Everolimus and long-term outcomes in renal transplantation. Transplantation. 2011;92:S3-26. [PMID: 21799392 DOI: 10.1097/TP.0b013e3182230900]

[Kidney transplantation]

Every patient with kidney failure requiring dialysis in Germany has the right to at least be evaluated for a transplantation. When an affected person can be considered for a transplantation, it must be clarified which allocation program is the right one for the person and whether a living organ donor can be considered. It should also be individually discussed with patients which type of donor organ should be accepted. Following a transplantation an individualized immunosuppression is relevant not only for the long-term survival of the transplant but also for the adherence of the patient.

An overview of the efficacy and safety of everolimus in adult solid organ transplant recipients

As the risk of graft loss due to acute rejection has declined, the goal of post-transplant management has switched to long-term preservation of organ function. Minimizing calcineurin inhibitor (CNI)-related nephrotoxicity is a key component of this objective. Everolimus is a mammalian target of rapamycin inhibitor/proliferation-signal inhibitor with potent immunosuppressive and anti-proliferative effects. It has been widely investigated in large randomized clinical studies that have shown it to have similar anti-rejection efficacy compared with standard-of-care regimens across organ transplant indications. With demonstrated potential to facilitate the reduction of CNI therapy and preserve renal function, everolimus is an alternative to the current standard-of-care CNI-based regimens used in de novo and maintenance solid organ transplantation recipients. Here, we provide an overview of the evidence from the everolimus clinical study program across kidney, liver, heart, and lung transplants, as well as other key data associated with its use in CNI reduction strategies in adult transplant recipients.

Steroid Withdrawal Using Everolimus in ABO-Incompatible Kidney Transplant Recipients With Post-Transplant Diabetes Mellitus

BACKGROUND

The effectiveness of everolimus (EVR) for ABO-incompatible (ABOi) kidney transplantation is unknown. We evaluated outcomes of conversion from steroid to EVR in ABOi kidney transplant recipients.

METHODS

We performed a retrospective observational cohort study of 33 de novo consecutive adult ABOi living donor kidney transplant recipients. Desensitization was performed using 0 to 4 sessions of plasmapheresis and 1 to 2 doses of 100 mg rituximab according to the anti-A/B antibody titer. ABOi recipients were administered a combination of tacrolimus, mycophenolate mofetil, and methylprednisolone. Diabetic patients were converted from methylprednisolone to EVR at 1 to 15 months post-transplantation to prevent diabetes progression. Graft outcomes, hemoglobin A1c (HbA1c) levels, and cytomegalovirus infection rates were compared between the EVR (n = 11) and steroid (n = 22) groups.

RESULTS

Mean postoperative duration was 814 and 727 days in the EVR and steroid groups, respectively (P = .65). Between the 2 groups, graft survival rate (100% vs 95.5%, P > .99), acute rejection rate (9.1% vs 18.2%, P = .64), and serum creatinine levels (1.46 mg/dL vs 1.68 mg/dL, P = .66) were comparable. Although HbA1c levels were elevated in the steroid group (5.47%, 5.87%; P = .003), no significant deterioration was observed in the EVR group without additional insulin administration (6.10%, 6.47%; P = .21). Cytomegalovirus infection rate was significantly lower in the EVR group than in the steroid group (18.2% vs 63.6%, P = .026).

CONCLUSION

Conversion from steroid to EVR in ABOi kidney transplant recipients maintained excellent graft outcomes and avoided diabetes progression and cytomegalovirus infection.

Glomerular Diseases and Renal Transplantation: Pathogenic Pathways and Evolution of Therapeutic Interventions

Glomerular diseases and renal transplantation are the main fields of nephrology in which the immune system plays a prevalent role. Glomerular diseases have traditionally been attributed to auto-immune conditions, whereas allograft rejection has been considered an allo-immune response. However, common immunopathologic mechanisms that include Toll-like receptors, complement and B-cell activation, as well as genetic and infectious factors appear to be involved in the pathogenesis of both entities. Novel therapeutic regimens directed against specific targets of the immune system show promising results in glomerulopathies as well as in renal transplantation.

Immunosuppression Modification by Everolimus With Minimization of Calcineurin Inhibitors Recovers Kidney Graft Function Even in Patients With Very Late Conversion and Also With Poor Graft Function

BACKGROUND

Although kidney graft survival within 5 years after transplantation is now achieved in >95% of recipients, chronic graft deterioration remains a factor limiting long-term survival. Chronic nephrotoxicity induced by calcineurin inhibitors (CNIs) is one of the major causes of chronic graft injury; thus, minimization of CNIs by administration of everolimus (EVR) is expected to relieve their toxic effects.

METHODS

Fifty-six kidney transplant recipients receiving CNI-based immunosuppression (tacrolimus, n = 34; cyclosporine, n = 22) were analyzed. The average posttransplant period at conversion was 7.4 years and no less than 3 years. Conversion of immunosuppression was accomplished by reducing CNI by 40% in dose and beginning EVR at 1 or 1.5 mg. Changes in graft function were examined, and adverse effects were evaluated.

RESULTS

Significant improvement in graft function was observed quickly after EVR administration, and it had persisted for 1 year after conversion as a 7% increase in estimated glomerular filtration rate. No obvious acute rejection was observed. Further analyses concerning "timing of EVR conversion" and "graft function at conversion" were performed. Graft function was significantly improved even in patients with late conversion at 2 to 10 years. The estimated glomerular filtration rate was significantly improved even in patients with poor function.

CONCLUSIONS

We concluded that this modification to the immunosuppressive regimen, as expected, reduced CNI nephrotoxicity. Our results showed that even patients with very late conversion or poor graft function also benefited from EVR conversion with CNI minimization.

Toxicity of rapamycin and its derivatives to pancreatic islets

The development of islet transplantation has been promoted by the proposal of the Edmonton protocol. Rapamycin, as a recommended immunosuppressive medicine of the Edmonton protocol, has been getting extraordinarily popular. At the same time, derivatives of rapamycin (everolimus, deforolimus, zotarolimus and temsirolimus) have also garnered great interest. While the immunosuppressive and anti-cancer effects of rapalogs were being discussed actively, researchers discovered their cytotoxic effect on pancreatic islets. Whether they could be ideal drugs for anti-rejection after islet transplantation needs further study. This review aims to elucidate the function and application of rapalogs as well as their toxicity to pancreatic islets.

Safety of mTOR inhibitors in adult solid organ transplantation

INTRODUCTION

Mammalian target of rapamycin (mTOR) inhibitors (sirolimus and everolimus) are a class of immunosuppressive drugs approved for solid organ transplantation (SOT). By inhibiting the ubiquitous mTOR pathway, they present a peculiar safety profile. The increased incidence of serious adverse events in early studies halted the enthusiasm as a kidney sparing alternative to calcineurin inhibitors (CNI).

AREAS COVERED

Herein we review mTOR inhibitors safety profile for adult organ transplantation, ranging from acute side effects, such as lymphoceles, delayed wound healing, or cytopenias, to long-term ones which increase morbidity and mortality, such as cancer risk and metabolic profile. Infection, proteinuria, and cutaneous safety profiles are also addressed.

EXPERT OPINION

In the authors' opinion, mTOR inhibitors are a safe alternative to standard immunosuppression therapy with CNI and mycophenolate/azathioprine. Mild adverse events can be easily managed with an increased awareness and close monitoring of trough levels. Most serious side effects are dose- and organ-dependent. In kidney and heart transplantation mTOR inhibitors may be safely used as either low-dose de novo or through early-conversion. In the liver, conversion 4 weeks post-transplantation may reduce long-term chronic kidney disease secondary to calcineurin nephrotoxicity, without increasing hepatic artery/portal vein thrombosis.

Drug target molecules to guide immunosuppression

The individual and interindividual variability of response to immunosuppressants combined with the prevailing concept of lifelong immunosuppression following any organ transplantation motivates the search for methods to further individualize such therapy. Traditional therapeutic drug monitoring, adapting dose according to concentrations in blood, targets the pharmacokinetic variability. It has been increasingly recognized, however, that there is also a considerable variability in the response to a given concentration. Attempts to overcome this variability in response include the efforts to identify relevant targets and methods for pharmacodynamic monitoring. For several of the currently used immunosuppressants there is experimental data suggesting markers that are relevant as indicators for individual monitoring of the effects of these drugs. There are also some clinical data to support these approaches; however what is generally missing, are studies that in a prospective manner demonstrates the benefits and effects on outcome. The monitoring of antithymocyte globulin by lymphocyte subset counts is actually the only well established example of pharmacodynamic monitoring. For drugs such as MPA and mTOR inhibitors, there are candidates such as IMPDH activity expression and p70SK6 phosphorylation status, respectively. The monitoring of CNIs using assays for NFAT RGE, either alone or combined with concentration measurements, is already well documented. Even here, some further investigations relating to the categories of organ transplant, combination of immunosuppressants etc. will be requested. Although some further standardization of the assay is warranted and there is a need for specific recommendations of target levels and how to adjust dose, the NFAT RGE approach to pharmacodynamic monitoring of CNIs may be close to implementation in clinical routine.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Racial comparisons of everolimus pharmacokinetics and pharmacodynamics in adult kidney transplant recipients

BACKGROUND

There is limited data analyzing the pharmacokinetic (PK) and pharmacodynamic (PD) properties of everolimus (EVR) between African Americans and Caucasians. The purpose of this study was to determine and compare the EVR PKs and concentration-associated efficacy and toxicity in African American and Caucasian adult kidney transplant recipients.

METHODS

This was a retrospective PK and PD analysis of all patients who received EVR at the Medical University of South Carolina Transplant Center between 2006 and 2012.

RESULTS

Forty-three patients received EVR (22 African Americans, 21 Caucasians). Baseline demographics, immunosuppression, and immunologic risk were similar between races, except for preexisting hypertension, deceased donor type, and cold ischemic time, which were higher in African American patients. PK analysis revealed that African American patients received higher initial EVR doses (2.1 ± 0.8 versus 1.6 ± 0.6 mg/d, P = 0.036), leading to higher early EVR concentrations (EVR >6 ng/mL during the first 60 days: 36% versus 10%, P = 0.037). Efficacy analysis demonstrated similar EVR effects on acute rejection rates (9% versus 10%, P = 0.961), chronic allograft changes (18% versus 14%, P = 0.729), and renal function, with both groups having improved creatinine clearance with EVR therapy (ΔeGFR: 27 versus 12 mL·min·1.73 m). Toxicity analysis demonstrated that African American patients had a trend toward higher rates of EVR discontinuation (46% versus 19%, P = 0.065) and significantly more diarrhea/gastrointestinal intolerance (73% versus 38%, P = 0.022).

CONCLUSIONS

These results demonstrate EVR therapy is effective at preventing rejection and improving graft function in both African American and Caucasian adult renal transplant patients. Conflicting with previous mammalian target of rapamycin PK/PD analyses in African American patients, this study cohort demonstrated higher early EVR levels in the African American patients.

Outcomes in ethnic minority renal transplant recipients receiving everolimus versus mycophenolate: comparative risk assessment results from a pooled analysis

Background

Everolimus (EVR) has demonstrated good efficacy after renal transplantation. Racial disparities in clinical outcomes after de novo renal transplantation are well documented; whether the efficacy of EVR varies based on recipient ethnicity is unknown. We conducted a comparative risk assessment of EVR by ethnicity.

Methods

Data on 2004 renal transplant recipients from three EVR studies were pooled to identify the impact of ethnicity on efficacy outcomes across EVR dosing groups and control groups. Ethnic groups compared were African Americans, non-U.S. blacks, Asians, Hispanics, and Caucasians. EVR groups received either 1.5 or 3 mg per day, with either standard-dose cyclosporine or reduced-dose cyclosporine. Control groups received mycophenolic acid (MPA) with standard-dose cyclosporine. Composite efficacy failure endpoint was graft loss, death, biopsy-proven acute rejection, or lost to follow-up. Adjusted odds ratios were calculated using a logistic regression model.

Results

The proportion of renal transplant recipients who met the composite endpoint was African Americans (46%), non-U.S. black (35%), Caucasian (31%), Hispanic (28%), and Asian (25%). The odds of meeting the composite endpoint were significantly (P=0.0001) greater for African Americans versus Caucasians but did not differ among the other ethnic groups (ethnic groups were only compared with Caucasians). EVR and MPA were associated with similar efficacy among each of the ethnic groups.

Conclusion

In this pooled data analysis in more than 2000 renal transplant recipients, EVR versus MPA resulted in similar composite endpoint incidence events across ethnicities. Consistent with previously published data, African Americans had poorer clinical outcomes. EVR is efficacious regardless of ethnicity.

Potential impact of Thai Kidney Transplant program on immunosuppressive utilization: an analysis of the national transplant registry

BACKGROUND

The Thai Kidney Transplant (TKT) program was launched in October 2008 to promote transplantation among previously disadvantaged populations, using fixed-rate provider payment. This study investigated if the introduction of this program could alter the natural practice trends of immunosuppressive drug use.

METHODS

Data from the Thai Transplantation Registry were analyzed. The change in trend of immunosuppressive use was assessed using the multivariate adaptive regression splines (MARS) technique.

RESULTS

During 1987-2012, 3975 kidney transplantations were done. The average age of patients was 42 years and 62% were male. Chronic glomerulonephritis accounted for one third of those with known causes of end-stage renal disease (ESRD). Eighty-six percent were on hemodialysis before transplantation. Prednisolone was used in 95.87% of all transplant recipients, whereas calcineurin inhibitors (CNIs), mycophenolates (MPAs), azathioprine (AZA), and mammalian target of rapamycin inhibitors (mTORis) were used in 95.67%, 64.22%, 12.25%, and 2.31%, respectively. Overall use after 2008 was decreased for AZA (18.16% to 3.40%) and mTORis (2.86% to 1.5%) but increased for MPAs (50.80% to 84.34%), CNIs (95.43% to 96.04%), and prednisolone (95.60% to 96.29%), as compared with before the program inception. The slopes of use trends of AZA, MPAs, and CNIs did not significantly marginally differ from their natural trends before the program inception (P = .496, .108, and .741, respectively). However, the natural increasing use trend of mTORis significantly changed to a decreasing pattern after the introduction of the TKT program (P = .018).

CONCLUSION

Fixed-rate provider payment might interfere with the natural practice trends of immunosuppressive drug use.

Does the calcineurin inhibitor have influence on cytomegalovirus infection in heart transplantation?

Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality in heart transplant (HTx). Our aim was to analyze the rate of CMV infection in HTx patients receiving treatment with cyclosporine (CsA) or tacrolimus (Tac). Ninety-five patients were randomized to receive either CsA (53.7%) or Tac (46.3%). We performed prophylaxis with valganciclovir in patients with the highest risk of CMV infection. We considered CMV infection as an increased viral load or the presence of CMV in histological samples. We analyzed baseline characteristics, CMV infection, and other complications. Event-free rates were calculated using the Kaplan-Meier method. There were no significant differences in baseline characteristics between both groups. CMV infection was detected in 31.6% of patients (in 66.7% due to asymptomatic replication). The group treated with Tac had a lower rate of CMV infection (15.9% vs. 45.1%, p = 0.002) and longer CMV infection-free survival time (1440 vs. 899 d, p = 0.001). No differences were observed in the complications analyzed in both groups. The independent risk factors for infection identified in the multivariate analysis were treatment with CsA and bacterial infections. This was the first study to demonstrate a lower rate of CMV infection in patients treated with Tac vs. those treated with CsA after HTx.

Cancer after heart transplant: implications for practice

Cancer after heart transplant is recognized as a leading cause of morbidity and mortality. A man's clinical course after receiving a heart transplant is described, with emphasis on important clinical considerations in the care of heart transplant recipients.

A drug safety evaluation of everolimus in kidney transplantation

INTRODUCTION

Calcineurin inhibitors (CNI) have greatly reduced the rate of acute rejection and improved short-term graft survival after organ transplantation, however, long-term survival has hardly changed since their introduction. CNIs are believed to contribute to graft fibrosis, have side effects that adversely affect cardiovascular risk, and are associated with an increased rate of post-transplant malignancies. Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, is not associated with graft fibrosis, has a superior cardiovascular risk profile to CNI therapy and has shown potential for the prevention and treatment of diverse forms of cancer.

AREAS COVERED

This review summarizes key aspects of everolimus, including its mechanism of action, pharmacokinetics, pharmacodynamics, drug-drug interactions and pivotal clinical studies with a focus on safety and efficacy.

EXPERT OPINION

Everolimus is effective in improving graft function in selected kidney transplant patients. Most adverse events are present for a short time after the introduction of everolimus, and are manageable. Everolimus has the potential to become an important agent in de novo and maintenance immunotherapy in kidney transplant recipients.

Evaluation of a perforated drug delivery system in mice for prolonged and constant release of a hydrophilic drug

A drug delivery system (DDS) consisting of a perforated microtube (polyimide, inside diameter = 1.8 mm, tube length = 20 mm, hole size = 0.15 mm) was characterized in vitro and in vivo for its usefulness for long-term release of hydrophilic drugs at a constant rate. Sodium fluorescein mixed with stearic acid was used as the model drug. The DDS was packed with sodium fluorescein and stearic acid in ratios of 50:50, 40:60, and 25:75, respectively, and in vitro drug release studies were performed in saline. Linear release rates with R (2) > 0.9700 were obtained for all groups. Release rates of 1,077.3 ± 264.6, 342.6 ± 146.4, and 14.4 ± 7.0 μg/day for sodium fluorescein were obtained from the three groups, respectively. After monitoring the in vitro release of fluorescein for 11 days, 7 tubes from the 40:60 group were implanted subcutaneously in each individual mice to study the in vivo release of fluorescein from the tubes by measuring the fluorescein in the urine for 84 days. An initial rapid release during the first 4 days was followed by a near zero order fluorescence from the tubes (R (2) = 0.9870). Following completion of the study, the DDSs were retrieved for histology. Morphological analysis indicated no clinical adverse reaction at the site of device implantation specific to the device. The DDS was found to be biocompatible and capable of long-term constant release of a hydrophilic drug such as sodium fluorescein.