Long-term exposure to belatacept in recipients of extended criteria donor kidneys

Belatacept for kidney transplant recipients

BACKGROUND

Most people who receive a kidney transplant die from either cardiovascular disease or cancer before their transplant fails. The most common reason for someone with a kidney transplant to lose the function of their transplanted kidney necessitating return to dialysis is chronic kidney transplant scarring. Immunosuppressant drugs have side effects that increase risks of cardiovascular disease, cancer and chronic kidney transplant scarring. Belatacept may provide sufficient immunosuppression while avoiding unwanted side effects of other immunosuppressant drugs. However, high rates of post-transplant lymphoproliferative disease (PTLD) have been reported when belatacept is used in particular kidney transplant recipients at high dosage.

OBJECTIVES

1) Compare the relative efficacy of belatacept versus any other primary immunosuppression regimen for preventing acute rejection, maintaining kidney transplant function, and preventing death. 2) Compare the incidence of several adverse events: PTLD; other malignancies; chronic transplant kidney scarring (IF/TA); infections; change in blood pressure, lipid and blood sugar control. 3) Assess any variation in effects by study, intervention and recipient characteristics, including: differences in pre-transplant Epstein Barr virus serostatus; belatacept dosage; and donor-category (living, standard criteria deceased, or extended criteria deceased).

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 1 September 2014 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCT) that compared belatacept versus any other immunosuppression regimen in kidney transplant recipients were eligible for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data for study quality and transplant outcomes and synthesized results using random effects meta-analysis, expressed as risk ratios (RR) and mean differences (MD), both with 95% confidence intervals (CI).  Subgroup analyses and univariate meta-regression were used to investigate potential heterogeneity.

MAIN RESULTS

We included five studies that compared belatacept and calcineurin inhibitors (CNI) that reported data from a total of 1535 kidney transplant recipients. Of the five studies, three (478 participants) compared belatacept and cyclosporin and two (43 recipients) compared belatacept and tacrolimus. Co-interventions included basiliximab (4 studies, 1434 recipients); anti-thymocyte globulin (1 study, 89 recipients); alemtuzumab (1 study, 12 recipients); mycophenolate mofetil (MMF, 5 studies, 1509 recipients); sirolimus (1 study, 26 recipients) and prednisone (5 studies, 1535 recipients).Up to three years following transplant, belatacept and CNI-treated recipients were at similar risk of dying (4 studies, 1516 recipients: RR 0.75, 95% CI 0.39 to 1.44), losing their kidney transplant and returning to dialysis (4 studies, 1516 recipients: RR 0.91, 95% CI 0.61 to 1.38), and having an episode of acute rejection (4 studies, 1516 recipients: RR 1.56, 95% CI 0.85 to 2.86). Belatacept-treated kidney transplant recipients were 28% less likely to have chronic kidney scarring (3 studies, 1360 recipients: RR 0.72, 95% CI 0.55 to 0.94) and also had better graft function (measured glomerular filtration rate (GFR) (3 studies 1083 recipients): 10.89 mL/min/1.73 m², 95% CI 4.01 to 17.77; estimated GFR (4 studies, 1083 recipients): MD 9.96 mL/min/1.73 m², 95% CI 3.28 to 16.64) than CNI-treated recipients. Blood pressure was lower (systolic (2 studies, 658 recipients): MD -7.51 mm Hg, 95% CI -10.57 to -4.46; diastolic (2 studies, 658 recipients): MD -3.07 mm Hg, 95% CI -4.83 to -1.31, lipid profile was better (non-HDL (3 studies 1101 recipients): MD -12.25 mg/dL, 95% CI -17.93 to -6.57; triglycerides (3 studies 1101 recipients): MD -24.09 mg/dL, 95% CI -44.55 to -3.64), and incidence of new-onset diabetes after transplant was reduced by 39% (4 studies (1049 recipients): RR 0.61, 95% CI 0.40 to 0.93) among belatacept-treated versus CNI-treated recipients.Risk of PTLD was similar in belatacept and CNI-treated recipients (4 studies, 1516 recipients: RR 2.79, 95% CI 0.61 to 12.66) and was no different among recipients who received different belatacept dosages (high versus low dosage: ratio of risk ratios (RRR) 1.06, 95% CI 0.11 to 9.80, test of difference = 0.96) or among those who were Epstein Barr virus seronegative compared with those who were seropositive before their kidney transplant (seronegative versus seropositive; RRR 1.49, 95% CI 0.15 to 14.76, test for difference = 0.73).The belatacept dose used (high versus low), type of donor kidney the recipient received (extended versus standard criteria) and whether the kidney transplant recipient received tacrolimus or cyclosporin made no difference to kidney transplant survival, incidence of acute rejection or estimated GFR. Selective outcome reporting meant that data for some key subgroup comparisons were sparse and that estimates of the effect of treatment in these groups of recipients remain imprecise.

AUTHORS' CONCLUSIONS

There is no evidence of any difference in the effectiveness of belatacept and CNI in preventing acute rejection, graft loss and death, but treatment with belatacept is associated with less chronic kidney scarring and better kidney transplant function. Treatment with belatacept is also associated with better blood pressure and lipid profile and a lower incidence of diabetes versus treatment with a CNI. Important side effects (particularly PTLD) remain poorly reported and so the relative benefits and harms of using belatacept remain unclear. Whether short-term advantages of treatment with belatacept are maintained over the medium- to long-term or translate into better cardiovascular outcomes or longer kidney transplant survival with function remains unclear. Longer-term, fully reported and published studies comparing belatacept versus tacrolimus are needed to help clinicians decide which patients might benefit most from using belatacept.

Conversion from calcineurin inhibitor-based immunosuppression to mammalian target of rapamycin inhibitors or belatacept in renal transplant recipients

The calcineurin inhibitors (CNIs) remain the standard of care for maintenance immunosuppression following renal transplantation. CNIs have demonstrated their effectiveness in reducing acute cellular rejection; however, some evidence suggests that these compounds negatively affect native renal function and are associated with allograft injury in renal transplant recipients. CNIs have also been linked with hypertension, new-onset diabetes after transplantation, tremor, and thrombotic microangiopathy, which have significant consequences for long-term allograft function and patient health overall. Thus, converting patients to a non-CNI-based regimen may improve renal function and also provide extrarenal benefits. A number of studies have been conducted that explore CNI conversion strategies in renal transplant recipients in an effort to improve long-term allograft function and survival. These include converting to alternative, non-nephrotoxic, maintenance immunosuppressants, such as the mammalian target of rapamycin inhibitors (sirolimus and everolimus) and the costimulation blocker belatacept. In this review of literature, evidence for the potential renal and extrarenal benefits of conversion to these non-CNI-based regimens is evaluated. Clinical challenges, including the adverse event profiles of non-CNI-based regimens and the selection of candidates for conversion, are also examined.

A network meta-analysis of the efficacy of belatacept, cyclosporine and tacrolimus for immunosuppression therapy in adult renal transplant recipients

Belatacept is a first in-class co-stimulation blocker developed for primary maintenance immunosuppression following renal transplantation. The objective of this study was to estimate the efficacy of belatacept relative to tacrolimus and cyclosporine among adults receiving a single kidney transplant. A systematic review was conducted of randomized clinical trials (RCTs) published between January 1990 and December 2013 using EMBASE, MEDLINE, the Cochrane Central Register of Controlled Trials, and unpublished study reports from two belatacept RCTs. Bayesian network meta-analysis (NMA) methods were used to compare the efficacy measures, mortality, graft loss, acute rejection and glomerular filtration rate (GFR). Heterogeneity was quantified using statistical metrics and potential sources were evaluated using meta-regression and subgroup analysis. A total of 28 RCTs comparing tacrolimus with cyclosporine, and three comparing belatacept with cyclosporine, were identified. All three agents provided comparable graft and patient survival, despite a higher risk of acute rejection associated with belatacept and cyclosporine. Belatacept was associated with significant improvement in GFR versus cyclosporine. Compared with tacrolimus, this difference was clinically meaningful yet statistically non-significant. The probability of being the best treatment was highest for belatacept for graft survival (68%), patient survival (97%) and renal function (89%), and highest for tacrolimus for acute rejection (99%).Variability in donor, recipient, and trial characteristics was present in the included RCTs; however, minimal statistical heterogeneity was detected in the analysis of acute rejection, graft or patient survival, and none of the characteristics were found to be significantly associated with relative effect. Although the direction of effect of immunosuppressants on GFR was consistent across RCTs, precise estimation of its magnitude was limited by a small number of RCTs and heterogeneity in relative effect sizes. Clinicians often seek an alternative to CNIs due to their nephrotoxic effects. The results of this indirect comparison indicate that belatacept is an effective immunosuppressive agent in renal transplantation among adults.

Beneficial effect of conversion to belatacept in kidney-transplant patients with a low glomerular-filtration rate

Belatacept has been found to be efficient at preserving good kidney function in maintenance kidney-transplant patients. Herein, we report on the use of belatacept as a rescue therapy for two kidney-transplant patients presenting with severe adverse events after treatment with calcineurin inhibitors (CNIs) and mammalian target-of-rapamycin (mTOR) inhibitors. Two kidney-transplant patients developed severely impaired kidney function after receiving CNIs. The use of everolimus was associated with severe angioedema. Belatacept was then successfully used to improve kidney function in both cases, even though estimated glomerular-filtration rate before conversion was <20 mL/min. These case reports show that belatacept can be used as a rescue therapy, even if kidney function is very low in kidney-transplant patients who cannot tolerate CNIs and/or mTOR inhibitors.