Planned randomized conversion from tacrolimus to sirolimus-based immunosuppressive regimen in de novo kidney transplant recipients

Immunosuppressive drug combinations after kidney transplantation and post-transplant diabetes: A systematic review and meta-analysis

Post-transplant diabetes mellitus (PTDM) is a frequent complication after kidney transplantation (KT). This systematic review investigated the effect of different immunosuppressive regimens on the risk of PTDM. We performed a systematic literature search in MEDLINE and CENTRAL for randomized controlled trials (RCTs) that included KT recipients with any immunosuppression and reported PTDM outcomes up to 1 October 2023. The analysis included 125 RCTs. We found no differences in PTDM risk within induction therapies. In de novo KT, there was an increased risk of developing PTDM with tacrolimus versus cyclosporin (RR 1.71, 95%CI [1.38-2.11]). No differences were observed between tacrolimus+mammalian target of rapamycin inhibitor (mTORi) and tacrolimus+MMF/MPA, but there was a tendency towards a higher risk of PTDM in the cyclosporin+mTORi group (RR 1.42, 95%CI [0.99-2.04]). Conversion from cyclosporin to an mTORi increased PTDM risk (RR 1.89, 95%CI [1.18-3.03]). De novo belatacept compared with a calcineurin inhibitor resulted in 50% lower risk of PTDM (RR 0.50, 95%CI [0.32-0.79]). Steroid avoidance resulted in 31% lower PTDM risk (RR 0.69, 95%CI [0.57-0.83]), whereas steroid withdrawal resulted in no differences. Immunosuppression should be decided on an individual basis, carefully weighing the risk of future PTDM and rejection.

Calcineurin and mTOR inhibitors in kidney transplantation: integrative metamodeling on transplant survival and kidney function

In our study, we examined the efficacy of mTOR (mammalian target of rapamycin) inhibitors, specifically rapamycin (Rap), compared to calcineurin inhibitors (CNIs) in kidney transplantation. By conducting a comprehensive search across reputable databases (EMBASE, Scopus, PubMed, Cochrane, and Crossref), we gathered data for a six-month post-transplantation period. Our analysis revealed that mTOR inhibitor administration resulted in improved glomerular filtration rate (GFR) and serum creatinine levels. However, it is important to note that the mTOR inhibitor group had a higher incidence of acute rejection after biopsy. Through molecular modeling, we observed that Rap exhibited a superior binding affinity for mTOR compared to CNIs' binding to calcineurin, probably contributing to the transplant rejection. Our meta-analysis supports the cautious use of an optimal mTOR inhibitor in conjunction with careful consideration of clinical features when minimizing CNIs early in the transplantation process. This is because mTOR inhibitors have complementary mechanisms of action, a low nephrotoxicity profile, and favorable outcomes in serum creatinine and GFR, which contribute to improved transplant survival.

A randomized controlled trial to evaluate efficacy and safety of early conversion to a low-dose calcineurin inhibitor combined with sirolimus in renal transplant patients

BACKGROUND

The calcineurin inhibitor (CNI)-based immune maintenance regimen that is commonly used after renal transplantation has greatly improved early graft survival after transplantation; however, the long-term prognosis of grafts has not been significantly improved. The nephrotoxicity of CNI drugs is one of the main risk factors for the poor long-term prognosis of grafts. Sirolimus (SRL) has been employed as an immunosuppressant in clinical practice for over 20 years and has been found to have no nephrotoxic effects on grafts. Presently, the regimen and timing of SRL application after renal transplantation vary, and clinical data are scarce. Multicenter prospective randomized controlled studies are particularly rare. This study aims to investigate the effects of early conversion to a low-dose CNI combined with SRL on the long-term prognosis of renal transplantation.

METHODS

Patients who receive four weeks of a standard regimen with CNI + mycophenolic acid (MPA) + glucocorticoid after renal transplantation in multiple transplant centers across China will be included in this study. At week 5, after the operation, patients in the experimental group will receive an additional administration of SRL, a reduction in the CNI drug doses, withdrawal of MPA medication, and maintenance of glucocorticoids. In addition, patients in the control group will receive the maintained standard of care. The patients' vital signs, routine blood tests, routine urine tests, blood biochemistry, serum creatinine, BK virus (BKV)/ cytomegalovirus (CMV), and trough concentrations of CNI drugs and SRL at the baseline and weeks 12, 24, 36, 48, 72, and 104 after conversion will be recorded. Patient survival, graft survival, and estimated glomerular filtration rate will be calculated, and concomitant medications and adverse events will also be recorded.

CONCLUSION

The study data will be utilized to evaluate the efficacy and safety of early conversion to low-dose CNIs combined with SRL in renal transplant patients.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800017277.

Personalized immunosuppression after kidney transplantation

With advances in immunosuppressive therapy, there have been significant improvements in acute rejection rates and short-term allograft survival in kidney transplant recipients. However, this success has not been translated into long-term benefits by the same magnitude. Optimization of immunosuppression is important to improve the clinical outcome of transplant recipients. It is important to note that each patient has unique attributes and immunosuppression management should not be a one-size-fits-all approach. Elderly transplant patients are less likely to develop acute rejection but more likely to die from infectious and cardiovascular causes than younger patients. For those with post-transplant cancers and BK polyomavirus-associated nephropathy, reduction of immunosuppression can increase the risk of rejection. Therapeutic drug monitoring (TDM) is routinely used for dosage adjustment of several immunosuppressive drugs. It has been hoped that pharmacogenetics can be used to complement TDM in optimizing drug exposure. Among the various drug-genotype pairs being investigated, tacrolimus and CYP3A5 gives the most promising results. Different studies have consistently shown that CYP3A5 expressers require a higher tacrolimus dose and take longer time to achieve target blood tacrolimus levels than nonexpressers. However, for pharmacogenetics to be widely used clinically, further trials are necessary to demonstrate the clinical benefits of genotype-guided dosing such as reduction of rejection and drug-related toxicities. The development of different biomarkers in recent years may help to achieve true personalized therapy in transplant patients.

Conversion From Calcineurin Inhibitors to Mammalian Target of Rapamycin Inhibitors in Kidney Transplant Recipients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Background

A systematic review and meta-analysis were performed to investigate the efficacy and safety of conversion from calcineurin inhibitors (CNIs) to mammalian target of rapamycin inhibitors (mTORi) in kidney transplant recipients (KTRs).

Methods

MEDLINE, EMBASE, PubMed, and Cochrane Library were searched to identify randomized controlled trials (RCTs) that compared the continuation of CNI with conversion to mTORi therapy.

Results

Twenty-nine RCTs (5,747 KTRs) were included in our analysis. Meta-analysis of the glomerular filtration rate (SMD 0.20; 95%CI 0.10-0.31; P<0.01) and malignancy (RR 0.74; 95%CI 0.55-0.99; P=0.04) demonstrated a significant advantage of mTORi conversion over CNI continuation. However, the risk of acute rejection (RR 1.58; 95%CI 1.22-2.04; P<0.01), infection (RR 1.55; 95%CI 1.01-1.31; P=0.04), proteinuria (RR 1.87; 95%CI 1.34-2.59; P<0.01), leukopenia (RR 1.56; 95%CI 1.27-1.91; P<0.01), acne (RR 6.43; 95%CI 3.43-12.04; P<0.01), and mouth ulcer (RR 11.70; 95%CI 6.18-22.17; P<0.01) were higher in the mTORi group. More patients in the conversion group had to discontinue study medication (RR 2.52; 95%CI 1.75-3.63; P<0.01). There was no significant difference between the two groups with regard to death, graft loss, diabetes, chronic allograft nephropathy, and interstitial fibrosis/tubular atrophy.

Conclusions

Posttransplant patients have a better graft function and lower incidence of malignancy after conversion from CNI to mTORi therapy. However, this conversion strategy may be prevented by the higher drug discontinuation rate due to mTORi-associated adverse events, such as more acute rejection, infection, proteinuria, leukopenia, acne, and mouth ulcer, indicating that conversion therapy may only be a treatment option in selected patients.

Calcineurin Inhibitors Nephrotoxicity Prevention Strategies With Stress on Belatacept-Based Rescue Immunotherapy: A Review of the Current Evidence

BACKGROUND

A traditional narrative review was performed to evaluate clinical studies that have examined the clinical implications, risk factors, and prevention of calcineurin inhibitors (CNIs) nephrotoxicity with stress on a belatacept-based rescue regimen.

METHODS

The Cochrane Library, PubMed/MEDLINE, EBSCO (Academic Search Ultimate), ProQuest (Central), and Excerpta Medical databases and Google scholar were searched using the keywords (CNI AND Nephrotoxicity prevention) OR ("Calcineurin inhibitor" AND Nephrotoxicity) OR (Tacrolimus AND Nephrotoxicity) OR (Ciclosporin AND Nephrotoxicity) OR (cyclosporine AND Nephrotoxicity) OR (Belatacept) OR (CNI Conversion) for the period from 1990 to 2020. Fifty-five related articles and reviews were found.

CONCLUSION

A better understanding of the mechanisms underlying calcineurin inhibitor nephrotoxicity could help in the individualization of therapy for and prevention of CNI nephrotoxicity. Identification of high-risk patients for CNI nephrotoxicity before renal transplantation enables better use and selection of immunosuppression with reduced adverse effects and, eventually, successful treatment of the kidney recipients. Belatacept conversion is a good and safe option in patients with deteriorating renal function attributed to CNI nephrotoxicity.

Current State of Evidence on Kidney Transplantation: How Fragile Are the Results?

BACKGROUND

The study aims is to use the fragility index (FI) to examine the strength of evidence of randomized controlled trials (RCTs) published in the last decade on kidney transplantation.

METHODS

We searched MEDLINE for studies on kidney transplantation. We included the RCTs that compared 2 groups with 1:1 randomization and reported significant P-values (<0.05) for a dichotomous outcome and were published in the top 10 transplant journals. We calculated the FI; a calculation used to determine the minimum number of subjects needed to change from a nonevent to an event to make the study results nonsignificant (P-value >0.05).

RESULTS

57 RCTs met our inclusion criteria. The median sample size was 100 participants in each arm, the median number of events was 16(IQR 8-30) in the intervention group. Among the included trials, 79% were industry-funded, 93% involved medications, and the majority were open-label. The median FI was 3 (IQR 1-11). In 43% of the trials, the number of patients reported lost to follow-up was higher than or equal to the FI. Only 4% of the RCTs imputed a value for the missing dichotomous outcome. Furthermore, the median number of subjects who discontinued the trial due to adverse effects was 21, which was greater than the FI in 60% of the RCTs.

CONCLUSION

The arbitrary classification of results into "significant" and "nonsignificant" based on p-value <0.05 should perhaps be interpreted with the help of other statistical parameters and FI is one of them.

Differentially expressed urinary exo-miRs and clinical outcomes in kidney recipients on short-term tacrolimus therapy: a pilot study

Aim: To analyze the expression of urinary exosome-derived miRNAs (exo-miRs) in kidney recipients on tacrolimus-based therapy. Patients & methods: Clinical and drug monitoring data were recorded from 23 kidney recipients. Expression of 93 exo-miRs was measured by quantitative PCR array and mRNA targets were explored. Results: 16 exo-miRs were differentially expressed, including marked upregulation of miR-155-5p, and downregulation of miR-223-3p and miR-1228-3p. Expression of miR-155-5p and miR-223-3p correlated with tacrolimus dose (p < 0.05), miR-223-3p with serum creatinine (p < 0.05), and miR-223-3p and miR-1228-3p with blood leukocytes (p < 0.05). 12 miRNAs have predicted targets involved in cell proliferation, apoptosis, stress response, PIK3/AKT/mTOR and TGF-β signaling pathways. Conclusion: Differentially expressed urinary exo-miRs may be useful markers to monitor tacrolimus therapy and graft function in kidney transplantation.

Differential expression of genes related to calcineurin and mTOR signaling and regulatory miRNAs in peripheral blood from kidney recipients under tacrolimus-based therapy

Background

Genetic and epigenetics factors have been implicated in drug response, graft function and rejection in solid organ transplantation. Differential expression of genes involved in calcineurin and mTOR signaling pathway and regulatory miRNAs was analyzed in the peripheral blood of kidney recipient cohort (n=36) under tacrolimus-based therapy.

Methods

PPP3CA, PPP3CB, MTOR, FKBP1A, FKBP1B and FKBP5 mRNA expression and polymorphisms in PPP3CA and MTOR were analyzed by qPCR. Expression of miRNAs targeting PPP3CA (miR-30a, miR-145), PPP3CB (miR-10b), MTOR (miR-99a, miR-100), and FKBP1A (miR-103a) was measured by qPCR array.

Results

PPP3CA and MTOR mRNA levels were reduced in the first three months of treatment compared to pre-transplant (P<0.05). PPP3CB, FKBP1A, FKBP1B, and FKBP5 expression was not changed. In the 3^rd month of treatment, the expression of miR-99a, which targets MTOR, increased compared to pre-transplant (P<0.05). PPP3CA c.249G>A (GG genotype) and MTOR c.2997C>T (TT genotype) were associated with reduced expression of PPP3CA mRNA and MTOR, respectively. FKBP1B mRNA levels were higher in patients with acute rejection (P=0.026).

Conclusions

The expression of PPP3CA, MTOR and miR-99a in the peripheral blood of renal recipients is influenced by tacrolimus-based therapy and by PPP3CA and MTOR variants. These molecules can be potential biomarkers for pharmacotherapy monitoring.

The 3C Study Collaborative Group, Haynes R, Blackwell L, Staplin N, Herrington WG, Emberson J, Judge PK, Storey BC, Landray MJ, Harden PN, Baigent C, Friend P. Campath, calcineurin inhibitor reduction, and chronic allograft nephropathy (the 3C Study) - results of a randomized controlled clinical trial

Calcineurin inhibitors (CNIs, eg, tacrolimus) reduce short-term kidney transplant failure, but chronic nephrotoxicity may contribute to late transplant loss. Elective conversion to inhibitors of the mammalian target of rapamycin (mTOR, eg, sirolimus) pathway might avoid long-term CNI renal damage and improve outcomes. The 3C Study was a pragmatic randomized controlled trial of sequential randomizations between alemtuzumab and basiliximab induction therapy (at the time of surgery) and between tacrolimus and sirolimus maintenance therapy at 6 months posttransplantation. The primary outcome of this analysis was estimated glomerular filtration rate (eGFR) at 18 months after maintenance therapy randomization; 197 patients were assigned sirolimus-based and 197 to tacrolimus-based therapy. Allocation to sirolimus had no significant effect on eGFR at 18 months: baseline-adjusted mean (SEM) eGFR was 53.7 (0.9) mL/min/1.73 m² in the sirolimus group versus 54.6 (0.9) mL/min/1.73 m² in the tacrolimus group (P = .50). Biopsy-proven acute rejection (29 [14.7%]) vs 6 [3.0%]; P < .001) and serious infections (defined as opportunistic infections or those requiring hospitalization; 95 [48.2%] vs 70 [35.5%]; P = .008) were more common among participants allocated sirolimus. Compared with tacrolimus-based therapy, sirolimus-based maintenance therapy did not improve transplant function at 18 months after conversion and was associated with significant hazards of rejection and infection. ClinicalTrials.gov identifier NCT01120028 and ISRCTN88894088.

Effects of mTOR-Is on malignancy and survival following renal transplantation: A systematic review and meta-analysis of randomized trials with a minimum follow-up of 24 months

Background

mTOR-Is positively influence the occurrence and course of certain tumors after solid organ transplantation. The effect of mTOR-Is on the overall incidence of tumors irrespective of their origin is not entirely clear. Furthermore, conflicting data have been shown on mortality under mTOR-Is.

Methods

The current literature was searched for prospective randomized controlled renal transplantation trials. There were 1415 trials screened of which 13 could be included (pts. = 5924). A minimum follow-up of 24 months was mandatory for inclusion. Incidence of malignancies and patient survival was assessed in meta-analyses.

Results

The average follow-up of all trials was 40.6 months. Malignancy was significantly reduced under mTOR-Is compared to CNIs (RR 0.70, CI 0.49–0.99, p = 0.046). This effect remained stable when combined with CNIs (RR 0.58, CI 0.34–1.00, p = 0.05). When NMSCs were excluded the risk for malignancy remained significantly reduced under mTOR-I therapy (mono and combi) (RR 0.43, CI 0.24–0.77, p = 0.0046). Graft survival was minimally decreased under mTOR-Is (RR 0.99, CI 0.98–1.00, p = 0.054). This effect was abrogated when mTOR-Is were combined with CNIs (RR 0.99, CI 0.97–1.02, p = 0.50). Patient survival was not different (RR 1.00, CI 0.99–1.01, p = 0.54).

Conclusions

Posttransplant patients have a lower incidence of malignancy when treated with an mTOR-I no matter if it is used in combination with CNIs or not. This beneficial effect remains significant even when NMSCs are excluded. With currently used mTOR-I-based regimen patient and graft survival is not different compared to CNI therapies.

Influence of immunosuppressive drugs on the CD30 molecule in kidney transplanted patients

BACKGROUND

Soluble CD30 (sCD30) is a suggested marker for kidney transplantation outcomes. We investigated whether sCD30 serum levels are influenced by immunosuppression and whether they correlate with findings in protocol biopsies and with CD30 gene expression in peripheral blood mononuclear cells (PBMC).

METHODS

We studied 118 kidney transplant recipients that initially received tacrolimus (TAC) and, at month-3, were converted or not to sirolimus (SRL).

RESULTS

sCD30 serum levels gradually declined after transplantation, being the decline more pronounced in the SRL group. CD30 gene expression in PBMC was higher in the SRL group than in the TAC group. Patients with IF/TA ≥ I in the month-24 protocol biopsy had higher sCD30 levels than patients without IF/TA, in the SRL group (P = .03) and in the TAC group (P = .07). CD30⁺ cells were observed in three out of 10 biopsies with inflammatory infiltrate from the SRL group. In mixed lymphocyte cultures, SRL and TAC diminished the number of CD30⁺ T cells and the sCD30 levels in the supernatant, but the effect of SRL was stronger.

CONCLUSIONS

Overall, sCD30 levels are lower in SRL-treated patients, but the association between increased sCD30 levels and IF/TA at month-24 post-transplantation is stronger in SRL than in TAC-treated patients.

Immunosuppressive therapy for kidney transplantation in adults: a systematic review and economic model

BACKGROUND

End-stage renal disease is a long-term irreversible decline in kidney function requiring renal replacement therapy: kidney transplantation, haemodialysis or peritoneal dialysis. The preferred option is kidney transplantation, followed by immunosuppressive therapy (induction and maintenance therapy) to reduce the risk of kidney rejection and prolong graft survival.

OBJECTIVES

To review and update the evidence for the clinical effectiveness and cost-effectiveness of basiliximab (BAS) (Simulect(®), Novartis Pharmaceuticals UK Ltd) and rabbit anti-human thymocyte immunoglobulin (rATG) (Thymoglobulin(®), Sanofi) as induction therapy, and immediate-release tacrolimus (TAC) (Adoport(®), Sandoz; Capexion(®), Mylan; Modigraf(®), Astellas Pharma; Perixis(®), Accord Healthcare; Prograf(®), Astellas Pharma; Tacni(®), Teva; Vivadex(®), Dexcel Pharma), prolonged-release tacrolimus (Advagraf(®) Astellas Pharma), belatacept (BEL) (Nulojix(®), Bristol-Myers Squibb), mycophenolate mofetil (MMF) (Arzip(®), Zentiva; CellCept(®), Roche Products; Myfenax(®), Teva), mycophenolate sodium (MPS) (Myfortic(®), Novartis Pharmaceuticals UK Ltd), sirolimus (SRL) (Rapamune(®), Pfizer) and everolimus (EVL) (Certican(®), Novartis) as maintenance therapy in adult renal transplantation.

METHODS

Clinical effectiveness searches were conducted until 18 November 2014 in MEDLINE (via Ovid), EMBASE (via Ovid), Cochrane Central Register of Controlled Trials (via Wiley Online Library) and Web of Science (via ISI), Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and Health Technology Assessment (The Cochrane Library via Wiley Online Library) and Health Management Information Consortium (via Ovid). Cost-effectiveness searches were conducted until 18 November 2014 using a costs or economic literature search filter in MEDLINE (via Ovid), EMBASE (via Ovid), NHS Economic Evaluation Database (via Wiley Online Library), Web of Science (via ISI), Health Economic Evaluations Database (via Wiley Online Library) and the American Economic Association's electronic bibliography (via EconLit, EBSCOhost). Included studies were selected according to predefined methods and criteria. A random-effects model was used to analyse clinical effectiveness data (odds ratios for binary data and mean differences for continuous data). Network meta-analyses were undertaken within a Bayesian framework. A new discrete time-state transition economic model (semi-Markov) was developed, with acute rejection, graft function (GRF) and new-onset diabetes mellitus used to extrapolate graft survival. Recipients were assumed to be in one of three health states: functioning graft, graft loss or death.

RESULTS

Eighty-nine randomised controlled trials (RCTs), of variable quality, were included. For induction therapy, no treatment appeared more effective than another in reducing graft loss or mortality. Compared with placebo/no induction, rATG and BAS appeared more effective in reducing biopsy-proven acute rejection (BPAR) and BAS appeared more effective at improving GRF. For maintenance therapy, no treatment was better for all outcomes and no treatment appeared most effective at reducing graft loss. BEL + MMF appeared more effective than TAC + MMF and SRL + MMF at reducing mortality. MMF + CSA (ciclosporin), TAC + MMF, SRL + TAC, TAC + AZA (azathioprine) and EVL + CSA appeared more effective than CSA + AZA and EVL + MPS at reducing BPAR. SRL + AZA, TAC + AZA, TAC + MMF and BEL + MMF appeared to improve GRF compared with CSA + AZA and MMF + CSA. In the base-case deterministic and probabilistic analyses, BAS, MMF and TAC were predicted to be cost-effective at £20,000 and £30,000 per quality-adjusted life-year (QALY). When comparing all regimens, only BAS + TAC + MMF was cost-effective at £20,000 and £30,000 per QALY.

LIMITATIONS

For included trials, there was substantial methodological heterogeneity, few trials reported follow-up beyond 1 year, and there were insufficient data to perform subgroup analysis. Treatment discontinuation and switching were not modelled.

FUTURE WORK

High-quality, better-reported, longer-term RCTs are needed. Ideally, these would be sufficiently powered for subgroup analysis and include health-related quality of life as an outcome.

CONCLUSION

Only a regimen of BAS induction followed by maintenance with TAC and MMF is likely to be cost-effective at £20,000-30,000 per QALY.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014013189.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

CMV and BKPyV Infections in Renal Transplant Recipients Receiving an mTOR Inhibitor-Based Regimen Versus a CNI-Based Regimen: A Systematic Review and Meta-Analysis of Randomized, Controlled Trials

BACKGROUND AND OBJECTIVES

The objective of this meta-analysis is to compare the incidences of cytomegalovirus and BK polyoma virus infections in renal transplant recipients receiving a mammalian target of rapamycin inhibitor (mTOR)-based regimen compared with a calcineurin inhibitor-based regimen.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a comprehensive search for randomized, controlled trials up to January of 2016 addressing our objective. Other outcomes included acute rejection, graft loss, serious adverse events, proteinuria, wound-healing complications, and eGFR. Two review authors selected eligible studies, abstracted data, and assessed risk of bias. We assessed quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation methodology.

RESULTS

We included 28 randomized, controlled trials with 6211 participants classified into comparison 1: mTOR inhibitor versus calcineurin inhibitor and comparison 2: mTOR inhibitor plus reduced dose of calcineurin inhibitor versus regular dose of calcineurin inhibitor. Results showed decreased incidence of cytomegalovirus infection in mTOR inhibitor-based group in both comparison 1 (risk ratio, 0.54; 95% confidence interval, 0.41 to 0.72), with high quality of evidence, and comparison 2 (risk ratio, 0.43; 95% confidence interval, 0.24 to 0.80), with moderate quality of evidence. The available evidence neither confirmed nor ruled out a reduction of BK polyoma virus infection in mTOR inhibitor-based group in both comparisons. Secondary outcomes revealed more serious adverse events and acute rejections in mTOR inhibitor-based group in comparison 1 and no difference in comparison 2. There was no difference in graft loss in both comparisons. eGFR was higher in the mTOR inhibitor-based group in comparison 1 (mean difference =4.07 ml/min per 1.73 m2; 95% confidence interval, 1.34 to 6.80) and similar to the calcineurin inhibitor-based group in comparison 2. More proteinuria and wound-healing complications occurred in the mTOR inhibitor-based groups.

CONCLUSIONS

We found moderate- to high-quality evidence of reduced risk of cytomegalovirus infection in renal transplant recipients in the mTOR inhibitor-based compared with the calcineurin inhibitor-based regimen. Our review also suggested that a combination of a mTOR inhibitor and a reduced dose of calcineurin inhibitor may be associated with similar eGFR and rates of acute rejections and serious adverse events compared with a standard calcineurin inhibitor-based regimen at the expense of higher incidence of proteinuria and wound-healing complications.

Influence of CYP3A4 and CYP3A5 polymorphisms on tacrolimus and sirolimus exposure in stable kidney transplant recipients

BACKGROUND

Polymorphisms in genes encoding for drug-metabolizing enzymes and drug transporters are among multiple factors that modulate the pharmacokinetic variability of tacrolimus (TAC) and sirolimus (SRL). This study aimed to evaluate the influence of single nucleotide polymorphisms (SNPs) on TAC and SRL dose-adjusted concentrations (C0/D) in stable kidney transplant recipients.

METHODS

This is an exploratory and prospective study, which includes 46 stable kidney transplant recipients. These patients were monitored from the 3rd to the 24th month after transplantation. The SRL group consisted of 25 patients receiving TAC, prednisone (PRED), and mycophenolate sodium (MPS), which were converted from TAC to SRL at 3rd month after transplantation. The TAC group consisted of 21 patients who underwent treatment with TAC, PRED, and MPS. Both groups were genotyped for CYP3A4 rs2242480 (g.20230G>A), CYP3A5 rs15524 (g.31611C>T), CYP2C8 rs10509681 (c.1196A>G) and ABCB1 rs1045642 (c.3435C>T), rs1128503 (c.1236C>T), and rs2032582 (c.2677G>T/A) polymorphisms.

RESULTS

In the TAC group, CYP3A4 rs2242480 A allele carriers were associated with lower TAC C0/D. For CYP3A5 rs15524 SNP, C0/D was higher among patients carrying TT genotype when compared with CT and CC genotype carriers in the SRL and, more consistently, in the TAC groups. For ABCB1 rs1045642 SNP, TT genotype was associated with reduced SRL C0/D, but only at month 15.

CONCLUSIONS

CYP3A4 rs2242480 and CYP3A5 rs15524 SNPs resulted in significant changes in SRL and TAC C0/D at different times after transplantation.

Wound Healing Complications in Kidney Transplant Recipients Receiving Everolimus

BACKGROUND

De novo use of mammalian target of rapamycin inhibitors after kidney transplantation is associated with a concentration-dependent incidence of wound healing adverse events (WHAE). The objective of this analysis was to compare the incidence of WHAE in patients receiving everolimus (EVR) or mycophenolate sodium (MPS).

METHODS

This was a predefined subanalysis of a single-center prospective randomized study in which 288 kidney transplant recipients receiving tacrolimus and prednisone were randomized for 3 different regimens: rabbit antithymocyte globulin (r-ATG)/EVR (N = 85); basiliximab (BAS)/EVR (N = 102); BAS/MPS (N = 101). Clinical WHAE were prospectively collected using a prespecified case report form in all study visits. Abdominal ultrasound was performed at 30 days posttransplant to capture subclinical abnormalities. Surgeons were blinded to randomized treatment and no specific surgical procedures were implemented.

RESULTS

A higher proportion of patients in BAS/EVR showed at least 1 clinical WHAE (22.3% vs 35.3% vs 22.0%, P = 0.03) and total clinical and subclinical WHAE (35% vs 42% vs 26%, P = 0.014) compared with BAS/MPS, respectively. A higher proportion of patients in r-ATG/EVR showed subclinical WHAE (13% vs 7% vs 4%, P = 0.025) compared with BAS/MPS, respectively. Patients receiving EVR showed a higher risk of developing clinical or subclinical WHAE (r-ATG/EVR vs BAS/MPS hazard ratio 1.30; BAS/EVR vs BAS/MPS hazard ratio 1.73, P = 0.028).

CONCLUSIONS

In this cohort of de novo kidney transplant recipients receiving tacrolimus and prednisone, the use of EVR was associated with higher incidence of combined clinical and subclinical WHAE compared with MPS.

Donor-Specific Anti-Human Leukocyte Antigens Antibodies, Acute Rejection, Renal Function, and Histology in Kidney Transplant Recipients Receiving Tacrolimus and Everolimus

BACKGROUND

This analysis compared efficacy, renal function, and histology in kidney transplant recipients receiving tacrolimus (TAC) combined with everolimus (EVR) or mycophenolate (MPS).

METHODS

This was a retrospective analysis from a randomized trial in kidney transplant recipients who received a single 3 mg/kg dose of rabbit antithymocyte globulin (r-ATG), TAC, EVR, and prednisone (PRED; r-ATG/EVR, n = 85), basiliximab (BAS), TAC, EVR, and PRED (BAS/EVR, n = 102) or BAS, TAC, MPS, and PRED (BAS/MPS, n = 101). We evaluated the incidence of de novo donor-specific anti-human leukocyte antigens antibodies (DSA) and histology on protocol biopsies at 12 months, and the incidence of acute rejection, estimated glomerular filtration rate (eGFR) and proteinuria at 36 months.

RESULTS

At 12 months, there were no differences in de novo DSA (6.4 vs. 3.4 vs. 5.5%) or in subclinical inflammation (2.0 vs. 4.8 vs. 10.2%), interstitial fibrosis/tubular atrophy (57.1 vs. 58.5 vs. 53.8%) and C4d deposition (2.0 vs. 7.3 vs. 2.6%). At 36 months, there were no differences in the incidence of treatment failure (19.0 vs. 27.7 vs. 27.7%, p = 0.186), first biopsy-proven acute rejection (9.5 vs. 21.8 vs. 16.8%, p = 0.073), and urine protein/creatinine ratios (0.53 ± 1.05 vs. 0.62 ± 0.75 vs. 0.71 ± 1.24). eGFR was lower in the BAS/EVR compared to that in the BAS/MPS group (53.4 ± 20.9 vs. 50.8 ± 19.5 vs. 60.7 ± 21.2 mL/min/1.73 m2, p = 0.017) but comparable using a sensitive analysis (49.5 ± 23 vs. 47.5 ± 22.6 vs. 53.6 ± 27.8 mL/min/1.73 m2, p = 0.207).

CONCLUSION

In this cohort, the use of EVR and reduced TAC concentrations were associated with comparable efficacy, renal function, and histological parameters compared to the standard-of-care immunosuppressive regimen.

Influence of ABCC2, CYP2C8, and CYP2J2 Polymorphisms on Tacrolimus and Mycophenolate Sodium-Based Treatment in Brazilian Kidney Transplant Recipients

STUDY OBJECTIVE

To investigate the influence of single nucleotide polymorphisms (SNPs) in genes encoding metabolizing enzymes (CYP2C8, CYP2J2, and UGT2B7) and transporters (ABCC2 and ABCG2) on dose and dose-adjusted trough blood concentrations (C:D ratio), clinical outcomes, and occurrence of adverse events of tacrolimus and mycophenolate sodium in Brazilian kidney transplant recipients.

DESIGN

Pharmacogenetic analysis of patients enrolled in a previously published study.

PATIENTS

One hundred forty-eight adult kidney transplant recipients treated with tacrolimus, enteric-coated mycophenolate sodium, and prednisone for 90 days posttransplantation.

MEASUREMENTS AND MAIN RESULTS

ABCC2 c.-24C>T and c.3972C>T, ABCG2 c.421C>A, CYP2C8*3, CYP2J2 c.-76G>T, and UGT2B7 c.372A>G SNPs were determined by real-time polymerase chain reaction. The CYP3A5*3C SNP data were used to eliminate the confounding effect of this variant on the results. ABCC2 c.3972T allele carriers showed higher tacrolimus C:D values than did carriers of the c.3972CC genotype. The CYP2C8*3 variant was also associated with slightly higher tacrolimus C:D values and higher estimated glomerular filtration rate but only in CYP3A5-nonexpressing patients (CYP3A5*3C/*3C carriers). None of the SNPs were associated with mycophenolate sodium dose or episodes of biopsy-confirmed acute rejection or delayed graft function. The CYP2J2 c.-76T allele was associated with increased risk for treatment-induced nausea and/or vomiting (OR: 5.30, 95% confidence interval 1.49-18.79, p<0.05).

CONCLUSION

The ABCC2 c.3972C >T polymorphism affected tacrolimus C:D in Brazilian kidney transplant recipients. Further, CYP2C8*3 and CYP2J2 c.-76G>T SNPs influenced the renal function of these patients and the occurrence of adverse events during treatment with tacrolimus and mycophenolate sodium.

Influence of the CYP3A4/5 genetic score and ABCB1 polymorphisms on tacrolimus exposure and renal function in Brazilian kidney transplant patients

BACKGROUND

Polymorphisms in genes encoding transport proteins and metabolizing enzymes involved in tacrolimus (TAC) disposition may be important sources of individual variability during treatment.

OBJECTIVE

The aim of this study was to investigate the effect of combined CYP3A4 and CYP3A5 variants, using a CYP3A4/5 genetic score, and ABCB1 polymorphisms on therapeutic TAC monitoring and their relationship with clinical outcomes.

MATERIAL AND METHODS

Brazilian kidney transplant recipients (n=151), who received TAC over 3 months after transplantation, were genotyped for CYP3A4 rs2242480 (g.20230G>A), CYP3A5 rs15524 (g.31611C>T) and rs776746 (g.6986A>G), ABCB1 rs1128503 (c.1236C>T), rs1045642 (c.3435C>T), and rs2032582 (c.2677G>T/A) polymorphisms.

RESULTS

Frequencies of CYP3A4 g.20230A, CYP3A5 g.31611C, and g.6986A were 0.37, 0.26, and 0.28, respectively. These alleles were associated with TAC rapid metabolization and were used for CYP3A4/5 genetic score construction. A higher CYP3A4/5 genetic score was associated with higher TAC dose and lower concentrations for dose administered (Co/D, P<0.05). Ninety days after transplantation, the presence of two or more rapid metabolization alleles contributed toward 27.7% of Co/D variability and was associated with a lower estimated glomerular filtration rate values (P<0.05). For ABCB1, the frequencies of c.1236T, c.3435T, and c.2677T/A alleles were 0.42, 0.42, and 0.33/0.04. At 30 days after transplantation, patients carrying ABCB1 c.1236TT+c.3435TT+(c.2677TT+TA) genotypes had higher TAC Co/D than those with common or heterozygous genotypes (P<0.05).

CONCLUSION

The results show the impact of the CYP3A4/5 genetic score on TAC exposure and renal function in Brazilian patients. Furthermore, ABCB1 polymorphisms, in a combined analysis, influenced TAC Co/D at 30 days after transplantation.

Association of the PPP3CA c.249G>A variant with clinical outcomes of tacrolimus-based therapy in kidney transplant recipients

BACKGROUND

The effects of genetic variants related to the pharmacodynamic mechanisms of immunosuppressive drugs on their therapeutic efficacy and safety have been poorly explored. This study was performed to investigate the influence of the PPP3CA c.249G>A variant on the clinical outcomes of kidney transplant recipients.

PATIENTS AND METHODS

A total of 148 Brazilian patients received tacrolimus (TAC)-based immunosuppressive therapy for 90 days post-kidney transplantation. The PPP3CA rs3730251 (c.249G>A) polymorphism was determined by real-time polymerase chain reaction. Single-nucleotide polymorphism (SNP) data for CYP3A5 rs776746 (CYP3A5*3C; g.6986A>G) were used to eliminate the confounding effects of this variant.

RESULTS

The PPP3CA c.249G>A SNP did not influence early TAC exposure, renal function, or other laboratory parameters, including levels of urea, creatinine, glucose, and lipids, and blood counts. This variant also did not account for the cumulative incidence of biopsy-confirmed acute rejection or delayed graft function. Regarding adverse events, PPP3CA c.249A allele carriers initially had a 3.05-fold increased probability of treatment-induced blood and lymphatic system disorders compared with c.249GG genotype individuals (95% confidence interval: 1.10-8.48, p=0.032). However, this result was not maintained after adjusting for body weight and CYP3A5*3C SNP status (p=0.086).

CONCLUSION

The PPP3CA c.249G>A variant does not influence the clinical outcomes of Brazilian patients in the early phase of TAC-based immunosuppressive regimen.

Systemic meta-analysis assessing the short term applicability of early conversion to mammalian target of rapamycin inhibitors in kidney transplant

AIM

To consolidate the present evidence of effectiveness in renal functioning and graft survival following early introduction of mammalian target of rapamycin (mTOR) inhibitors with or without calcineurin inhibitors (CNIs) in renal transplant recipients.

METHODS

We analysed the current literature following PROSPERO approval describing the role of immunosuppressive agent, mTOR inhibitors as an alternative to CNI within six months of renal transplant by searching the PubMed, EMBASE, Cochrane, Crossref, and Scopus using MeSH terms.

RESULTS

Six articles of early withdrawal of CNI and introduction of mTOR-inhibitors within six months of renal transplantation were sought. Glomerular filtration rate (GFR) and serum creatinine were significantly better in mTOR inhibitor group with equivalent survival at 12 mo, even though Biopsy Proven Acute rejection was significantly higher in mTOR-inhibitor group.

CONCLUSION

The evidence reviewed in this meta-analysis suggests that early introduction mTOR-inhibitors substantial CNI minimization. The mTOR inhibitors such as everolimus and sirolimus, due to their complementary mechanism of action and favourable nephrotoxicity profile; better glomerular filtration, lower serum creatinine with equivalent survival. Having said that, due to the higher rejection rate, may influence the use of these regimens to patients with moderate to high immunological risk patients.

Safety and Efficacy Outcomes 3 Years After Switching to Belatacept From a Calcineurin Inhibitor in Kidney Transplant Recipients: Results From a Phase 2 Randomized Trial

BACKGROUND

In a phase 2 study, kidney transplant recipients of low immunologic risk who switched from a calcineurin inhibitor (CNI) to belatacept had improved kidney function at 12 months postconversion versus those continuing CNI therapy, with a low rate of acute rejection and no transplant loss.

STUDY DESIGN

36-month follow-up of the intention-to-treat population.

SETTING & PARTICIPANTS

CNI-treated adult kidney transplant recipients with stable transplant function (estimated glomerular filtration rate [eGFR], 35-75mL/min/1.73m²).

INTERVENTIONS

At 6 to 36 months posttransplantation, patients were randomly assigned to switch to belatacept-based immunosuppression (n=84) or continue CNI-based therapy (n=89).

OUTCOMES

Safety was the primary outcome. eGFR, acute rejection, transplant loss, and death were also assessed.

MEASUREMENTS

Treatment exposure-adjusted incidence rates for safety, repeated-measures modeling for eGFR, Kaplan-Meier analyses for efficacy.

RESULTS

Serious adverse events occurred in 33 (39%) belatacept-treated patients and 36 (40%) patients in the CNI group. Treatment exposure-adjusted incidence rates for serious infections (belatacept vs CNI, 10.21 vs 9.31 per 100 person-years) and malignancies (3.01 vs 3.41 per 100 person-years) were similar. More patients in the belatacept versus CNI group had any-grade viral infections (14.60 vs 11.00 per 100 person-years). No posttransplantation lymphoproliferative disorder was reported. Belatacept-treated patients had a significantly greater estimated gain in mean eGFR (1.90 vs 0.07mL/min/1.73m² per year; P for time-by-treatment interaction effect = 0.01). The probability of acute rejection was not significantly different for belatacept (8.38% vs 3.60%; HR, 2.50 [95% CI, 0.65-9.65; P=0.2). HR for the comparison of belatacept to the CNI group for time to death or transplant loss was 1.00 (95% CI, 0.14-7.07; P=0.9).

LIMITATIONS

Exploratory post hoc analysis with a small sample size.

CONCLUSIONS

Switching patients from a CNI to belatacept may represent a safe approach to immunosuppression and is being further explored in an ongoing phase 3b trial.

Immunosuppression for kidney transplantation: Where are we now and where are we going?

Advances in immunosuppression have propelled kidney transplantation from a scientific curiosity to the optimal treatment for patients with end stage kidney disease. Declining rates of acute rejection have led to improvements in short term kidney transplant survival, culminating in incrementally better long term patient and allograft outcomes. Contextualized around established immune-suppressing drug targets, this review summarizes the history of the clinical science and highlights the pivotal trials that have led to present-day treatment standards at the level of both individual agents and multidrug regimens for kidney recipients. Finally, recently approved and emerging therapies are discussed, with an emphasis on challenges faced by clinicians managing this increasingly complex patient population.

Calcineurin Inhibitor Minimization, Conversion, Withdrawal, and Avoidance Strategies in Renal Transplantation: A Systematic Review and Meta-Analysis

Despite their clinical efficacy, concerns about calcineurin inhibitor (CNI) toxicity make alternative regimens that reduce CNI exposure attractive for renal transplant recipients. In this systematic review and meta-analysis, we assessed four CNI immunosuppression strategies (minimization, conversion, withdrawal, and avoidance) designed to reduce CNI exposure and assessed the impact of each on patient and allograft survival, acute rejection and renal function. We evaluated 92 comparisons from 88 randomized controlled trials and found moderate- to high-strength evidence suggesting that minimization strategies result in better clinical outcomes compared with standard-dose regimens; moderate-strength evidence indicating that conversion to a mammalian target of rapamycin inhibitor or belatacept was associated with improved renal function but increased rejection risk; and moderate- to high-strength evidence suggesting planned CNI withdrawal could result in improved renal function despite an association with increased rejection risk. The evidence base for avoidance studies was insufficient to draw meaningful conclusions. The applicability of the review is limited by the large number of studies examining cyclosporine-based strategies and low-risk populations. Additional research is needed with tacrolimus-based regimens and higher risk populations. Moreover, research is necessary to clarify the effect of induction and adjunctive agents in alternative immunosuppression strategies and should include more comprehensive and consistent reporting of patient-centered outcomes.

Open-Label, Randomized Study of Transition From Tacrolimus to Sirolimus Immunosuppression in Renal Allograft Recipients

Calcineurin inhibitor–associated nephrotoxicity and other adverse events have prompted efforts to minimize/eliminate calcineurin inhibitor use in kidney transplant recipients.

Time-Dependent and Immunosuppressive Drug-Associated Adverse Event Profiles in De Novo Kidney Transplant Recipients Converted from Tacrolimus to Sirolimus Regimens

STUDY OBJECTIVE

To evaluate the safety and tolerability of immunosuppressive drugs used in a planned randomized conversion from a calcineurin inhibitor, tacrolimus, to a mammalian target of rapamycin inhibitor, sirolimus, in de novo kidney transplant recipients.

DESIGN

Prospective safety analysis of data from a prospective, randomized, open-label, controlled study.

PATIENTS

A total of 119 adult kidney transplant recipients who received tacrolimus (TAC), mycophenolate sodium (MPS), and prednisone between February 2008 and May 2010; after 3 months of this regimen, 60 of these patients were randomized to conversion from TAC to sirolimus (SRL/MPS group), and 59 patients continued with the TAC regimen (TAC/MPS group).

MEASUREMENTS AND MAIN RESULTS

Both groups were followed for 24 months after transplantation for immunosuppressive regimen-associated and time-dependent occurrences of adverse events (AEs) and serious adverse events (SAEs). Before conversion from TAC to SRL, the cumulative incidence of AEs was 98%; 25% were SAEs. Gastrointestinal AEs (66%) and infections (58%) were the most frequent AEs. The incidences of TAC and MPS dose reductions due to AEs were 1.7% and 12%, respectively. After conversion, no significant differences were noted in the SRL/MPS group versus the TAC/MPS group in the cumulative incidences of AEs (100% vs. 98%) and SAEs (27% vs. 30%). The most common AEs were gastrointestinal (70% vs. 54%, p=0.23) and infection (77% vs. 73%, p=0.79) in the SRL/MPS versus TAC/MPS groups. The incidence of aphthous ulcer (28% vs. 0%, p=< 0.01), sinusitis (10% vs. 0%, p=0.01), dermatitis (15% vs. 3%, p=0.03), and dyslipidemia (35% vs. 14%, p=0.02) were higher in the SRL/MPS group compared with the TAC/MPS group. Cox proportion regression analysis showed a higher relative risk for gastrointestinal (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.2-3.01, p<0.05) and skin and subcutaneous tissue (HR 2.5, 95% CI 1.1-4.1, p<0.05) AEs in the SRL/MPS group compared with the TAC/MPS group. AE-related dose reductions occurred in 18.3% of patients receiving SRL and 3.3% of patients receiving TAC. MPS dose reductions due to AEs occurred in 11.7% of patients receiving SRL and 13.6% of patients receiving TAC.

CONCLUSION

SRL/MPS treatment was associated with a time-dependent higher incidence of gastrointestinal and skin and subcutaneous tissue AEs, which occurred mainly during the first 6 months after conversion from TAC/MPS. Although the treatments with SRL or TAC after 3 months of transplantation showed different safety profiles, both regimens demonstrated adequate tolerability, with low rates of early discontinuation related to AEs.

Sirolimus-Based Immunosuppressive Regimens in Renal Transplantation: A Systemic Review

Sirolimus (SRL)-based immunosuppressive regimens have been used for preventing rejection after kidney transplantation. This review analyzes their merits and demerits compared with other conventional regimes from the aspects of acute rejection rate, graft function, as well as patient/graft survival rates. In general, SRL is mostly recommended to be used as conversion therapy from calcineurin inhibitor (CNI) after kidney transplantation in most studies. Minimization or withdrawal of cyclosporine A (CsA) could also be considered when it was combined with SRL. SRL can replace mycophenolate mofetil (MMF), and the CNI dose should be reduced appropriately in this setting. Quadruple maintenance regimens containing SRL need future study to clarify their superiority. De novo use of low-dose CNI combined with SRL has no apparent merits and thus is not recommended. De novo use of standard-dose CNI combined with SRL followed by maintenance, de novo use of CNI-free regimens, as well as SRL use in delayed graft function (DGF) patients who spare antibody induction and postpone CNI administration should also be avoided. SRL supports steroids withdrawal after kidney transplantation, and SRL combined with tacrolimus is recommended in this setting. Loading dose is recommended when initiating SRL treatment and its trough blood level should be routinely monitored.

Reviewing 15 years of experience with sirolimus

Here, we review 15 years of clinical use of sirolimus in our transplant center, in context with the developing immunosuppressive strategies use worldwide. The majority of studies were conducted in de novo kidney transplant recipients, using sirolimus (SRL) in combination with calcineurin inhibitors (CNIs). We also explored steroid (ST) or CNI-sparing therapies, including CNI minimization, elimination, or conversion strategies in combination with mycophenolate (MMF/MPS). Pooled long-term outcomes were comparable with those obtained with CNI and antimetabolite combination. Surprisingly, there are still several areas that need further investigation to improve the risk/benefit profile of SRL in kidney transplantation, including pharmacokinetic/pharmacodynamic drug-to-drug interaction with cyclosporine (CsA) or tacrolimus (TAC), mechanisms of SRL-associated adverse reactions and combinations with other drugs such as belatacept and once-daily TAC, possibly leading to improved long-term adherence. These studies, along with others investigating the benefits of SRL associated lower viral infections and malignancies, are essential as we do not expect the introduction of new immunosuppressive drugs in the near future.

Sirolimus effects on cancer incidence after kidney transplantation: a meta-analysis

Sirolimus, an immunosuppressant option for kidney transplant recipients, may reduce cancer risk by interrupting the mammalian target of rapamycin pathway. However, studies of sirolimus and cancer incidence in kidney recipients have not been definitive, and have had limited ability to examine specific cancer types. The literature was systematically reviewed to identify randomized controlled trials (RCTs) and observational studies of kidney recipients that compared sirolimus users to sirolimus nonusers. Meta-analytic methods were used to obtain pooled estimates of the association between sirolimus use and incidence of total cancer and specific cancer types. Estimates were stratified by study type (RCT vs. observational) and use of cyclosporine (an immunosuppressant that affects DNA repair). Twenty RCTs and two observational studies were eligible for meta-analysis, including 39,039 kidney recipients overall. Sirolimus use was associated with lower overall cancer incidence (incidence rate ratio [IRR] = 0.71, 95% CI = 0.56-0.90), driven by a reduction in incidence of nonmelanoma skin cancer (NMSC, IRR = 0.49, 95% CI = 0.32-0.76). The protective effect of sirolimus on NMSC risk was most notable in studies comparing sirolimus against cyclosporine (IRR = 0.19, 95% CI = 0.04-0.84). After excluding NMSCs, there was no overall association between sirolimus and incidence of other cancers (IRR = 1.06, 95% CI = 0.69-1.63). However, sirolimus use had associations with lower kidney cancer incidence (IRR = 0.40, 95% CI = 0.20-0.81), and higher prostate cancer incidence (IRR = 1.85, 95% CI = 1.17-2.91). Among kidney recipients, sirolimus users have lower NMSC risk, which may be partly due to removal of cyclosporine. Sirolimus may also reduce kidney cancer risk but did not appear protective for other cancers, and it may actually increase prostate cancer risk.

Fibrosis progression according to epithelial-mesenchymal transition profile: a randomized trial of everolimus versus CsA

Markers of epithelial-mesenchymal transition (EMT) may identify patients at high risk of graft fibrogenesis who could benefit from early calcineurin inhibitor (CNI) withdrawal. In a randomized, open-label, 12-month trial, de novo kidney transplant patients received cyclosporine, enteric-coated mycophenolate sodium (EC-MPS) and steroids to month 3. Patients were stratified as EMT+ or EMT- based on month 3 biopsy, then randomized to start everolimus with half-dose EC-MPS (720 mg/day) and cyclosporine withdrawal (CNI-free) or continue cyclosporine with standard EC-MPS (CNI). The primary endpoint was progression of graft fibrosis (interstitial fibrosis/tubular atrophy [IF/TA] grade increase ≥1 between months 3-12) in EMT+ patients. 194 patients were randomized (96 CNI-free, 98 CNI); 153 (69 CNI-free, 84 CNI) were included in histological analyses. Fibrosis progression occurred in 46.2% (12/26) CNI-free EMT+ patients versus 51.6% (16/31) CNI EMT+ patients (p = 0.68). Biopsy-proven acute rejection (BPAR, including subclinical events) occurred in 25.0% and 5.1% of CNI-free and CNI patients, respectively (p < 0.001). In conclusion, early CNI withdrawal with everolimus initiation does not prevent interstitial fibrosis. Using this CNI-free protocol, in which everolimus exposure was relatively low and administered with half-dose EC-MPS, CNI-free patients were overwhelmingly under-immunosuppressed and experienced an increased risk of BPAR.

Post-transplant soluble CD30 levels are associated with early subclinical rejection in kidney transplantation

Several studies have shown association of high pre- or post-transplant levels of soluble CD30 (sCD30) with acute rejection and poor late kidney transplant outcome. Our goal was to investigate whether sCD30 levels at month-3 post-transplant are associated with subclinical rejection, presence of CD30(+) cells within the graft, and expression of immune response genes in peripheral blood mononuclear cells. The study comprised 118 adult first kidney graft recipients, transplanted at a single center, receiving tacrolimus in low concentration. All were submitted to a protocol biopsy at month-3. Subclinical rejection was identified in 10 biopsies and sCD30 levels ≥ 61.88 ng/mL (P = 0.004), younger recipient age (P = 0.030) and non-Caucasian ethnicity (P = 0.011) were independently associated with this outcome. Rare CD30(+) cells were present in only two biopsies. There was a correlation between sCD30 levels and CD30 gene expression in peripheral blood mononuclear cells (r = 0.385, P = 0.043). These results show that high sCD30 levels are independent predictors of graft dysfunction and may contribute to patient selection protocols by indicating those who could benefit from a more thorough evaluation.

Recent trials in immunosuppression and their consequences for current therapy

PURPOSE OF REVIEW

Although the scarcity of clinical trials with de-novo immunosuppression has been typical over the last 2 years, several attempts have been made in drug conversion, dosing optimization, and bioequivalence. On the basis of recent clinical and animal studies, future directions of management and treatment are outlined.

RECENT FINDINGS

Studies with new tacrolimus formulations showed better bioavailability and lower doses, which might translate into less toxicity. The long-term results of studies with costimulation blockade confirmed their safety and efficacy. Calcineurin inhibitor (CNI)-free regimens based on mTOR inhibitors were shown to be associated with increased risk of the humoral response. Therefore, ongoing trials are predominantly designed to minimize calcineurin inhibitor dose only. Biologics, such as B-cell-specific agents (bortezomib and rituximab) and complement inhibitors (eculizumab) used to treat antibody-mediated rejection, recurrence of glomerulonephritis, are shifted to more preventive applications. The pretransplant quantification of alloreactive memory/effector T cell response may help to better stratify a patient's immunologic risk and allow for drug minimization.

SUMMARY

Despite clinical trials with innovative protocols with already established agents, tacrolimus-based and induction-based protocols have been shown to be the mainstay of immunosuppressive regimens. In the future, research aims to focus on biomarker-driven immunosuppression and cell therapy approaches.

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.

Risk of metabolic complications in kidney transplantation after conversion to mTOR inhibitor: a systematic review and meta-analysis

Mammalian target of rapamycin (mTOR) inhibitors have been used in transplantation with the hope of minimizing calcineurin inhibitor (CNI)-induced nephrotoxicity. However, mTOR inhibitors are also associated with a range of side effects, including metabolic complications. We aimed to determine the risks of metabolic complications after the conversion from CNI to mTOR inhibitor postkidney transplant. A systematic search in PubMed up to September 2013 identified nine relevant trials (a total of 2323 patients). The primary end points were the relative risks (RRs) of new-onset diabetes after transplant (NODAT) and hypercholesterolemia. The overall RRs of NODAT and hypercholesterolemia associated with mTOR inhibitors were 1.32 (95% confidence interval [CI] 0.92-1.87) and 2.15 (95% CI 1.35-3.41), respectively, compared with CNI-based regimen. Subgroup analyses revealed no differences in the incidence of NODAT or hypercholesterolemia between sirolimus- versus everolimus-based regimen, or between early versus late conversion. Analyses of secondary outcomes revealed a higher risk of acute rejection, proteinuria and anemia, but no difference in the risk of opportunistic infections after mTOR inhibitor conversion. In conclusion, the conversion from CNI to mTOR inhibitor in low-to-moderate risk kidney transplant recipients was associated with nonsignificant trend toward increased risk of NODAT and significant increase in hypercholesterolemia, acute rejection, proteinuria and anemia.

Renal function three years after early conversion from a calcineurin inhibitor to everolimus: results from a randomized trial in kidney transplantation

In a 36-month, open-label, multicenter trial, 202 kidney transplant recipients were randomized at week 7 post-transplant to convert to everolimus or remain on cyclosporine: 182 were analyzed to month 36 (92 everolimus, 90 controls). Mean (SD) change in measured GFR (mGFR) from randomization to month 36 was 1.3 (14.0) ml/min with everolimus versus -1.7 (15.4) ml/min in controls (P = 0.210). In patients who remained on treatment, mean mGFR improved from randomization to month 36 by 7.9 (11.5) ml/min with everolimus (n = 37) but decreased by 1.4 (14.7) ml/min in controls (n = 62) (P = 0.001). During months 12-36, death-censored graft survival was 100%, patient survival was 98.9% and 96.7% in the everolimus and control groups, respectively, and 13.0% and 11.1% of everolimus and control patients, respectively, experienced mild biopsy-proven acute rejection (BPAR). Protocol biopsies in a limited number of on-treatment patients showed similar interstitial fibrosis progression. Donor-specific antibodies were present at month 36 in 6.3% (2/32) and 18.0% (9/50) of on-treatment everolimus and control patients with available data (P = 0.281). During months 12-36, adverse events were comparable, but discontinuation was more frequent with everolimus (33.7% vs. 10.0%). Conversion from cyclosporine to everolimus at 7 weeks post-transplant was associated with a significant benefit in renal function at 3 years when everolimus was continued.

Rapamycin promotes Schwann cell migration and nerve growth factor secretion

Rapamycin, similar to FK506, can promote neural regeneration in vitro. We assumed that the mechanisms of action of rapamycin and FK506 in promoting peripheral nerve regeneration were similar. This study compared the effects of different concentrations of rapamycin and FK506 on Schwann cells and investigated effects and mechanisms of rapamycin on improving peripheral nerve regeneration. Results demonstrated that the lowest rapamycin concentration (1.53 nmol/L) more significantly promoted Schwann cell migration than the highest FK506 concentration (100μmol/L). Rapamycin promoted the secretion of nerve growth factors and upregulated growth-associated protein 43 expression in Schwann cells, but did not significantly affect Schwann cell proliferation. Therefore, rapamycin has potential application in peripheral nerve regeneration therapy.

Renal function to 5 years after late conversion of kidney transplant patients to everolimus: a randomized trial

BACKGROUND

Few trials have investigated late preemptive conversion of kidney transplant patients from a calcineurin inhibitor (CNI) to an mTOR inhibitor.

METHODS

In an open-label, 12-month, prospective, randomized, parallel-group study, maintenance kidney transplant patients (>6 months post-transplant) either switched from CNI to everolimus or continued their current CNI regimen. Patients who completed the core study were followed to 5 years post-randomization.

RESULTS

Of 93 randomized patients, 78 completed the core study and 67 attended the final 60-month study visit. Mean time post-transplant at baseline was 82.6 months and 70.5 months in the everolimus and CNI groups, respectively. At month 60, adjusted mean eGFR (Nankivell) was 63.0 (95% CI 57.8, 68.2) mL/min/1.73 m(2) in the everolimus group versus 57.9 (95% CI 52.6, 63.1) mL/min/1.73 m(2) in the CNI group, a difference of 5.1 (95% CI -0.6, 10.8) mL/min/1.73 m(2) (p = 0.076). Among patients who remained on randomized study drug at month 60, mean eGFR (Nankivell) was 71.6 (95% CI 64.2, 79.0) mL/min/1.73 m(2) in everolimus-treated patients (n = 21) versus 60.6 (95% CI 55.1, 66.1) mL/min/1.73 m(2) in CNI-treated patients (n = 29) (mean difference 11.0; 95% CI 3.6, 18.5 mL/min/1.73 m(2); p = 0.005). No cases of BPAR occurred from randomization to month 60 in either group. Graft loss occurred in three everolimus-treated patients and one CNI-treated patient. No unexpected safety concerns were observed in either group.

CONCLUSION

Late preemptive conversion of maintenance kidney transplant patients from CNI to everolimus may be associated with improved long-term renal function and preserves immunosuppressive efficacy. Patient numbers were low, but these findings merit further investigation.