Belatacept-based immunosuppression in de novo liver transplant recipients: 1-year experience from a phase II randomized study.

This exploratory phase II study evaluated the safety and efficacy of belatacept in de novo adult liver transplant recipients. Patients were randomized (N = 260) to one of the following immunosuppressive regimens: (i) basiliximab + belatacept high dose [HD] + mycophenolate mofetil (MMF), (ii) belatacept HD + MMF, (iii) belatacept low dose [LD] + MMF, (iv) tacrolimus + MMF, or (v) tacrolimus alone. All received corticosteroids. Demographic characteristics were similar among groups. The proportion of patients who met the primary end point (composite of acute rejection, graft loss, death by month 6) was higher in the belatacept groups (42­48%) versus tacrolimus groups (15­38%), with the highest number of deaths and grafts losses in the belatacept LD group. By month 12, the proportion surviving with a functioning graft was higher with tacrolimus + MMF (93%) and lower with belatacept LD (67%) versus other groups (90%: basiliximab + belatacept HD; 83%: belatacept HD; 88%: tacrolimus). Mean calculated GFR was 15­34 mL/min higher in belatacept-treated patients at 1 year. Two cases of posttransplant lymphoproliferative disease and one case of progressive multifocal leukoencephalopathy occurred in belatacept-treated patients. Follow-up beyond month 12 revealed an increase in death and graft loss in another belatacept group (belatacept HD), after which the study was terminated.

Three-year outcomes from BENEFIT, a randomized, active-controlled, parallel-group study in adult kidney transplant recipients.

The clinical profile of belatacept in kidney transplant recipients was evaluated to determine if earlier results in the BENEFIT study were sustained at 3 years. BENEFIT is a randomized 3 year, phase III study in adults receiving a kidney transplant from a living or standard criteria deceased donor. Patients were randomized to a more (MI) or less intensive (LI) regimen of belatacept, or cyclosporine. 471/666 patients completed ≥3 years of therapy. A total of 92% (MI), 92% (LI), and 89% (cyclosporine) of patients survived with a functioning graft. The mean calculated GFR (cGFR) was ∼21 mL/min/1.73 m(2) higher in the belatacept groups versus cyclosporine at year 3. From month 3 to month 36, the mean cGFR increased in the belatacept groups by +1.0 mL/min/1.73 m(2) /year (MI) and +1.2 mL/min/1.73 m(2) /year (LI) versus a decline of -2.0 mL/min/1.73 m(2) /year (cyclosporine). One cyclosporine-treated patient experienced acute rejection between year 2 and year 3. There were no new safety signals and no new posttransplant lymphoproliferative disorder (PTLD) cases after month 18. Belatacept-treated patients maintained a high rate of patient and graft survival that was comparable to cyclosporine-treated patients, despite an early increased occurrence of acute rejection and PTLD.

Three-year outcomes from BENEFIT-EXT: a phase III study of belatacept versus cyclosporine in recipients of extended criteria donor kidneys.

Recipients of extended-criteria donor (ECD) kidneys have poorer long-term outcomes compared to standard-criteria donor kidney recipients. We report 3-year outcomes from a randomized, phase III study in recipients of de novo ECD kidneys (n = 543) assigned (1:1:1) to either a more intensive (MI) or less intensive (LI) belatacept regimen, or cyclosporine. Three hundred twenty-three patients completed treatment by year 3. Patient survival with a functioning graft was comparable between groups (80% in MI, 82% in LI, 80% in cyclosporine). Mean calculated GFR (cGFR) was 11 mL/min higher in belatacept-treated versus cyclosporine-treated patients (42.7 in MI, 42.2 in LI, 31.5 mL/min in cyclosporine). More cyclosporine-treated patients (44%) progressed to GFR <30 mL/min (chronic kidney disease [CKD] stage 4/5) than belatacept-treated patients (27-30%). Acute rejection rates were similar between groups. Posttransplant lymphoproliferative disorder (PTLD) occurrence was higher in belatacept-treated patients (two in MI, three in LI), most of which occurred during the first 18 months; four additional cases (3 in LI, 1 in cyclosporine) occurred after 3 years. Tuberculosis was reported in two MI, four LI and no cyclosporine patients. In conclusion, at 3 years after transplantation, immunosuppression with belatacept resulted in similar patient survival, graft survival and acute rejection, with better renal function compared with cyclosporine. As previously reported, PTLD and tuberculosis were the principal safety findings associated with belatacept in this study population.

Reduced risk of cytomegalovirus infection in solid organ transplant recipients treated with sirolimus: a pooled analysis of clinical trials.

INTRODUCTION: Cytomegalovirus (CMV) is an opportunistic infection that causes substantial morbidity and mortality in transplant recipients. This pooled analysis of Wyeth clinical trials explored the incidence of CMV infection in solid organ transplant recipients treated with sirolimus versus comparator immunosuppressant drugs. METHODS: Wyeth-conducted, multicenter, randomized, comparative trials with at least one non-sirolimus-containing arm and at least 6 months' complete data were included. Cases of CMV were investigator-identified. The occurrence of CMV in sirolimus-treated patients was assessed versus all other comparator agents, versus antimetabolite agents, and versus calcineurin inhibitors. RESULTS: Nine trials in recipients of renal, liver, and cardiac transplants met the inclusion criteria; eight enrolled de novo allograft recipients, and one was a conversion trial. The primary pooled analysis revealed an odd ratio for CMV infection of 0.64 (95% confidence interval [CI] 0.42 to 1.0, P = .047) on sirolimus versus comparator immunosuppressant drugs. The subanalysis of sirolimus versus antimetabolites showed an odds ratio for CMV of 0.39 (95% CI 0.19 to 0.81, P = .012), and for sirolimus versus calcineurin inhibitors the odds ratio was 0.58 (95% CI 0.34 to 1.01, P = .054). CONCLUSION: This pooled analysis demonstrated a reduced risk of CMV infection among sirolimus-treated patients as compared to those receiving alternative forms of immunosuppression in Wyeth-sponsored clinical trials in solid organ transplantation. This risk reduction persisted in subgroup analyses stratified by class of comparator treatment.

Highly stoichiometric, stable, and specific association of integrin alpha3beta1 with CD151 provides a major link to phosphatidylinositol 4-kinase, and may regulate cell migration.

Here we describe an association between alpha3beta1 integrin and transmembrane-4 superfamily (TM4SF) protein CD151. This association is maintained in relatively stringent detergents and thus is remarkably stable in comparison with previously reported integrin-TM4SF protein associations. Also, the association is highly specific (i.e., observed in vitro in absence of any other cell surface proteins), and highly stoichiometric (nearly 90% of alpha3beta1 associated with CD151). In addition, alpha3beta1 and CD151 appeared in parallel on many cell lines and showed nearly identical skin staining patterns. Compared with other integrins, alpha3beta1 exhibited a considerably higher level of associated phosphatidylinositol-4-kinase (PtdIns 4-kinase) activity, most of which was removed upon immunodepletion of CD151. Specificity for CD151 and PtdIns 4-kinase association resided in the extracellular domain of alpha3beta1, thus establishing a novel paradigm for the specific recruitment of an intracellular signaling molecule. Finally, antibodies to either CD151 or alpha3beta1 caused a approximately 88-92% reduction in neutrophil motility in response to f-Met-Leu-Phe on fibronectin, suggesting an functionally important role of these complexes in cell migration.

Increased neutrophil motility by beta-glucan in the absence of chemoattractant.

Systemic candidasis is a life-threatening complication of antibiotic and immunosuppressive therapies and can alter host defense mechanisms through pathways that are poorly understood. Promotion of polymorphonuclear leukocyte (PMN) chemotaxis by beta-glucan towards fMLP or IL-8 gradients demonstrates a fundamental effect on host defenses by pathogenic fungi. The aim of the present study was to determine whether recognition of beta-glucan is sufficient to alter PMN motility in the absence of agonists of G-coupled protein chemotactic receptors. Present findings demonstrate a profound increase in PMN motility by beta-glucan supplementation of a fibronectin substratum in an underagarose migration assay. Motility on beta-glucan included a 3-fold increase in distance of migration, as well as a 5-fold increase in the number of PMNs recruited into the motile phase as compared to motility on fibronectin alone. This promotion of motility is determined by the beta2 integrin complement receptor 3 (CR3) (CD11b/CD18) rather than the beta1 integrin very late antigen 3 (VLA-3), which mediates chemotaxis on beta-glucan-supplemented matrix towards fMLP. PMN motility on beta-glucan-supplemented fibronectin was selectively decreased by inhibitors of pp60 src and ras, whereas motility was promoted by inhibition of p38-MAPK. No effect of these inhibitors was seen on PMNs migrating on fibronectin alone. Migration on beta-glucan-supplemented fibronectin, but not on fibronectin alone, was negatively regulated by protein kinase C (PKC) or cAMP activation. These findings indicate that beta-glucan is sufficient to alter the migratory capacity of PMN in the absence of costimulation by fMLP. Enhanced PMN migration on beta-glucan is mediated through specific integrins and second messenger pathways that are distinct from those utilized by PMNs migrating in the absence of beta-glucan.

Promotion of neutrophil chemotaxis through differential regulation of beta 1 and beta 2 integrins.

Migration of neutrophils requires sequential adhesive and deadhesive interactions between beta 1 and beta 2 integrins and components of the extracellular matrix. Prompted by reports that describe interaction of soluble beta-glucan with the beta 2 integrin Mac-1, a role for beta-glucan in regulation of integrin-mediated migration was investigated. Neutrophil migration in response to fMLP was assessed using an agarose overlay method with slides precoated with fibronectin (Fn) +/- beta-glucan. On Fn, random migration in excess of directed migration was observed. In contrast, migration on Fn + beta-glucan was directional, with marked diminution of random migration. This conversion of random to directed migration was seen neither when Fn was supplemented with alternative polysaccharides nor when beta-glucan was applied to other components of the extracellular matrix. This effect of beta-glucan was shown to be cation dependent and to be effected by Arg-Gly-Asp-containing peptides consistent with an integrin-mediated event. mAb inhibition studies demonstrate that beta-glucan effects this shift toward directed migration through suppression of migration mediated by Mac-1 and very late Ag 5 and enhancement of very late Ag 3-mediated migration. Adhesion assays suggest that the prochemotactic influence of beta-glucan is due, in part but not entirely, to modulation of PMN adhesion to Fn. In summary, these data support a novel role for beta-glucan in regulation of beta 1- and beta 2-mediated neutrophil migration on Fn.