Conversion to everolimus in kidney transplant recipients with decreased renal function

Calcineurin inhibitor sparing strategies in renal transplantation, part one: Late sparing strategies

Kidney transplantation improves quality of life and reduces the risk of mortality. A majority of the success of kidney transplantation is attributable to the calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, and their ability to reduce acute rejection rates. However, long-term graft survival rates have not improved over time, and although controversial, evidence does suggest a role of chronic CNI toxicity in this failure to improve outcomes. Consequently, there is interest in reducing or removing CNIs from immunosuppressive regimens in an attempt to improve outcomes. Several strategies exist to spare calcineurin inhibitors, including use of agents such as mycophenolate mofetil (MMF), mycophenolate sodium (MPS), sirolimus, everolimus or belatacept to facilitate late calcineurin inhibitor withdrawal, beyond 6 mo post-transplant; or using these agents to plan early withdrawal within 6 mo; or to avoid the CNIs all together using CNI-free regimens. Although numerous reviews have been written on this topic, practice varies significantly between centers. This review organizes the data based on patient characteristics (i.e., the baseline immunosuppressive regimen) as a means to aid the practicing clinician in caring for their patients, by matching up their situation with the relevant literature. The current review, the first in a series of two, examines the potential of immunosuppressive agents to facilitate late CNI withdrawal beyond 6 mo post-transplant, and has demonstrated that the strongest evidence resides with MMF/MPS. MMF or MPS can be successfully introduced/maintained to facilitate late CNI withdrawal and improve renal function in the setting of graft deterioration, albeit with an increased risk of acute rejection and infection. Additional benefits may include improved blood pressure, lipid profile and serum glucose. Sirolimus has less data directly comparing CNI withdrawal to an active CNI-containing regimen, but modest improvement in short-term renal function is possible, with an increased risk of proteinuria, especially in the setting of baseline renal dysfunction and/or proteinuria. Renal outcomes may be improved when sirolimus is used in combination with MMF. Although data with everolimus is less robust, results appear similar to those observed with sirolimus.

Cyclosporine versus everolimus: effects on the glomerulus

Inhibitors of the mammalian target of rapamycin (mTOR) have been associated with proteinuria. We studied the development of proteinuria in renal transplant recipients (RTR) treated with the mTOR inhibitor everolimus in comparison with a calcineurin inhibitor. We related the presence of proteinuria to histopathological glomerular findings in two-yr protocol biopsies. In a single-center study, nested in a multicenter randomized controlled trial, we determined eGFR, proteinuria, and renal biopsy data (light- and electron microscopy) of RTR receiving prednisolone/everolimus (P/EVL) (n = 16) in comparison with patients treated with prednisolone/cyclosporine A (P/CsA) (n = 7). All patients had been on the above-described maintenance immunosuppression for 18 months. Renal function at two yr after transplantation did not differ between patients receiving P/EVL or P/CsA (eGFR 45.5 vs. 45.7 mL/min/1.73 m(2)). Proteinuria was slightly increased in P/EVL vs. P/CsA group (0.29 vs. 0.14 g/24 h, p = 0.06). There were no differences in light- or electron microscopic findings. We could not demonstrate increased podocyte effacement or changes in glomerular basement membrane (GBM) thickness in P/EVL-treated patients. In conclusion, long-term treatment with everolimus leaves the GBM and podocytes unaffected.

Maintenance immunosuppression in renal transplantation

The need to maintain allograft recipients on immunosuppression is nearly universal. Immunosuppressive agents used in organ transplantation target one or more steps of the host alloimmune response, specifically processes related to CD4-positive T lymphocytes. Calcineurin-inhibitor based steroid-containing regimens have been the mainstay of maintenance immunosuppression over the last two decades. Newer agents have shown efficacy in this role in recent trials with comparable allograft and patient outcomes. These agents have permitted calcineurin-inhibitor minimization and steroid-sparing strategies in selected groups of patients.

Conversion to everolimus in kidney transplant recipients: to believe or not believe?

INTRODUCTION

Immunosuppression with calcineurin inhibitors (CNI) in renal transplantation is associated with chronic graft dysfunction, increased cardiovascular risk, and malignancies. Everolimus (EVR) appears to permit a CNI-sparing regimen among stable kidney recipients.

AIM

The aim of this study was to analyze the efficacy and safety of conversion from CNI to EVR.

MATERIAL AND METHODS

This was a retrospective registry-based study of all kidney transplant recipients converted from CNI to EVR between 2006 and 2010. One hundred fifty-one patients, including 69.5% males and with an overall mean age of 50.2 ± 12.7 years, underwent conversion to EVR at 37.0 ± 49.8 (16) months after transplantation with 33.7% during the first 6 months. Reasons for conversion included: CNI nephrotoxicity prevention (54.3%), chronic graft dysfunction (25.8%), malignant tumors (10.6%), CNI-adverse reactions (6.6%), and biopsy-proven CNI nephrotoxicity (2.6%). During a follow-up of 17.9 ± 9.9 months (range, 6-58.5), 18 patients (11.9%) were reconverted to CNI, 2 died with functioning grafts, and 2 lost kidney function.

RESULTS

We observed a significant (P < .001) increase in estimated glomerular filtration rate-Modification of Diet in Renal Disease (eGFR-MDRD) by 11.3% within 6 months: 56.7 ± 22.1 to 64.1 ± 23.4 mL/min/1.73 m(2). At final evaluation it was 13.7%, namely, to 65.5 ± 23.0 mL/min/1.73 m(2). At the end of follow-up the proportion of patients with >300 mg/d proteinuria increased from 7.9% to 23.3% (P = .001). Dyslipidemia prevalence increased from 69.5% to 77.5% (P = not significant [NS]) and arterial hypertension increased from 49% to 65.9% (P < .001) at the end of follow-up. Other reported side effects included oral ulcers (2.6%), edema (5.3%), interstitial pneumonitis (1.3%), and toxic hepatitis (1.3%), some of them leading to EVR discontinuation.

CONCLUSION

In our population, renal function improved significantly after conversion from CNI to EVR. Although side effects were common, most were mild, withdrawal of EVR was necessary in a low percentage of cases. EVR appears to be an effective, safe alternative to CNI for maintenance therapy in selected kidney transplant recipients.

Early treatment with everolimus exerts nephroprotective effect in rats with adriamycin-induced nephrotic syndrome

BACKGROUND

Nephrotic syndrome (NS) is a clinical state characterized by massive proteinuria and excessive fluid retention. The effects of early versus late treatment with low or high doses of oral everolimus, a mammalian target of rapamycin inhibitor, on proteinuria in NS have not been previously described.

METHODS

The effects of early treatment (2 days prior to NS induction) versus late treatment (beginning 2 weeks following the establishment of NS) with a low (20 mg/L) or high (100 mg/L) dose of everolimus for 5-7 weeks on proteinuria and nephrin/podocin abundance were assessed in male adult SD rats with adriamycin-induced NS.

RESULTS

Adriamycin caused a significant increase in daily and cumulative proteinuria throughout the experimental period. Early, and to a lesser extent late treatment, with a low dose of everolimus, significantly decreased both daily and cumulative proteinuria and improved renal function. The anti-proteinuric effects of low-dose everolimus were associated with restoration of the disruptive glomerular nephrin/podocin abundance. In contrast, administration of a high dose of everolimus resulted in a decrease in proteinuria in NS rats, subsequently to deterioration of renal function.

CONCLUSIONS

Early, and to a lesser extent late treatment, with a low but not a high dose of everolimus is effective in reducing proteinuria in nephrotic rats. The mechanism may be via nephrin/podocin protection.

Conversion of long-term kidney transplant recipients from calcineurin inhibitor therapy to everolimus: a randomized, multicenter, 24-month study

BACKGROUND

Benefits of conversion from calcineurin inhibitor (CNI) to mammalian target of rapamycin inhibitor-based immunosuppression in long-term kidney transplant patients remain uncertain.

METHODS

ASCERTAIN was a 24-month, open-label, multicenter study. Kidney transplant patients more than 6 months posttransplant receiving CNI (baseline glomerular filtration rate [GFR] 30-70 mL/min/1.73 m) were randomized to everolimus with CNI elimination (n=127) or CNI minimization (n=144), or continued CNI unchanged (controls, n=123) to assess the effect on measured GFR at month 24 after randomization.

RESULTS

Renal function was stable in all groups to month 24. Mean measured GFR at month 24, the primary endpoint, was 48.0±22.0 mL/min/1.73 m, 46.6±21.1 mL/min/1.73 m, and 46.0±20.4 mL/min/1.73 m in the CNI elimination, CNI minimization, and control groups, respectively. Differences between CNI elimination (1.12 mL/min/1.73 m, 95% confidence interval [CI] -3.51 to 5.76, P=0.63) and CNI minimization (0.59 mL/min/1.73 m, 95% CI -3.88 to 5.07, P=0.79) versus controls at month 24 were nonsignificant that is, the primary endpoint was not met. No efficacy endpoint differed significantly between groups. Post hoc analyses showed that patients with baseline creatinine clearance (CrCl) more than 50 mL/min had a significantly greater increase in measured GFR after CNI elimination versus controls (difference 11.4 mL/min/1.73 m, 95% CI 2.1 to 20.8 mL/min/1.73 m, P=0.017). Adverse events resulted in discontinuation in 36 (28.3%) CNI elimination patients, 24 (16.7%) CNI minimization patients, and 5 (4.1%) controls (P<0.001 vs. CNI elimination; P=0.020 vs. CNI minimization).

CONCLUSION

Conversion to everolimus with CNI elimination or minimization a mean of 5.6 years after kidney transplantation had no overall renal benefit and was associated with more frequent adverse events and discontinuations. Patients with CrCl more than 50 mL/min may benefit from a change in therapy more than 6 months after renal transplantation.