonly used in solid organ transplantation and can include antibodies blocking CD25. However, regulatory T cells (Tregs) also rely on CD25 for their proliferation, survival, and regulatory function. Therefore, CD25-blockade may compromise Treg protective role against rejection. We analysed in vitro the effect of basiliximab (BXM) on the viability, phenotype, proliferation and cytokine production of Treg cells. We also evaluated in vivo the effect of BXM on Treg in thymectomized heart transplant children receiving BXM in comparison to patients not receiving induction therapy. Our results show that BXM reduces Treg counts and function in vitro by affecting their proliferation, Foxp3 expression, and IL-10 secretion capacity. In pediatric heart-transplant patients, we observed decreased Treg counts and a diminished Treg/Teff ratio in BXM-treated patients up to 6-month after treatment, recovering baseline values at the end of the 12-month follow up period. These results reveal that the use of BXM could produce detrimental effects on Tregs, and support the evidence suggesting that BXM induction could impair the protective role of Tregs in the period of highest incidence of acute graft rejection.

Psychiatric symptoms in anti glutamic acid decarboxylase associated limbic encephalitis in adults: a systematic review

Autoimmune Limbic Encephalitis (LE) is a relatively new category of immune-mediated diseases with a wide range of neuropsychiatric symptoms. LE associated with Glutamic Acid Decarboxylase (GAD) antibodies is difficult to diagnose due to its possible atypical presentation with neuropsychiatric and behavioral features. We performed a systematic review of literature and retrieved 21 cases of anti GAD-associated LE with neuropsychiatric signs. Median age at onset was 27 years with a female predominance (81.0 %) and median diagnostic delay of 6 months. Clinical presentation included typical LE symptoms such as anterograde amnesia (95.2 %) and temporal lobe or tonico-clonic seizures (95.2 %). Psychiatric symptoms were described in 61.9 % of patients, presenting as anxiety, depressive symptoms, apathy and behavioral changes. Extra-limbic symptoms were present in 14.3 % of patients. No neoplasia associated was found. Some patients had poor epileptic, cognitive and psychiatric outcomes requiring prolonged immunosuppressive treatment. The description of the neuropsychiatric spectrum of anti-GAD LE and its specificities aims to improve our understanding of this entity, and may lead to earlier diagnosis as well as better outcome.

Pharmacokinetics of Basiliximab for the Prevention of Graft-versus-Host Disease in Patients Undergoing Hematopoietic Cell Transplantation with Minimal-Intensity Cyclophosphamide and Fludarabine

STUDY OBJECTIVE

Basiliximab is an immunosuppressive monoclonal antibody used for rejection prevention following solid organ transplantation; the pharmacokinetics (PK) of basiliximab in this setting are known. Basiliximab may also be used for prophylaxis and treatment of graft-versus-host disease (GVHD) in patients undergoing allogeneic hematopoietic cell transplantation (HCT); however, the PK of basiliximab in this setting are not known. Clinical transplant providers expect variation in the volume of distribution and clearance after nonmyeloablative allogeneic transplantation (NMAT) compared with solid organ transplantation. Blood loss, organ site-specific antibody accumulation, and differences in blood product use during the two transplantation approaches may generate differences in basiliximab PK. Therefore, the objective of this study was to describe the PK of basiliximab after its addition to a minimally intense NMAT regimen, in conjunction with cyclosporine, for GVHD prophylaxis in patients with hematologic malignancies.

DESIGN

Population PK analysis of a single-center, single-arm, phase II clinical trial.

SETTING

Academic cancer research center.

PATIENTS

Fourteen adults with hematologic malignancies (acute myeloid leukemia, acute lymphoblastic leukemia, chronic lymphocytic leukemia, myelodysplastic syndrome, non-Hodgkin's lymphoma, Hodgkin's lymphoma, myelofibrosis, or severe aplastic anemia) and undergoing NMAT with a fully HLA-matched (10 of 10 antigen matched) related or unrelated donor.

MEASUREMENTS AND MAIN RESULTS

Basiliximab was used in conjunction with cyclosporine to deplete activated T cells in vivo as GVHD prophylaxis. We developed a novel competitive enzyme-linked immunosorbent assay (ELISA) method using recombinant interleukin-2 receptor alpha-chain (IL-2Ra) and a commercially available soluble sIL-2R ELISA kit to permit the quantification of serum basiliximab concentrations and characterization of the PK properties of the drug in this patient population. Using a nonlinear mixed effects model with NONMEM software, a one-compartment model with first-order elimination best described the PK, as covariate analysis using stepwise covariate modeling did not improve the base model.

CONCLUSION

We suggest a one-compartment population model with first-order elimination to capture the PK profile for basiliximab for this patient population.

[Clinical research of HLA-haploidentical peripheral hematopoietic stem cell transplantation following reduced intensity conditioning regimen with hematological malignancy patients over 50 years old]

目的

分析减低剂量预处理单倍型外周血造血干细胞移植（RIC-haplo-PBSCT）治疗50岁以上恶性血液肿瘤患者的疗效。

方法

18例50岁以上恶性血液肿瘤患者纳入研究，男8例，女10例，中位年龄52（50~66）岁；急性髓系白血病（AML）8例，慢性髓性白血病（CML）2例，骨髓增生异常综合征（MDS）5例，急性淋巴细胞白血病（ALL）2例，急性NK细胞白血病（ANKL）1例；采用FAB+ATG（氟达拉滨+阿糖胞苷+白消安+兔抗人胸腺细胞免疫球蛋白）减低剂量预处理方案，输注供者高剂量非去T细胞外周血造血干细胞（PBSC），应用强化移植物抗宿主病（GVHD）预防方案及感染防控措施。

结果

16例患者在移植后15 d获得完全供者嵌合，其中1例在移植后1个月发生移植排斥，其余2例在移植后15 d为混合嵌合并于移植后1个月发生移植排斥。急性GVHD发生率为61.1%（95%CI 49.6%~72.6%），Ⅱ~Ⅳ度急性GVHD发生率为35.4%（95%CI 21.1%~49.7%），Ⅲ/Ⅳ度急性GVHD发生率为13.8%（95%CI 4.7%~22.9%）。2年慢性GVHD累积发生率为38.2%（95%CI 25.5%~50.9%），未发生广泛型慢性GVHD。中位随访14.5（3~44）个月，2年总生存率、无病生存率分别为72.6%（95%CI 60.1%~85.1%）、63.7%（95%CI 49.2%~78.2%），2年累积复发率为31.2%（95%CI 16.5%~45.9%），2年非复发死亡率为12.5%（95%CI 4.2%~20.8%）。

结论

RIC-haplo-PBSCT治疗50岁以上恶性血液肿瘤患者可获得较好的疗效。

A CD4-mimetic compound enhances vaccine efficacy against stringent immunodeficiency virus challenge

The envelope glycoprotein (Env) trimer ((gp120/gp41)₃) mediates human immunodeficiency virus (HIV-1) entry into cells. The “closed,” antibody-resistant Env trimer is driven to more open conformations by binding the host receptor, CD4. Broadly neutralizing antibodies that recognize conserved elements of the closed Env are potentially protective, but are elicited inefficiently. HIV-1 has evolved multiple mechanisms to evade readily elicited antibodies against more open Env conformations. Small-molecule CD4-mimetic compounds (CD4mc) bind the HIV-1 gp120 Env and promote conformational changes similar to those induced by CD4, exposing conserved Env elements to antibodies. Here, we show that a CD4mc synergizes with antibodies elicited by monomeric HIV-1 gp120 to protect monkeys from multiple high-dose intrarectal challenges with a heterologous simian-human immunodeficiency virus (SHIV). The protective immune response persists for at least six months after vaccination. CD4mc should increase the protective efficacy of any HIV-1 Env vaccine that elicits antibodies against CD4-induced conformations of Env.

The HIV Env trimer exhibits a closed confirmation and restricts access to known antibody binding sites. Here the authors show that a small-molecule CD4-mimetic compound binds the HIV Env trimer and enhances antibody-mediated protection in a non-human primate model of infection.

Low-dose basiliximab induction therapy in heart transplantation

We prospectively studied efficacy and safety outcomes of two 10-mg doses of intravenous basiliximab on day 0 and day 4 for induction therapy in 17 consecutive de novo heart transplant recipients. By the 2-week assessment post-transplant, there were no deaths, graft failures, or acute cellular rejections (ACRs) ISHLT grade ≥ 2R. By the 1-year assessment post-transplant, there were 1 (6%) infectious death, no graft failures, 2 (12%) grade 2R ACRs, 6 (35%) asymptomatic cytomegalovirus (CMV) infections, and 4 (25%) treated infections. Our study was the first to show that low-dose basiliximab induction in heart transplant resulted in favorable efficacy and safety outcomes. Additionally, calcineurin inhibitor (CNI) initiation in a low-risk population could be safely delayed using the strategy of modified low-dose postoperative basiliximab. This strategy also appears to allow subsequent early corticosteroid wean, although with the concomitant maintenance of higher CNI levels and higher dosing of mycophenolate.

Use of Basiliximab and Daclizumab in Kidney Transplantation

Kidney transplantation represents a major medical victory in patients with whom dialysis and medical therapy have failed. To increase survival rates and optimize the use of limited organs, both patient care and immunosuppression therapy must be improved. Reduction in rejection episodes or severity of rejection may ultimately improve long-term allograft survival. Traditional engineered monoclonal antibodies have been associated with severe cytokine release reactions and an increased risk of opportunistic infections. Basiliximab and daclizumab are chimeric and humanized monoclonal antibodies that inhibit thymus-dependent lymphocyte proliferation. Interleukin 2 also affects the proliferation of natural killer cells, macrophages and monocytes, bursa-equivalent lymphocytes, epidermal dendritic cells, and lymphokine-activated killer cells. Interleukin-2 receptor antagonists have been shown to reduce the incidence of acute rejection without increasing the incidence of opportunistic infections or malignancy. Further studies are needed to evaluate the overall effect of these agents on long-term patient and allograft survival.

A systematic review and meta-analysis on the prevalence of Dupuytren disease in the general population of Western countries

BACKGROUND

Dupuytren disease is a fibroproliferative disease of palmar fascia of the hand. Its prevalence has been the subject of several reviews; however, an accurate description of the prevalence range in the general population--and of the relation between age and disease--is lacking.

METHODS

Embase and PubMed were searched using database-specific Medical Subject Headings; titles and abstracts were searched for the words "Dupuytren," "incidence," and "prevalence." Two reviewers independently assessed the articles using inclusion and exclusion criteria, and rated the included studies with a quality assessment instrument. In a meta-analysis, the median prevalence, as a function of age by sex, was estimated, accompanied by 95 percent prediction intervals. The observed heterogeneity in prevalence was investigated with respect to study quality and geographic location.

RESULTS

Twenty-three of 199 unique identified articles were included. The number of participants ranged from 37 to 97,537, and age ranged from 18 to 100 years. Prevalence varied from 0.6 to 31.6 percent. The quality of studies differed but could not explain the heterogeneity among studies. Mean prevalence was estimated as 12, 21, and 29 percent at ages 55, 65, and 75 years, respectively, based on the relation between age and prevalence determined from 10 studies.

CONCLUSIONS

The authors describe a prevalence range of Dupuytren disease in the general population of Western countries. The relation between age and prevalence of Dupuytren disease is given according to sex, including 95 percent prediction intervals. It is possible to determine disease prevalence at a certain age for the total population, and for men and women separately.

A systematic review and meta-analysis on the prevalence of Dupuytren disease in the general population of Western countries

BACKGROUND

Dupuytren disease is a fibroproliferative disease of palmar fascia of the hand. Its prevalence has been the subject of several reviews; however, an accurate description of the prevalence range in the general population--and of the relation between age and disease--is lacking.

METHODS

Embase and PubMed were searched using database-specific Medical Subject Headings; titles and abstracts were searched for the words "Dupuytren," "incidence," and "prevalence." Two reviewers independently assessed the articles using inclusion and exclusion criteria, and rated the included studies with a quality assessment instrument. In a meta-analysis, the median prevalence, as a function of age by sex, was estimated, accompanied by 95 percent prediction intervals. The observed heterogeneity in prevalence was investigated with respect to study quality and geographic location.

RESULTS

Twenty-three of 199 unique identified articles were included. The number of participants ranged from 37 to 97,537, and age ranged from 18 to 100 years. Prevalence varied from 0.6 to 31.6 percent. The quality of studies differed but could not explain the heterogeneity among studies. Mean prevalence was estimated as 12, 21, and 29 percent at ages 55, 65, and 75 years, respectively, based on the relation between age and prevalence determined from 10 studies.

CONCLUSIONS

The authors describe a prevalence range of Dupuytren disease in the general population of Western countries. The relation between age and prevalence of Dupuytren disease is given according to sex, including 95 percent prediction intervals. It is possible to determine disease prevalence at a certain age for the total population, and for men and women separately.

Basiliximab: efficacy and safety evaluation in kidney transplantation

INTRODUCTION

Basiliximab is a chimeric monoclonal antibody directed against the alpha chain of interleukin-2 receptor (IL-2R). When administered intravenously at a dosage of 20 mg at the time of transplantation and 4 days later, basiliximab saturates the alpha chain of IL-2R for 4 weeks.

AREAS COVERED

This review evaluates the efficacy and safety of basiliximab in kidney transplantation. Randomized controlled trials showed that basiliximab can significantly reduce the incidence of acute rejection without increasing the risk of adverse events. When compared with other antibodies used for induction, basiliximab showed efficacy and safety profiles similar to daclizumab, another monoclonal antibody directed against the alpha chain of IL-2R. In comparison with rabbit anti-thymocyte globulins (rATG), basiliximab showed a similar efficacy. However, in patients at higher risk of rejection, rATG proved to be more effective. No serious safety problems related to basiliximab have been reported.

EXPERT OPINION

There is a solid evidence that basiliximab can significantly decrease the risk of acute rejection in kidney transplant recipients without increasing adverse events. This can allow decreased dosage or avoidance of glucocorticoids and reduced dosage of calcineurin inhibitors. On the basis of efficacy, tolerability, ease of administration, and cost effectiveness, basiliximab may be considered the drug of choice for the prophylaxis of acute rejection in standard renal transplant recipients.

Pharmacokinetics, pharmacodynamics and physiologically-based pharmacokinetic modelling of monoclonal antibodies

Development of monoclonal antibodies (mAbs) and their functional derivatives represents a growing segment of the development pipeline in the pharmaceutical industry. More than 25 mAbs and derivatives have been approved for a variety of therapeutic applications. In addition, around 500 mAbs and derivatives are currently in different stages of development. mAbs are considered to be large molecule therapeutics (in general, they are 2-3 orders of magnitude larger than small chemical molecule therapeutics), but they are not just big chemicals. These compounds demonstrate much more complex pharmacokinetic and pharmacodynamic behaviour than small molecules. Because of their large size and relatively poor membrane permeability and instability in the conditions of the gastrointestinal tract, parenteral administration is the most usual route of administration. The rate and extent of mAb distribution is very slow and depends on extravasation in tissue, distribution within the particular tissue, and degradation. Elimination primarily happens via catabolism to peptides and amino acids. Although not definitive, work has been published to define the human tissues mainly involved in the elimination of mAbs, and it seems that many cells throughout the body are involved. mAbs can be targeted against many soluble or membrane-bound targets, thus these compounds may act by a variety of mechanisms to achieve their pharmacological effect. mAbs targeting soluble antigen generally exhibit linear elimination, whereas those targeting membrane-bound antigen often exhibit non-linear elimination, mainly due to target-mediated drug disposition (TMDD). The high-affinity interaction of mAbs and their derivatives with the pharmacological target can often result in non-linear pharmacokinetics. Because of species differences (particularly due to differences in target affinity and abundance) in the pharmacokinetics and pharmacodynamics of mAbs, pharmacokinetic/pharmacodynamic modelling of mAbs has been used routinely to expedite the development of mAbs and their derivatives and has been utilized to help in the selection of appropriate dose regimens. Although modelling approaches have helped to explain variability in both pharmacokinetic and pharmacodynamic properties of these drugs, there is a clear need for more complex models to improve understanding of pharmacokinetic processes and pharmacodynamic interactions of mAbs with the immune system. There are different approaches applied to physiologically based pharmacokinetic (PBPK) modelling of mAbs and important differences between the models developed. Some key additional features that need to be accounted for in PBPK models of mAbs are neonatal Fc receptor (FcRn; an important salvage mechanism for antibodies) binding, TMDD and lymph flow. Several models have been described incorporating some or all of these features and the use of PBPK models are expected to expand over the next few years.

Molecular targets in the treatment of alcoholic hepatitis

Alcohol related costs to health and society are high. One of the most serious complications of alcohol misuse to the individual is the development of alcoholic hepatitis (AH), a clinical syndrome of jaundice and progressive inflammatory liver injury in patients with a history of recent heavy alcohol use. It has a poor outcome and few existing successful therapies. The use of glucocorticoids in patients with severe AH is still controversial and there remains a group of patients with glucocorticoid-resistant disease. However, as our understanding of the pathogenesis of the condition improves there are opportunities to develop new targeted therapies with specific actions to control liver inflammation without having a detrimental effect on the immune system as a whole. In this article we review the molecular mechanisms of AH concentrating on the activation of the innate and adaptive immune response. We consider existing treatments including glucocorticoids, anti-tumor necrosis factor therapy and pentoxifylline and their limitations. Using our knowledge of the disease pathogenesis we discuss possible novel therapeutic approaches. New targets include pro-inflammatory cytokines such as interleukin (IL)-17, chemokines and their receptors (for example IL-8, CXCL9 and CXCR3) and augmentation of anti-inflammatory molecules such as IL-10 and IL-22. And there is also future potential to consider combination therapy to selectively modulate the immune response and gain control of disease.

Basiliximab does not increase efficacy of corticosteroids in patients with steroid-refractory ulcerative colitis

BACKGROUND & AIMS

Basiliximab is a chimeric monoclonal antibody that binds CD25 and thereby inhibits interleukin (IL)-2-mediated proliferation of lymphocytes. IL-2 might contribute to the resistance of T cells to corticosteroids. We investigated the efficacy and safety of basiliximab as a corticosteroid-sensitizing agent in patients with corticosteroid-refractory ulcerative colitis (UC).

METHODS

We studied 149 patients with moderate to severe UC (Mayo score ≥6 and endoscopic subscore ≥2) despite treatment for at least 14 days with oral prednisone (40-50 mg/day). Subjects were randomly assigned to groups that were given 20 mg (n = 46) or 40 mg (n = 52) basiliximab or placebo (n = 51) at weeks 0, 2, and 4. All subjects received 30 mg/day prednisone through week 2; the dose was reduced by 5 mg each week to 20 mg/day, which was maintained until week 8. At week 8, we compared the rates of clinical remission (Mayo score ≤2, no subscore >1) for patients given basiliximab with the rate for patients given placebo.

RESULTS

Twenty-eight percent of patients given placebo, 29% of those given the 40-mg dose of basiliximab, and 26% of those given the 20-mg dose of basiliximab achieved clinical remission (P = 1.00 vs placebo for each dose). Basiliximab was generally well tolerated. Six subjects who received basiliximab had serious adverse events (6.1%) compared with 2 who received placebo (3.9%; P = .72). In subjects given basiliximab, incomplete saturation of CD25 (<50%) on peripheral T cells was associated with the presence of anti-basiliximab antibodies (odds ratio, 21; 95% confidence interval, 2.4-184).

CONCLUSIONS

Basiliximab does not increase the effect of corticosteroids in the induction of remission in outpatients with corticosteroid-resistant moderate to severe UC.

Long-term outcome of ATG vs. Basiliximab induction

BACKGROUND

An evaluation of the long-term efficacy and incidence of adverse events after induction therapy with antithymocyte globulin (ATG) vs. Basiliximab in renal transplant patients.

METHODS

Sixty recipients receiving ATG induction and a dual immunosuppression with Tacrolimus and steroids were compared retrospectively with 60 patients treated with Basiliximab. The following characteristics were evaluated: concomitant immunosuppression, recipient age, donor age, time on dialysis, cold ischemia time, year of transplantation and HLA mismatches.

RESULTS

The 6-year patient survival in the ATG group was 91·7% compared to 85% in the Basiliximab group (not significant, n.s.). Graft survival at 6 years was 89·7% and. 83·6% in the ATG and the Basiliximab group (n.s.), respectively. Incidence of biopsy proven acute rejection episodes (33·3% vs. 26·7%) and delayed graft function (30% vs. 33·3%) were similar in both groups. Kidney function was not significantly different at 1 and 6 years. CMV infections were more prevalent in the ATG arm (22% vs. 5%; P = 0·05), and a significantly higher rate of haematological complications was observed following ATG induction.

CONCLUSIONS

ATG induction was associated with an improved (but n.s.) trend in patient and graft survival. Patients induced with ATG had a higher rate of CMV infections and haematological complications.

The role of basiliximab in the evolving renal transplantation immunosuppression protocol

Basiliximab is a chimeric mouse-human monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2) receptor on activated T lymphocytes. It was shown in phase III trials to reduce the number and severity of acute rejection episodes in the first year following renal transplantation in adults and children, with a reasonable cost-benefit ratio. The drug does not increase the incidence of opportunistic infections or malignancies above baseline in patients treated with conventional calcineurin inhibitor-based immunosuppression. In the field of renal transplantation, basiliximab does not increase kidney or patient survival, despite the reduction in the number of rejection episodes. Basiliximab may reduce the incidence of delayed graft function. In comparison with lymphocyte-depleting antibodies basiliximab appears to have equal efficacy in standard immunological risk patients. Recently, IL-2 receptor monoclonal antibodies have been used with the objective of reducing or eliminating the more toxic elements of the standard immunosuppression protocol. Several trials have incorporated basiliximab in protocols designed to avoid or withdraw rapidly corticosteroids, as well as protocols which substitute target-of-rapamycin (TOR) inhibitors for calcineurin inhibitors.

The use of monoclonal antibodies for the treatment of graft-versus-host disease following allogeneic stem cell transplantation

INTRODUCTION

Graft-versus-host disease (GVHD) remains the leading cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Steroids along with calcineurin inhibitors remain the standard initial therapy, however, less than half of the patients completely respond and there is no uniformly accepted therapy for patients with steroid-resistant GVHD.

AREAS COVERED

This paper reviews the current role and ongoing development of mAbs in the treatment of GVHD. Various mAbs to cell surface antigens on GVHD effector cells have been investigated for the treatment of acute GVHD: these include anti-TNF-α antibodies, IL-2 receptor antagonists, anti-CD3 and anti-CD52 mAbs, while anti-CD20 mAb has been extensively investigated in the setting of chronic GVHD. Overall, response rates have been reported to be greater than 60%, although it should be emphasized that the long-term survival still remains suboptimal, mainly due to the detrimental side effects of infectious complications, progressive GVHD and relapse of underlying malignancy.

EXPERT OPINION

Future challenges will include more appropriate definition of these agents in the therapeutic scenario of GVHD. Combinations of mAbs or mAb combined with newer immunosuppressive drugs might potentially achieve greater success, especially if used early in the disease process.

Anti-interleukin-2 receptor antibodies-basiliximab and daclizumab-for the prevention of acute rejection in renal transplantation

The use of antibody induction after kidney transplantation has increased from 25% to 63% in the past decade and roughly one half of the induction agent used is anti-interleukin-2 receptor antibody (IL-2RA, ie, basiliximab or daclizumab). When combined with calcineurin inhibitor (CNI)-based immunosuppression, IL-2RAs have been shown to reduce the incidence of acute rejection, one of the predictors of poor graft survival, without increasing risks of infections and malignancies in kidney transplantation. For low-immunological-risk patients, IL-2RAs, as compared with lymphocyte-depleting antibodies, are equally efficacious and have better safety profiles. For high-risk patients, however, IL-2RAs may be inferior to lymphocyte-depleting antibodies for the prophylaxis of acute rejection. In an effort to reduce toxicities of other immunosuppressive medications without increasing the risk of acute rejection and chronic graft loss, IL-2RAs have often been combined with steroid- and CNI-sparing immunosuppression protocols. More data support the benefits of early steroid withdrawal with IL-2RA in low-risk patients, but preferred induction therapy for high-risk patients has yet to be determined. Although CNI-sparing protocols with IL-2RA may preserve renal function and improve long-term survival in selected patients, further studies are needed to identify those who benefit most from this strategy.

A randomized trial of basiliximab with three different patterns of cyclosporin A initiation in renal transplant from expanded criteria donors and at high risk of delayed graft function

This study assays therapy with basiliximab and different patterns of cyclosporin A (CsA) initiation in renal transplant (RT) recipients from expanded criteria donors (ECD) and at high risk of delayed graft function (DGF). A multicentre six-month open-label randomized trial with three parallel groups treated with basiliximab plus steroids, mycophenolate mofetil and different patterns of CsA initiation: early within 24 h post-RT at 3 mg/kg/d (Group 1; n = 38), and at 5 mg/kg/d (Group 2; n = 40), or delayed after 7-10 d at 5 mg/kg/d (Group 3; n = 36). There were no differences among groups in six months GFR (43.1 +/- 12, 48.0 +/- 14 and 47.2 +/- 17 mL/min, respectively), DGF (Group 1: 31%, Group 2: 37%, Group 3: 42%), nor biopsy-proven acute rejection, although clinically treated and biopsy-proven acute rejection was significantly higher in Group 3 (25%) vs. Group 1 (5.3%, p < 0.05). At six months no differences were observed in death-censored graft survival or patient survival. Induction therapy with basiliximab and three CsA-ME initiation patterns in RT recipients from ECD and at high risk of DGF presented good renal function and graft survival at six months. Late onset group did not achieve improvement in DGF rate and showed a higher incidence of clinically treated and biopsy-proven acute rejection.

Basiliximab versus daclizumab combined with triple immunosuppression in deceased donor renal graft recipients

In this prospective, randomized, open-label, single-center study, we compared the efficacy and safety of two anti-interleukin-2 receptor monoclonal antibodies among adult recipients of at least 1 HLA-mismatched deceased donor renal grafts. Eligible patients were randomized to induction with either basiliximab or daclizumab. Both groups received cyclosporine microemulsion (CsA Neoral), mycophenolate mofetil, and methylprednisolone. An intent-to-treat analysis of 1-year data assessed the incidence of acute rejection episodes, the renal graft function, the safety, and the patient and graft survivals. Among 127 patients, six (10.0%) and seven (11.5%) patients experienced biopsy-confirmed acute rejection at 12 months, in the basiliximab and the daclizumab groups, respectively. Two renal grafts were lost in the basiliximab and six in the daclizumab cohort, one of them due to rejection. One basiliximab and two daclizumab patients died. Hospital treatment was required for 25 and 33 infections in basiliximab and daclizumab groups, respectively. One basal cell carcinoma of skin was detected. One hypersensitivity reaction was observed with daclizumab. At 12 months, serum creatinine was 101+/-28 micromol/L with basiliximab and 109+/-41 micromol/L with daclizumab. Patient survival was 98.4% with basiliximab and 96.7% with daclizumab, and graft survival was 96.8% versus 90.8%, respectively. No significant differences were observed between the groups. Basiliximab or daclizumab combined with triple therapy was an efficient and safe immunosuppression strategy, demonstrated with low incidence of acute rejection episodes, an acceptable adverse event profile, excellent graft function, and high survival rates in adult recipients within the first year after deceased donor renal transplantation.

Single bolus antithymocyte globulin versus basiliximab induction in kidney transplantation with cyclosporine triple immunosuppression: efficacy and safety

BACKGROUND

The aim of this prospective randomized study was to examine the effect of induction immunosuppression and low initial cyclosporine (CsA) on the onset of graft function and its long-term consequences.

METHODS

During 1999-2001, 155 patients were randomized to single 9 mg/kg dose antithymocyte globulin (ATG)-Fresenius (group A) or two 20-mg doses of basiliximab (group B) with reduced dose CsA or conventional CsA triple therapy without induction (group C).

RESULTS

Delayed function (DGF) was lower in group A than in groups B or C (5.7% vs. 24.1% and 15.9%, P<0.025) and need of dialysis was less in groups A and B compared to C (10.3 and 10.4 vs. 20.0 days, P<0.05). Acute rejections occurred in 11.3%, 12.1% and 20.5%, and the mean (median) time to rejection was 16 (13), 97 (46) and 101 (35) days in groups A, B, and C, respectively (P<0.005). One-and 5-year graft survivals (GS) were 98.1% and 90.6% (group A), 96.6% and 96.6% (group B), and 93.2% and 84.1% (group C). Five-year GS was significantly better in group B than in group C (P<0.05). The death censored 5-year GS in groups A, B, and C were 94.3%, 96.6%, and 90.0% (P=NS). Single high-dose ATG induction was associated with hemodynamic and pulmonary disturbances without, however, serious or long-term consequences.

CONCLUSIONS

ATG induction significantly reduced DGF. Both induction regimens together with low initial CsA led to significantly less posttransplant dialysis and excellent survival. The high dose ATG was associated with significant hemodynamic and pulmonary side effects during drug infusion.

Renal function with delayed or immediate cyclosporine microemulsion in combination with enteric-coated mycophenolate sodium and steroids: results of follow up to 30 months post-transplant

BACKGROUND

In the multicenter, open-label Myriade study, renal transplant patients were randomized to early cyclosporine microemulsion (CsA-ME, day 0) or delayed CsA-ME (day 6) with enteric-coated mycophenolate sodium (EC-MPS), steroids and interleukin-2 receptor induction. One-yr results have been published previously. We now report the results of an extension study in which patients were followed up for a period of three yr post-transplant.

METHODS

All patients completing the one-yr core study on-treatment were eligible to enter the extension study.

RESULTS

Of the 203 patients, 153 completed the core trial on-treatment; 144 (94%) entered the extension study with a minimum follow-up of one yr (73 early CsA-ME, 71 delayed CsA-ME). In 75% of patients receiving EC-MPS during the extension, the recommended dose was administered (1440 mg/d). Median creatinine clearance remained constant (57 mL/min) at 12, 24 and 30 months post-transplant and was similar in the early and delayed CsA-ME groups as well as in subpopulations with or without delayed graft function. One patient in the early CsA-ME group died. No grafts were lost. The incidence of BPAR from time of transplant to the end of the extension study was 17% (24/139). Seven patients (5%) discontinued the extension study prematurely because of adverse events.

CONCLUSION

These results suggest that a regimen of CsA-ME, EC-MPS and steroids results in excellent survival rates with stable renal function over a mean follow-up of 30 months. Immediate introduction of CsA-ME has no deleterious effect on long-term renal function, even among patients with delayed graft function.

Immunogenicity screening in protein drug development

Most therapeutic proteins in clinical trials or on the market are, to a variable extent, immunogenic. Formation of antidrug antibodies poses a risk that should be assessed during drug development, as it possibly compromises drug safety and alters pharmacokinetics. The generation of these antibodies is critically dependent on the presence of T helper cell epitopes, which have classically been identified by in vitro methods using blood cells from human donors. As a novel development, in silico methods that identify T cell epitopes have been coming on line. These methods are relatively inexpensive and allow the mapping of epitopes from virtually all human leukocyte antigen molecules derived from a wide genetic background. In vitro assays remain important, but guided by in silico data they can focus on selected peptides and human leukocyte antigen haplotypes, thereby significantly reducing time and cost.

The role of basiliximab induction therapy in organ transplantation

Basiliximab is a chimeric monoclonal antibody that selectively binds to the alpha-subunit (CD25) of IL-2 receptors on the surface of activated T lymphocytes, and is a highly effective prophylaxis agent against rejection in organ transplant recipients. Its pharmacokinetic profile is characterized by a biphasic and slow clearance with long terminal half-life and a volume of distribution within the central compartment and outside the circulatory system. Basiliximab induction demonstrated an excellent safety profile, with no increase in the incidence of malignancy, infections or death. It has also been used effectively in high-risk recipients, steroid-sparing and steroid-minimization protocols, and in post-transplant patients with renal dysfunction who would benefit from delayed introduction of calcineurin inhibitors. Basiliximab induction therapy given at days 0 and 4 after transplantation appears to be safe and cost-effective for immunoprophylaxis in solid organ transplant recipients, specifically in kidney and liver transplantation, when given in conjunction with dual or triple immunosuppressive therapy.

Effective Immunoprophylaxis With Basiliximab Plus Triple Therapy in Renal Transplantation: Five-Year Single-Center Experience

We studied prospectively the efficacy and safety of basiliximab combined with triple immunosuppression in adult recipients of > or = 1 HLA-mismatched deceased donor renal grafts. All studied patients received equal immunosuppressive drugs: 20 mg infusion of basiliximab on day 0 and on day 4, cyclosporine microemulsion (Neoral), mycophenolate mofetil, and methylprednisolone. An analysis of 1-year data assessed the incidence of acute rejection episodes, safety of this therapy, renal graft function, and patient and graft survivals. One hundred seventy-two patients were studied. The HLA-antigen mismatches were 2.9 +/- 0.9 (mean +/- SD), and the cold ischemia time was 22.0 +/- 7.5 hours. Fifty-three (31.5%) patients experienced delayed graft function. At 12 months, 5 (3.0%) patients experienced acute rejection. Six renal grafts were lost, but not from rejection. Two patients died. Sixty-six infections required treatment in the hospital. One carcinoma of cervix (in situ) and two basal cell carcinomas of skin were detected. Hypersensitivity reactions and cytokine-release syndrome were not observed. At 12 months, serum creatinine was significantly higher (119 +/- 46 micromol/L; P < .001) in patients with delayed graft function than in patients with immediate graft function (99 +/- 26 micromol/L). Patient and graft survivals were 98.8% and 97.1%, respectively. Basiliximab combined with this triple therapy was an efficient and safe immunosuppression strategy, demonstrated with very low incidence of acute rejections, an acceptable adverse event profile, excellent graft function, and high short-term survival rates in adult recipients of deceased donor renal transplant.

Interleukin-2 receptor antagonist induction in modern immunosuppression regimens for renal transplant recipients

Addition of interleukin-2 receptor antagonist (IL-2RA) induction to calcineurin inhibitor (CNI)-based regimens reduces biopsy-proven acute rejection by 30-40%. IL-2RA induction facilitates early withdrawal of steroids, and supports the safe use of reduced-exposure CNI or delayed CNI introduction. IL-2RAs and rabbit antithymocyte globulin (Thymoglobulin) show comparable efficacy in patients at standard or low immunologic risk, but the adverse event profiles of lymphocyte-depleting agents are less favorable. IL-2RAs, uniquely, provide effective immunosuppression with similar tolerability to placebo.

Safety and success of kidney transplantation and concomitant immunosuppression in HIV-positive patients

BACKGROUND

Human immunodeficiency virus-associated nephropathy (HIVAN) has become the third leading cause of end-stage renal disease (ESRD) in African Americans, and is expected to grow exponentially. Highly active antiretroviral therapy (HAART) has significantly prolonged the survival of patients with HIV infection. Despite the growing number of HIV-positive dialysis patients with prolonged life expectancy, kidney transplantation with immunosuppression has been declined because it is considered a waste of scarce donor kidneys due to potential increases in morbidity and mortality.

METHODS

The institutional review board of Drexel University College of Medicine and Hahnemann University Hospital approved this prospective study. The aim was to find out safety and success of kidney transplantation, and the effect of immunosuppression on HIV infection. Forty HIV-positive dialysis patients received kidney transplantation between February 2001 and January 2004. Patient inclusion criteria were maintenance of HAART, plasma HIV-1 RNA of <400 copies/mL, absolute CD4 counts of 200 cells/muL or more. Immunosuppression was basiliximab induction and maintenance with cyclosporine, sirolimus, and steroids. HAART was continued post-transplant. Acute rejections were diagnosed by biopsy and treated with methylprednisolone. Surveillance biopsies were completed at 1, 6, 12, and 24 months, and evaluated for subclinical acute rejection, chronic allograft nephropathy, and HIVAN.

RESULTS

One- and 2-year actuarial patient survival was 85% and 82%, respectively, and graft survival was 75% and 71%, respectively. Plasma HIV-1 RNA remained undetectable, and CD4 counts remained in excess of 400 cells per muL with no evidence of AIDS for up to 2 years.

CONCLUSION

One- and 2-year graft survival is comparable to other high-risk populations receiving kidney transplantation. One- and 2-year patient survival is higher than HIV patients maintained on dialysis. Immunosuppression does not adversely affect HIV recipients maintained on HAART in the short term.

Efficacy of the interleukin-2 receptor antagonist basiliximab in steroid-refractory acute graft-versus-host disease

Acute graft-versus-host disease (aGVHD) occurs in up to 80% of patients who undergo allogeneic stem cell transplantation (SCT) and contributes significantly to transplant-related mortality (TRM). We conducted a prospective phase II trial to assess the efficacy and feasibility of treating steroid-refractory aGVHD with basiliximab, a chimaeric monoclonal antibody directed against the alpha chain of the interleukin-2 (IL-2) receptor. Basiliximab was administered intravenously at a dose of 20 mg on days 1 and 4. Twenty-three patients were enrolled between October 1999 and July 2004. We found a primary overall response rate of 82.5% with four patients (17.5%) showing a complete response and 15 patients (65%) a partial response. Six patients were again treated successfully with an IL-2 receptor antagonist because of recurrence of aGVHD. The rates of infections, chronic GVHD, malignancy recurrence and 1-year TRM following immunosuppression with basiliximab were comparable with those found with other treatment modalities for aGVHD. We conclude that basiliximab is efficient and feasible for steroid-refractory aGVHD and merits further evaluation.

Efficacy and safety of basiliximab in kidney transplantation

The efficacy and safety of basiliximab, in combination with different maintenance regimens, are extensively addressed in the available literature. Basiliximab reduces the incidence of acute rejection, allows a safe reduction of steroid dosage, and is associated with economic savings, although there is substantially no proof that basiliximab prolongs either patient or graft survival. Initial basiliximab administration entails a low-risk and is associated with fewer adverse events than T cell depleting agents. However, life-threatening reactions were reported following re-exposure to basiliximab in recipients who lost graft function early after transplantation and, therefore, discontinued all immunosuppressive agents.

Antibodies in the prevention of renal allograft rejection

The rejection of renal allografts is mediated largely by the intragraft accumulation of alloreactive T lymphocytes. Current immunosuppressive drugs impair lymphocyte function, but also have specific toxicities and lead to nonspecific impairment of immune responses, resulting in an increased risk of infections and malignancy. Initial studies examined the usefulness of antibodies that depleted lymphocytes in preventing rejection. More recently, antibodies that impair lymphocyte function by blocking the interleukin-2 receptor-alpha (IL-2Ralpha), thereby reducing IL-2-mediated activation of T cells, were shown to reduce the risk of rejection. As an additional strategy, antibodies that impair lymphocyte trafficking have been investigated for their effect on acute rejection. This review describes the results of clinical trials of depleting antilymphocyte antibodies, IL-2Ralpha blockers and antibodies to intercellular adhesion molecule-1, lymphocyte function-associated antigen-1, CD154 and CD52 in the prevention of allograft rejection. Particular emphasis has been placed on therapies for which there is evidence obtained from good, randomised, controlled trials or registry data.

Population pharmacokinetics of sibrotuzumab, a novel therapeutic monoclonal antibody, in cancer patients

Population pharmacokinetics of sibrotuzumab, a humanized monoclonal antibody directed against fibroblast activation protein, were determined after multiple intravenous infusions of dosages ranging from 5 mg/m(2) to an absolute dose of 100 mg, in patients with advanced or metastatic carcinoma. In total, 1844 serum concentrations from 60 patients in three Phase I and II clinical studies were analyzed. The structural model incorporated two disposition compartments and two parallel elimination pathways from the central compartment, one linear and one nonlinear. Finally estimated pharmacokinetic parameters (%RSE) were: linear clearance CLL 22.1 ml/h (9.6), central distribution volume V1 4.13l (3.7), peripheral volume V2 3.19l (8.8), inter-compartmental clearance Q 37.6 ml/h (9.6); for the nonlinear clearance Vmax was 0.0338 mg/h (25) and Km 0.219 microg/ml (57). At serum concentrations between approximately 20 ng/ml and 7 microg/ml, the effect of the nonlinear clearance on pharmacokinetics was marked. Only at >7 microg/ml did CLL dominate overall clearance. Interindividual variability was 57% for CLL, 20% for V1 and V2, and 29% for Vmax and was larger than the inter-occasional variability of 13%. Of the many investigated patient covariates, only body weight was found to contribute to the population model. It significantly affected CLL, V1, V2 and Vmax resulting in marked differences in the model-predicted concentration-time profiles after multiple dosing in patients with low and high body weights. In conclusion, a robust population pharmacokinetic model was developed and evaluated for sibrotuzumab, which identified a possible need to consider body weight when designing dosage regimen for future clinical cancer trials.

Meta-analysis of basiliximab for immunoprophylaxis in renal transplantation

BACKGROUND

Basiliximab is a high-affinity chimeric monoclonal antibody directed against the alpha-chain of the interleukin (IL)-2 receptor. Individual studies have shown that it is highly effective in preventing acute rejection and causes no measurable incremental toxicity. However, incorporation of basiliximab immunoprophylaxis into routine practice depends upon the demonstration of benefit across treatment regimens and quantitation of the treatment effect.

METHODS

This study employed a meta-analysis to examine the clinical benefit of basiliximab. Parameter estimates were derived from four randomised prospective double-blind studies conducted in 93 renal transplant centres in 18 countries. A total of 1185 adult primary allograft recipients were randomised within the centres to receive either basiliximab 20mg intravenously on days 0 and 4 or placebo, in addition to double or triple immunosuppression consisting of cyclosporin-microemulsion (Neoral((R))The use of tradenames is for product identification purposes only and does not imply endorsement.), corticosteroids, and azathioprine or mycophenolate mofetil. Key clinical events included patient and graft survival, graft rejection and complications. Analysis was performed using a variable model; odds ratios and the numbers needed to treat (NNT) to benefit or to harm one patient were calculated for each principal outcome at 6 or 12 months post-transplant.

RESULTS

Basiliximab reduced the relative risk (RR) and absolute risk (AR) of clinical and biopsy-proven acute graft rejection across all treatment regimens. The overall RR of clinical acute graft rejection was decreased by 35% in patients receiving basiliximab. AR was reduced by 15.6% (pooled incidence: 28.8% vs 44.4%, p < 0.0001), and the NNT for efficacy was six. The reduction in RR of biopsy-proven rejection was similar (32%) with an absolute risk reduction (ARR) of 11.7% (pooled incidence: 25.1% vs 36.8%, p < 0.0001) and NNT of nine over 6 months. There was a concomitant reduction in the risk of graft loss which did not reach statistical significance (p = 0.14). The RR of graft loss was reduced by 26% with an AR reduction of 2.3% (pooled incidence: 6.4% vs 8.7%) and an NNT of 42 over 6 months. The risk of death was unchanged.

CONCLUSIONS

Immunoprophylaxis with basiliximab produces a significant reduction in the RR and AR of clinical and biopsy-proven acute graft rejection with a trend towards a concomitant reduction in the risk of graft loss. The magnitude of protection provided by basiliximab, the fact that it is observed across treatment regimens and the safety of this therapy are arguments for its routine use in renal transplantation.

Should living-unrelated renal transplant recipients receive antibody induction? Results of a clinical experience trial

BACKGROUND

Living-donor kidney transplant recipients generally do not receive antibody induction. Induction avoidance may not be appropriate, particularly for living-unrelated renal transplant (LURT) recipients, in whom matching may not be optimal. We compared the incidence of acute rejection and graft outcome of LURT recipients who were administered no induction and cadaveric renal transplant (CRT) recipients who were administered anti-CD25 antibody. These groups both had immediate graft function and similar maintenance immunosuppression.

METHODS

This retrospective analysis included patients who received kidney transplants between 1999 and 2000. CRT recipients received basiliximab, corticosteroids, mycophenolate mofetil (MMF), and delayed tacrolimus (serum creatinine <3 mg/dL). LURT recipients received tacrolimus (initiated pretransplantation), MMF, and corticosteroids.

RESULTS

The analysis included 136 LURT recipients and 126 CRT recipients. CRT recipients included more African Americans (52.4% vs. 30.9%, P<0.01). LURT recipients included more patients with at least one human leukocyte antigen mismatch (97.8% vs. 85.7%, P<0.01). A higher acute rejection rate was observed in LURT recipients at both 6 months (LURT recipients 19.1% vs. CRT recipients 3.2%, P<0.01) and 1 year (21.3% vs. 4.0%, P<0.0004); a higher rate also was observed in African American LURT recipients compared with African American CRT recipients (35.7% vs. 4.5%, P<0.0015) at 1 year. LURT recipients demonstrated a threefold greater rejection risk than CRT recipients who were administered basiliximab (relative risk: 3.6, P<0.002). Graft survival was similar at 1 year.

CONCLUSION

The higher rejection rates in LURT recipients (no induction) compared with CRT recipients (basiliximab induction), despite similar chronic immunosuppression (tacrolimus, MMF, and steroids) and immediate graft function, indicate the potential advantage of anti-CD25 induction in LURT protocols to reduce the risk of acute rejection.

Rituximab for reduction of anti-HLA antibodies in patients awaiting renal transplantation: 1. Safety, pharmacodynamics, and pharmacokinetics1

BACKGROUND

Preformed HLA antibodies (Ab), reported as panel-reactive antibody (PRA), prolong patient waiting time for kidney transplantation. We hypothesized that rituximab (RTX) could reduce PRA via B-cell depletion. This initial study reports the safety, pharmacokinetics, and pharmacodynamics of RTX in patients with end-stage renal failure.

METHODS

The study was an investigator-initiated single-dose, dose-escalation phase I trial of RTX in chronic dialysis patients (PRA >50%). It was approved by the Institutional Review Board and the Food and Drug Administration. Nine subjects were treated with a single dose of RTX (n=3 per group) at 50, 150, or 375 mg/m. Peripheral lymphocyte cell surface markers and HLA Ab levels (%PRA and titers) were tested using flow cytometry.

RESULTS

There were four significant adverse events: a suspected histoplasmosis infection; two Tenchkoff dialysis catheter infections; and fever (38.7 degrees C) during infusion. At 2 days after RTX therapy, there was depletion of CD19 cells (pre-RTX 181+/-137 vs. post-RTX 12+/-5.6, P =0.006). In 2 (22%) of 9 subjects, there was no appreciable change in PRA. Among the other seven patients, one had a decrease in PRA from 87% to 51% with a concurrent decrease in fluorescence intensity; five patients had changes in histogram architecture suggesting loss of antibody specificity; and one patient had a fourfold decrease in PRA titer from 1:64 to 1:16 at 6 months after treatment. In addition, one of the seven patients converted a donor-specific crossmatch to negative and underwent a successful living donor kidney transplantation.

CONCLUSIONS

RTX can be safely administered and may be an effective agent to reduce high-titer anti-HLA Abs in subjects awaiting kidney transplantation.

Donor-specific tolerance induced by simultaneous allogeneic islet transplantation with CD4+CD25+T-cells into hepatic parenchyma in mice

BACKGROUND

The allogeneic islets transplantation is an ideal therapeutic strategy for patients with diabetes mellitus. However, it has been difficult to induce immunological tolerance against islets grafts. The CD4+CD25+ regulatory T-cells (Treg) play a role in suppressing T-cell activation. Thus, we evaluated whether Treg can regulate donor-specific T-cell tolerance that received allogeneic islets into the hepatic parenchyma (ITxHP) along with Treg.

METHODS

C3H/He mice were used as donors; and streptozotocin-induced diabetic BALB/c mice were recipients. The protocol included three groups: Group A recipients received only 300 IE islets; Group B was given 300 IE islets and whole splenocytes; Group C was given 300 IE islets and Treg purified from peripheral lymph nodes.

RESULTS

For all mice in Groups A and B, the fasting blood sugar exceeded 250mg/dl and graft rejection was observed. GVHD was observed earlier in Group B than in Group A. In contrast graft survival exceeded 30 days for two mice in Group C (50%, mean POD 28.5 +/- 24.0, P<0.05). Mixed lymphocyte reaction showed that T-cells from tolerant mice had very weak responses against spleen cells from C3H mice.

CONCLUSIONS

The simultaneous ITxHP with CD4+CD25+ T-cells administration prolonged islet graft survivals and induced donor-specific hyporesponsiveness.

Anaphylactic shock caused by immunoglobulin E sensitization after retreatment with the chimeric anti-interleukin-2 receptor monoclonal antibody basiliximab

BACKGROUND

Repeated administration of chimeric or humanized monoclonal antibodies is generally well tolerated. Anti-idiotypic sensitization is rare and is considered to be of no clinical significance. We observed a child who experienced anaphylactic shock when he received a second course of basiliximab at the time of his second renal transplantation. We therefore searched for the presence of anti-basiliximab immunoglobulin (Ig) E in this patient.

METHODS

Serum levels of anti-basiliximab IgE, assay of the anti-murine reactivity of circulating anti-basiliximab IgE, and assays for serum anti-mouse antibodies and global anti-basiliximab anti-idiotypic antibodies were carried out by enzyme-linked immunosorbent assay. Anti-basiliximab IgE antibodies on circulating basophils were evaluated by the ability of the patient's blood to produce leukotrienes in vitro after exposure to basiliximab.

RESULTS

Sequential assays of serum samples by enzyme-linked immunosorbent assay indicated that anti-basiliximab IgE antibodies appeared after the second basiliximab course. There was no IgE reactivity toward a control murine IgG2a monoclonal antibody (mAb), indicating that the IgE response was directed exclusively against basiliximab idiotypes. There was no IgE reactivity against the humanized anti-interleukin-2 receptor mAb daclizumab, which was derived from a distinct parental murine mAb. Patient basophils harvested months after the anaphylactic shock produced leukotrienes in vitro on exposure to basiliximab.

CONCLUSIONS

Patients exposed to chimeric antibodies may develop an anti-idiotypic IgE response that can trigger anaphylactic shock on further exposure. Specific anti-idiotypic IgE may be bound to basophils even in the absence of circulating IgE.

Basiliximab plus low-dose cyclosporin vs. OKT3 for induction immunosuppression following renal transplantation

BACKGROUND

Current immunosuppressive therapies are very effective in preventing acute rejection (AR) and graft loss following renal transplantation. Newer agents now make it possible to develop equally efficacious but better tolerated and less toxic strategies. This is especially relevant for our ageing recipients. We now compare the efficacy of basiliximab combined with early low-dose cyclosporin therapy to standard OKT3 induction therapy.

METHODS

In this single-centre study, 100 consecutive recipients of cadaveric kidney transplants from November 1998 to August 2000 were treated with basiliximab combined with early low-dose cyclosporin, reduced steroids and mycophenolate mofetil (MMF). Clinical outcomes at 100 d and 1 yr were compared with a group of 26 patients transplanted from March 1995 to November 1998 who received OKT3, delayed full-dose cyclosporin, high-dose steroids and MMF. Amongst basiliximab treated patients, we compared clinical outcomes in those older and younger than 60 yr.

RESULTS

Both groups were similar except for a shorter cold ischaemic time in the basiliximab group. Length of stay, number of readmissions, total hospitalization days and cytomegalovirus infections were lower in the basiliximab group. Despite a 40% reduction in steroids, basiliximab-treated patients had fewer biopsy-proven episodes of AR (basiliximab 14% vs. OKT3 35%) and required less antilymphocyte antibody therapy. Clinical outcomes including patient and graft survival were no different between groups. Long-term graft survival for patients over 60 yr was limited primarily by mortality.

CONCLUSIONS

Compared with OKT3 induction therapy, the combination of early low-dose cyclosporin and basiliximab is steroid sparing, effective, well tolerated and relatively safe.

Basiliximab interferes with the detection of soluble IL-2 receptor by the Immulite Immunoassay system

The use of the Immulite Automated Immunoassay system is becoming an increasingly popular method for accurate and fast measurement of sIL-2R in serum. Here, we report that detection of sIL-2R using the Immulite Immunoassay system in serum samples of patients who are treated with basiliximab, a monoclonal antibody against the alpha-chain of the IL-2 receptor, may lead to false measurements.