Mycophenolate mofetil monotherapy in liver transplantation

Immunosuppressive Drugs in Liver Transplant: An Insight

Liver transplantation (LT) is the standard of care for end-stage liver failure and hepatocellular carcinoma. Over the years, immunosuppression regimens have improved, resulting in enhanced graft and patient survival. At present, the side effects of immunosuppressive agents are a significant threat to post-LT quality of life and long-term outcome. The role of personalized immunosuppression is to reach a delicate balance between optimal immunosuppression and minimal side effects. Today, immunosuppression in LT is more of an art than a science. There are no validated markers for overimmunosuppression and underimmunosuppression, only a few drugs have therapeutic drug monitoring and immunosuppression regimens vary from center to center. The immunosuppressive agents are broadly classified into biological agents and pharmacological agents. Most regimens use multiple agents with different modes of action to reduce the dosage and minimize the toxicities. The calcineurin inhibitor (CNI)-related toxicities are reduced by antibody induction or using mTOR inhibitor/antimetabolites as CNI sparing or CNI minimization strategies. Post-liver transplant immunosuppression has an intensive phase in the first three months when alloreactivity is high, followed by a maintenance phase when immunosuppression minimization protocols are implemented. Over time some patients achieve "tolerance," defined as the successful stopping of immunosuppression with good graft function and no indication of rejection. Cell-based therapy using immune cells with tolerogenic potential is the future and may permit complete withdrawal of immunosuppressive agents.

Clickable, acid labile immunosuppressive prodrugs forin vivotargeting

Clickable immunosuppressive prodrugs enablein vivoreplenishment of drugs in biomaterial depots to maintain long-term immunosuppression in tissue/organ transplantation.

Suppression of autophagy by mycophenolic acid contributes to inhibition of HCV replication in human hepatoma cells

Previous studies have shown that mycophenolic acid (MPA) has an anti-HCV activity. However, the mechanism of MPA-mediated inhibition of HCV replication remains to be determined. This study investigated whether MPA has an effect on autophagy, a cellular machinery required for HCV replication, thereby, inhibits HCV replication in Huh7 cells. MPA treatment of Huh7 cells could suppress autophagy, evidenced by decreased LC3B-II level and conversion of LC3B-I to LC3B-II, decreased autophagosome formation, and increased p62 level compared to MPA-untreated cells. Tunicamycin treatment or HCV infection could induce cellular autophagy, however, MPA also exhibited its inhibitory effect on tunicamycin- or HCV infection-induced autophagy. The expression of three autophagy-related genes, Atg3, Atg5, and Atg7 were identified to be inhibited by MPA treatment. Over-expression of these genes could partly recover HCV replication inhibited by MPA; however, silencing their expression by siRNAs could enhance the inhibitory effect of MPA on HCV. Collectively, these results reveal that suppression of autophagy by MPA plays a role in its anti-HCV activity. Down-regulating the expression of three autophagy-related genes by MPA involves in its antiviral mechanism.

Efficacy and safety of a reduced calcineurin inhibitor dose combined with mycophenolate mofetil in liver transplant patients with chronic renal dysfunction

Calcineurin inhibitors (CNIs) are frequently given at a reduced dose in combination with mycophenolate mofetil (MMF) to avoid nephrotoxicity, but the optimal reduction in CNI dose has not been established. In this prospective, open-label, multicenter study, liver transplant recipients with chronic renal dysfunction who were administered a CNI-based immunosuppressive regimen were included in the intent-to-treat (ITT) population. The primary endpoint was declination in renal function, which was defined as a ≥ 20% decrease in the glomerular filtration rate during the year following regimen adjustment. In the ITT population, renal function declined after regimen adjustment in three patients (7%) in the MMF plus 50% CNI reduction group. Additionally, three of 40 patients (7.5%) in the MMF plus 75% CNI reduction group experienced at least one clinically suspected or biopsy-proven acute rejection. There were no differences between the two groups. The corrected mean improvement in creatinine clearance at week 52 was 6.551 mL/min in the MMF plus 50% CNI reduction group and 6.442 mL/min in the MMF plus at least 75% CNI reduction group. Thus, a regimen of MMF combined with a 50% or at least 70% reduction in CNI dose could improve renal function and was both tolerable and safe.

Protecting the Kidney in Liver Transplant Recipients: Practice-Based Recommendations From the American Society of Transplantation Liver and Intestine Community of Practice

Both acute and chronic kidney disease are common after liver transplantation and result in significant morbidity and mortality. The introduction of the Model for End-stage Liver Disease score has directly correlated with an increased prevalence of perioperative renal dysfunction and the number of simultaneous liver-kidney transplantations performed. Kidney dysfunction in this population is typically multifactorial and related to preexisting conditions, pretransplantation renal injury, perioperative events, and posttransplantation nephrotoxic immunosuppressive therapies. The management of kidney disease after liver transplantation is challenging, as by the time the serum creatinine level is significantly elevated, few interventions affect the course of progression. Also, immunological factors such as antibody-mediated kidney rejection have become of greater interest given the rising liver-kidney transplant population. Therefore, this review, assembled by experts in the field and endorsed by the American Society of Transplantation Liver and Intestine Community of Practice, provides a critical assessment of measures of renal function and interventions aimed at preserving renal function early and late after liver and simultaneous liver-kidney transplantation. Key points and practice-based recommendations for the prevention and management of kidney injury in this population are provided to offer guidance for clinicians and identify gaps in knowledge for future investigations.

New Antiproliferative Immunosuppressive Agents

Since the early 1980s, the combination of cyclosporine, azathioprine, and prednisone has been the mainstay tripledrug immunosuppressive regimen used in transplantation. However, advances in drug research, design, and development have allowed for the introduction of new agents that have greatly increased the number of immunosuppressive agents available for use in transplant recipients. Particularly, the newer antiproliferative immunosuppressive drugs (agents that directly inhibit the proliferation of T and B lymphocytes) have had an important impact on patient outcomes posttransplant. These agents are mycophenolate mofetil and sirolimus.

Selection and use of immunosuppressive therapies after liver transplantation: current German practice

In recent years, immunosuppression (IS) after liver transplantation (LT) has become increasingly diversified as the choice of agents has expanded and clinicians seek to optimize the balance of immunosuppressive potency with the risk of adverse events in individual patients. Calcineurin inhibitors (CNIs) are the primary agents used for patients undergoing liver transplantation. Other therapeutic agents like interleukin-2 receptor antagonists are not universally administered, but can be considered for the delay or reduction in CNI exposure. An early addition of mycophenolate mofetil (MMF) or the mTOR inhibitor everolimus also allows for the reduction in the CNI dose. To reduce the risk of malignancy, in particular of skin tumors, as well as to prevent the deterioration of renal function, everolimus-based therapy may be advantageous. Apart from patients with autoimmune hepatitis, steroids are withdrawn within 3-6 months after transplantation. Overall, immunosuppression can only be standardized in a limited proportion of patients due to specific clinical requirements and risk factors. Future studies should attempt to refine accurate individualization of the immunosuppressive regimen in specific difficult-to-treat patient subpopulations.

Post-liver transplant hepatitis C virus recurrence: an unresolved thorny problem

Hepatitis C virus (HCV)-related cirrhosis represents the leading cause of liver transplantation in developed, Western and Eastern countries. Unfortunately, liver transplantation does not cure recipient HCV infection: reinfection universally occurs and disease progression is faster after liver transplant. In this review we focus on what happens throughout the peri-transplant phase and in the first 6-12 mo after transplantation: during this crucial period a completely new balance between HCV, liver graft, the recipient's immune response and anti-rejection therapy is achieved that will deeply affect subsequent outcomes. Nearly all patients show an early graft reinfection, with HCV viremia reaching and exceeding pre-transplant levels; in this setting, histological assessment is essential to differentiate recurrent hepatitis C from acute or chronic rejection; however, differentiating the two patterns remains difficult. The host immune response (mainly cellular mediated) appears to be crucial both in the control of HCV infection and in the genesis of rejection, and it is also strongly influenced by immunosuppressive treatment. At present no clear immunosuppressive strategy could be strongly recommended in HCV-positive recipients to prevent HCV recurrence, even immunotherapy appears to be ineffective. Nonetheless it seems reasonable that episodes of rejection and over-immunosuppression are more likely to enhance the risk of HCV recurrence through immunological mechanisms. Both complete prevention of rejection and optimization of immunosuppression should represent the main goals towards reducing the rate of graft HCV reinfection. In conclusion, post-transplant HCV recurrence remains an unresolved, thorny problem because many factors remain obscure and need to be better determined.

Multiple regression analysis of factors predicting mycophenolic acid free fraction in 91 adult organ transplant recipients

BACKGROUND

Mycophenolic acid (MPA) is an antirejection drug used in various types of solid organ transplants. MPA is extensively bound to albumin, and free MPA is thought to be the primary immunosuppressive agent. Little is known of what contributes to the wide interindividual variability in the observed MPA free fraction (MPAf) in humans. The purpose of this study was to determine, using multiple regression analysis of demographic and laboratory variables that are routinely collected during clinic visits, patient factors that predict MPAf in a large sample (n = 91) of organ transplant recipients.

METHODS

Age, weight, height, total daily MPA dose, albumin, serum creatinine (SrCr), and MPAf were obtained from islet (n = 16), kidney (n = 28), and heart/lung (n = 47) transplant recipients. Multiple linear regression analysis and the The Spearman rank correlation were conducted using SigmaStat (version 3.5 for Windows). Significance was set a priori at P = 0.05.

RESULTS

The pooled data can be described as (mean ± SD) follows: age (52 ± 13 years), weight (72 ± 15 kg), height (169 ± 9 cm), total daily MPA dose (1632 ± 667 mg), albumin (42 ± 7 g/L), SrCr (112 ± 34 µmol/L), and MPAf (2.9% ± 3.5%). Multiple regression of all commonly acquired variables generated the following equation: MPAf = 1.865 + (0.0357 × age (yrs)) + (0.0125 × weight (kg)) - (0.0202 × height (cm)) - (0.000323 × total daily dose (mg)) + (0.0122 × albumin (g/L)) + (0.0160 × SrCr (µmol/L)) (r = 0.06), but none of the variables were significant predictors of MPAf (P > 0.05). The Spearman rank correlation of each individual variable confirmed lack of significant correlation with MPAf.

CONCLUSIONS

To our knowledge, this is the first study attempting to describe factors predicting MPAf in adult organ transplant recipients involving a large sample size. The novel findings of lack of significant predictors warrant further investigations using additional patient factors.

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.

Immunosuppression in HCV-positive liver-transplant recipients

PURPOSE OF REVIEW

The purpose of this review is to evaluate the historical and recent literature as it pertains to current immunosuppression regimens in hepatitis C virus (HCV)-positive (+) liver-transplant recipients.

RECENT FINDINGS

Recent findings suggest that there are unique differences between HCV transplant recipients and non-HCV transplant recipients, not only in the graft's inflammatory response, but also to the treatments used to prevent and combat rejection.

SUMMARY

HCV (+) transplant recipients present unique challenges. Over the years, there has been progress but there is clearly no consensus regarding the optimal immunosuppressive medications or drug regimens; however, there continues to be advancements in the management of patients with HCV. Though current studies do not provide clear evidence as to optimal immunosuppression, they do identify questions ideally addressed by large, randomized controlled trials.

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.

Immunomodulating options for liver transplant patients

Much has changed since the early years of liver transplantation. Improvements in post-transplant survival are largely due to more selective and less toxic immunosuppression regimens and advances in operative and perioperative care. This has allowed liver transplantation to become an extremely successful treatment option for patients with endstage liver disease. Beginning with cyclosporine, a cyclic endecapeptide of fungal origin and the first of the calcineurin inhibitors to find widespread use, immunosuppressive regimens have evolved to include additional calcineurin inhibitors, steroids, mTOR inhibitors, antimetabolites and antibodies, mostly targeting T-cell activation. This review will present currently available immunosuppressive agents used in the perioperative period of liver transplantation, as well as maintenance treatments, tailoring therapeutic strategies for specific populations, and advances in immune monitoring and tolerance.

Early tacrolimus exposure after liver transplantation: relationship with moderate/severe acute rejection and long-term outcome

BACKGROUND & AIMS

Liver transplant (LT) patients might be overimmunosuppressed as recommendations for tacrolimus trough concentrations (TC) within 4-6 weeks after liver transplantation are set too high (10-15 ng/ml). Early tacrolimus exposure was evaluated in relation to acute rejection and long-term outcomes.

METHODS

Four hundred and ninety-three consecutive LT patients receiving tacrolimus as primary immunosuppression (1995-2008) were analyzed. Acute rejection was diagnosed using protocol biopsies at day 6.1 ± 2.5. Median follow-up was 7.3 years (IQR 3.9-10.5). Early tacrolimus exposure (<15 days) was evaluated against moderate/severe acute rejection, chronic rejection, graft loss, chronic renal impairment and mortality using multiple logistic and Cox regression.

RESULTS

Maintenance immunosuppression was tacrolimus monotherapy (48.1%), double therapy combination with antimetabolites or steroids (18%), or triple therapy combination with antimetabolites and steroids (33.9%). Histological grade of acute rejection was moderate in 157 cases (31.8%) and severe in 19 cases (3.9%). Tacrolimus TC>7 ng/ml on the day of protocol biopsy was associated with less moderate/severe rejection (23.8%) compared with<7 ng/ml (41.2%) (p = 0.004). Mean tacrolimus TC 7-10 ng/ml within 15 days after LT were associated with reduced risk of graft loss (RR = 0.46; p = 0.014) compared to TC 10-15 ng/ml. A peak TC>20 ng/ml within this period was independently related to higher mortality (RR = 1.67; p = 0.005), particularly due to cardiovascular events, infections and malignancy (RR = 2.15; p = 0.001). Early tacrolimus exposure did not influence chronic rejection (p = 0.58), or chronic renal impairment (p = 0.25).

CONCLUSIONS

During the first 2 weeks after LT, tacrolimus TC between 7 and 10 ng/ml are safe in terms of acute rejection and are associated with longer graft survival.

Immunomodulating therapy in liver transplantation: principles and practice

Liver transplantation has enjoyed dramatic success as a treatment option for patients suffering from chronic end-stage liver diseases. It also serves as a definitive treatment for certain genetic conditions such as familial amyloidosis and primary oxalosis, and as a potential curative therapy in selected cases of primary liver cancer. Currently, over 50,000 patients are alive with functioning liver transplants. Liver transplantation owes its success to advances in surgical technique, improvements in anesthesia and critical care, and advances in treatment of post-transplant complications including improved therapies for cytomegalovirus infections. But perhaps the most important advances in liver transplantation arise in the context of improvements in our understanding of the molecular biology of transplant immunology and the development of new agents that allow for manipulation of immunological signaling pathways. These improvements in immunosuppressive therapy have dramatically increased both graft and patient survival.

Calcineurin inhibitor sparing with mycophenolate mofetil in liver transplantion: a systematic review of randomized controlled trials

Liver transplant recipients are at high risk of developing acute and chronic renal failure. Moreover, introduction of the model for end-stage liver disease (MELD) score for primary allocation of liver grafts favors patients with pretransplant kidney dysfunction, which in turn have a higher risk of posttransplant renal failure. Calcineurin inhibitors (CNI) further increase the risk of renal failure and therefore sparing CNI with the use of mycophenolate mofetil (MMF) may improve renal function. MMF may either be used de novo in the immediate posttransplant period in combination with low-dose CNI (scenario 1) or patients that receive immunosuppression based on CNI may be converted to MMF in combination with minimization or elimination of CNI (scenario 2). Although many retrospective cohort studies and nonrandomized trials have implicated efficacy of this approach the evidence from randomized controlled studies has not been summarized. In the current review we report the results of a systematic review and meta-analysis of randomized controlled trials.

Tacrolimus trough levels, rejection and renal impairment in liver transplantation: a systematic review and meta-analysis

We hypothesized that current trough concentrations of tacrolimus after liver transplantation are set too high, considering that clinical consequences of rejection are not severe while side effects are increased.We systematically reviewed 64 studies (32 randomized controlled trials and 32 observational studies) to determine how lower tacrolimus trough concentrations than currently recommended affect acute rejection rates and renal impairment. Among randomized trials the mean of tacrolimus trough concentration during the first month was positively correlated with renal impairment within 1 year (r = 0.73; p = 0.003), but not with acute rejection, either defined using protocol biopsies (r = -0.37; p = 0.32) or not (r = 0.11; p = 0.49). A meta-analysis of randomized trials directly comparing tacrolimus trough concentrations (five trials for acute rejection [n = 957] and two trials for renal impairment [n = 712]) showed that "reduced tacrolimus" trough concentrations (<10 ng/mL) within the first month after liver transplantation were associated with less renal impairment at 1 year (RR = 0.51 [0.38-0.69]), with no significant influence on acute rejection (RR = 0.92 [0.65-1.31]) compared to "conventional tacrolimus" trough levels (>10 ng/mL). Lower trough concentrations of tacrolimus (6-10 ng/mL during the first month) would be more appropriate after liver transplantation. Regulatory authorities and the pharmaceutical industry should allow changes of regulatory drug information.

Chronic kidney disease after nonrenal solid organ transplantation: a histological assessment and utility of chronic allograft damage index scoring

BACKGROUND

It is proposed that chronic calcineurin inhibitor (CNI) nephrotoxicity has a central role in chronic kidney disease after nonrenal solid organ transplantation (NRSOT), although there are little data on renal histology in this setting. The aim of this study was to assess the histological features and renal outcomes of a cohort of patients with chronic kidney disease after NRSOT.

METHODS

Renal biopsies of 62 NRSOT recipients were evaluated for histological diagnoses. Biopsies were graded for chronic allograft damage index parameters and for arteriolar hyalinosis. The sum of all chronic allograft damage index parameters and arteriolar hyalinosis scores was called chronic damage index.

RESULTS

The biopsies were performed at a median of 4 (range: 0.3-15.9) years after NRSOT and at serum creatinine of 318±17.7 μmol/L (mean±standard deviation). Twenty-two (35.5%) biopsies showed predominant features of chronic CNI nephrotoxicity, 27 (43.5%) predominant features of hypertensive nephropathy, and 12 (19.3%) an alternative primary renal pathology. Twenty-four (38.7%) patients had progression to end-stage renal disease, at a median of 1.5 (0-10.1) years after biopsy and 6.9 (0.3-19.2) years after NRSOT. The risk of renal progression was associated with in situ damage measured by chronic damage index.

CONCLUSIONS

Although CNI nephrotoxicity is an important cause of renal failure after NRSOT, many patients do not have overt histological evidence of CNI toxicity. Quantitative parameters of chronic damage can stratify renal prognosis.

Long-term outcomes of calcineurin inhibitor withdrawal for post-liver transplant renal dysfunction

BACKGROUND

It has become common practice to withdraw or reduce calcineurin inhibitors (CNI) in patients with renal dysfunction after liver transplantation; however, little is known about the long-term outcome of this strategy. This study investigates the long-term results of CNI withdrawal for post-liver transplant renal dysfunction and examines for factors that predict a significant improvement in renal function.

METHODS

A retrospective database review was performed to examine outcomes in patients with CNI withdrawn for chronic renal impairment. Univariate analyses were used to identify predictors of an improvement in creatinine clearance (CrC).

RESULTS

Sixty patients (44 males) were included. Of these, 82% of patients were switched to mycophenolate mofetil and 18% azathioprine. Median follow-up after CNI withdrawal was 48 (range 3-72) months. Postwithdrawal, there was an initial improvement in CrCl (mean 5.5 mL), which remained above baseline levels at 6 years. Acute cellular rejection developed in six patients (10%), but there was no rejection-associated graft loss. A shorter time from transplantation to conversion was associated with greatest improvement in CrCI.

CONCLUSIONS

CNI withdrawal is associated with a significant initial improvement and then arrest in long-term decline of renal function. Rejection in this setting is uncommon. The greatest benefit is seen in patients switched within the early years after transplantation.

Mycophenolate mofetil monotherapy in liver transplantation: 5-year follow-up of a prospective randomized trial

BACKGROUND

Calcineurin inhibitors (CNIs) play the key role in immunosuppressive protocols yet are often associated with numerous side effects. Renal insufficiency, hypertension, hyperglycemia, and increased risk of secondary malignancy are major problems in short- and long-term follow-up of liver transplant patients. Mycophenolate mofetil (MMF) has proved to be a potent immunosuppressive agent free of the CNI-associated side effects.

PATIENTS AND METHODS

One hundred fifty patients who received liver transplantation at our institution (1998-2003) were prospectively randomized: 75 patients continued CNI standard therapy, 75 patients were switched to MMF monotherapy, and follow-up was 5 years. Incidence of rejection, renal complication, cardiovascular, neurological and gastrointestinal adverse effects, and diabetes and malignancy development was recorded. Graft biopsies were performed every 2 to 3 years.

RESULTS

No significant difference regarding the incidence of acute rejection was detected. A trend to higher rejection frequency was apparent in the MMF monotherapy group. Chronic rejection was absent; organ and patient survival were identical in the two groups. No significant difference occurred concerning the incidence of cardiovascular, gastrointestinal or neurological adverse effects, or the development of malignancies. Renal function improved significantly in patients with renal insufficiency when patients treated with CNI were switched to MMF monotherapy.

CONCLUSION

MMF monotherapy may serve as safe long-term immunosuppression after liver transplantation for a subgroup of patients. Especially for patients with renal insufficiency MMF offers immunosuppression without the risk of nephrotoxicity.

Mycophenolate mofetil monotherapy in liver transplant recipients

INTRODUCTION

Complete conversion of calcineurin inhibitor (CNI) immunosuppressant therapy to non-nephrotoxic agents such as mycophenolate mofetil (MMF) is controversial, but may be safe in selected patients, although appropriate protocols and long-term benefits of conversion are not well reported.

METHODS

We analyzed all liver transplant (LT) recipients at our institution who were converted from CNI-based therapy to MMF monotherapy because of renal dysfunction (n = 23) and compared them with patients remaining on CNI-based therapy (n = 23). Renal function, rejection episodes, and markers of CNI-related comorbidities (lipid profile, blood pressure, and glycosylated hemoglobin) were noted.

RESULTS

Overall, serum creatinine (SCr) and calculated glomerular filtration rate improved on MMF monotherapy. This improvement was significant when compared with patients who remained on CNI-based therapy. Improvement was most pronounced in patients with milder renal dysfunction (SCr <2.2 mg/dL prior to conversion) (n = 14) with decrease in SCr from 1.63 ± 0.29 to 1.34 ± 0.26 mg/dL (p = 0.02) at last follow-up. Five patients on MMF monotherapy (21.7%) progressed to end-stage renal disease (ESRD), while only two (8.7%) had rejection episodes following conversion. Clinical markers of CNI-related comorbidities also improved. MMF monotherapy was well tolerated.

CONCLUSION

In summary, our data support the safety and efficacy of CNI to MMF monotherapy conversion.

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.

Basiliximab induction and delayed calcineurin inhibitor initiation in liver transplant recipients with renal insufficiency

BACKGROUND

Renal insufficiency (RI) is common after liver transplantation (LT) and may worsen due to calcineurin inhibitor (CNI) use. We compared LT outcomes using basiliximab induction and delayed CNI initiation to controls with a standard CNI regimen in patients with peri-LT RI.

METHODS

All adults transplanted January 2004 to December 2007 with peri-LT RI (hemodialysis or creatinine ≥1.5 within 1 week of LT) were included in a retrospective nonrandomized cohort. Outcomes including 30-day and 1-year patient and graft survival and renal function were compared between basiliximab and control groups.

RESULTS

Two hundred twenty-nine patients (102 basiliximab, 127 controls) were analyzed, mean age 54 years, 72% men, 54% with hepatitis C virus. Mean model for end-stage liver disease (28.2 vs. 20.0; P<0.001) and creatinine (1.9 vs. 1.6; P=0.001) were higher and more patients were on hemodialysis at LT (29% vs. 6%; P<0.001) in the basiliximab group. 30-day patient (99% vs. 97%; P=0.26) and graft survival (98% vs. 95%; P=0.17), 1-year patient (87% vs. 87%; P=0.89) and graft survival (86% vs. 82%; P=0.37), mean creatinine at 1-year (1.5 vs. 1.5 mg/dL; P=0.82), and treated acute rejection (6% vs. 6%; P=0.90) were similar between basiliximab and control groups, respectively. In multivariable logistic regression, basiliximab was not significantly associated with 30-day (odds ratio, 0.10; P=0.11) or 1-year (odds ratio, 0.97; P=0.94) survival, controlling for age, previous LT, model for end-stage liver disease, and hepatitis C virus.

CONCLUSIONS

Basiliximab induction resulted in 30-day and 1-year patient, graft and renal outcomes comparable with a control group receiving standard CNI-based immunosuppression. Antibody induction with delayed CNI should be further studied prospectively.

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.

Long-term, maintenance MMF monotherapy improves the fibrosis progression in liver transplant recipients with recurrent hepatitis C

Hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (LT) is universal. We designed a retrospective case-control study to evaluate the effect of mycophenolate mofetil (MMF) monotherapy in patients with recurrent hepatitis C. Fifteen patients with histologically proven hepatitis C recurrence after LT were switched from calcineurin inhibitors (CNIs) to MMF monotherapy because of impairment of kidney function and/or metabolic side effects, and treated for 48 months (MMF group). Fifteen well-matched LT recipients who continued to receive CNIs therapy over the same period served as control group. Demographics, clinical data, time after LT, and baseline liver biopsies were similar in the two groups. There was no worsening of hepatic fibrosis during the study in the MMF group [2.6 ± 1.5 (baseline) Ishak Units vs. 2.7 ± 1.8 (after 48 months of MMF treatment), P = 0.6]. In contrast, a significant increase in the fibrosis score [2 ± 1.1 (baseline) vs. 3.2 ± 1.7 (after 48 months of CNI treatment), P = 0.0002] was observed in the control group. The yearly fibrosis progression rate was of 0.05 ± 0.44 in the MMF group and 0.33 ± 0.24 in the CNI group (P = 0.04). MMF monotherapy is associated with a favourable effect on hepatic fibrosis progression in HCV liver transplant recipients.

Reduced-dose tacrolimus with mycophenolate mofetil vs. standard-dose tacrolimus in liver transplantation: a randomized study

We conducted a multicenter randomized study in liver transplantation to compare standard-dose tacrolimus to reduced-dose tacrolimus with mycophenolate mofetil to reduce the occurrence of tacrolimus side effects. Two primary outcomes (censored criteria) were monitored during 48 weeks post-transplantation: occurrence of renal dysfunction or arterial hypertension or diabetes (evaluating benefit) and occurrence of acute graft rejection (evaluating risk). Interim analyses were performed every 40 patients to stop the study in the case of increased risk of graft rejection. One hundred and ninety-five patients (control: 100; experimental: 95) had been included when the study was stopped. Acute graft rejection occurred in 46 (46%) and 28 (30%) patients in control and experimental groups, respectively (HR = 0.59; 95% CI: [0.37-0.94]; p = 0.024). Renal dysfunction or arterial hypertension or diabetes occurred in 80 (80%) and 61 (64%) patients in control and experimental groups, respectively (HR = 0.68; 95% CI: [0.49-0.95]; p = 0.021). Renal dysfunction occurred in 42 (42%) and 23 (24%) patients in control and experimental groups, respectively (HR = 0.49; 95% CI: [0.29-0.81]; p = 0.004). Leucopoenia (p = 0.001), thrombocytopenia (p = 0.017) and diarrhea (p = 0.002) occurred more frequently in the experimental group. Reduced-dose tacrolimus with mycophenolate mofetil reduces the occurrence of renal dysfunction and the risk of graft rejection. This immunosuppressive regimen could replace full-dose tacrolimus in adult liver transplantation.

Mycophenolate monitoring in liver, thoracic, pancreas, and small bowel transplantation: a consensus report

Assessing the value of mycophenolic acid (MPA) monitoring outside renal transplantation is hindered by the absence of any trial comparing fixed-dose and concentration-controlled therapy. However, in liver and thoracic transplantation particularly, clinical trials, observational studies with comparison groups, and case series have described MPA efficacy, exposure/efficacy relationships, pharmacokinetic variability, and clinical outcomes relating to plasma MPA concentrations. On the basis of this evidence, this report identifies MPA as an immunosuppressant for which the combination of variable disposition, efficacy, and adverse effects contributes to interindividual differences seemingly in excess of those optimal for a fixed-dosage mycophenolate regimen. Combined with experiences of MPA monitoring in other transplant indications, the data have been rationalized to define circumstances in which measurement of MPA concentrations can contribute to improved management of mycophenolate therapy in nonrenal transplant recipients.

Sustained renal response to mycophenolate mofetil and CNI taper promotes survival in liver transplant patients with CNI-related renal dysfunction

AIM

The aim of this trial was to evaluate the impact of conversion from a calcineurin-inhibitor (CNI)-based immunosuppressive regimen to mycophenolate mofetil (MMF) and reduced-dose CNI on long-term renal function and survival in a series of 63 liver transplant patients with CNI-induced renal dysfunction.

METHODS

CNI dosage was significantly tapered after introduction of 2,000 mg MMF per day. Renal function was assessed by determination of serum creatinine levels and calculated creatinine clearance (CCl). The impact of relevant clinical parameters on renal function and survival post-conversion was analyzed by univariate and multivariate analysis.

RESULTS

At 60 months post-conversion, mean creatinine level had significantly declined from 197.2±58.3 μmol/l at baseline to 160.0±76.5 μmol/l, and mean CCl has significantly increased from 38.4±13.4 ml/min at baseline to 47.9±21.1 ml/min (p<0.001), respectively. Forty-six patients (73.1%) demonstrated sustained renal response to modified immunosuppression. Full-dose MMF medication (p=0.006) and the early conversion (p=0.02) were identified as independent predictors of persistent renal function improvement. Sustained renal response to MMF plus reduced-dose CNI was identified as the most relevant independent promoter of long-term survival (hazard ratio 6.9). Five-year survival rate post-conversion was 93.9% in renal responders and 64.3% in renal non-responders (log rank<0.001).

CONCLUSIONS

Sustained renal response to MMF and CNI dose reduction promotes long-term survival in liver transplant patients with CNI-induced renal dysfunction.

The renal benefit of mycophenolate mofetil after liver transplantation

BACKGROUND

The risk and benefit of adding mycophenolate mofetil (MMF) to a standard immunosuppressive regimen at the time of liver transplantation (LT) is not well described.

METHODS

We performed a retrospective case-control analysis comparing one-yr outcomes of all LT recipients at our institution treated with post-operative tacrolimus (TAC), MMF, and steroids vs. TAC and steroids.

RESULTS

A total of 101 LT recipients (50:51 case:control) were analyzed. Despite more renal dysfunction at LT, the MMF + TAC group had similar serum creatinine (Cr) and glomerular filtration rate (GFR) as the TAC group one-yr post-LT. In this time period, Cr decreased (1.57-1.22 mg/dL, p = 0.04) and GFR increased (57.5-65.1 mL/min per 1.73 m(2), p = 0.05) in the MMF + TAC group, while Cr increased (1.11-1.35, p < 0.01) and GFR declined (73.5-60.1, p < 0.001) in the TAC group. These findings occurred without a difference in absolute rejection episodes, hospitalizations, infections, deaths, or time to above events (p > 0.05). Subgroup analysis of patients stratified by pre-transplant renal dysfunction (Cr ≥ 1.2 mg/dL) supported the previous. MMF was reasonably well tolerated with a low rate of discontinuation.

CONCLUSIONS

The use of adjunctive MMF immediately after LT may protect against calcineurin inhibitor nephrotoxicity, potentially without the need for dose reduction or increased risk of adverse events.

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.

Improvement of renal function after conversion to mycophenolate mofetil combined with low-level calcineurin inhibitor in liver transplant recipients with chronic renal dysfunction

INTRODUCTION

Calcineurin inhibitors (CNI) are the main pathogenic factors for renal dysfunction in solid organ transplant recipients. Introduction of non-nephrotoxic immunosuppressive drugs, such as mycophenolate mofetil (MMF), may allow discontinuation or reduction of CNI treatment, thereby improving renal function. The aim of this study was to assess the feasibility, efficacy and safety of MMF introduction and CNI dosage reduction in the maintenance immunosuppressive protocol to improve renal function in liver transplant recipients with chronic renal dysfunction.

PATIENTS AND METHODS

We prospectively included 88 liver transplant recipients including 74 men and an overall mean age of 58.8 +/- 10.3 years who all displayed chronic renal dysfunction (creatinine >1.4 mg/dL) and proteinuria <1 g/d. They were subdivided into 3 groups according to the basal creatinine value 1.4-1.7 mg/dL (group I; n = 41); 1.8-2.0 mg/dL (group II; n = 28); and >2 mg/dL (group III; n = 19). MMF was initiated at 1.5-2.0 g/d. Reduction of tacrolimus or cyclosporine dosage was performed to achieve respective target trough levels of <5 ng/mL or <50 ng/mL. We performed periodic determinations of arterial pressure, liver function tests, serum creatinine, blood cells count, CNI levels, and proteinuria.

RESULTS

Creatinine values after conversion were 1.4 +/- 0.5 mg/dL in the overall group. Improvement of renal function was more frequent among groups I (80.4%) and II (92.8%) versus III (73.6%). Normalization of creatinine values was more frequent in group I (68.2%) with respect to cohorts II (21.4%) and III (10.5%). Rejection was not detected.

CONCLUSION

Application of an immunosuppressive protocol with MMF and low-level CNI in liver transplant recipients with chronic renal dysfunction was associated with improvement or normalization of creatinine, without an increased risk of rejection. Early conversion is needed to achieve the best results.

Comparison of pharmacokinetics of mycophenolic acid and its metabolites between living donor liver transplant recipients and deceased donor liver transplant recipients

Living-donor liver transplantation (LDLT) has been considered an alternative method for treatment of patients with end-stage liver disease. However, the characteristics of pharmacokinetics of mycophenolic acid (MPA) in patients who underwent LDLT were not clear. This study was designed to compare the pharmacokinetics of MPA and its metabolites between LDLT patients and deceased donor liver transplant (DDLT) patients after oral administration of mycophenolate mofetil (MMF). Thirteen patients who underwent LDLT and 14 patients who underwent DDLT were enrolled prospectively. All patients received oral MMF administration (1.0 g, twice daily) in combination with tacrolimus (TAC). The plasma concentrations of MPA, free MPA, glucuronide (MPAG), and acyl glucuronide (AcMPAG) was determined by high-performance liquid chromatography method. There was a wide variation in various pharmacokinetic parameters of MPA and its metabolites in patients who underwent LDLT and DDLT after oral MMF administration. Although mean MPA area under the plasma concentration time curve for 0-12 hours (AUC(0-12h)) of MPA and MPAG in DDLT patients were higher than those in LDLT patients, there was no significant difference between the two groups. MPA concentration at 6 hours (C(6h)), C(10h), C(12h), and MPA AUC(6-12h) were significantly higher in DDLT group than those in LDLT group (P < 0.05). Inversely, higher free MPA AUC(0-12h) and significant free MPA fraction (P < 0.05) in LDLT patients were observed in DDLT patients when compared with DDLT group. AcMPAG concentrations at 4, 8, and 10 hours and AcMPAG AUC(0-12h) were significantly higher in the DDLT group (P < 0.05). In conclusion, after a fixed oral dose of MMF, DDLT patients had higher enterohepatic recycling contributing to total MPA exposure compared with LDLT patients. The function of glucuronide conjugation in LDLT patients was decreased compared with that in DDLT patients. Higher free MPA AUC(0-12h) and a significantly higher fraction of free MPA in LDLT patients suggested that a lower oral dose of MMF may be administered for patients who underwent LDLT.

Overview of immunosuppression in liver transplantation

Continued advances in surgical techniques and immunosuppressive therapy have allowed liver transplantation to become an extremely successful treatment option for patients with end-stage liver disease. Beginning with the revolutionary discovery of cyclosporine in the 1970s, immunosuppressive regimens have evolved greatly and current statistics confirm one-year graft survival rates in excess of 80%. Immunosuppressive regimens include calcineurin inhibitors, anti-metabolites, mTOR inhibitors, steroids and antibody-based therapies. These agents target different sites in the T cell activation cascade, usually by inhibiting T cell activation or via T cell depletion. They are used as induction therapy in the immediate peri- and post-operative period, as long-term maintenance medications to preserve graft function and as salvage therapy for acute rejection in liver transplant recipients. This review will focus on existing immunosuppressive agents for liver transplantation and consider newer medications on the horizon.

Azathioprine in liver transplantation: a reevaluation of its use and a comparison with mycophenolate mofetil

Calcineurin inhibitors (CNIs) combined with steroids with or without azathioprine (AZA), have been a standard immunosuppression regimen after liver transplantation (LT). Since 2000 many centers have substituted AZA by mycophenolate mofetil (MMF). However, in LT the superiority of MMF over AZA is not clearly demonstrated. Therefore, we questioned the benefit of MMF versus AZA in LT with regard to rejection, renal dysfunction and hepatitis C virus (HCV) recurrence and survival. Using a literature search, relevant randomized controlled trials (RCT) and cohort studies were identified: two RCTs compared MMF to AZA only for acute rejection. Treated rejection was less with MMF in only one RCT (38.5% vs. 47.7%; p = 0.025), with no difference in patient and graft survival. No RCTs compared MMF and AZA in patients with CNI-related chronic renal dysfunction. Among two studies evaluating MMF, with substitution of AZA, one was stopped due to severe rejection. Recurrent HCV was less severe in 5/9 studies with AZA compared with 2/17 using MMF, six of which documented worse recurrence. Published data in LT show little, if any, clinical benefit of MMF versus AZA. RCTs should reevaluate AZA in LT. Evaluation of HCV replication and recurrence will be particularly important as AZA may have advantages over MMF.

Management of renal dysfunction in the liver transplant recipient

PURPOSE OF REVIEW

Acute and chronic kidney injury following orthotopic liver transplantation (OLT) is associated with increased morbidity and mortality. With the increasing longevity of liver transplant recipients, chronic kidney disease (CKD) has become an increasingly prevalent complication among long-term survivors. This article provides an overview of the literature on suggested risk factors for acute and CKD following OLT and a discussion of an approach to their medical management.

RECENT FINDINGS

In OLT candidates with pretransplant renal dysfunction, the use of interleukin-2 receptor blockers or antithymocyte globulin induction therapy in conjunction with delayed introduction of calcineurin inhibitors may preserve early renal function. In long-term stable OLT recipients with established calcineurin inhibitor nephrotoxicity, calcineurin inhibitor minimization or withdrawal protocols may halt or ameliorate renal dysfunction without compromising patient and graft survival. However, large-scale, multicenter, randomized controlled trials are still needed.

SUMMARY

The occurrence of acute kidney injury is common immediately after OLT, whereas the incidence of CKD and end-stage renal disease increases with time. Identifying patients at risk for acute kidney injury and CKD following OLT and early implementation of measures to preserve, halt, or ameliorate the progression of renal dysfunction should be an integral part in the management of OLT recipients.

A comprehensive review of immunosuppression used for liver transplantation

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.

Renal biopsy in liver transplant recipients

BACKGROUND

Renal impairment post-liver transplant (LT) is often attributed to calcineurin inhibitors (CNIs). A renal biopsy can be a useful tool but may be complicated in LT recipients. We aimed to determine the clinical scenarios that prompted a decision to perform a renal biopsy in this patient population, to assess histological findings and evaluate patient management and survival and renal outcome.

METHODS

Information on clinical variables and renal histology was extracted from single-centre prospectively compiled databases from 1996 onwards.

RESULTS

Over 2100 adults received an LT in the time period studied, and 54 of these (35 males and 19 females) were referred for renal review. Of these, 43% underwent a renal biopsy. They had a higher creatinine (P = 0.02), a greater deterioration in creatinine over the year prior to review and were more likely to be nephrotic (both P < 0.01). Histological findings included hypertensive changes (44%), CNI nephrotoxicity (48%), IgA nephropathy (9%), membranoproliferative glomerulonephritis (17%), acute tubular necrosis (4%), crescentic glomerulonephritis (4%) and diabetic nephropathy (9%). Major bleeding complications occurred in 17%. Treatment changed in the majority but, it was not significantly different in the two groups. Although initial renal function was worse in the biopsied group, final patient and renal survival did not differ between the two groups.

CONCLUSION

A renal biopsy is a valuable tool in those with renal insufficiency and/or proteinuria and haematuria but the benefits must be weighed against the relatively high complication rate in LT recipients.

Mycophenolate mofetil monotherapy for severe side effects of calcineurin inhibitors following liver transplantation

Withdrawal of calcineurin inhibitors (CNI) followed by mycophenolate mofetil (MMF) monotherapy after liver transplantation (LT) remains controversial due to the increased risk of acute rejection and graft loss. The aim of the present study, performed in a large cohort of liver-transplanted patients with severe CNI-induced side effects, was to assess renal function recovery, and safety in terms of liver function, of complete CNI withdrawal and replacement by MMF monotherapy. Fifty-two patients treated with MMF monotherapy for CNI-induced toxicity were analyzed. Mean estimated glomerular filtration rate (eGFR) increased significantly during the period of MMF monotherapy, from 37 +/- 10 to 44.7 +/- 15 mL/min/1.73 m(2) at 6 months (p = 0.001) corresponding to a benefit of +17.4% in renal function. eGFR stabilized or improved in 86.5%, 81% and 79% of cases, and chronic renal dysfunction worsened in 13.5%, 19% and 21% of cases, at 6, 12 and 24 months after CNI withdrawal, respectively. Only two patients experienced acute rejection. MMF monotherapy may be efficient at reversing/stabilizing CRD, and appears relatively safe in terms of liver graft function in long-term liver-transplanted patients. However, clinicians must bear in mind the potential risk of rejection and graft loss, and should be very cautious in the management of such 'difficult-to-treat patients'.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

A randomized controlled trial of late conversion from calcineurin inhibitor (CNI)-based to sirolimus-based immunosuppression in liver transplant recipients with impaired renal function

Renal impairment is common in patients after liver transplantation and is attributable in large part to the use of calcineurin inhibitor (CNI)-based immunosuppression. We sought to determine whether conversion to sirolimus-based immunosuppression was associated with improved renal function. In a single-center, randomized, controlled trial, 30 patients at least 6 months post liver transplantation were randomized to remain on CNI-based immunosuppression or to switch to sirolimus-based immunosuppression. The primary outcome measure was change in measured glomerular filtration rate (GFR) between baseline and 12 months. Of 30 patients randomized, 3 were withdrawn at randomization, leaving 14 patients on CNI and 13 on sirolimus. There was a significant improvement in delta GFR following conversion to sirolimus at 3 months (7.7 mL/minute/1.73 m2; 95% confidence interval, 3.5-11.9) and 1 yr (6.1 mL/minute/1.73 m2; 95% confidence interval, 0.9-11.4). The difference in absolute GFR between the 2 study groups was significant at 3 months (P=0.02), but not at 12 months (P=0.07). The principal adverse events following conversion were the development of skin rash (9 of 13 patients, 69%) and mouth ulcers (5 of 13 patients, 38%). Two patients developed acute rejection at 2 and 3 months following conversion, 1 in association with low sirolimus levels and 1 having stopped the drug inadvertently. In conclusion, overall, this study suggests that conversion to sirolimus immunosuppression is associated with a modest improvement in renal function. Side effects were common, but tolerable in most patients and controlled with dose reduction.