Sirolimus conversion in liver transplant recipients with renal dysfunction: a prospective, randomized, single-center trial

Third dose of BNT162b2 improves immune response in liver transplant recipients to ancestral strain but not Omicron BA.1 and XBB

Vaccine immunogenicity in transplant recipients can be impacted by the immunosuppressive (IS) regimens they receive. While BNT162b2 vaccination has been shown to induce an immune response in liver transplant recipients (LTRs), it remains unclear how different IS regimens may affect vaccine immunogenicity after a third BNT162b2 dose in LTRs, which is especially important given the emergence of the Omicron sublineages of SARS-CoV-2. A total of 95 LTRs receiving single and multiple IS regimens were recruited and offered three doses of BNT162b2 during the study period. Blood samples were collected on days 0, 90, and 180 after the first BNT162b2 dose. At each time point, levels of anti-spike antibodies, their neutralizing activity, and specific memory B and T cell responses were assessed. LTRs receiving single IS regimens showed an absence of poor immunogenicity, while LTRs receiving multiple IS regimens showed lower levels of spike-specific antibodies and immunological memory compared to vaccinated healthy controls after two doses of BNT162b2. With a third dose of BNT162b2, spike-specific humoral, memory B, and T cell responses in LTR significantly improved against the ancestral strain of SARS-CoV-2 and were comparable to those seen in healthy controls who received only two doses of BNT162b2. However, LTRs receiving multiple IS regimens still showed poor antibody responses against Omicron sublineages BA.1 and XBB. A third dose of BNT162b2 may be beneficial in boosting antibody, memory B, and T cell responses in LTRs receiving multiple IS regimens, especially against the ancestral Wuhan strain of SARS-CoV-2. However, due to the continued vulnerability of LTRs to presently circulating Omicron variants, antiviral treatments such as medications need to be considered to prevent severe COVID-19 in these individuals.

mTORi-based immunosuppression reduces HCC recurrence at the expense of increased adverse side effects: A systematic review and meta-analysis

Sirolimus and everolimus are mammalian target of rapamycin inhibitors (mTORi) that can reduce relapse rates following liver transplantation (LT) for hepatocellular carcinoma (HCC). Herein, we performed a systematic review and meta-analysis to investigate the efficacy of mTORi and calcineurin inhibitors (CNI) in reducing HCC recurrence and survival adverse effects (AEs) in HCC patients after LT. Systematic literature searches were conducted using MEDLINE, EMBASE, and Cochrane Library databases up to October 2021. The primary outcomes of interest were tumor recurrence rates and overall survival. The secondary outcomes were the characterization and incidence of AEs. A total of 38 trials involving 10,607 participants was included in the analysis. The incidence of recurrence and overall mortality was significantly lower in the mTORi than in the CNI group (relative ratio [RR]: .78, 95% confidence interval [CI]: .68-.89 and RR: .76, 95% CI: .67-.86, respectively). The incidence of some AEs and complications such as acne, anemia, abnormal healing, dyslipidemia, depression, diarrhea, edema, headache/migraine, hypercholesterolemia, incisional hernia, infection, leukopenia, mouth ulceration, pyrexia, proteinuria, pruritis, rash, and thrombocytopenia were higher in the mTORi than in the CNI group. mTORi reduced the recurrence incidence and overall 5-year mortality rate but increased many other incidences of AEs compared with that by CNI. Therefore, clinicians should be aware of the risks and benefits of mTORi use when managing patients undergoing LT for HCC.

Peritransplant Renal Dysfunction in Liver Transplant Candidates

Renal function is intricately tied to Model for End-Stage Liver Disease score and overall prognosis among patients with cirrhosis. The estimation of glomerular filtration rate (GFR) and etiology of renal impairment are even more magnified among cirrhotic patients in the period surrounding liver transplantation. Novel biomarkers including cystatin C and urinary neutrophil gelatinase-associated lipocalin have been demonstrated to more accurately assess renal dysfunction and aid in the diagnosis of competing etiologies. Accurately identifying the severity and chronicity of renal dysfunction among transplant candidates is an imperative component with respect to stratifying patients toward simultaneous liver-kidney transplantation versus liver transplantation alone.

[Kidney failure after liver transplantation]

One third of cirrhotic patients present impaired kidney function. It has multifactorial causes and has a harmful effect on patients' morbi-mortality before and after liver transplant. Kidney function does not improve in all patients after liver transplantation and liver-transplant recipients are at high risk of developing chronic kidney disease. Causes for renal dysfunction can be divided in three groups: preoperative, peroperative and postoperative factors. To date, there is no consensus for the modality of evaluation the risk for chronic kidney disease after liver transplantation, and for its prevention. In the present review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease to determine a risk stratification for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this setting, and highlight the indications of combined liver-kidney transplantation.

Kidney Disease After Nonkidney Solid Organ Transplant

Nonkidney solid organ transplants (NKSOTs) are increasing in the United States with improving long-term allograft and patient survival. CKD is prevalent in patients with NKSOT and is associated with increased morbidity and mortality especially in those who progress to end-stage kidney disease. Calcineurin inhibitor nephrotoxicity is a main contributor to CKD after NKSOT, but other factors in the pretransplant, peritransplant, and post-transplant period can predispose to progressive kidney dysfunction. The management of CKD after NKSOT generally follows society guidelines for native kidney disease. Kidney-protective and calcineurin inhibitor-sparing immunosuppression has been explored in this population and warrants a discussion with transplant teams. Kidney transplantation in NKSOT recipients remains the kidney replacement therapy of choice for suitable candidates, as it provides a survival benefit over remaining on dialysis.

Kidney Failure after Liver Transplantation

One-third of patients with cirrhosis present kidney failure (AKI and CKD). It has multifactorial causes and a harmful effect on morbidity and mortality before and after liver transplantation. Kidney function does not improve in all patients after liver transplantation, and liver transplant recipients are at a high risk of developing chronic kidney disease. The causes of renal dysfunction can be divided into three groups: pre-operative, perioperative and post-operative factors. To date, there is no consensus on the modality to evaluate the risk of chronic kidney disease after liver transplantation, or for its prevention. In this narrative review, we describe the outcome of kidney function after liver transplantation, and the prognostic factors of chronic kidney disease in order to establish a risk categorization for each patient. Furthermore, we discuss therapeutic options to prevent kidney dysfunction in this context, and highlight the indications of combined liver–kidney transplantation.

Effect of cyclosporin and tacrolimus on kidney function in liver recipients

Introduction. Chronic renal failure is a significant issue regarding treatment of patients after liver transplantation. One of the factors determining the impaired renal function after liver transplantation is a long-term immunosuppressive therapy based on calcineurin inhibitors. The objective of the study was to evaluate the dynamics of renal function, depending on the use of various calcineurin inhibitors in the long-term postoperative period in liver recipients in real clinical practice.

Materials and methods. A retrospective analysis of the renal function in patients operated in the State Public Health Budget Institution “Scientific Research Institute – S.V. Ochapovsky Regional Clinic Hospital № 1”, Krasnodar Region, was carried out. This article describes dynamics of creatinine level and glomerular filtration rate (GFR) in patients before liver transplant, as well as 6 months, 1, 2 and 3 years after surgery. GFR was calculated using the CKD-EPI formula (Chronic Kidney Disease Epidemiology Collaboration). Statistical processing of the results was carried out using the Statistica 10 software package.

Results and discussion. Before transplantation, the level of creatinine in the blood plasma was 82.9±19.8 mmol/l, 6 months later a20.4% increase in creatinine was registered (p=0.004), 12, 24 and 36 months later – it increased by 24.8% (p=0.00001), 24.4% (p=0.0004), and 26.0% (p=0.0005), respectively. Both cyclosporine and tacrolimus caused an increase in the level of creatinine. Baseline GFR was 83.4±25.9, the reduction in GFR occurred in comparison with the baseline by 14.2% (p=0.0005), 18.8% (p=0.00001), 20.2% (p=0.00003), 22.6% % (p=0.00006) 6, 12, 24 and 36 months later, respectively. The degree of the decrease in GFR against the background of tacrolimus therapy did not differ significantly from that in case of cyclosporine. Verification of chronic kidney disease and the administration of statins were recorded in isolated cases.

Conclusions. In liver recipients, the level of creatinine rises and GFR decreases. Reduction of kidney function occurs against the background of both inhibitors of calcineurin, in connection with which it is necessary to increase the doctors’ alertness for early detection of a decrease in glomerular filtration rate with further verification of chronic kidney disease.

Proteinuria and baseline renal function predict mortality and renal outcomes after sirolimus therapy in liver transplantation recipients

Background

Chronic kidney disease is a significant complication after liver transplantation (LT), but the role of pre-existing renal insufficiency and proteinuria remains unclear among LT recipients receiving sirolimus.

Methods

We assessed the effects of proteinuria and baseline renal function on long-term renal and survival outcomes among 576 LT recipients who received SRL in a medical center between 2005 and 2014. Renal outcomes were the incidences of >50% reduction in their baseline estimated glomerular filtration rate and end stage kidney disease requiring renal replacement therapy. Proteinuria was identified using morning dipstick results (≥30 mg/dL) at baseline and within the first year after the initiation of SRL therapy. A Kaplan-Meier analysis was performed to estimate time to event. Factors associated with the outcomes were determined using the Cox proportional hazards model with a significance level set at P <0.05.

Results

During the study period, renal function deteriorated in 135 (25.3%) patients and 68 (11.8%) patients died. Persistent and new onset proteinuria contributed to a high rate of mortality and the deterioration of renal function (both log-rank tests, P <0.0001). After adjustments, new onset proteinuria within the first year after the initiation of SRL therapy increased the risk of deteriorating renal function, regardless of baseline estimated glomerular filtration rate. Moreover, pre-existing (hazard ratio = 1.91; P <0.001) and new onset diabetes (hazard ratio = 2.34; P <0.0001) were significantly associated with new onset proteinuria among SRL users.

Conclusions

These findings support the effective monitoring and early management of the predictable risks for proteinuria among new SRL users in order to delay the progression of renal disease.

Maintenance immunosuppression for adults undergoing liver transplantation: a network meta-analysis

BACKGROUND

As part of liver transplantation, immunosuppression (suppressing the host immunity) is given to prevent graft rejections resulting from the immune response of the body against transplanted organ or tissues from a different person whose tissue antigens are not compatible with those of the recipient. The optimal maintenance immunosuppressive regimen after liver transplantation remains uncertain.

OBJECTIVES

To assess the comparative benefits and harms of different maintenance immunosuppressive regimens in adults undergoing liver transplantation through a network meta-analysis and to generate rankings of the different immunosuppressive regimens according to their safety and efficacy.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Science Citation Index Expanded, World Health Organization International Clinical Trials Registry Platform, and trials registers until October 2016 to identify randomised clinical trials on immunosuppression for liver transplantation.

SELECTION CRITERIA

We included only randomised clinical trials (irrespective of language, blinding, or publication status) in adult participants undergoing liver transplantation (or liver retransplantation) for any reason. We excluded trials in which participants had undergone multivisceral transplantation or participants with established graft rejections. We considered any of the various maintenance immunosuppressive regimens compared with each other.

DATA COLLECTION AND ANALYSIS

We performed a network meta-analysis with OpenBUGS using Bayesian methods and calculated the odds ratio, rate ratio, and hazard ratio (HR) with 95% credible intervals (CrI) based on an available-case analysis, according to National Institute of Health and Care Excellence Decision Support Unit guidance.

MAIN RESULTS

We included a total of 26 trials (3842 participants) in the review, and 23 trials (3693 participants) were included in one or more outcomes in the review. The vast majority of the participants underwent primary liver transplantation. All of the trials were at high risk of bias, and all of the evidence was of low or very low quality. In addition, because of sparse data involving trials at high risk of bias, it is not possible to entirely rely on the results of the network meta-analysis. The trials included mainly participants undergoing primary liver transplantation of varied aetiologies. The follow-up in the trials ranged from 3 to 144 months. The most common maintenance immunosuppression used as a control was tacrolimus. There was no evidence of difference in mortality (21 trials; 3492 participants) or graft loss (15 trials; 2961 participants) at maximal follow-up between the different maintenance immunosuppressive regimens based on the network meta-analysis. In the direct comparison, based on a single trial including 222 participants, tacrolimus plus sirolimus had increased mortality (HR 2.76, 95% CrI 1.30 to 6.69) and graft loss (HR 2.34, 95% CrI 1.28 to 4.61) at maximal follow-up compared with tacrolimus. There was no evidence of differences in the proportion of people with serious adverse events (1 trial; 719 participants), proportion of people with any adverse events (2 trials; 940 participants), renal impairment (8 trials; 2233 participants), chronic kidney disease (1 trial; 100 participants), graft rejections (any) (16 trials; 2726 participants), and graft rejections requiring treatment (5 trials; 1025 participants) between the different immunosuppressive regimens. The network meta-analysis showed that the number of adverse events was lower with cyclosporine A than with many other immunosuppressive regimens (12 trials; 1748 participants), and the risk of retransplantation (13 trials; 1994 participants) was higher with cyclosporine A than with tacrolimus (HR 3.08, 95% CrI 1.13 to 9.90). None of the trials reported number of serious adverse events, health-related quality of life, or costs.

FUNDING

14 trials were funded by pharmaceutical companies who would benefit from the results of the trial; two trials were funded by parties who had no vested interest in the results of the trial; and 10 trials did not report the source of funding.

AUTHORS' CONCLUSIONS

Based on low-quality evidence from a single small trial from direct comparison, tacrolimus plus sirolimus increases mortality and graft loss at maximal follow-up compared with tacrolimus. Based on very low-quality evidence from network meta-analysis, we found no evidence of difference between different immunosuppressive regimens. We found very low-quality evidence from network meta-analysis and low-quality evidence from direct comparison that cyclosporine A causes more retransplantation compared with tacrolimus. Future randomised clinical trials should be adequately powered; performed in people who are generally seen in the clinic rather than in highly selected participants; employ blinding; avoid postrandomisation dropouts or planned cross-overs; and use clinically important outcomes such as mortality, graft loss, renal impairment, chronic kidney disease, and retransplantation. Such trials should use tacrolimus as one of the control groups. Moreover, such trials ought to be designed in such a way as to ensure low risk of bias and low risks of random errors.

Conversion From Calcineurin to Mammalian Target of Rapamycin Inhibitors in Liver Transplantation: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Conversion to mammalian target of rapamycin inhibitors (mTORi) is often used in liver transplantation to overcome calcineurin inhibitor (CNI) nephrotoxicity but the evidence base for this approach is not well defined. To summarize the evidence, from randomized clinical trials (RCTs), for conversion from CNI to mTORi-based immunosuppression after liver transplantation.

METHODS

Databases and conference abstracts were searched up to August 2015. The RCTs evaluating conversion from CNI to mTORi-based maintenance immunosuppression after adult liver transplantation. Descriptive and quantitative information was extracted; summary mean difference and risk ratio (RR) estimates were synthesized under a random-effects model. Heterogeneity was assessed using the Q statistic and I.

RESULTS

Ten RCTs, with a total of 1927 patients, met the final inclusion criteria. Patients converted to mTORi had significantly better renal function at 1 year after randomization compared with patients remaining on CNI (mean difference, 7.48 mL/min per 1.73 m; 95% confidence interval [95% CI], 3.18-11.8). The risks of graft loss (RR, 0.77; 95% CI, 0.29-2.09; I, 31%) and patient death (RR, 1.05; 95% CI, 0.63-1.73; I, 0%) were similar for patients converted to mTORi and patients remaining on CNI. However, conversion to mTORi was associated with a higher risk of acute rejection (RR, 1.76; 95% CI, 1.33-2.34; I, 0%) and study discontinuation due to adverse events (RR, 2.17; 95% CI, 1.38-3.44; I, 63%) up to 1 year after randomization.

CONCLUSIONS

Conversion from CNI to mTORi after liver transplantation is associated with improved renal function after 1 year but increases the risk of acute rejection and may be poorly tolerated.

Liver transplantation: Current status and challenges

Great progress has been made in the field of liver transplantation over the past two decades. This progress, however, also brings up the next set of challenges: First, organ shortage remains a major limitation, and accounts for a large proportion of wait list mortality. While living donation has successfully increased the total number of liver transplants done in Asian countries, the total number of such transplants has been stagnant in the western hemisphere. As such, there has been a significant effort over the past decade to increase the existing deceased donor pool. This effort has resulted in a greater use of liver allografts following donation after cardiac death (DCD) along with marginal and extended criteria donors. Improved understanding of the pathophysiology of liver allografts procured after circulatory arrest has not only resulted in better selection and management of DCD donors, but has also helped in the development of mechanical perfusion strategies. Early outcomes demonstrating the clinical applicability of both hypothermic and normothermic perfusion and its potential to impact patient survival and allograft function have generated much interest. Second, long-term outcomes of liver transplant recipients have not improved significantly, as recipients continue to succumb to complications of long-term immunosuppression, such as infection, malignancy and renal failure. Furthermore, recent evidence suggests that chronic immune-mediated injury to the liver may also impact graft function.

Review on immunosuppression in liver transplantation

The optimal level of immunosuppression in solid organ transplantation, in particular for the liver, is a delicate balance between the benefit of preventing rejection and the adverse side effects of immunosuppression. There is uncertainty about when this level is achieved in any individual recipient. Immunosuppression regimens vary between individual centers and changes with time as new agents and data are available. Presently concerns about the adverse side effects of calcineurin inhibitor, the main class of immunosuppressive agents used in liver transplantation (LT), has led to consideration of the use of antibody induction therapies for patients at higher risk of developing adverse side effects. The longevity of the transplanted organ is potentially improved by better management of rejection episodes and special consideration for tailoring of immunosuppression to the individual with viral hepatitis C, hepatocellular carcinoma or pregnancy. This review provides an overview of the current strategies for post LT immunosuppression and discusses modifications to consider for special patient populations.

The benefit of sirolimus maintenance immunosuppression and rabbit antithymocyte globulin induction in liver transplant recipients that develop acute kidney injury in the early postoperative period

Published data are limited describing renal outcomes in orthotopic liver transplant (OLT) recipients prescribed sirolimus (SRL) maintenance immunosuppression (MIS) and rabbit antithymocyte globulin (rATG) induction. We investigated whether SRL MIS and rATG induction facilitated recovery of acute kidney injury in the early postoperative period. This retrospective descriptive study screened 308 consecutive OLTs performed between 2006 and 2009. All patients received rATG induction with steroid avoidance. MIS consisted of SRL or TAC with mycophenolate mofetil. A total of 197 patients were included: 168 (85%) received TAC and 29 (15%) received SRL for a median of 365 days. Demographics were similar between groups except for a higher incidence of pretransplant renal dysfunction in the SRL recipients (SRL 59% versus TAC 21%; P < 0.05). The eGFR was significantly (P < 0.05) higher for all time points in the TAC group with the exception of month 2. However, improvement in eGFR was significantly (P < 0.05) greater in the SRL group postoperatively. Our study suggests that rATG induction and SRL maintenance immunosuppression facilitate renal recovery for liver transplant recipients that develop acute kidney injury in the early postoperative period.

mTOR inhibitors and dyslipidemia in transplant recipients: a cause for concern?

Post-transplant dyslipidemia is exacerbated by mammalian target of rapamycin (mTOR) inhibitors. Early clinical trials of mTOR inhibitors used fixed dosing with no concomitant reduction in calcineurin inhibitor (CNI) exposure, leading to concerns when consistent and marked dyslipidemia was observed. With use of modern concentration-controlled mTOR inhibitor regimens within CNI-free or reduced-exposure CNI regimens, however, the dyslipidemic effect persists but is less pronounced. Typically, total cholesterol levels are at the upper end of normal, or indicate borderline risk, in kidney and liver transplant recipients, and are lower in heart transplant patients under near-universal statin therapy. Of note, it is possible that mTOR inhibitors may offer a cardioprotective effect. Experimental evidence for delayed progression of atherosclerosis is consistent with evidence from heart transplantation that coronary artery intimal thickening and the incidence of cardiac allograft vasculopathy are reduced with everolimus versus cyclosporine therapy. Preliminary data also indicate that mTOR inhibitors may improve arterial stiffness, a predictor of cardiovascular events, and may reduce ventricular remodeling and decrease left ventricular mass through an anti-fibrotic effect. Post-transplant dyslipidemia under mTOR inhibitor therapy should be monitored and managed closely, but unless unresponsive to therapy should not be regarded as a barrier to its use.

The Role of mTOR Inhibitors in Liver Transplantation: Reviewing the Evidence

Despite the success of liver transplantation, long-term complications remain, including de novo malignancies, metabolic syndrome, and the recurrence of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC). The current mainstay of treatment, calcineurin inhibitors (CNIs), can also worsen posttransplant renal dysfunction, neurotoxicity, and diabetes. Clearly there is a need for better immunosuppressive agents that maintain similar rates of efficacy and renal function whilst minimizing adverse effects. The mammalian target of rapamycin (mTOR) inhibitors with a mechanism of action that is different from other immunosuppressive agents has the potential to address some of these issues. In this review we surveyed the literature for reports of the use of mTOR inhibitors in adult liver transplantation with respect to renal function, efficacy, safety, neurological symptoms, de novo tumors, and the recurrence of HCC and HCV. The results of our review indicate that mTOR inhibitors are associated with efficacy comparable to CNIs while having benefits on renal function in liver transplantation. We also consider newer dosing schedules that may limit side effects. Finally, we discuss evidence that mTOR inhibitors may have benefits in the oncology setting and in relation to HCV-related allograft fibrosis, metabolic syndrome, and neurotoxicity.

Immunosuppression minimization vs. complete drug withdrawal in liver transplantation

Despite the increase in long-term survival, liver transplant recipients still exhibit higher morbidity and mortality than the general population. This is in part attributed to the lifelong administration of immunosuppression and its associated side effects. Several studies reported in the last decades have evaluated the impact of immunosuppression minimization in liver transplant recipients, but results have been inconsistent due to the heterogeneity of study designs and insufficient sample sizes. On the other hand, complete immunosuppression withdrawal has proven to be feasible in approximately 20% of carefully selected liver transplant recipients, especially in older patients and those with longer duration after transplantation. The long-term risks and clinical benefits of this strategy, however, also need to be clarified. As a consequence, and despite the general perception that a large proportion of liver recipients are over-immunosuppressed, it is currently not possible to derive evidence-based guidelines on how to manage long-term immunosuppression to improve clinical outcomes. Large clinical trials of drug minimization and/or withdrawal focused on clinically-relevant long-term outcomes are required. Development of personalized medicine tools and a deeper understanding of the pathogenesis of idiopathic inflammatory graft lesions will be pre-requisites to achieve these goals.

Calcineurin inhibitor-free mycophenolate mofetil/sirolimus maintenance in liver transplantation: the randomized spare-the-nephron trial

Mycophenolate mofetil (MMF) and sirolimus (SRL) have been used for calcineurin inhibitor (CNI) minimization to reduce nephrotoxicity following liver transplantation. In this prospective, open-label, multicenter study, patients undergoing transplantation from July 2005 to June 2007 who were maintained on MMF/CNI were randomized 4 to 12 weeks after transplantation to receive MMF/SRL (n = 148) or continue MMF/CNI (n = 145) and included in the intent-to-treat population. The primary efficacy endpoints were the mean percentage change in the calculated glomerular filtration rate (GFR) and a composite of biopsy-proven acute rejection (BPAR), graft lost, death, and lost to follow-up 12 months after transplantation. Patients were followed for a median of 519 days after randomization. MMF/SRL was associated with a significantly greater renal function improvement from baseline with a mean percentage change in GFR of 19.7 ± 40.6 (versus 1.2 ± 39.9 for MMF/CNI, P = 0.0012). The composite endpoint demonstrated the noninferiority of MMF/SRL versus MMF/CNI (16.4% versus 15.4%, 90% confidence interval = -7.1% to 9.0%). The incidence of BPAR was significantly greater with MMF/SRL (12.2%) versus MMF/CNI (4.1%, P = 0.02). Graft loss (including death) occurred in 3.4% of the MMF/SRL-treated patients and in 8.3% of the MMF/CNI-treated patients (P = 0.04). Malignancy-related deaths were less frequent with MMF/SRL. Adverse events caused withdrawal for 34.2% of the MMF/SRL-treated patients and for 24.1% of the MMF/CNI-treated patients (P = 0.06). The use of MMF/SRL is an option for liver transplant recipients who can benefit from improved renal function but is associated with an increased risk of rejection (but not graft loss).

Current status of immunosuppression in liver transplantation

With advancements in immunosuppressive strategies and availability of better immunosuppressive agents, survival rate following liver transplantation has improved significantly in the recent times. Besides improvements in surgical techniques, the most important factor that has contributed to this better outcome is the progress made in the field of immunosuppression. Over the last several years, the trend has changed to tailored immunosuppression with the aim of achieving optimal graft function while avoiding its undesirable side effects. Induction agents are no longer used routinely and the aim is to provide minimal immunosuppression in the maintenance phase. The present review discusses the various types of immunosuppressive agents, their mechanism of action, clinical utility, advantages and disadvantages, and their side effects in short and long-term. It also discusses about tailoring immunosuppression in presence of various situations such as renal dysfunction, metabolic syndrome, hepatitis C recurrence, cytomegalovirus infections and so on. The issue of chronic kidney disease and the available renal sparing immunosuppressive strategies has been particularly stressed upon. Finally, it discusses about the practical aspects of various immunosuppression regimens including drug monitoring.

Calcineurin inhibitors in liver transplantation - still champions or threatened by serious competitors?

Current strategies for immunosuppression in liver transplant (LT) recipients include the design of protocols targeting a more individualized approach to reduce risk factors such as renal failure, cardiovascular complications and malignancies. Renal injury in LT recipients may be often multifactorial and is associated with increased risk of post-transplant morbidity and mortality. The quest for low toxicity immunosuppressive regimens has been challenging and resulted in CNI minimization protocols or CNI withdrawal and conversion to mycophenolate mofetil (MMF) and/or mammalian target of rapamycin inhibitor-based immunosuppressive regimens. Use of antibody induction to delay CNI administration may be an option in particular in immunocompromized, critically ill patients with high MELD scores. Protocols including MMF introduction and concomitant CNI minimization have the potential to recover renal function even in the medium and long term after LT. We review on hot topics in the prevention and management of acute and chronic renal injury in LT patients. For this purpose, we present and critically discuss results from immunosuppressive studies published in the current literature or presented at recent LT meetings.

Anti-CD25 monoclonal antibody replacement therapy for chronic kidney disease in liver transplant recipients

BACKGROUND

Chronic kidney disease (CKD) is a frequent complication after liver transplantation (LT) and is associated with increased mortality. Strategies to reduce calcineurin inhibitor (CNI) dose or conversion to either mycophenolate mofetil and/or rapamycin resulted in variable results and side-effect profiles.

METHODS

We evaluated the effectiveness of CNI conversion to long-term anti-CD25 monoclonal antibody (mAb)-based immunosuppression in 15 adult LT patients with CKD at 7.6±4 years posttransplant (intervention group). Three patients had been previously switched to rapamycin, and 12 patients were on CNI. The control group included 15 LT patients on CNI with stable renal function over a similar posttransplant follow-up period.

RESULTS

Anti-CD25 mAb were given over a period of 26±15 months (range, 2-51 months) and were well tolerated. The slope of calculated creatinine clearance was -0.66 mL/min/month over 6 months before conversion and -0.05 mL/min/month after conversion to anti-CD25 mAb (P=0.16 and P=0.86 vs. controls). Three acute rejection episodes occurred in the intervention group. Acute rejection was reversible in two patients. However, one patient died of chronic rejection 1 year after having been switched to tacrolimus. Anti-CD25 mAb were replaced with either CNI or rapamycin in six patients (acute rejection [n=2], progression to end-stage renal disease [n=2], poor venous status [n=1], increased liver enzymes [n=1]).

CONCLUSION

The use of long-term anti-CD25 mAb therapy as a replacement to CNI and rapamycin-based immunosuppression may be feasible. It is crucial that rejection surveillance is intensified. A randomized controlled trial is required to confirm the benefits of this strategy.

Everolimus and enteric-coated mycophenolate sodium ab initio after liver transplantation: midterm results

BACKGROUND AND AIM

Everolimus (EVR) use in liver transplantation (OLT) has been prescribed with calcineurin inhibitors (CNIs), steroids, and monoclonal antibodies. The aim of our study was to evaluate the safety, feasibility, and impact on renal function of EVR ab initio, in combination with enteric-coated mycophenolate sodium (EC-MPS) without the use of induction treatment, steroids, or CNIs.

PATIENTS AND METHODS

We retrospective analyzed nine consecutive patients who underwent OLT at our institution. The initial dose of EVR (1.5 mg/d) was adjusted to achieve trough levels of 8 to 12 ng/mL. EC-MPS introduced at 1080 mg/d was maintained at the same dose over time.

RESULTS

At a mean follow-up of 21.48 (standard deviation [SD] 1.4) months from OLT, 7/9 recipients were alive with stable graft function. The 2-year patient and graft survivals were 77%. One recipient died due to cerebral hemorrhage and one, lung failure. No clinical evidence of an acute rejection episode was observed. Mean estimated glomerular filtration rate value, according to the Modification of Diet in Renal Disease formula increased from 59.5 (SD 9.89) mL/min/1.73 m(2) at OLT to 100.2 (SD 47.5) mL/min/1.73 m(2) (P = .03) after 12 months and 98.71 (SD 33.74) mL/min/1.73 m(2) (P = .03) after 24 months' follow-up.

CONCLUSION

A double immunosuppression therapy with EVR and EC-MPS ab initio seemed to be efficacions and safe, representing a valid alternative to CNIs to prevent renal failure after OLT.

Proteinuria following sirolimus conversion is associated with deterioration of kidney function in liver transplant recipients. Transplantation. 2012;93:1006-1012. [PMID: 22357174 DOI: 10.1097/tp.0b013e31824bbd01]

BACKGROUND

The role of sirolimus (SRL) conversion in the preservation of kidney function in liver transplant (LT) recipients with calcineurin inhibitor (CNI) nephrotoxicity is unclear.

METHODS

Data on 102 LT recipients with deteriorating kidney function after CNI exposure who were later converted to SRL were retrospectively reviewed. Kidney function was assessed using serum creatinine and estimated glomerular filtration rate (eGFR) at time of conversion and serially thereafter. The primary endpoint was stabilization or improvement of kidney function as assessed by eGFR at last recorded follow-up compared with eGFR at the time of conversion.

RESULT

After a median (interquartile range) of 3.1 (1.6-4.5) years of follow-up, serum creatinine decreased from 1.9 ± 0.8 to 1.8 ± 0.7 mg/dL (P=0.25) and eGFR increased from 40.8 ± 16.7 to 44.3 ± 20.0 mL/min (P=0.03). During the same time period, 24-hr urinary protein excretion increased from median (interquartile range) of 72 (0-155) to 382 (169-999) mg/day (P=0.0001). Sixty-five (64%) patients achieved the primary endpoint and 37 (36%) experienced deterioration in kidney function. Independent predictors of deterioration of kidney function after SRL conversion were development of proteinuria ≥ 1000 mg/day (odds ratio [OR]: 3.3, confidence interval [CI]: 1.1-9.5 P=0.03), post-LT diabetes (OR: 4.2, CI: 1.6-11.1, P=0.004), and higher eGFR at time of conversion (OR: 1.6, CI: 1.2-2.2, P=0.003).

CONCLUSION

Improvement or stabilization of kidney function occurred in the majority of LT recipients converted to SRL for CNI nephrotoxicity. Proteinuria ≥ 1000 mg/day, post-LT diabetes, and higher baseline eGFR were independent predictors of kidney function loss after SRL conversion.

Prophylaxis of chronic kidney disease after liver transplantation - experience from west China

AIM: To evaluate the prophylaxis of chronic kidney disease (CKD) after liver transplantation (LT) with low-dose calcineurin inhibitor (CNI) and mycophenolate mofetil (MMF).

METHODS: From March 1999 to December 2009, a total of 572 patients (478 males and 94 females) underwent LT enrolled in the study. Initial immunosuppression was by triple-drug regimens that included a CNI, MMF, and prednisone. The initial dose of CNI was 0.05-0.10 mg/kg per day for tacrolimus (TAC) and 5-10 mg/kg per d for cyclosporine A (CSA) respectively, and was gradually reduced based on a stable graft function. The serum trough level of CNI was 6-8 ng/mL for TAC and 120-150 ng/mL for CSA 3-mo post-operation, 4-6 ng/mL for TAC and 80-120 ng/mL for CSA 1-year after transplantation was expected with stable liver function. MMF was personalized between 1.0-1.5 g/d. Glomerular filtration rate (GFR) was estimated by an abbreviated Modification of Diet in Renal Disease formula. Risk factors of CKD were examined by univariate and multivariate logistic regression.

RESULTS: With a definition of GFR < 60 mL/min per 1.73 m², the incidence of CKD was 17.3% 5-year after LT. There were 68.3% (293 of 429 cases) patients managed to control their TAC trough concentrations within 8 ng/mL and 58.0% (83 of 143 cases) patients’ CSA trough concentrations within 150 ng/mL. Of the 450 recipients followed-up over 1 year, 55.5% (183 of 330 cases) of which were treated with TAC had a trough concentration ≤ 6 ng/mL while 65.8% (79 of 120 cases) of which were treated with CSA had a concentration ≤ 120 ng/mL. The incidence of CKD in the groups of lower CNI trough concentrations was significantly lower than the groups with CNI concentrations above the ideal range. Patients with CKD had much higher CNI trough concentrations than that of patients without CKD. MMF was adopted in 359 patients (62.8%). Patients administrated with MMF had a relatively low CNI trough concentrations but with no significant difference. The graft function remained stable during follow-up. No difference was found between different groups of CNI trough concentrations. Pre-LT renal dysfunction, ages, acute kidney injury, high blood trough concentrations of CNI in 3 mo (TAC > 8 ng/mL, CSA > 150 ng/mL) and hypertension after operation were associated with CKD progression, while male gender and adoption of MMF were protection factors.

CONCLUSION: Low dose of CNI combined with MMF managed to prevent CKD after LT with stable graft function.

Sirolimus conversion regimen versus continued calcineurin inhibitors in liver allograft recipients: a randomized trial

A large prospective, open-label, randomized trial evaluated conversion from calcineurin inhibitor (CNI)- to sirolimus (SRL)-based immunosuppression for preservation of renal function in liver transplantation patients. Eligible patients received liver allografts 6-144 months previously and maintenance immunosuppression with CNI (cyclosporine or tacrolimus) since early posttransplantation. In total, 607 patients were randomized (2:1) to abrupt conversion (<24 h) from CNI to SRL (n = 393) or CNI continuation for up to 6 years (n = 214). Between-group changes in baseline-adjusted mean Cockcroft-Gault GFR at month 12 (primary efficacy end point) were not significant. The primary safety end point, noninferiority of cumulative rate of graft loss or death at 12 months, was not met (6.6% vs. 5.6% in the SRL and CNI groups, respectively). Rates of death at 12 months were not significantly different, and no true graft losses (e.g. liver transplantation) were observed during the 12-month period. At 52 weeks, SRL conversion was associated with higher rates of biopsy-confirmed acute rejection (p = 0.02) and discontinuations (p < 0.001), primarily for adverse events. Adverse events were consistent with known safety profiles. In conclusion, liver transplantation patients showed no demonstrable benefit 1 year after conversion from CNI- to SRL-based immunosuppression.

Optimization of the use of Calcineurin inhibitors in liver transplantation

Calcineurin inhibitors (CNIs), such as cyclosporin A and tacrolimus, are the cornerstone of maintenance immunosuppressive regimens in liver transplantation. CNIs prevent rejection by inhibition of calcineurin, via which lymphocyte proliferation and interleukin (IL)-2 production is prevented. Tacrolimus is now the first-choice immunosuppressant after liver transplantation, since it is associated with fewer episodes of rejection than cyclosporin A. In this review we will discuss interindividual differences, which influence tacrolimus metabolism. Because of these factors and the narrow therapeutic index of tacrolimus, monitoring of drug trough levels is necessary. Furthermore, we will discuss studies concerning conversion from the tacrolimus twice daily to tacrolimus once daily formulation in stable LT patients. Due to adverse effects of CNIs, such as chronic renal failure, hypertension, de novo malignancy and new-onset diabetes mellitus, CNI minimization strategies have been developed, which will be discussed too.

Conversion to everolimus in liver transplant patients with renal dysfunction

Calcineurin inhibitor (CNI) immunosuppressive therapy post-liver transplantation (OLT) is important to reduce graft rejection episodes. However, these drugs show important side effects, particularly renal dysfunction (RDF). Changing from CNI to a nonnephrotoxic drug, as mammalian target of rapamycin (mTOR) inhibitor may solve the problem. Our objective was to evaluate renal function (RF) among liver transplant patients initially receiving CNI, among whom the patients with RDF were converted completely or partially to an mTOR inhibitor like everolimus (EVE). We performed a prospective study in liver transplant patients from 2000 to 2009. Creatinine levels and creatinine clearances (Cockroft-Gault) expressed as mean values ± standard deviations were measured pre- and postswitch for comparisons using Wilcoxon nonparametric tests. Six patients were converted fully or partially to EVE. Their mean age at the moment of introducing the new therapy was 52.2 ± 13.6 years (range = 28-60). Immunosuppression time prior to switching from CNI to EVE was 23.8 ± 26.6 months (range = 6-70). Postconversion follow-up was 25.8 ± 16.5 months (range = 8-42). All patients showed improvement in RF. The creatinine level improvement was significant (P = .03) namely, from a mean of 2.26 ± 0.49 to 1.21 ± 0.57 mg/dL. Glomerular filtration rate improved from a mean of 40 ± 15.13 to 72.60 ± 17.3 mL/min/m(2) (P = .03). Conversion from CNI to EVE improved creatinine concentrations and creatinine clearances with long-term effects free of graft rejection.

Sirolimus-based immunosuppression in liver transplantation for hepatocellular carcinoma: a meta-analysis

Sirolimus (SRL) is a novel immunosuppressant with antitumor properties. We performed a meta-analysis to determine whether SRL can improve patient survival and decrease the risks of tumor recurrence in patients with a pretransplant diagnosis of hepatocellular carcinoma (HCC). We searched databases for controlled clinical trials assessing the survival and oncological benefits of SRL for liver transplant recipients with pretransplant HCC. Five studies with a total of 2950 participants were included in this study. In comparison with SRL-free regimens, SRL-based regimens improved overall survival at 1 [odds ratio (OR) = 4.53, 95% confidence interval (95% CI) = 2.31-8.89], 3 (OR = 1.97, 95% CI = 1.29-3.00), and 5 years (OR = 2.47, 95% CI = 1.72-3.55). The pooled results showed that in comparison with SRL-free regimens, SRL-based regimens decreased tumor recurrence (OR = 0.42, 95% CI = 0.21-0.83). No significant differences in the frequencies of episodes of major posttransplant complications were observed between the groups. In conclusion, SRL is generally safe and prolongs patient survival in liver transplant recipients with pretransplant HCC.

m-TOR inhibitors: what role in liver transplantation?

The development of calcineurin inhibitors (CNIs) led to marked improvements in patient and graft survival after liver transplantation (LTx). We have been left, however, with a dependence on immunosuppressive agents with nephrotoxicity, neurotoxicity, adverse impacts on cardiac risk profile, and risk for malignancy. These challenges need to be met against a dominance of hepatitis C virus (HCV) and hepatocellular carcinoma (HCC) as indications for liver transplant. Unmet needs for immunosuppression (IS) in LTx include: (1) Effective drugs that avoid CNIs toxicities. (2) Agents without adverse impact on HCV recurrence. (3) Compounds that minimize risk of HCC recurrence. New immunosuppressives will need to address the above needs while supporting patient and graft survival equivalent to those achievable with CNIs, ideally without important new toxicities. Two new classes of agents are currently in advanced clinical development: belatacept, and the mammalian target of rapamycin inhibitors (m-TORi). This manuscript will review evidence for a role for m-TORi in LTx in a range of clinical scenarios including patients with CNI nephrotoxicity or neurotoxicity, patients at risk of (or with) HCV recurrence, and patients at risk of HCC recurrence.

Calcineurin-inhibitor minimization in liver transplant patients with calcineurin-inhibitor-related renal dysfunction: a meta-analysis

Background

Introduction of calcineurin-inhibitor (CNI) has made transplantation a miracle in the past century. However, the side effects of long-term use of CNI turn out to be one of the major challenges in the current century. Among these, renal dysfunction attracts more and more attention. Herein, we undertook a meta-analysis to evaluate the efficacy and safety of calcineurin-inhibitor (CNI) minimization protocols in liver transplant recipients with CNI-related renal dysfunction.

Methods

We included randomized trials with no year and language restriction. All data were analyzed using random effect model by Review Manager 5.0. The primary endpoints were glomerular filtration rate (GFR), serum creatinine level (sCr) and creatinine clearance rate (CrCl), and the secondary endpoints were acute rejection episodes, incidence of infection and patient survival at the end of follow-up.

Results

GFR was significantly improved in CNI minimization group than in routine CNI regimen group (Z = 5.45, P<0.00001; I² = 0%). Likely, sCr level was significantly lower in the CNI minimization group (Z = 2.84, P = 0.005; I² = 39%). However, CrCl was not significantly higher in the CNI minimization group (Z = 1.59, P = 0.11; I² = 0%). Both acute rejection episodes and patient survival were comparable between two groups (rejection: Z = 0.01, P = 0.99; I² = 0%; survival: Z = 0.28, P = 0.78; I² = 0%, respectively). However, current CNI minimization protocols may be related to a higher incidence of infections (Z = 3.06, P = 0.002; I² = 0%).

Conclusion

CNI minimization can preserve or even improve renal function in liver transplant patients with renal impairment, while sharing similar short term acute rejection rate and patient survival with routine CNI regimen.

Suitable calcineurin inhibitor concentrations for liver transplant recipients in the Chinese population

AIM

The aim was to deduce suitable calcineurin inhibitor concentrations for the Chinese liver transplantation population.

METHODS

We retrospectively studied 97 liver transplant recipients who displayed stable liver and renal function. No grafts were obtained from prisoners, procurements were performed with donor consent conforming to international ethics regulations. At 3, 6, and 12 months, we increased the concentrations and doses of calcineurin inhibitors as well as the values of alanine transaminase and serum creatinine.

RESULTS

Twenty-eight recipients received cyclosporine and 69 tacrolimus. The mean cyclosporine daily dosages were 203 ± 62 mg at 3, 188 ± 55 mg at 6, and 173 ± 52 mg at 12 months, the tacrolimus daily dosages were 3.08 ± 0.98, 2.82 ± 0.98, and 2.58 ± 0.93 mg, respectively. The corresponding mean cyclosporine peak concentrations (C(2)) were 806 ± 322 ng/mL, 681 ± 206 ng/mL, and 644 ± 190 ng/mL and the mean tacrolimus trought concentrations (C(0)) 6.61 ± 3.02 ng/mL, 5.85 ± 2.44 ng/mL, and 5.22 ± 2.33 ng/mL, respectively. In both groups, transaminases and serum creatinine were stable over time.

CONCLUSIONS

An individualized immunosuppressive regimen for the local population is necessary. We delayed calcineurin inhibitors with subsequent low-dose mycophenolate mofetil plus minimized calcineurin inhibitors, which seemed to be nephroprotective and safe for Chinese liver transplantation patients.

Evolving concepts in the selection of immunosuppression regimen for liver transplant recipients

The introduction of calcineurin inhibitor (CNI) based immunosuppression has revolutionized the field of liver transplantation by dramatically reducing the incidence of acute cellular rejection and prolonging patient and allograft survival. However, the introduction of CNIs has also come at the price of increased patient morbidity, particularly with regard to the well-known nephrotoxic effects of the medications. In an effort to minimize the adverse effects, immunosuppression regimen have evolved to include the use of various induction agents and purine synthesis inhibitors to limit the dose of CNI necessary to achieve low acute cellular rejection rates. Careful assessments of risks and benefits are needed as these newer agents have their own side effect profiles. In addition, the impact of newer immunosuppression regimen on hepatitis C (HCV) recurrence has not been completely elucidated. This review will provide an overview of the most common immunosuppression regimen used in liver transplantation and discuss their impact on acute cellular rejection, patient and allograft survival, and HCV recurrence.

Switching to sirolimus-based immune suppression after liver transplantation is safe and effective: a single-center experience

BACKGROUND

Sirolimus is unlicensed for use in liver transplantation because of concerns over safety, particularly in regard to hepatic artery thrombosis and excess mortality. However, sirolimus offers potential advantages over calcineurin inhibitor-based immunosuppression, relating to its renal sparing and antiproliferative properties.

METHODS

A review was undertaken of 148 liver transplant patients converted to sirolimus over 10 years at a single center.

RESULTS

The main indications for sirolimus were renal impairment and hepatitis C virus fibrosis. One hundred eleven (75%) patients remained on sirolimus after median follow-up of 1006 days. Mean (+/-standard deviation) glomerular filtration rate improved significantly from 59+/-29 mL/min preconversion to 72+/-39 mL/min at censor point (P<0.05). Improvement in glomerular filtration rate was most marked in patients converted for renal impairment. Liver function tests remained stable or improved, particularly in patients transplanted for hepatitis C virus. Side effects attributed to sirolimus occurred in 101 (68%) patients requiring withdrawal in 20 patients (14%). Moderate increases in serum lipids were observed and controlled effectively with statins. The incidence of proteinuria increased postconversion but had no deleterious impact on renal function. No episodes of hepatic artery thrombosis were observed.

CONCLUSIONS

Sirolimus was safe and may improve outcome in selected patients after liver transplantation.

Tolerability of everolimus-based immunosuppression in maintenance liver transplant recipients

BACKGROUND

The aim of this study was to evaluate the tolerability of the conversion from calcineurin inhibitor (CNI) to everolimus (ERL) in maintenance liver transplant (LT) recipients.

METHODS

From January 2005 to March 2008, ERL was introduced after LT as maintenance immunosuppressive therapy because of (i) de novo or recurrent cancer after LT, (ii) pre-existing liver carcinoma on the liver explant or (iii) CNI toxicity. CNI dosage was progressively reduced until discontinuation.

RESULTS

The study population included 94 patients, of mean age 57 ± 10. The mean delay between LT and ERL introduction was 5 ± 5 yr. After a mean follow-up of 12 ± 7 months, 70% of the patients did present at least one side effect. The mean trough level of ERL was 6 μg/L at the end of follow-up. Main side effects included hyperlipidemia (37%), dermatitis (19%), mucositis (15%), and proteinuria (18%). Biopsy-proven acute rejection occurred in 9% of patients. Global ERL discontinuation rate was 21% (16% because of side effects).

CONCLUSIONS

The results of our experience indicate that conversion to ERL is associated with adverse effects in 70% of patients leading to drug discontinuation in 16% (and amenable to dose reduction in the remainders). Longer follow-up periods are necessary to capture the impact of ERL fully on renal function and survival in cancer patients.

Early withdrawal of calcineurin inhibitors and everolimus monotherapy in de novo liver transplant recipients preserves renal function

We designed a randomized trial to assess whether the early withdrawal of cyclosporine (CsA) followed by the initiation of everolimus (Evr) monotherapy in de novo liver transplantation (LT) patients would result in superior renal function compared to a CsA-based immunosuppression protocol. All patients were treated with CsA for the first 10 days and then randomized to receive Evr in combination with CsA up to day 30, then either continued on Evr monotherapy (Evr group) or maintained on CsA with/without mycophenolate mofetil (CsA group) in case of chronic kidney disease (CKD). Seventy-eight patients were randomized (Evr n = 52; CsA n = 26). The 1-year freedom from efficacy failure in Evr group was 75% versus 69.2% in CsA group, p = 0.36. There was no statistically significant difference in patient survival between the two groups. Mean modification of diet in renal disease (MDRD) was significantly better in the Evr group at 12 months (87.7 ± 26.1 vs. 59.9 ± 12.6 mL/min; p < 0.001). The incidence of CKD stage ≥ 3 (estimated glomerular filtration rate < 60 mL/min) was higher in the CsA group at 1 year (52.2% vs. 15.4%, p = 0.005). The results indicate that early withdrawal of CsA followed by Evr monotherapy in de novo LT patients is associated with an improvement in renal function, with a similar incidence of rejection and major complications.

Use of sirolimus in liver transplant recipients with renal insufficiency: a systematic review and meta-analysis

Sirolimus is used in patients with renal insufficiency after liver transplantation (LT) and especially in those with calcineurin inhibitor (CNI)-associated nephrotoxicity. We conducted a systematic review of all randomized controlled trials and observational studies to test the hypothesis that the use of sirolimus is associated with an improvement in renal function at 1 year in LT recipients with renal insufficiency [glomerular filtration rate (GFR) < 60 mL/minute or creatinine level ≥ 1.5 mg/dL]. We performed a search of all major databases, conference proceedings, and relevant journals through December 2009 and contacted content experts, corresponding authors, and the pharmaceutical manufacturer. A random effects model was used to determine the pooled estimate of the change in renal function and pooled risk estimates of adverse events that may be associated with sirolimus-based therapy at 1 year. Eleven studies (three randomized controlled trials and eight observational studies) met the final inclusion criteria. A nonsignificant improvement of 3.38 mL/minute [95% confidence interval (CI) = -2.93 to 9.69] was observed in methodologically sound observational studies and controlled trials reporting the primary outcome. In controlled trials, baseline GFR >50 mL/min sirolimus use was associated with an improvement of 10.35 mL/minute (95% CI = 3.98-16.77) in GFR or creatinine clearance. Sirolimus was not significantly associated with death [relative risk (RR) = 1.12, 95% CI = 0.66-1.88] or graft failure (RR = 0.80, 95% CI = 0.45-1.41), although reporting was incomplete. It was associated with a statistically significant risk of infection (RR = 2.47, 95% CI = 1.14-5.36), rash (RR = 7.57, 95% CI = 1.75-32.70), ulcers (RR = 7.44, 95% CI = 2.03-27.28), and discontinuation of therapy (RR = 3.61, 95% CI = 1.32-9.89).

CONCLUSION

Conversion to sirolimus from CNIs is associated with a nonsignificant improvement in renal function in LT recipients with renal insufficiency, although the results are limited by heterogeneity, a risk of bias, and a lack of standardized reporting.

Conversion from a calcineurin inhibitor to everolimus therapy in maintenance liver transplant recipients: a prospective, randomized, multicenter trial

Calcineurin inhibitors (CNIs) contribute to renal dysfunction following liver transplantation. This prospective, randomized, multicenter, 6-month study (with an additional 6 months of follow-up) evaluated whether everolimus with CNI reduction or discontinuation would improve renal function in maintenance liver transplant recipients experiencing CNI-related renal impairment. Patients started everolimus therapy with CNI reduction or discontinuation (n = 72) or continued receiving standard-exposure CNI (n = 73). At month 6, 80% of the patients who had converted to everolimus had discontinued the CNI. The mean change in creatinine clearance (CrCl) from baseline to month 6 was similar between groups (everolimus, 1.0 +/- 10.2 mL/minute; controls, 2.3 +/- 7.8 mL/minute; P = 0.46), so the primary study endpoint (8 mL/minute difference in the change in CrCl) was not achieved. Among patients who continued everolimus according to the protocol, the mean increase in CrCl was 2.1 (n = 53) and 3.8 mL/minute (n = 38) at months 6 and 12, respectively, versus 2.4 (n = 68) and 3.5 mL/minute in controls (n = 51). The high frequency of CNI dose reductions in controls (77% of the patients) and the relatively long mean time post-transplant (>3 years) likely contributed to the small difference in CrCl. Biopsy-proven acute rejection occurred in 1.4% of the patients in each group, with no graft losses. Study drug discontinuation was higher in everolimus-treated patients, and adverse events were more frequent. These data demonstrate that everolimus allows for discontinuation or a major reduction of CNI exposure in liver allograft recipients suffering CNI-related renal dysfunction without a loss of efficacy. Trials targeting earlier conversion post-transplantation are required to confirm the efficacy and safety of everolimus for improving renal function after liver transplantation.

A comprehensive review of immunosuppression used for liver transplantation. J Transplant. 2009;2009:701464. [PMID: 20130772 PMCID: PMC2809333 DOI: 10.1155/2009/701464]

Since liver transplantation was approved for the treatment of end stage liver disease, calcineurin inhibitors (CNI's) have played a critical role in the preservation of allograft function. Unfortunately, these medications cause a variety of Side effects such as diabetes, hypertension and nephrotoxicity which in turn result in significant morbidity and reduced quality of life. A variety of newer immunosuppressants have been evaluated over the last decade in an attempt to either substitute for CNI's or use with reduced dose CNI's while still preserving allograft function However, current data does not recommend complete cessation of CNI's due to unacceptably high rates of allograft rejection. As these medications have their own unique adverse effects, a careful assessment on their risks and benefits is essential, particularly when additive or synergistic effects with CNI's may occur. Furthermore, the impact of these newer medications on the risk of hepatitis C recurrence and progression remains to be elucidated. Controlled trials are urgently required to assist transplant physicians with choosing the optimum immunosuppressive regimen for their patients. This review will discuss commonly used immunosuppressants prescribed in liver transplantation, emerging therapties and where appropriate, the impact of these medications on the recurrence of hepatitis C after liver transplantation.

Renal impairment after liver transplantation - a pilot trial of calcineurin inhibitor-free vs. calcineurin inhibitor sparing immunosuppression in patients with mildly impaired renal function after liver transplantation

Objectives

Chronic kidney disease is frequent in patients after orthotopic liver transplantation (OLT) and has impact on survival. Patients receiving calcineurin inhibitors (CNI) are at increased risk to develop impaired renal function. Early CNI reduction and concomitant use of mycophenolat mofetil (MMF) has been shown to improve renal function.

Methods

The aim of this trial was to compare dose-reduced CNI/MMF versus CNI-free MMF/prednisone-based treatment in stable patients after OLT with respect to glomerular filtration rate (GFR). 21 patients [GFR 44.9 ± 9.9 mL/min/1.73 m² measured by 99m-Tc-DTPA-clearance, serum creatinine (SCr) 1.5 ± 0.42 mg/dL] were randomized either to exchange CNI for 10 mg prednisone (group 1; n = 8) or to receive CNI at 25% of the initial dose (group 2; n = 13) each in combination with 1000 mg MMF b.i.d.

Results

At month 12 mean SCr (-0.3 ± 0.4 mg/dL, p = 0.031) and GFR improved (8.6 ± 13.1 mL/min/1.73 m², p = 0.015) in group 2 but remained unchanged in group 1. Main side effects were gastroinstestinal symptoms (14.3%) and infections (4.8%). Two biopsy proven, steroid-responsive rejections occurred. In group 1 mean diastolic blood pressure (BP) increased by 11 ± 22 mmHg (p = 0.03).

Conclusions

Reduced dose CNI in combination with MMF but not CNI-free-immunosuppression leads to improvement of GFR in patients with moderately elevated SCr levels after OLT. Addition of steroids resulted in increased diastolic blood pressure presumably counterbalancing the benefits of CNI withdrawal on renal function.

Microproteinuria for detecting calcineurin inhibitor-related nephrotoxicity after liver transplantation

AIM: To investigate whether microproteinuria could be used as an early and sensitive indicator to detect calcineurin inhibitor (CNI)-related nephrotoxicity after liver transplantation.

METHODS: All liver transplant recipients with normal serum creatinine (SCr) and detectable microproteinuria at baseline were included in this study. The renal function was monitored by the blood clearance of ^99mTc-diethylenetriaminepentaacetic acid every 6 mo. Microproteinuria, SCr and blood urea nitrogen (BUN) were measured at entry and at subsequent follow-up visits. The patients were divided into different groups according to the mean values of glomerular filtration rate (GFR) at the follow-up time points: Group 1, GFR decreased from baseline by 0%-10%; Group 2, GFR decreased from baseline by 11%-20%; Group 3, GFR decreased from baseline by 21%-40%; Group 4, GFR decreased from baseline by > 40% and/or SCr was increasing.

RESULTS: A total of 143 patients were enrolled into this study (23 females and 120 males). The mean follow-up was 32 mo (range 16-36 mo). Downward trends in renal function over time were observed in the study groups. SCr and BUN increased significantly only in Group 4 patients (P < 0.001). β2-microglobulin (β2m) and α1-microglobulin (α1m) significantly increased with the subtle change of renal function in recipients who were exposed to CNI-based immunosuppression regimens. The reductions in GFR were closely correlated with elevated α1m (r² = -0.728, P < 0.001) and β2m (r² = -0.787, P < 0.001).

CONCLUSION: β2m and α1m could be useful as early and sensitive indicators of CNI-induced nephrotoxicity.

Relationship between renal resistance index and renal function in liver transplant recipients after cessation of calcineurin inhibitor

End stage renal disease is a major complication after orthotopic liver transplantation (OLT). Vasoconstriction of renal arterial vessels because of calcineurin inhibitor (CNI) treatment plays a pivotal role in the development of renal insufficiency following OLT. Renal resistance can be measured non-invasively by determining the resistance index (RI) of segmental arteries by color-coded duplex ultrasonography, a measure with predictive value for future renal failure. Sixteen OLT patients on long-term CNI therapy were recruited prospectively and randomly assigned either to receive the m-TOR inhibitor sirolimus (SRL) or to continue on CNI treatment, and were followed for one yr. Serum creatinine (crea) declined after conversion to SRL, whereas it tended to increase in patients remaining on CNI (meanDelta crea SRL: -27, -18, -18, -15 micromol/L; meanDelta crea CNI: 4, 5, 8, 11 micromol/L at 1, 3, 6, 12 months, p = 0.02). RI improved after switching to SRL and was lower on SRL than on CNI (meanDeltaRI SRL: -0.04, -0.04, -0.03, -0.03; meanDeltaRI CNI: -0.006, 0.004, -0.007, -0.01 after 1, 3, 6, 12 months, p = 0.016). Individual changes of RI correlated significantly with individual changes of crea (r = 0.54, p < 0.001). Conversion from CNI to SRL can ameliorate renal function accompanied by a reduction of intrarenal RI after OLT.

Calcineurin inhibitor minimization protocols in liver transplantation

Liver transplant recipients are at increasingly high risk for suffering from impaired renal function and probable need of renal replacement therapy. Extended criteria organs and transplantation of patients with higher model for end-stage liver disease scores further increase this problem. Acute and chronic nephrotoxicity are the trade-off in immunosuppression with potent calcineurin inhibitors (CNIs). As a good renal function is associated with better graft and patient survival, CNI minimization protocols have been developed. Current strategies to overcome CNI toxicity include reduction or withdrawal of CNIs concurrently with switching over to mammalian target of rapamycin inhibitor or mycophenolate mofetil (MMF)-based regimens. This strategy caused an improvement in renal function in a significant number of liver transplantation patients according to several studies. However, total CNI avoidance seems to result in higher rejection rates. To prevent chronic renal dysfunction in patients prone to or with acute renal failure, CNI delay - with induction therapy for bridging - followed by low-dose CNI in combination with MMF are proven strategies without risking higher rejection rates. An individualized, tailor-made immunosuppressive regime, with a special focus on renal function is recommended. This review gave an overview on CNI minimization protocols in liver transplantation also focusing on recently analyzed studies.