Long-term impact of discontinued or reduced calcineurin inhibitor in patients with chronic allograft nephropathy

Phenotype of immunosuppression reduction after kidney transplantation

BACKGROUND

Immunosuppressive regimens are delivered without direct measure of the net state of immunosuppression. Besides therapeutic drug monitoring, adjustments in immunosuppressive medications are largely event-driven.

METHODS

We studied the clinical phenotype of immunosuppression reduction (ISR) among kidney transplant recipients from 2005 to 2012. Patients were grouped into: no ISR, ISR for infection, or ISR for intolerance. Outcome measures were rejection, rejection-free survival, and IFTA-free survival.

RESULTS

1114 adult kidney transplant recipients were included: 57% had no ISR, 16% had ISR for infection, and 27% had ISR for intolerance. ISR for infection was mainly on MMF, while ISR for intolerance was mainly on FK. ISR was associated with higher rates of acute rejection. The Kaplan-Meier analysis showed increased prevalence of rejection among patients with ISR due to infection (P = .003) or intolerance (P = .05). The risk of interstitial fibrosis and tubular atrophy was increased in patients with ISR due to infection (P = .001) or intolerance (P = .018).

CONCLUSION

Immunosuppression reduction is associated with increased prevalence of rejection. The clinical phenotype of ISR is dominated by IFTA remote from the onset of ISR. Solely focusing on acute rejection may underestimate effects of ISR on long-term graft function and survival.

Peritoneal Dialysis in the Patient with a Failing Renal Allograft

Background

Patients returning to dialysis treatment after a period with a functioning allograft represent a special case in the integrated care model of renal replacement therapy. They are known to nephrologists— and thus are ideal candidates for a timely commencement of dialysis—but they have had time to accrue additional cardiovascular risk. Furthermore, they have been exposed to prolonged immunosuppression.

Purpose

The present study aimed to establish the clinical outcomes of patients returning to peritoneal dialysis (PD) with failing allografts [survival, technique survival, longitudinal residual renal function (Kt/VR), peritoneal membrane function (solute transport), and plasma albumin] and to compare those outcomes with outcomes in new, contemporary patients.

Setting

The study was conducted in a single center where prospective collection of data now known to be important in determining outcome on peritoneal dialysis (age, comorbidity, albumin, Kt/VR, and solute transport) has been performed since 1989.

Methods

All patients commencing PD between 1989 and 2001 after failure of an allograft that had functioned for more than 6 months were identified. Outcomes in that group were compared to outcomes in all new PD patients and in all dialysis patients with failed grafts who were returning to hemodialysis (HD) in the same period.

Results

The study identified 45 patients with failed allografts: 28 were commencing PD treatment, and 17 were commencing HD treatment. Those patients were significantly younger than the 469 new patients commencing PD [FailedTx→ PD 41.2 years, FailedTx→ HD 38.9 years, NewPD 54.7 years; analysis of variance (ANOVA): p < 0.001]. We saw no significant difference in the survival of failed transplant patients commencing PD as compared with those commencing HD (log rank: p = 0.11). Kaplan–Meier plots of patient survival were better for failed transplant patients as compared with all new PD patients. When corrected using Cox regression, the survival advantage was seen to be due to age and comorbidity at start of PD. Pure technique failure (excluding death) was not different between the groups. Compared with all new PD patients, patients with failed allografts had similar longitudinal plasma albumin and a tendency toward an earlier increase in solute transport, but a more rapid loss of Kt/VR, ( p < 0.05 at 6 – 48 months).

Conclusions

Peritoneal dialysis would appear to be a good option for patients with failing allografts. Co-morbidity is the predominant determinant of survival. That finding underlines the need for attention to factors that might prevent accrual of cardiovascular risk during the post-transplantation period. The earlier loss of Kt/VR in those patients might be prevented by developing strategies of continued immunosuppression after commencement of dialysis, although infection risk is an important issue.

Reduced Tacrolimus Trough Level Is Reflected by Estimated Glomerular Filtration Rate (eGFR) Changes in Stable Renal Transplantation Recipients: Results of the OPTIMUM Phase 3 Randomized Controlled Study

Background

Minimizing the tacrolimus dosage in patients with stable allograft function needs further investigation.

Material/Methods

We performed an open-label, randomized, controlled study from 2010 to 2016 in 7 tertiary teaching hospitals in Korea and enrolled 345 kidney transplant recipients with a stable graft status. The study group received reduced-dose tacrolimus, 1080–1440 mg/day of enteric-coated mycophenolate sodium (EC-MPS), and corticosteroids. The control group received the standard tacrolimus dosage and 540–720 mg/day of EC-MPS with steroids. The primary endpoint was the mean estimated glomerular filtration rate (eGFR) and change in the eGFR at 12 months after randomization.

Results

The mean tacrolimus trough level of the study group was 4.51±1.62 ng/mL, which was lower than that of the control group, at 6.75±2.82 ng/mL (P<0.001). The primary endpoint was better in the study group in terms of change in eGFR (P<0.001). The month 12 eGFRs were 73.6±28.4 and 68.3±18.1 mL/min/1.73 m² in the study and the control groups, respectively, but the difference did not reach statistical significance (P=0.07). The incidence of adverse events was similar between the study and the control groups.

Conclusions

Minimizing tacrolimus to a trough level below 5 ng/mL combined with conventional EC-MPS can be considered in patients with a steady follow-up, as it was associated with small benefits in the changes of the eGFR (Clinicaltrials.gov number: NCT01159080).

Graft outcomes following immunosuppressive therapy with different combinations in kidney transplant recipients: a nationwide cohort study

Background

Immunosuppression plays an essential role to overcome immune-related allograft rejection, but it also causes some nephrotoxicity. This study aimed to investigate how the immunosuppressant combinations affect graft outcomes in kidney transplant recipients.

Methods

A nationwide population-based cohort study using the Taiwan National Health Insurance Database was conducted. A total of 3,441 kidney transplant recipients who underwent kidney transplantation during the targeted period were included. The effects on graft outcomes contributed by conventional immunosuppressants, including corticosteroid, calcineurin inhibitors, antimetabolite purine antagonists, and mammalian target of rapamycin inhibitors, were compared.

Results

A total of 423 graft failures developed after the index date. Therapy regimens incorporated with purine antagonists had a comparable reduction of graft failure among four main drug groups regardless of whether they were given as monotherapy or in combination (adjusted hazard ratio: 0.52, 95% confidence interval: 0.42–0.63). Corticosteroid was found to have inferior effects among four groups (adjusted hazard ratio: 1.67, 95% confidence interval: 1.28–2.21). Furthermore, all 15 arrangements of mutually exclusive treatment combinations were analyzed by referencing with corticosteroid monotherapy. As referenced with steroid-based treatment, regimens incorporated with purine antagonists all have superior advantage on graft survival regardless of whether given in monotherapy (65% of graft failure reduced), dual therapy (48%–67% reduced), or quadruple therapy (43% reduced). In all triple therapies, only corticosteroid combined with calcineurin inhibitor and purine antagonist demonstrated superior protection on graft survival (52% of graft failure reduced).

Conclusion

The results may recommend several superior regimens for contributing to graft survival, and for supporting a steroid-minimizing strategy in immunosuppression maintenance.

Early Kidney Allograft Dysfunction (Threatened Allograft): Comparative Effectiveness of Continuing Versus Discontinuation of Tacrolimus and Use of Sirolimus to Prevent Graft Failure: A Retrospective Patient-Centered Outcome Study

Supplemental digital content is available in the text.

Background

Due to lack of treatment options for early acute allograft dysfunction in the presence of tubular-interstitial injury without histological features of rejection, kidney transplant recipients are often treated with sirolimus-based therapy to prevent cumulative calcineurin inhibitor exposure and to prevent premature graft failure.

Methods

We analyzed transplant recipients treated with sirolimus-based (n = 220) compared with continued tacrolimus-based (n = 276) immunosuppression in recipients of early-onset graft dysfunction (threatened allograft) with the use of propensity score-based inverse probability treatment weighted models to balance for potential confounding by indication between 2 nonrandomized groups.

Results

Weighted odds for death-censored graft failure (odds ratio [OR], 1.20; 95% confidence interval [95% CI], 0.66-2.19, P = 0.555) was similar in the 2 groups, but a trend for increased risk of greater than 50% loss in estimated glomerular filtration rate from baseline in sirolimus group (OR, 1.90; 95% CI, 0.96-3.76; P = 0.067) compared with tacrolimus group. Sirloimus group compared with tacrolimus group had increased risk for death with functioning graft (OR, 2.01; 95% CI, 1.29-3.14; P = 0.002) as well as increased risk of late death (death after graft failure while on dialysis) (OR, 2.39; 95% CI, 1.59-3.59; P < 0.001). Analysis of subgroups based on the absence or presence of T cell–mediated rejection or tubulointerstitial inflammation in the index biopsy, or the use of different types of induction agents, and all subgroups had increased risk of death with functioning graft and late death if exposed to sirolimus-based therapy.

Conclusions

Use of sirolimus compared with tacrolimus in recipients with early allograft dysfunction during the first year of transplant may not prevent worsening of allograft function and could potentially lead to poor survival along with increased risk of late death.

Chronic Allograft Nephropathy: Pathogenesis and Management of an Important Posttransplant Complication

Chronic allograft nephropathy is a devastating complication of kidney transplantation that is responsible for a significant proportion of graft loss. This complication is characterized by a progressive decline in kidney function, which is not attributable to a specific cause. Many risk factors exist for the development of chronic allograft nephropathy, including donor-, recipient-, and transplant-related factors (eg, use of calcineurin inhibitors and acute rejection episodes), as well as comorbid conditions such as hypertension and hyperlipidemia. There is no definitive treatment for this complication; management has focused on minimization or withdrawal of calcineurin inhibitors in conjunction with addition of sirolimus or mycophenolate mofetil. Alterations in the immunosuppressive regimen must be done cautiously, as precipitating acute rejection will cause further damage to the allograft. Optimal control of blood pressure, particularly with the use of agents such as angiotensin II receptor blockers, in conjunction with management of dyslipidemia may be effective concurrent therapies in patients with chronic allograft nephropathy.

Safety and efficacy of the early introduction of everolimus with reduced-exposure cyclosporine a in de novo kidney recipients

BACKGROUND

Everolimus and cyclosporine A (CsA) exhibit synergistic immunosuppressive activity when used in combination. We examined the safety and efficacy of the use of everolimus with a cyclosporine-sparing strategy in de novo renal transplant recipients.

METHODS

A comparative, parallel, randomized, open-label 1-year study has been performed in 148 patients from five transplant centers to compare the efficacy and tolerability of everolimus and reduced exposure CsA (the investigational group) or enteric-coated mycophenolate sodium and standard-exposure CsA (the control group) in combination with basiliximab and steroids. The eligible subjects were randomly assigned at 1 month after transplantation. Efficacy failure (biopsy-proven acute rejection, death, graft loss, or loss to follow-up), safety, and renal function were evaluated.

RESULTS

One graft loss has been reported in the control group and no patient death were reported in either group. The incidence of biopsy-proven acute rejection until 12 months after transplantation of the investigational group was 7.5%, compared to 11.1% of the control group (P=0.565). The mean estimated glomerular filtration rates of the investigational group at 12 months after transplantation was significantly higher (68.1 ± 16.8 ml/min/1.73 m(2)) than that of the control group (60.6 ± 15.8 ml/min/1.73 m(2); P=0.016). There was no significant difference (P>0.05) in the incidence of discontinuations and serious adverse events between the groups.

CONCLUSION

The results of this study provide the evidences that (1) the calcineurin inhibitor (CNI) minimization by the introduction of everolimus after 1-month posttransplantation keeps the incidences of acute rejection and additional risks as low as the conventional immunosuppression; (2) it allows minimizing CNI exposure, consequently reducing CNI nephrotoxicity and preserving renal function.

Calcineurin inhibitor-sparing regimens based on mycophenolic acid after kidney transplantation

The use of calcineurin inhibitors (CNIs) has dramatically reduced the number of acute rejections and improved kidney allograft survival. However, CNIs can also cause kidney damage and several adverse events. This has prompted transplant physicians to use CNI-sparing regimens. CNI withdrawal, minimization, or avoidance protocols have been conducted using mycophenolic acid (MPA), and/or mammalian-target-of-rapamycin inhibitors, and/or belatacept. Herein, we review the outcomes of minimizing, withdrawing, or avoiding CNIs when giving mycophenolic acid to de novo and maintenance kidney transplant patients. Protocols on CNI withdrawal, when based on MPA without mammalian-target-of-rapamycin inhibitors (mTORi) or belatacept, in de novo and maintenance kidney transplant patients, are associated with an increased risk of acute rejection. Consequently, these strategies have been abandoned and are not recommended. Protocols on CNI minimization show a beneficial impact of kidney function and acceptable acute rejection rates mainly in patients who have been recipients of a graft for >3-5 years. However, no significant improvement to graft survival has been observed.

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.

Mechanisms and rescue strategies of calcineurin inhibitor mediated tolerance abrogation induced by anti-CD4 mAb treatment

To ensure safety tolerance induction protocols are accompanied by conventional immunosuppressive drugs (IS). But IS such as calcineurin inhibitors (CNI), for example, cyclosporin A (CsA), can interfere with tolerance induction. We investigated the effect of an additional transient CsA treatment on anti-CD4mAb-induced tolerance induction upon rat kidney transplantation. Additional CsA treatment induced deteriorated graft function, resulting in chronic rejection characterized by glomerulosclerosis, interstitial fibrosis, tubular atrophy and vascular changes. Microarray analysis revealed enhanced intragraft expression of the B cell attracting chemokine CXCL13 early during CsA treatment. Increase in CXCL13 expression is accompanied by enhanced B cell infiltration with local and systemic IgG production and C3d deposition as early as 5 days upon CsA withdrawal. Adding different CNIs to cultures of primary mesangial cells isolated from glomeruli resulted in a concentration-dependent increase in CXCL13 transcription. CsA in synergy with TNF-α can enhance the B cell attracting and activating potential of mesangial cells. Transient B cell depletion or transfer of splenocytes from tolerant recipients 3 weeks after transplantation could rescue tolerance induction and did inhibit intragraft B cell accumulation, alloantibody production and ameliorate chronic rejection.

Steroid withdrawal and reduction of cyclosporine A under mycophenolate mofetil after heart transplantation

Survival and quality of life after heart transplantation are limited by a significant incidence of cardiovascular complications. Side effects of immunosuppressives contribute unfavorably. Aim of this study was to determine (1) whether withdrawal of corticosteroids and dose reduction of cyclosporine A can be performed safely under immunosuppressive therapy with mycophenolate mofetil and (2) if this is beneficial for renal function and cardiovascular risk reduction. Long term heart transplant recipients on steroids and cyclosporine A were examined in a monocentric, prospective, single-arm cohort study. Steroids were withdrawn, mycophenolate mofetil introduced and cyclosporine A dose reduced (target level 50-90 ng/ml). Follow up was 24 months. 23 patients were analyzed: Renal parameters (creatinine, urea, uric acid) improved significantly (p<0.01), as did cardiovascular parameters (heart rate [p<0.05], systolic and diastolic blood pressure [p<0.01]), HbA1c (p<0.05) and triglycerides (p<0.05). In contrast, the self-percepted state of health (SF36™) decreased. Drop outs occurred mostly due to steroid withdrawal syndrome [n=7]. The incidence of adverse events reflected the usual course after heart transplantation. We conclude that CS free immunosuppression comprising reduced cyclosporine levels and addition of MMF in long term heart transplant recipients is safe and improves the cardiovascular risk profile, carbohydrate metabolism and renal function.

Long-term outcomes after cyclosporine or mycophenolate withdrawal in kidney transplantation - results from an aborted trial

Long-term triple immunosuppressive therapy with cyclosporine (CsA), mycophenolate mofetil (MMF) and prednisolone may be excessively powerful for many transplant recipients. We compared withdrawal of either MMF or CsA in stable kidney transplants on triple immunosuppression. The study was a prospective, randomized, controlled 12-months trial in stable kidney transplants. The patients who withdrew CsA were given MMF 2 g/d, and CsA troughs were between 75 and 125 ng/mL in MMF withdrawal. Planned inclusion was 298 patients. The study was prematurely aborted after inclusion of 39 patients. Acute rejection rates were 6/20 (30%) in the MMF group compared with 0/19 (0%) in the CsA group (p = 0.02). Time to acute rejections was 4.0-28.7 months after withdrawal. Trough concentrations of mycophenolic acid (MPA) and CsA showed therapeutic levels. The subjects have been observed for eight yr, and of the 28 patients remaining on randomized therapy, the MMF patients preserved graft function better than CsA patients. Death-censored graft survival was 75% and 95% (p = 0.18) and patient survival was 70% and 68% (p = 0.99) in the MMF and CsA groups, respectively, at the end of long-term follow-up. CsA withdrawal was associated with a high rate of acute rejections. Initially, the treatment of acute rejections was successful. However, five of six lost their grafts in the long term.

Reduced-dose cyclosporine with mycophenolate mofetil and prednisone significantly improves the long-term glomerular filtration rate and graft survival

OBJECTIVE

It remains debated whether reduced doses of chronic calcineurin inhibitors benefit graft survival.

METHODS

This retrospective study analyzed 60 first cadaveric renal transplant recipients who received cyclosporine (CSA), mycophenolate mofetil (MMF) and prednisone (CMP group) and 71 recipients who received reduced-dose CSA with prednisone and MMF (RCMP group). All recipients were followed for at least 96 months. The Modification of Diet in Renal Disease (MDRD) glomerular filtration rate (GFR) calculated at different time points, graft survival, the incidence of chronic allograft nephropathy (CAN) and the acute rejection rate within six months were analyzed and compared between the two groups.

RESULTS

The incidence of acute rejection within six months post-transplant was 15.5% (11/71) in the RCMP group and 13.3% (8/60) in the CMP group. This difference was not significant (p=0.727). The MDRD-calculated GFR in the CMP group reached a peak at 24 months post-transplant (66.6 ± 20.2 mL/min/1.73 m(2)) then decreased gradually. In contrast, in the RCMP group, the GFR reached a peak at 36 months post-transplant (76.9 ± 19.6 mL/min/1.73 m(2)). The GFR from month 36 to month 96 was significantly higher in the RCMP group than in the CMP group. The Kaplan-Meier calculated death-censored graft survival in the RCMP group was significantly higher than that observed in the CMP group, with an estimated cumulative proportion surviving at 96 months of 95.5% in the RCMP group and 83.5% in the CMP group. The incidence of CAN within 96 months was 5.6% (4/71) in the RCMP group vs. 16.7% (10/60) in the CMP group (p=0.042).

CONCLUSION

An RCMP regimen can significantly improve the long-term GFR level and benefit graft survival.

Effect of mycophenolic acid on cyclosporin A-induced fibronectin expression in rat mesangial cells

This study was undertaken to determine if mycophenolic acid (MPA) inhibits the profibrotic action of cyclosporin A (CsA) and, if so, to determine the molecular mechanisms involved. The effect of MPA treatment on CsA-induced signaling through the transforming growth factor-β (TGF-β)/Smad pathway was evaluated by immunoblot analysis in cultured primary rat mesangial cells. Treatment of cells with 1 µmol/l MPA did not significantly decrease the CsA-induced expression of TGF-β(1), but partially reversed the increases in Smad3 phosphorylation and fibronectin (FBN) production, and increased Smad7 expression. These results suggest that MPA may ameliorate CsA-induced FBN production by modulating the Smad signaling pathway. This study provides evidence that MPA can attenuate CsA-induced renal injury after kidney transplantation.

Permanent CNI treatment for prevention of renal allograft rejection in sensitized hosts can be replaced by regulatory T cells

Recent data suggest that donor-specific memory T cells (T(mem)) are an independent risk factor for rejection and poor graft function in patients and a major challenge for immunosuppression minimizing strategies. Many tolerance induction protocols successfully proven in small animal models e.g. costimulatory blockade, T cell depletion failed in patients. Consequently, there is a need for more predictive transplant models to evaluate novel promising strategies, such as adoptive transfer of regulatory T cells (Treg). We established a clinically more relevant, life-supporting rat kidney transplant model using a high responder (DA to LEW) recipients that received donor-specific CD4(+)/ 8(+) GFP(+) T(mem) before transplantation to achieve similar pre-transplant frequencies of donor-specific T(mem) as seen in many patients. T cell depletion alone induced long-term graft survival in naïve recipients but could not prevent acute rejection in T(mem)(+) rats, like in patients. Only if T cell depletion was combined with permanent CNI-treatment, the intragraft inflammation, and acute/chronic allograft rejection could be controlled long-term. Remarkably, combining 10 days CNI treatment and adoptive transfer of Tregs (day 3) but not Treg alone also induced long-term graft survival and an intragraft tolerance profile (e.g. high TOAG-1) in T(mem)(+) rats. Our model allows evaluation of novel therapies under clinically relevant conditions.

Peritoneal dialysis in transplant recipient patients: outcomes and management

Transplant recipient patients performing dialysis represent a growing population in the integrated model of renal replacement therapy. This includes both patients with kidney allograft loss and non-renal organ transplant recipients requiring dialysis. Although a number of possible advantages of peritoneal dialysis over haemodialysis could hypothetically favour its choice when starting dialysis, peritoneal dialysis penetration is relatively residual in this population. Questions about its safety and adequacy in these patients can explain this fact. The purpose of this review is to address unfounded fears and document evidence that peritoneal dialysis should be considered a viable and safe choice in patients returning to dialysis. Specific issues that still need further investigation are also discussed.

Can the early elimination of calcineurin inhibitors result in clinical benefits?

Ideally, every kidney should serve its owner for his or her remaining life expectancy. Current approaches with immunosuppression have steadily reduced early rejection rates. However, we have not seen a comparable improvement in graft longevity. Reduction of acute rejection rates should improve survival, unless concurrent nephrotoxicity offsets this benefit. An important question is whether selective substitution of other drugs/biologicals for calcineurin inhibitors will permit adequate immunoprophylaxis, yet improve graft longevity.

Renal function outcomes in kidney transplant recipients after conversion to everolimus-based immunosuppression regimen with CNI reduction or elimination

BACKGROUND

Chronic allograft nephropathy (CAN) is a major cause of progressive renal failure in kidney transplant recipients. Its etiology is multifactorial and can be due to immunologic or nonimmunologic conditions including calcineurin inhibitor (CNI) toxicity.

OBJECTIVE

To evaluate the effect of conversion from CNIs to everolimus in kidney transplant recipients with CAN.

PATIENTS AND METHODS

In this 12-month pilot study in renal transplant recipients with biopsy-proved CAN, therapy was changed to an everolimus-based immunosuppression regimen. Cyclosporine or tacrolimus dosage was reduced by 80% (group 1, n = 10) or discontinued (group 2, n = 10). Mycophenolate mofetil or azathioprine were withdrawn in group 1, whereas both agents were maintained in group 2. All patients received prednisone.

RESULTS

Twenty renal allograft recipients switched to an everolimus-based regimen, and patients were followed up for a mean (SD) of 12 (0.1) months. Baseline and end-of-study data were as follows: serum creatinine concentration, 1.27 (0.35) mg/dL vs 1.24 (0.4) mg/dL in group 1, and 1.27 mg/dL (0.36) vs 1.25 (0.3) mg/dL in group 2 (difference not significant); and estimated glomerular filtration rate, 72.4 (19.86) mL/min vs 76.26 (22.69) mL/min in group 1 (not significant), and 66.2 (12.95) mL/min vs 66.2 (13.73) mL/min in group 2 (not significant). One patient in group 1 experienced an acute rejection episode (Banff grade Ib), and 2 patients in group 1 and 1 patient in group 2 demonstrated borderline changes, all associated with everolimus blood concentration less than 3 ng/mL.

CONCLUSIONS

Reduction or withdrawal of CNI and introduction of everolimus may be useful to slow the rate of loss of renal function in patients with CAN.

Optimizing immunosuppression with sirolimus in the first year posttransplantation: experience in the United States

Early and late kidney graft survival has improved considerably due to advances in clinical care, particularly immunosuppression. Many of the kidney transplants functioning today should serve their new owners for their life expectancy. What challenges this viewpoint and the main cause of late kidney function deterioration remains allograft nephropathy. Often this reflects an influence of the immunosuppression. Subclinical rejection, chronic nephrotoxicity, recurrent disease, infections, or diabetes may also contribute to this process. Optimal early and late immunosuppression is required, which provides efficacy without attendent risk for graft dysfunction due to nephrotoxicity. Since 1-year serum creatinine level often provides an indication of long-term graft function, early evaluation of subtle degrees of graft dysfunction should prompt a graft biopsy to identify treatable causes.

A prospective randomized open study in liver transplant recipients: daclizumab, mycophenolate mofetil, and tacrolimus versus tacrolimus and steroids

This open-label, randomized study compared the efficacy of a regimen of corticosteroids and tacrolimus (standard therapy group, n = 79) with a regimen of daclizumab induction therapy in combination with mycophenolate mofetil and tacrolimus (modified therapy group, n = 78) in primary liver transplant recipients. The primary endpoint was biopsy-proven acute rejection (BPAR) at 24 weeks. Secondary endpoints included time to rejection and patient and graft survival. The incidence of BPAR was significantly reduced in the modified therapy group compared to the standard therapy group (11.5% versus 26.6%, respectively, P = 0.017). The time to rejection was significantly shorter in the standard therapy group compared with the modified therapy group (P = 0.044). There was no significant difference between groups in patient or graft survival. Hepatitis C virus-positive patients exhibited no differences from hepatitis C virus-negative patients with respect to the incidence of BPAR. A steroid-sparing regimen of daclizumab, mycophenolate mofetil, and tacrolimus was effective and well tolerated in the prevention of BPAR in adult liver transplant recipients in comparison with a standard regimen of tacrolimus and steroids.

Mycophenolate mofetil and calcineurin-inhibitor reduction: recent progress

Mycophenolate mofetil (MMF) in combination with calcineurin inhibitors (CNIs) has greatly contributed to acute rejection rate reduction. Because of its immunosuppressive potency it was initially thought that MMF would help in reducing/avoiding CNI-related nephrotoxicity. Elective avoidance of CNI in induction and maintenance MMF-based immunosuppression has resulted in an increased risk for acute and chronic rejection. A recent meta-analysis suggests that CNI elimination in patients on MMF with progressive renal dysfunction is associated with a better outcome, although more data are needed to support any recommendation. So far, the more conservative approach involving CNI minimization with MMF has been associated with amelioration of renal function and low risk for rejection, providing an adequate risk/benefit balance. However, MMF with belatacept might pave the way for CNI-free induction and maintenance immunosuppression. Meanwhile, the assessment of immunological risk by new monitoring tools could be a prerequisite to further implement such CNI sparing strategies.

Fate of the mate: the influence of delayed graft function in renal transplantation on the mate recipient

Delayed graft function (DGF) in a deceased-donor renal recipient is associated with allograft dysfunction 1-year posttransplant. There is limited research about the influence to allograft function on the mate of a DGF recipient over time. Using a retrospective cohort design, we studied 55 recipients from a single center. The primary outcome was the change in glomerular filtration rate (GFR) 1-year posttransplant. The secondary outcome was the GFR at baseline. We found that mates to DGF recipients had a mean change in GFR 1-year posttransplant of -11.2 mL/min, while the control group had a mean change of -0.4 mL/min. The difference in the primary outcome was significant (p = 0.025) in a multivariate analysis, adjusting for cold ischemic time, panel reactive antibody level, allograft loss, human leukocyte antibody (HLA)-B mismatches and HLA-DR mismatches. No significant difference between groups was found in baseline GFR. In conclusion, mates to DGF recipients had a significantly larger decline in allograft function 1-year posttransplant compared to controls with similar renal function at baseline. We believe strategies that may preserve allograft function in these'at-risk'recipients should be developed and tested.

Established and newly proposed mechanisms of chronic cyclosporine nephropathy

Cyclosporine (CsA) has improved patient and graft survival rates following solid-organ transplantation and has shown significant clinical benefits in the management of autoimmune diseases. However, the clinical use of CsA is often limited by acute or chronic nephropathy, which remains a major problem. Acute nephropathy depends on the dosage of CsA and appears to be caused by a reduction in renal blood flow related to afferent arteriolar vasoconstriction. However, the mechanisms underlying chronic CsA nephropathy are not completely understood. Activation of the intrarenal renin-angiotensin system (RAS), increased release of endothelin-1, dysregulation of nitric oxide (NO) and NO synthase, up-regulation of transforming growth factor-beta1 (TGF-beta1), inappropriate apoptosis, stimulation of inflammatory mediators, enhanced innate immunity, endoplasmic reticulum stress, and autophagy have all been implicated in the pathogenesis of chronic CsA nephropathy. Reducing the CsA dosage or using other renoprotective drugs (angiotensin II receptor antagonist, mycophenolate mofetil, and statins, etc.) may ameliorate chronic CsA-induced renal injury. This review discusses old and new concepts in CsA nephropathy and preventive strategies for this clinical dilemma.

Mycophenolic acid formulations in adult renal transplantation - update on efficacy and tolerability

The description more than 30 years ago of the role of de novo purine synthesis in T and B lymphocytes clonal proliferation opened the possibility for selective immunosuppression by targeting specific enzymatic pathways. Mycophenolic acid (MPA) blocks the key enzyme inosine monophosphate dehydrogenase and the production of guanosine nucleotides required for DNA synthesis. Two MPA formulations are currently used in clinical transplantation as part of the maintenance immunosuppressive regimen. Mycophenolate mofetil (MMF) was the first MPA agent to be approved for the prevention of acute rejection following renal transplantation, in combination with cyclosporine and steroids. Enteric-coated mycophenolate sodium (EC-MPS) is an alternative MPA formulation available in clinical transplantation. In this review, we will discuss the clinical trials that have evaluated the efficacy and safety of MPA in adult kidney transplantation for the prevention of acute rejection and their use in new combination regimens aiming at minimizing calcineurin inhibitor toxicity and chronic allograft nephropathy. We will also discuss MPA pharmacokinetics and the rationale for therapeutic drug monitoring in optimizing the balance between efficacy and safety in individual patients.

Improved long-term graft function in pediatric transplant renal recipients with chronic allograft nephropathy

CAN is the leading cause of graft loss in pediatric renal transplant recipients. A retrospective single centre analysis of pediatric transplant patients with CAN treated with MMF in conjunction with CNI minimisation/withdrawal is reported. 35 children were successfully started on MMF. The mean age at transplant was 7.9 +/- 0.1 years. MMF was introduced 3.5 +/- 0.1 years after transplantation and patients were followed up for a mean of 32.2 +/- 0.5 months. CAN was confirmed on biopsy in 31 patients. CNI was stopped in 23 patients at a mean time of 16.5 +/- 0.6 months after MMF introduction and minimised in the remaining patients. Prior to MMF introduction, GFR was deteriorating by 21.6 +/- 0.07 ml/min/1.73 m(2)/yr. After MMF, there was an overall improvement in GFR of 4.0 +/- 0.03 ml/min/1.73 m(2)/yr. This was most marked in the first six months when the GFR improved by 20.8 +/- 0.06 ml/min/1.73 m(2)/day. Mean acute rejection episode rate prior to MMF was significantly reduced after MMF introduction. MMF was discontinued in a total of 4 patients due to adverse effects. CNI minimisation/withdrawal with MMF introduction is safe and leads to significant initial improvement with subsequent stabilisation of GFR and improved long term graft survival in pediatric renal transplant recipients with CAN.

Mycophenolate mofetil-based immunosuppressive minimization and withdrawal strategies in renal transplantation: possible risks and benefits

The toxicity of standard triple-therapy immunosuppressive regimens has been identified as a possible factor in the failure to extend long-term renal allograft survival despite a continued decline of acute rejection rates. The result has been increasing focus on the use of mycophenolate mofetil-based, low-toxicity immunosuppressive regimens, which have been shown in randomized studies to have the potential to improve long-term graft survival. This Clinical Update discusses the likely risks and benefits for switching the immunosuppressive regimen in clinical practice.

[Screening biopsies in kidney transplantation: from subclinical acute rejection to chronic allograft lesions]

Kidney biopsies for screening purposes have the advantage of revealing the early appearance of lesions having a poor prognosis before kidney function is altered. Early screening of subclinical rejections allows preventive treatment of kidney transplantation in patients taking cyclosporine or azathioprine, thus improving their renal function and reducing the incidence of chronic histological lesions. However, this benefit has yet to be demonstrated in patients taking tacrolimus or mycophenolic acid. As for interstitial fibrosis lesions and tubular atrophy, biopsies can screen subclinical immunological lesions or those related to nephrotoxicity of anticalcineurins, which have a negative prognostic value in terms of graft survival. In addition, detection of these lesions could be a very useful criterion of efficacy in clinical studies. Moreover, they could help decide on modifying immunosuppressor treatment and evaluate the therapeutic strategies in patients at risk for humoral rejection. Finally, given the cost of biopsies and the inconvenience for the patient, the question of the timing and the number of screening biopsies is crucial. However, interventional studies evaluating notably immunosuppressor treatment modifications based on histological data are necessary to justify the daily use of screening biopsies.

[Immunosuppressive strategies and chronic graft dysfunction in kidney transplantation]

Chronic graft dysfunction is a major cause of return to dialysis. In the majority of cases, it is correlated with histological signs of cellular and/or humoral rejection, the nephrotoxicity of anticalcineurins, or nonspecific lesions of interstitial fibrosis and tubular atrophy. Although the incidence of acute rejection has considerably decreased, renal toxicity of the calcineurin inhibitors remains problematic. In cases of established nephrotoxicity, the use of non-nephrotoxic immunosuppressors such as mycophenolic acid or the proliferation signal inhibitors makes it possible to reduce or even stop the anticalcineurins. In prevention of anticalcineurin nephrotoxicity, many attempts to minimize or wean patients from them have shown that improvement in renal function is only obtained at the cost of an increase in the incidence of acute rejection. This makes it necessary to select patients who may benefit from anticalcineurin-sparing treatment, based on clinical, histological, and biological markers. Finally, long-term follow-up is also fundamental in order to validate the positive impact on renal function of this strategy in terms of graft survival.

Clinical outcomes after failed renal transplantation-does dialysis modality matter?

Patients returning to dialysis after graft loss (DAGL) are an increasing segment of the end-stage renal disease (ESRD) population. It is unclear whether patients with previous graft loss have equivalent or reduced survival from the time of restarting dialysis when compared with ESRD patients initiating dialysis for the first time. Moreover, the impact of dialysis modality on the survival of patients returning to DAGL is not known. Studies of patients with transplant graft failure returning to hemodialysis (HD) have suggested decreased survival when compared with transplant-naïve dialysis patients, yet some studies of patients with graft failure returning to peritoneal dialysis (PD) have demonstrated equivalent survival. Based on these data, it is unclear whether survival differences may exist between the dialysis modalities, and if they do, whether they can be attributed to either differences in patient characteristics or to factors related to the dialysis modalities. For patients starting back onto dialysis, in whom preservation of residual renal function is important, it is also unclear how immunosuppression reduction or transplant nephrectomy may affect survival. In this review, we will summarize the available literature on survival rates of patients returning to DAGL; compare and contrast survival after initiation of HD and PD and discuss what is known about the impact of transplant nephrectomy and the different approaches to immunosuppression reduction. Practical considerations will be discussed with a specific emphasis on patients treated by PD.

Minimization of calcineurin inhibitors to improve long-term outcomes in kidney transplantation

Long-term outcomes after kidney transplantation remain suboptimal, despite the great achievements observed in recent years with the use of modern immunosuppressive drugs. Currently, the calcineurin inhibitors (CNI) cyclosporine and tacrolimus remain the cornerstones of immunosuppressive regimens in many centers worldwide, regardless of their well described side-effects, including nephrotoxicity. In this article, we review recent CNI-minimization strategies in kidney transplantation, while emphasizing on the importance of long-term follow-up and patient monitoring. Finally, accumulating data indicate that low-dose CNI-based regimens would provide an interesting balance between efficacy and toxicity.

Immunological monitoring of renal transplant recipients to predict acute allograft rejection following the discontinuation of tacrolimus

Background

Transplant patients would benefit from reduction of immunosuppression providing that graft rejection is prevented. We have evaluated a number of immunological markers in blood of patients in whom tacrolimus was withdrawn after renal transplantation. The alloreactive precursor frequency of CD4+ and CD8+ T cells, the frequency of T cell subsets and the functional capacity of CD4+CD25+FoxP3+ regulatory T cells (Treg) were analyzed before transplantation and before tacrolimus reduction. In a case-control design, the results were compared between patients with (n = 15) and without (n = 28) acute rejection after tacrolimus withdrawal.

Principal Findings

Prior to tacrolimus reduction, the ratio between memory CD8+ T cells and Treg was higher in rejectors compared to non-rejectors. Rejectors also had a higher ratio between memory CD4+ T cells and Treg, and ratios <20 were only observed in non-rejectors. Between the time of transplantation and the start of tacrolimus withdrawal, an increase in naive T cell frequencies and a reciprocal decrease of effector T cell percentages was observed in rejectors. The proportion of Treg within the CD4+ T cells decreased after transplantation, but anti-donor regulatory capacity of Treg remained unaltered in rejectors and non-rejectors.

Conclusions

Immunological monitoring revealed an association between acute rejection following the withdrawal of tacrolimus and 1) the ratio of memory T cells and Treg prior to the start of tacrolimus reduction, and 2) changes in the distribution of naive, effector and memory T cells over time. Combination of these two biomarkers allowed highly specific identification of patients in whom immunosuppression could be safely reduced.

Lifetime cost-effectiveness of calcineurin inhibitor withdrawal after de novo renal transplantation

After renal transplantation, immunosuppressive regimens associated with high short-term survival rates are not necessarily associated with high long-term survival rates, suggesting that regimens may need to be optimized over time. Calcineurin inhibitor (CNI) withdrawal from a sirolimus-based immunosuppressive regimen may maximize the likelihood of long-term graft and patient survival by minimizing CNI-associated nephrotoxicity. In this study, a lifetime Markov model was created to compare the cost-effectiveness of a sirolimus-based CNI withdrawal regimen (sirolimus plus steroids) with other common CNI-containing regimens in adult de novo renal transplantation patients. Long-term graft survival was estimated by renal function and data from published studies and the US transplant registry, including short- and long-term outcomes, utility weights, and health-state costs were incorporated. Drug costs were based on average daily consumption and wholesale acquisition costs. The model suggests that treatment with sirolimus plus steroids is more efficacious and less costly than regimens consisting of a CNI, mycophenolate mofetil, and steroids; therefore, CNI withdrawal not only shows potential for long-term clinical benefits but also is expected to be cost-saving over a patient's life compared with the most commonly prescribed CNI-containing regimens.

Calcineurin inhibitor-sparing regimens in solid organ transplantation: focus on improving renal function and nephrotoxicity

BACKGROUND

The calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, have had a revolutionary effect on the overall success of renal transplantation through reduction in early immunologic injury and acute rejection rates. However, the CNIs have a significant adverse impact on renal function and cardiovascular disease, and extended long-term graft survival has not been achieved. The recognition of these effects sparked interest in CNI-sparing strategies. Strategies to limit CNI exposure include CNI minimization, avoidance, and withdrawal. We sought to review the impact of CNI-sparing strategies in kidney, liver, and heart transplantation.

MATERIALS AND METHODS

A PubMed search 1966 to August 2006 was conducted to identify relevant research articles, and the references of these articles as well as the authors' personal files were reviewed.

RESULTS

Calcineurin inhibitor minimization using mycophenolate mofetil or sirolimus may be associated with a modest increase in creatinine clearance (CrCl) and a decrease in serum creatinine (SCr) in the short term. Despite improvement in CrCl or SCr, CNI nephrotoxicity and chronic allograft nephrotoxicity are progressive over time when CNI exposure is maintained. In kidney transplantation, the tubulo-interstitial and glomerular damage are irreversible. Mycophenolate mofetil may improve renal outcomes during CNI minimization more than sirolimus, and antibody induction may be effective to limit CNI exposure, but longer-term follow-up data are required. Use of sirolimus with mycophenolate mofetil or azathioprine to avoid CNI exposure de novo has improved glomerular filtration rate for at least two yr in most studies in kidney transplantation; however, experience is limited in liver and heart transplantation, and reports of delayed graft function and wound healing with sirolimus may have dampened enthusiasm for de novo use. Late CNI withdrawal has achieved variable results, possibly because withdrawal was attempted after the kidney damage was too extensive. Early CNI withdrawal, prior to significant graft damage, has generally improved CrCl and markers of fibrosis and decreased chronic allograft lesions, a finding also observed with sirolimus in most CNI avoidance studies. Successful withdrawal appears to be more effective than CNI minimization.

CONCLUSIONS

Calcineurin inhibitors are associated with significant nephrotoxicity and chronic kidney damage. Minimization is associated with a modest increase in renal function, but persistent damage is observed on biopsies as long as the CNIs are continued. Avoidance is hampered by lack of experience and possible sirolimus-induced side effects. CNI withdrawal may be the best option by delivering CNIs during the early period of immunologic graft injury and then converting them to less nephrotoxic agents before significant renal damage occurs.

Randomized controlled study comparing reduced calcineurin inhibitors exposure versus standard cyclosporine-based immunosuppression

BACKGROUND

Immunosuppressive regimens based on low doses of cyclosporine A (CsA) or tacrolimus (TAC) may improve short-term outcome after kidney transplantation (KT), but the optimal immunosuppressive protocol is currently unknown.

METHODS

This study compared the 24-month efficacy and safety of two immunosuppressive regimens using reduced calcineurin inhibitors (CNIs) exposure with standard dosage of CsA in 240 patients who were randomized into three groups: group A (n=80): Thymoglobulin, CsA (4 mg/kg twice daily) plus azathioprine (1.5 mg/kg once daily); group B (n=80): basiliximab, CsA (2 mg/kg/ twice daily) plus mycophenolate mofetil (MMF; 1 g twice daily); and group C (n=80): basiliximab, TAC (0.05 mg/kg/ twice daily) plus MMF (1 g twice daily). Steroid administration was identical for all groups.

RESULTS

A significantly better creatinine clearance at 12 months, estimated by Cockcroft-Gault (57+/-12, 65.2+/-20, 73.5+/-27 ml/min, P=0.044), the Jelliffe-2 (51.5+/-16, 56+/-19, 59.4+/-19 ml/min/1.73 m2, P=0.041) and the Modification of Diet in Renal Disease equations (53+/-17, 58.5+/-20, 61.6+/-22 ml/min/1.73 m2, P=0.035), was observed in group C compared with group A. No significant differences were observed between groups B and C. The incidence of biopsy-proven acute rejection was similar between groups (15%, 13.8%, and 16.3%). In addition, patient and graft survival at 24 months were not different between groups. Adverse effects were similar among groups, but cytomegalovirus infections was significantly higher in group A (41% vs. 20% vs. 25%; P=0.008).

CONCLUSIONS

Immunosuppressive regimens with reduced CNI exposure provide similar preservation of renal function compared with standard dose of CsA after KT and do not lead to underimmunosuppression.

Calcineurin Inhibitor Reduction Based on Maintenance Immunosuppression With Mycophenolate Mofetil in Renal Transplant Patients: POP Study

Since calcineurin inhibitors (CNI) have been introduced, they have become the cornerstone of immunosuppression for renal transplant patients, but their cardiovascular and neurological toxicities, and primarily their renal toxicity, have brought about an increased effort to find combinations of immunosuppressants that are either CNI-free or that use minimum doses of these drugs. The weight of immunosuppression therefore lies with drugs that have a better toxicity profile. The POP observational transverse study including 213 renal transplant patients was designed to study CNI minimization strategies. The mean time of transplant evolution to the time of reduction was 9.9 +/- 11.8 months. The acute rejection rate to the start of reduction was 9.4%. Almost all the patients were undergoing treatment with CNI + mycophenolate mofetil (MMF) + steroids in the immediate posttransplantation period. When reduction was chosen, all patients were undergoing treatment with MMF (mean dose at the start of reduction = 1490.7 +/- 478.0 mg/d). Among the cohort, 66.7% of patients were being treated with tacrolimus (mean C0 levels 13.3 +/- 6.6 ng/mL) and 33.3% with cyclosporine (mean C0 levels 192.2 +/- 94.0 ng/mL; mean C2 levels 1097.5 +/- 457.6). The main reasons for withdrawal were nephrotoxicity (55.9% of the cases), as well as prevention of adverse effects (21.6%). The mean target CNI dose reduction was 41.4% +/- 21.45% in the tacrolimus group and 28.6 +/- 10.0% in the cyclosporine group. In conclusion, CNI toxicity, primarily renal toxicity, makes reduction of these drugs based on the use of full MMF doses an alternative to manage renal transplant patients.

Calcineurin inhibitor-free immunosuppression in kidney transplantation

The introduction of calcineurin inhibitors (CNI) revolutionized kidney transplantation (KTx). Exceptionally low acute rejection rates and excellent graft survival could be achieved with CNI-based (cyclosporine and tacrolimus) immunosuppressive protocols. However, despite short-term success, long-term graft attrition continues to be a significant problem, thus leaving clinicians looking for possible interventions. CNI nephrotoxicity is but one of numerous factors that may be contributing to long-term damage in transplant kidneys. Therefore, newer immunosuppressive agents such as mycophenolate mofetil and sirolimus (Rapa) have raised the possibility of withdrawing or avoiding CNIs altogether. Protocols exploring these options have gained greater attention over the last few years. Herein, we review studies addressing either CNI withdrawal or CNI avoidance strategies as well as discuss the risks versus benefits of these protocols. Given the accumulated experience to date, in our opinion, the use of CNIs as a part of immunosuppressive regimens remains the proven standard of care for renal transplant patients. The long-term safety and efficacy of CNI withdrawal and avoidance strategies need to be further validated in controlled clinical trials.

Chronic Allograft Nephropathy

Chronic allograft nephropathy (CAN) remains the Achilles heel of renal transplantation. In spite of the significant strides achieved in one-year renal allograft survival with newer immunosuppressant strategies, the fate of long-term renal allograft survival remains unchanged. The number of renal transplant recipients returning to dialysis has doubled in the past decade. This is especially important since these patients pose a significantly increased likelihood of dying while on the waiting list for retransplantation, due to increasing disparity between donor organ availability versus demand and longer waiting time secondary to heightened immunologic sensitization from their prior transplants. In this review we analyze the latest literature in detail and discuss the definition, natural history, pathophysiology, alloantigen dependent and independent factors that play a crucial role in CAN and the potential newer therapeutic targets on the horizon. This article highlights the importance of early identification and careful management of all the potential contributing factors with particular emphasis on prevention rather than cure of CAN as the core management strategy.

Early withdrawal of calcineurin inhibitors and rescue immunosuppression with sirolimus-based therapy in renal transplant recipients with moderate to severe renal dysfunction

Mammalian Target-of-Rapamycin inhibitors (mTOR inhibitors) can be used to replace the calcineurin inhibitors (CNIs) to prevent progression in chronic kidney disease (CKD) following organ transplantation. Discontinuation of tacrolimus in 136 recipients of kidney transplants with progressive renal dysfunction significantly decreased the rate of loss of estimated glomerular filtration rate (eGFR, mL/min/1.73 m(2)) (pre-intervention vs. post-intervention slopes, -0.013 vs. -0.002, p < 0.0001). Discontinuation of tacrolimus was associated with a sustained and significant improvement in graft function (pre-eGFR vs. post-eGFR; 26.0 +/- 1.1 vs. 47.4 +/- 2.1, p < 0.0001) in 74% of patients. This intervention was ineffective if the mean and (median) values of creatinine (mg/dL) and eGFR were 3.8 +/- 0.2 (3.4) and 18.4 +/- 1.9 (22.4), respectively, at the time of conversion therapy. During the follow-up (range, 1.5-34.6, months), a total of 13 patients had their first acute rejection following the conversion therapy, an annual incidence of less than 10% and none of these episodes resulted in graft loss. The salutary effects of sirolimus therapy following discontinuation of tacrolimus in patients with moderate to severe graft dysfunction due to allograft nephropathy even in high-risk patients improves kidney function and prevents acute rejection.