Timing of sirolimus conversion influences recovery of renal function in liver transplant recipients

The Role of mTOR Inhibitors after Liver Transplantation for Hepatocellular Carcinoma

Liver transplantation is a treatment option for nonresectable patients with early-stage HCC, with more significant advantages when Milan criteria are fulfilled. An immunosuppressive regimen is required to reduce the risk of graft rejection after transplantation, and CNIs represent the drugs of choice in this setting. However, their inhibitory effect on T-cell activity accounts for a higher risk of tumour regrowth. mTOR inhibitors (mTORi) have been introduced as an alternative immunosuppressive approach to conventional CNI-based regimens to address both immunosuppression and cancer control. The PI3K-AKT-mTOR signalling pathway regulates protein translation, cell growth, and metabolism, and the pathway is frequently deregulated in human tumours. Several studies have suggested the role of mTORi in reducing HCC progression after LT, accounting for a lower recurrence rate. Furthermore, mTOR immunosuppression controls the renal damage associated with CNI exposure. Conversion to mTOR inhibitors is associated with stabilizing and recovering renal dysfunction, suggesting an essential renoprotective effect. Limitations in this therapeutic approach are related to their negative impact on lipid and glucose metabolism as well as on proteinuria development and wound healing. This review aims to summarize the roles of mTORi in managing patients with HCC undergoing LT. Strategies to overcome common adverse effects are also proposed.

Combination of everolimus and low-dose tacrolimus controls histological liver allograft injury as sufficiently as high-dose tacrolimus

Introduction

The combination of everolimus (EVR) and low-dose tacrolimus (lowTAC) prevents T cell-mediated rejection of liver grafts as sufficiently as high-dose tacrolimus (highTAC) and mycophenolate, but is associated with a preserved kidney function within the first years after orthotopic liver transplantation (OLT). However, none of the available studies assessed the histological pattern of graft injury or fibrosis in surveillance biopsies (svLbx).

Methods

All svLbx taken under at least one month of stable immunosuppression with either EVR (aim 3-8 ng/ml) combined with lowTAC (aim 3-5 ng/ml) or highTAC (aim 5-8 ng/ml) combined with mycophenolate (500-1500 mg/day) within the first three to four years after OLT at our center were included. Patients who were switched to EVR because of insufficient control of alloreactivity were excluded.

Results

Reasons for switches to EVR were mainly malignancies before or after OLT, or chronic kidney injury. We were able to include 20 svLbx with EVR/lowTAC and 49 with highTAC/mycophenolate. Both groups had similar liver enzymes and similar kidney function. The EVR/lowTAC group exhibited lower TAC trough levels at svLbx (4.4 vs. 6.6 ng/ml; p<.001) in comparison to highTAC/mycophenolate. Histological graft injury quantified by the rejection activity index and hepatitis activity index (Ishak), as well as fibrosis were not significantly different between the EVR/lowTAC and highTAC/mycophenolate groups. Likewise, subclinical TCMR, histological criteria justifying immunosuppression minimization, and steatosis had equal prevalence in both regimens. Immunosuppression was adjusted according to the svLbx findings. Immunosuppression regimens had similarly low rates of rejection after immunosuppression reduction, when relevant graft injury was absent in the biopsy.

Discussion

In conclusion, EVR/lowTAC seems to control alloreactivity and histological graft injury as sufficiently as highTAC/mycophenolate within the first 3-4 years after OLT.

CORAL Models for Drug-Induced Nephrotoxicity

Drug-induced nephrotoxicity is a major cause of kidney dysfunction with potentially fatal consequences. The poor prediction of clinical responses based on preclinical research hampers the development of new pharmaceuticals. This emphasises the need for new methods for earlier and more accurate diagnosis to avoid drug-induced kidney injuries. Computational predictions of drug-induced nephrotoxicity are an attractive approach to facilitate such an assessment and such models could serve as robust and reliable replacements for animal testing. To provide the chemical information for computational prediction, we used the convenient and common SMILES format. We examined several versions of so-called optimal SMILES-based descriptors. We obtained the highest statistical values, considering the specificity, sensitivity and accuracy of the prediction, by applying recently suggested atoms pairs proportions vectors and the index of ideality of correlation, which is a special statistical measure of the predictive potential. Implementation of this tool in the drug development process might lead to safer drugs in the future.

Metabolic and Renal Effects of Mammalian Target of Rapamycin Inhibitors Treatment After Liver Transplantation: Real-Life Single-Center Experience

BACKGROUND

Mammalian target of rapamycin (mTOR) inhibitors following liver transplantation (LT) are used to minimize calcineurin inhibitor (CNI)-related nephrotoxicity. Data about metabolic effects of mTOR inhibitors are still limited.

AIM

This study aims to determine the renal and metabolic effects of different mTOR inhibitor-based protocols in real-life LT patients.

METHODS

This is a retrospective cohort study of patients treated with mTOR inhibitors after LT. Demographics, treatment protocols, glomerular filtration rate (GFR), and metabolic parameters were collected over a period of 4 years. Initiation of blood pressure (BP), diabetes mellitus, and lipid medications was also noted.

RESULTS

Fifty-two LT recipients received mTOR inhibitors. GFR improved significantly (by 1.96 mL/min/year), with greater improvement in patients with baseline renal dysfunction (+13.3 mL/min vs +4.5 mL/min at 3 years). Conversion to an mTOR inhibitor during the first post-transplant year resulted in a more durable improvement in GFR (for 4 years vs only 1 year for later conversion).No significant weight gain or new-onset diabetes mellitus was observed. However, there was some increase in total cholesterol (+7 mg/dL) and blood pressure (+2 mm Hg during the third year and +8 mm Hg in the fourth years), followed by initiation of lipid-lowering and BP medications in 25% and 13% of patients, respectively.

CONCLUSIONS

Treatment with an mTOR inhibitor following LT resulted in improved kidney functions without significant negative metabolic effects such as weight gain or new-onset diabetes mellitus. This makes mTOR inhibitors a valuable immunosuppressive option in the face of the growing incidence of nonalcoholic steatohepatitis as a leading cause for LT.

Infections in Liver Transplantation

Liver transplantation has become an important treatment modality for patients with end-stage liver disease/cirrhosis, acute liver failure, and hepatocellular carcinoma. Although surgical techniques and immunosuppressive regimens for liver transplantation have improved significantly over the past 20 years, infectious complications continue to contribute to the morbidity and mortality in this patient population. The use of standardized screening protocols for both donors and recipients, coupled with targeted prophylaxis against specific pathogens, has helped to mitigate the risk of infection in liver transplant recipients. Patients with chronic liver disease and cirrhosis have immunological deficits that place them at increased risk for infection while awaiting liver transplantation. The patient undergoing liver transplantation is prone to develop healthcare-acquired infections due to multidrug-resistant organisms that could potentially affect patient outcomes after transplantation. The complex nature of liver transplant surgery that involves multiple vascular and hepatobiliary anastomoses further increases the risk of infection after liver transplantation. During the early post-transplantation period, healthcare-acquired bacterial and fungal infections are the most common types of infection encountered in liver transplant recipients. The period of maximal immunosuppression that occurs at 1–6 months after transplantation can be complicated by opportunistic infections due to both primary infection and reactivation of latent infection. Severe community-acquired infections can complicate the course of liver transplantation beyond 12 months after transplant surgery. This chapter provides an overview of liver transplantation including indications, donor-recipient selection criteria, surgical procedures, and immunosuppressive therapies. A focus on infections in patients with chronic liver disease/cirrhosis and an overview of the specific infectious complications in liver transplant recipients are presented.

Sirolimus and Metformin Synergistically Inhibits Colon Cancer In Vitro and In Vivo

We estimated the effect of various immunosuppressants (ISs) and metformin (M) to provide theoretical background of optimal therapeutic strategy for de novo colon cancer after liver transplantation (LT). Three colon cancer cell lines (HT29, SW620, and HCT116) were used in in vitro studies. HT29 was also used in BALB/c-nude mice animal models. Following groups were used in both in vitro and in vivo studies: sirolimus (S), tacrolimus (T), cyclosporin A (CsA), M, metformin/sirolimus (Met/S), metformin/tacrolimus (Met/T), and metformin/cyclosporin A (Met/CsA). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed and western blot analyses were performed for mTOR pathway proteins, apoptosis proteins, and epithelial-mesenchymal-transition (EMT) proteins. Tumor volume was measured for 4 weeks after inoculation. MTT-assay revealed significant cell viability inhibition in all 3 colon cancer cell lines in groups of S, M, and Met/S. Of note, group Met/S showed synergistic effect compare to M or S group. Western blot analysis showed significant low levels of all investigated proteins in groups of S and Met/S in both in vitro and in vivo experiment. Tumor growth was significantly inhibited only in the Met/S group. Combination of Met and S showed the most potent inhibition in all colon cancer cell lines. This finding might have application for de novo colon cancer.

Gastrointestinal Perforation After Liver Transplant: A Single Center Experience

OBJECTIVES

The aim of this study was to evaluate the incidence, possible risk factors, clinical presentation, and follow-up of patients with a gastrointestinal perforation after liver transplant.

MATERIALS AND METHODS

We did a retrospective chart review of all patients who presented with a gastrointestinal perforation after liver transplant at our liver transplantation center between December 2009 and June 2011.

RESULTS

In total, we performed 271 liver transplants during this period. Nine patients (3.3%), 5 pediatric and 4 adult patients (median age, 21.3 ± 16.2 y; range, 1-55 y), developed a gastrointestinal perforation after liver transplant. Six of the patients had living donors, and 3 had deceased-donor transplants. Four patients underwent prior abdominal surgery for unrelated reasons. The mean time between liver transplant and diagnosis of the gastrointestinal perforation was 12.9 ± 9.3 days (range, 4-30 d), and the mean hospitalization length was 50 ± 29.3 days (range, 18-102 d). Perforations were located in the stomach (n = 1), jejunum (n = 3), ileum (n = 2), jejunum and ileum (n = 1), and colon (n = 2). Seven patients were managed by ostomies, and 2 by primary repair. Despite administration of proper antibiotic therapy and fluid resuscitation to all patients, 2 adults died of septic shock: 1 was caused by perforation and 1 was caused by anastomotic leakage after colostomy closure.

CONCLUSIONS

A gastrointestinal perforation after a liver transplant is a rare but mortal complication. Considering delayed wound healing owing to immunosuppression, potentially larger ischemic tissue around the perforation site owing to cautery burns and the atypical clinical course that may be further masked by bile leakage, ostomy treatment should be preferred to primary repair. A loop ostomy for small and large bowel perforations after the liver transplant decreases mortality and morbidity.

Role of mTOR inhibitors for the control of viral infection in solid organ transplant recipients

Appropriate post-transplant immunosuppressive regimens that avoid acute rejection, while reducing risk of viral reactivation, have been sought, but remain a chimera. Recent evidence suggesting potential regulatory and antiviral effects of mammalian target of rapamycin inhibitors (mTORi) is of great interest. Although the concept of an immunosuppressive drug with antiviral properties is not new, little effort has been made to put the evidence together to assess the management of immunosuppressive therapy in the presence of a viral infection. This review was developed to gather the evidence on antiviral activity of the mTORi against the viruses that most commonly reactivate in adult solid organ recipients: cytomegalovirus (CMV), polyomavirus, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), and hepatitis C virus (HCV). A rapid review methodology and evaluation of quality and consistency of evidence based on the GRADE system was used. The existing literature was variable in nature, although indicating a potential advantage of mTORi in CMV, polyomavirus, and HHV8 infection, and a most doubtful relation with EBV and HCV infection. Several recommendations about the management of these infections are presented that can change certain current patterns of immunosuppression and help to improve the prognosis of the direct and indirect effects of viral infection in solid organ recipients.

The efficacy and safety of mammalian target of rapamycin inhibitors ab initio after liver transplantation without corticosteroids or induction therapy

BACKGROUND

Mammalian target of rapamycin inhibitors have been used along with corticosteroids and/or induction therapy immediately after liver transplantation. Our aim was to assess the safety and tolerability of everolimus ab initio after liver transplantation without corticosteroids or induction, as well as efficacy in terms of liver function, rejection and graft loss.

METHODS

A retrospective observational study of 50 adult patients (86% males, median age 54 years, range 25-68) who were liver transplanted between 2009 and 2013 and followed for 12 months. All recipients received everolimus plus low doses of calcineurin inhibitors (n=38) or mycophenolate (n=12) without corticosteroids and/or induction from the day of transplant.

RESULTS

The overall patient and graft survival was 80%. Liver function was stable during one year follow-up. No rejections or graft loss were observed. Only five patients (10%) required therapy for onset dyslipidemia.

CONCLUSION

Everolimus-based immunosuppression regimen without corticosteroids and/or induction immediately after liver transplantation seems to be safe and effective when administered with low doses of calcineurin-inhibitor or mycophenolate; although these findings require further investigation, these regimens could avoid adverse effects of standard immunosuppression regimens with higher doses.

Incidence of cardiovascular and cerebrovascular events associated with sirolimus use after liver transplantation

BACKGROUND

Sirolimus (SRL) is an immunosuppressant often used in liver transplantation (LT) to mitigate renal insufficiency associated with calcineurin inhibitors. Sirolimus can cause hyperlipidemia, but its association with coronary artery disease (CAD) and cerebrovascular accidents (CVAs) is unclear. The purpose of this study was to assess the risk of CAD and CVAs with the use of SRL in LT recipients.

METHODS

We retrospectively reviewed all of our LT recipients from 2000 to 2011. Patients with multiorgan transplant, multiple liver transplants, everolimus therapy, or survival <3 months were excluded. The 803 remaining patients were divided into 3 groups: 1) 134 patients who received and tolerated SRL; 2) 604 patients who never received SRL; and 3) 65 patients who started but discontinued SRL. The primary outcome was the development of CAD or CVA beyond 4 months after transplantation with the use of time-dependent Kaplan-Meier analysis.

RESULTS

In group 1, there were 6 CAD and 2 CVA events; in group 2, 27 CAD and 16 CVA events; and in group 3, 10 CAD and 2 CVA events. The event-free survival for CAD/CVA at 1, 3, and 5 years was 100%, 98.1%, and 97.2% respectively for group 1; 99.7%, 98.4%, and 96.1% for group 2; and 92.3%, 92.3%, and 85.6% for group 3. On an unadjusted basis, compared with group 2, there was no difference in CAD/CVA rates in group 1 (hazard ratio [HR] 0.92; not significant), but there was an increase in group 3 (HR 2.94; P = .0019). However, on multivariate analysis, only age at transplantation (HR 1.06; P = .001) and diabetes before transplantation (P = .011) were associated with increased CAD/CVA risk.

CONCLUSIONS

Our analysis showed that patients receiving SRL after LT had no increased risk of CAD/CVA events compared with patients maintained on a calcineurin inhibitor. The risk of CAD/CVA should not be a factor in avoiding SRL.

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.

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.

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).

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.

What's New, What's Hot in Solid Organ Transplantation? Summary of the American Transplant Congress 2011

Breakthroughs in basic and clinical science in solid organ transplantation were presented at the American Transplant Congress 2011. Key areas of presentation included the pathogenesis of late allograft failure, immune regulation and tolerance, pathways in allograft injury, electing appropriate patients for transplantation, determining the best allocation schemes to maximize effective utilization, organ preservation, monitoring the alloimmune response and immunosuppressive management. In this review, we present highlights of the meeting. These presentations demonstrate the exciting promise in translating from the bench to affect patient care.

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.

Timing of conversion to mammalian target of rapamycin inhibitors is crucial in liver transplant recipients with impaired renal function at transplantation

BACKGROUND

Renal dysfunction, primarily related to long-term use of calcineurin inhibitor-based immunosuppression, is the most common complication after liver transplantation.

OBJECTIVE

To evaluate whether liver transplant recipients with impaired kidney function at transplantation can benefit from early conversion to mammalian target of rapamycin inhibitor therapy (mTORi) compared with patients with late induction of mTORi-based therapy.

MATERIALS AND METHODS

Between 2003 and 2008, therapy was changed to an mTORi-based regimen in 57 patients. Patients were divided into 4 groups: group 1, early conversion (≤3 months after orthotopic liver transplantation) to mTORi therapy, and with impaired perioperative renal function; group 2, early conversion to mTORi therapy, and with normal perioperative renal function; group 3, late conversion to mTORi therapy, and with impaired perioperative renal function; and group 4, late conversion to mTORi therapy, and with normal perioperative renal function.

RESULTS

One month after conversion, the mean (SD) increase in calculated glomerular filtration rate in groups 1 (early conversion) and 3 (late conversion) was comparable: 8 (9) mL/min vs 7 (10) mL/min. At month 3, the increase in calculated glomerular filtration rate between groups 1 and 3 was significant (15 [11] mL/min vs 9 [15] mL/min; P = .04), an effect that persisted at month 6 (16 [12] mL/min vs 10 [12] mL/min; P = .05) and month 12 (22 [14] mL/min vs 12 [15] mL/min; P = .04).

CONCLUSION

In liver transplant recipients with perioperatively impaired renal function, early conversion to mTORi therapy should be performed because this approach seems to be more effective in improving long-term renal function.

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.