Tacrolimus/sirolimus versus tacrolimus/mycophenolate in kidney transplantation: improved 3-year graft and patient survival in recent era

Place of mTOR inhibitors in management of BKV infection after kidney transplantation

CONTEXT

BK virus (BKV) viremia and BKV-associated nephropathy (BKVAN) have become a serious nuisance to kidney transplant (KT) patients since the mid-nineties, when the incidence of this disease has increased significantly.

EVIDENCE ACQUISITION

Directory of open access journals (DOAJ), EMBASE, Google Scholar, PubMed, EBSCO, and Web of Science have been searched.

RESULTS

Many hypothesis have been made as to why this phenomenon has developed; it is of general opinion that a more potent immunosuppression is at the core of the problem. The use of the association of tacrolimus (TAC) with mycophenolic acid (MPA) has gained momentum in the same years as the increase in BKV viremia incidence making it seem to be the most likely culprit. m-TOR inhibitors (m-TORIs) have been shown to have antiviral properties in vitro and this fact has encouraged different transplant teams to use these agents when confronted with BKV infection (viremia or nephropathy). However, the results are mitigated. There had been conflicting results for example when converting from TAC-to sirolimus-based immunosuppression in the setting of established BKVAN.

CONCLUSIONS

In order to prevent BKV infection we have to minimize to some extent immunosuppression, but it is not always possible, e.g. in high immunological risk patients. Conversely, we could use m-TORIs associated with low-dose calcineurin inhibitors (CNIs). This could be actually the key to a safe immunosuppression regimen both from the immunological stand point and from the viral one.

Differential regulation of Tregs and Th17/Th1 cells by a sirolimus-based regimen might be dependent on STAT-signaling in renal transplant recipients

BACKGROUND

Sirolimus (SRL), a mammalian target of rapamycin inhibitor, has been used as a de novo base therapy with steroids and mycophenolate mofetil to avoid the use of calcineurin inhibitors. Our aim was to determine whether immunoregulation is promoted after conversion from tacrolimus (TAC) to SRL.

METHODS

The study included 24 renal transplant recipients who converted from TAC to SRL therapy and 24 normal controls. The frequency of T helper (Th) cells and the presence of signal transducer and activator of transcription (STAT) proteins in peripheral blood were analyzed by flow cytometry before conversion and at 3 and 6 months after conversion. Plasma levels of interleukin (IL)-1β, interferon-γ (IFN-γ), IL-17, IL-6, and IL-10 were analyzed by the Bio-Plex® suspension array system before and at 3 months after conversion.

RESULTS

Renal transplant recipients who switched to SRL showed a significant increase in regulatory T cell (Treg) frequencies and better renal function compared with preconversion (P<0.05). The plasma concentrations of inflammatory cytokines IL-1β, IL-6, IL-17, and IFN-γ were significantly decreased after conversion to SRL. Furthermore, recipients who switched to SRL showed an increase in STAT5 activation and a decrease in STAT3 activation compared with the TAC group.

CONCLUSION

Our results indicate that conversion to SRL might both minimize calcineurin inhibitor toxicity and promote immune tolerance.

Registration on the renal transplantation waiting list and mortality on dialysis: an analysis of the French REIN registry using a multi-state model

BACKGROUND

Access to the renal transplantation (RT) waiting list depends on factors related to lower mortality rates and often occurs after dialysis initiation. The aim of the study was to use a flexible regression model to determine if registration on the RT waiting list is associated with mortality on dialysis, independent of the comorbidities associated with such registration.

METHODS

Data from the French REIN registry on 7138 incident hemodialysis (HD) patients were analyzed. A multi-state model including four states ('HD, not wait-listed', 'HD, wait-listed', 'death', and 'RT') was used to estimate the effect of being wait-listed on the probability of death.

RESULTS

During the study, 1392 (19.5%) patients were wait-listed. Of the 2954 deaths observed in the entire cohort during follow-up, 2921 (98.9%) were observed in the not wait-listed group compared with only 33 (1.1%) in the wait-listed group. In the multivariable analysis, the adjusted hazard ratio for death associated with non-registration on the waiting list was 3.52 (95% CI, 1.70-7.30). The risk factors for death identified for not wait-listed patients were not found to be significant risk factors for wait-listed patients, with the exception of age.

CONCLUSIONS

The use of a multi-state model allowed a flexible analysis of mortality on dialysis. Patients who were not wait-listed had a much higher risk of death, regardless of co-morbidities associated with being wait-listed, and did not share the same risk factors of death as wait-listed patients. Registration on the waiting list should therefore be taken into account in survival analysis of patients on dialysis.

Safety of immunosuppressive drugs used as maintenance therapy in kidney transplantation: a systematic review and meta-analysis

To evaluate the safety of regimens containing calcineurin inhibitors (CNI), proliferation signal inhibitors (TOR-I) and antimetabolites, we conducted a meta-analysis of randomized clinical trials (RCTs) and observational studies. A total of 4,960 citations were identified in our electronic search and 14 additional articles were identified through hand searching. Forty-eight articles (11,432 participants) from 42 studies (38 RCTs and four cohorts) met the inclusion criteria. Meta-analysis results revealed the following: (i) tacrolimus was associated with an increased risk for diabetes and lower risk of dyslipidemia, compared to cyclosporine; (ii) mycophenolate mofetil (MMF) was associated with increased risk for total infections, abdominal pain, diarrhea and vomiting, compared with azathioprine; (iii) sirolimus was associated with higher risk of anemia, diabetes, dyslipidemia, lymphoceles and withdrawal compared to tacrolimus or cyclosporine, and cyclosporine was associated with an increased risk of CMV infection; (iv) the combination of CNI with antimetabolites was associated with more adverse events than CNI alone; (v) TOR-I was related to more adverse events than MMF. The data observed in this meta-analysis are similar to those describe by others authors; thus, the choice of treatment must be made by the clinical staff based on specific patient characteristics.

Long-term kidney allograft function and survival in prednisone-free regimens: tacrolimus/mycophenolate mofetil versus tacrolimus/sirolimus

BACKGROUND AND OBJECTIVES

The optimal maintenance immunosuppressive regimen to improve long-term renal allograft function and graft survival is yet to be determined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This observational study prospectively compared tacrolimus/sirolimus with tacrolimus/mycophenolate mofetil in renal transplant recipients using a prednisone-free regimen with over 8.5 years of follow-up. Patients received methylprednisonlone and anti-IL2 receptor antagonist (Basiliximab) induction and were blindly randomized to either the tacrolimus/mycophenolate mofetil (n=45) or tacrolimus/sirolimus (n=37) groups. Outcome measures included patient and renal allograft survival, incidence of acute rejection, and estimated GFR.

RESULTS

The tacrolimus/mycophenolate mofetil group compared with the tacrolimus/sirolimus group had overall better renal allograft survival (91% versus 70%, P=0.02); 13 patients (35.1%) in the tacrolimus/sirolimus group and 8 patients (17.8%) in the tacrolimus/mycophenolate mofetil group experienced biopsy-proven acute cellular rejection (P=0.07). By 3 months post-transplant, estimated GFR was significantly lower in the tacrolimus/sirolimus group compared with the tacrolimus/mycophenolate mofetil group (47.7 versus 59.6 ml/min per 1.73 m(2), P=0.0002), and this trend persisted throughout the follow-up period. Also, the slope of decline in the tacrolimus/sirolimus group was significantly steeper than in the tacrolimus/mycophenolate mofetil group.

CONCLUSIONS

This study shows that, in a prednisone-free immunosuppressive regimen, long-term renal graft survival and function are significantly worse in the tacrolimus/sirolimus group than the tacrolimus/mycophenolate mofetil group. The synergistic nephrotoxic effect and higher acute rejection rates in the tacrolimus/sirolimus compared with the tacrolimus/mycophenolate mofetil group adversely affect graft survival.

The influence of immunosuppressive agents on BK virus risk following kidney transplantation, and implications for choice of regimen

The increasing incidence of BK-associated nephropathy following kidney transplantation has prompted an examination of strategies for risk reduction and management through immunosuppression manipulation. Evidence from retrospective and prospective studies suggests that BK viruria and viremia, and the need for BK virus treatment, are higher with tacrolimus than cyclosporine. Combined therapy with tacrolimus and mycophenolic acid may be associated with a particularly higher risk of BK infection, but data are conflicting as to whether mycophenolic acid per se is an independent risk factor. The incidence of BK-related events may be reduced in patients receiving mTOR inhibitors (everolimus or sirolimus) with cyclosporine vs a calcineurin inhibitor with mycophenolic acid. De novo immunosuppression regimens that avoid rabbit antithymocyte globulin and tacrolimus, particularly tacrolimus with mycophenolic acid, may be advantageous, whereas low-exposure cyclosporine with an mTOR inhibitor appears a favorable option. Routine screening for BK infection during the first 2 years posttransplant is recommended to allow preemptive modification of the immunosuppressive regimen. In patients at high risk of BK virus infection, appropriate de novo immunosuppression or very early conversion to an mTOR inhibitor to facilitate reduction or discontinuation of calcineurin inhibitors or antimetabolites should be considered. Extensive further research into optimal avoidance, screening, and treatment strategies is required.

Histological progression of chronic renal allograft injury comparing sirolimus and mycophenolate mofetil-based protocols. A single-center, prospective, randomized, controlled study

In an effort to mitigate progression of IF/TA associated with chronic renal allograft injury, we hypothesize that adjuvant immunosuppression with sirolimus (SRL) will delay progression compared with MMF. Subjects 5-17 yr old, >1-yr post-transplant with mild or moderate IF/TA (Banff criteria) and tacrolimus dose minimization were randomized to continue MMF or convert to SRL and followed for two yr. For the entire cohort (n = 20), there was significant progression of %GGS, ci, ct, cv, and ah scores over the follow-up period (p < 0.05). There was no difference in rates of progression of Banff scores, %GGS, or % IF over two yr between the two groups, though power was low. Both groups exhibited similar rates of eGFR decline (MMF: -12.3 vs. SRL: -11.8 mL/min/1.73 m²/yr), which was correlated with ct score (p < 0.05). The SRL group had more episodes of acute allograft dysfunction and oral ulcers. Proteinuria at 24 months was significantly increased in the SRL group (6/9 subjects) but was not correlated with eGFR or %GGS. We conclude that neither MMF nor SRL, combined with low-dose tacrolimus, was effective at mitigating progressive histological changes or functional decline associated with chronic renal allograft injury.

Role of tacrolimus combination therapy with mycophenolate mofetil in the prevention of organ rejection in kidney transplant patients

Introduction:

Several new medications are now available for immunosuppression in the kidney transplant field. Tacrolimus and mycophenolate mofetil were first introduced for immunosuppression in renal transplantation in the mid 1990s. Since then, the combination of tacrolimus and mycophenolate mofetil has been evaluated in numerous clinical trials. The outcomes of these trials have varied due to differences in induction and/or maintenance therapy, drug dosing and monitoring protocols, and study design. The aim of this review is to analyze the literature critically and to provide an overview of tacrolimus and mycophenolate mofetil combination therapy in renal transplantation.