Use of the New Proliferation Signal Inhibitor Everolimus in Renal Transplant Patients in Spain: Preliminary Results of the EVERODATA Registry

Predictive factors of allosensitization in renal transplant patients switched from calcineurin to mTOR inhibitors

Conversion of kidney-transplant recipients from calcineurin inhibitors to mTOR inhibitors has been suggested to be a risk factor for increased alloimmune response. We have analyzed the development of new HLA-antibodies (HLA-Abs) early after conversion in 184 patients converted in stable phase at our hospital and compared with a control group of nonconverted comparable 63 transplants. Using single-antigen solid-phase immunoassay analysis, a preconversion and a 3-6 months postconversion sera were prospectively analyzed in every patient for the appearance of new HLA-Abs. Renal function at 2 years postconversion and cumulative graft survival were compared between groups. In 16 patients, new HLA-Abs (3-DSA and 13-NonDSA), not present at the moment of conversion, were detected (8.7% vs. 3.1% in the control group). The type of mTORi used, type of CNI preconversion, the presence of steroids, time of conversion, or indication for conversion did not have influence on this effect but the presence of HLA-Abs before conversion highly correlated with the appearance of new specificities. Patients with de novo HLA-Abs showed a trend to worst graft function and survival. In conclusion, conversion to mTORi can be followed by early appearance of de novo HLA-Abs, especially in patients with HLA-Abs preconversion, and this complication should be screened early after conversion.

Conversion to everolimus in kidney transplant recipients: to believe or not believe?

INTRODUCTION

Immunosuppression with calcineurin inhibitors (CNI) in renal transplantation is associated with chronic graft dysfunction, increased cardiovascular risk, and malignancies. Everolimus (EVR) appears to permit a CNI-sparing regimen among stable kidney recipients.

AIM

The aim of this study was to analyze the efficacy and safety of conversion from CNI to EVR.

MATERIAL AND METHODS

This was a retrospective registry-based study of all kidney transplant recipients converted from CNI to EVR between 2006 and 2010. One hundred fifty-one patients, including 69.5% males and with an overall mean age of 50.2 ± 12.7 years, underwent conversion to EVR at 37.0 ± 49.8 (16) months after transplantation with 33.7% during the first 6 months. Reasons for conversion included: CNI nephrotoxicity prevention (54.3%), chronic graft dysfunction (25.8%), malignant tumors (10.6%), CNI-adverse reactions (6.6%), and biopsy-proven CNI nephrotoxicity (2.6%). During a follow-up of 17.9 ± 9.9 months (range, 6-58.5), 18 patients (11.9%) were reconverted to CNI, 2 died with functioning grafts, and 2 lost kidney function.

RESULTS

We observed a significant (P < .001) increase in estimated glomerular filtration rate-Modification of Diet in Renal Disease (eGFR-MDRD) by 11.3% within 6 months: 56.7 ± 22.1 to 64.1 ± 23.4 mL/min/1.73 m(2). At final evaluation it was 13.7%, namely, to 65.5 ± 23.0 mL/min/1.73 m(2). At the end of follow-up the proportion of patients with >300 mg/d proteinuria increased from 7.9% to 23.3% (P = .001). Dyslipidemia prevalence increased from 69.5% to 77.5% (P = not significant [NS]) and arterial hypertension increased from 49% to 65.9% (P < .001) at the end of follow-up. Other reported side effects included oral ulcers (2.6%), edema (5.3%), interstitial pneumonitis (1.3%), and toxic hepatitis (1.3%), some of them leading to EVR discontinuation.

CONCLUSION

In our population, renal function improved significantly after conversion from CNI to EVR. Although side effects were common, most were mild, withdrawal of EVR was necessary in a low percentage of cases. EVR appears to be an effective, safe alternative to CNI for maintenance therapy in selected kidney transplant recipients.

Proliferation signal inhibitors and post-transplant malignancies in heart transplantation: practical clinical management questions

Although malignancy is a major threat to long-term survival of heart transplant (HT) recipients, clear strategies to manage immunosuppression in these patients are lacking. Several lines of evidences support the hypothesis of an anticancer effect of proliferation signal inhibitors (PSIs: mammalian target of rapamycin [mTOR] inhibitors) in HT recipients. This property may arise from PSI's ability to replace immunosuppressive therapies that promote cancer progression, such as calcineurin inhibitors or azathioprine, and/or through their direct biological actions in preventing tumor development and progression. Given the lack of randomized studies specifically exploring these issues in the transplant setting, a collaborative group reviewed current literature and personal clinical experience to reach a consensus aimed to provide practical guidance for the clinical conduct in HT recipients with malignancy, or at high risk of malignancy, with a special focus on advice relevant to potential role of PSIs.

The influence of pharmacogenetics and cofactors on clinical outcomes in kidney transplantation

INTRODUCTION

Immunosuppressive drugs have a narrow therapeutic range and large inter-individual response variability. This has prompted pharmacogenetic studies, mostly with regard to their dose-concentration relationships, but also about proteins involved in their pharmacodynamics. Some polymorphisms of genes involved in their disposition pathways were shown to affect their dose-concentration relationships. The impact of pharmacogenetics on tissue distribution and the resulting clinical effects have less often been studied. More importantly, a few single nucleotide polymorphisms seem to have a significant impact on the incidence of acute rejection or the adverse effects of immunosuppressants. Environmental factors often interact with such genotype-phenotype relationships.

AREAS COVERED

This article reviews the impact of genetic polymorphisms of the metabolic enzymes, membrane transporters and target proteins of mycophenolic acid, calcineurin inhibitors and mammalian target of rapamycin inhibitors on clinical outcomes in kidney transplantation.

EXPERT OPINION

The current level of evidence is not yet high enough to recommend pharmacogenetic personalization of immunosuppressive regimens in transplant recipients. The prevention of cellular toxicity associated with local metabolism or transport, which cannot be addressed by routine monitoring, is worth investigating further.

Complete switch to everolimus in long-term kidney transplants: evolution of the renal function

INTRODUCTION

The use of M-tor inhibitors plus withdrawal of anticalcineurins after 3 months of posttransplantation is usually linked to improvements in renal function. The long-term effects of substitution of anticalcineurinis by everolimus remain unknown. The aim in this study was to evaluate the evolution of renal function and the proteinuria after a complete switch of long-term functioning allograft patients to everolimus. We treated 30 renal transplanted patients with everolimus, at a mean time posttransplantation of 123.8 +/- 74.2 months. The 27 patients, including 17 treated with tacrolimus and 10 with cyclosporine, who were controlled for at least 6 months were included in this study. Seventeen of them were diagnosed to display chronic allograft nephropathy (CAN).

RESULTS

The patients with CAN showed a basal creatinine of 1.81 +/- 0.4; with after a year, 1.61 +/- 0.38; and after 2 years, 1.56 +/- 0.49 mg/dL (P < .05). No significant changes were observed among patients without CAN: 1.1 +/- 0.32, 0.97 +/- 0.15, and 0.97 +/- 0.15 mg/dL, respectively. In CAN patients, the protein/creatinine quotient was: basal = 0.30 +/- 0.13, one year = 0.63 +/- 0.68, and 2 years = 0.48 +/- 0.34. In the other patients the values were 0.2 +/- 0.07, 0.73 +/- 0.7, and 0.32 +/- 0.17, respectively, after a late switch to everolimus.

CONCLUSION

The improved renal function occurred mainly in patients with CAN. Patients who did not suffer from it showed a greater rise in proteinuria. Nevertheless, both groups experienced decreased proteinuria after 2 years.

Minimization of maintenance immunosuppression early after renal transplantation: an interim analysis

INTRODUCTION

Chronic allograft nephropathy is the main cause of long-term renal transplant failure. Chronic use of calcineurin inhibitors contributes to its pathogenesis. Here, we report on a multicenter randomized trial to study the effects of withdrawal of cyclosporine A (CsA) from a triple immunosuppressive regimen containing CsA, prednisolone (P), and mycophenolate sodium (MPS) early after transplantation.

METHODS

Patients continued on P/CsA, P/MPS, or P and everolimus (EVL). Before withdrawal, a transplant biopsy was performed ensuring no subclinical rejection was present. Drug levels were closely monitored. The primary outcome was interstitial graft fibrosis and hyalinosis. Secondary outcome was among others graft rejection.

RESULTS

According to trial regulations, an interim analysis was performed after enrollment of half of the intended number of patients (n=113). Mean follow-up was 14+/-5 months from transplantation and 8+/-5 months from conversion. After conversion, acute rejection percentages were 3% in the P/CsA group, 22% in the P/MPS group, and 0% in the P/EVL group (P<0.009).

CONCLUSIONS

We conclude that switching immunosuppressive therapy from P/CsA/MPS to therapy with P/CsA or P/EVL at 6 months after renal transplantation is effective in preventing rejection. Double therapy with P/MPS after withdrawal of P/CsA resulted in an increase in severe acute rejection episodes. These results were the immediate reason to halt the P/MPS arm. Serum creatinine values at the latest follow-up (8+/-5 months after conversion and 14+/-5 months after transplantation) in the P/EVL group were lower than in the P/CsA group.

Progression of renal dysfunction in cardiac transplantation after the introduction of everolimus in the immunosuppressive regime

The aim of this study was to analyze, in heart transplant patients, if renal function improvement after cyclosporine replacement by everolimus persists at the middle term and its predictors. We studied prospectively 56 patients in whom conversion was consecutively made. Forty-five patients completed the follow-up period. Significant improvement was observed at 6 and 12 months in plasma creatinine levels (1.92+/-0.7 vs. 1.67+/-0.6 and 1.69+/-0.6 mg/dL; P=0.047) and glomerular filtration rate (43.9+/-17 vs. 52.5+/-23 and 51.3+/-22.3 mL/min; P=0.004). Glomerular filtration rate increased in 32 patients (71%). Baseline characteristics comparison showed a lower percentage of patients with smoking history and new onset diabetes in responders group, but only previous smoking was shown as independent factor (Exp B: 0.083; 95% confidence interval: 0.010-0.793; P=0.024). No differences regarding age, gender, body mass index, disease leading to transplantation, time between transplantation and replacement, cardiovascular risk factors, lipid levels, and hematologic parameters were found.

Disposition of everolimus in mdr1a-/1b- mice and after a pre-treatment of lapatinib in Swiss mice

The aim of this study was to document the in vivo transport of everolimus (inhibitor of mTOR) by P-glycoprotein (P-gp), and to investigate the influence of lapatinib (inhibitor of P-gp) on everolimus disposition. Pharmacokinetics of everolimus (0.25mg/kg) has been investigated after oral administration in mdr1a-/1b- mice compared to the wild type. Also, everolimus pharmacokinetics was characterized after oral administration on Swiss mice either alone or after 2 days of pre-treatment of lapatinib (200mg/kg). The influence of lapatinib pre-treatment on intestinal P-gp expression was investigated by Western blot analysis. The non-compartimental analysis was performed using Winonlin professional version 4.1 software (Pharsight, Mountain View, CA). The areas under the plasma concentration-time curve (AUC) were compared using Bailer's method. A significant 1.3-fold increase of everolimus AUC observed in mdr1a-/1b- mice suggested that everolimus is transported in vivo by intestinal P-gp in mice. In addition, a 2.6-fold significant increase of everolimus AUC with lapatinib pre-treatment as compared with the everolimus alone group was noticed. The elimination half-life was comparable (t(1/2)=5.3h vs. t(1/2)=4h). A 38.5% significant decrease of P-gp expression was observed in duodenum segment in lapatinib pre-treated group as compared with control group. In conclusion, lapatinib enhanced everolimus absorption by decreasing intestinal P-gp expression. An inhibition of CYP 450 could not be excluded. These results confirm the necessity of a therapeutic monitoring of everolimus combined with an inhibitor of the P-gp and CYP 450 like lapatinib in a future anti-tumor treatment.

Late conversion to everolimus complicated with necrotizing glomerulonephritis in a renal allograft recipient: case report

Conversion from calcineurin inhibitors (CNI) to proliferation signal inhibitors (PSI), such as sirolimus or everolimus (EV), may improve the course of chronic allograft nephropathy. Herein we have presented a case of a kidney recipient with chronic cyclosporine (CsA) nephrotoxicity who was converted from CsA to EV at 5.5 years posttransplantation. There were no significant changes in immunofluorescence (IFL) or in electron microscopy (EM) in the preconversion biopsy. Two months after conversion, proteinuria and creatinine increased. The biopsy showed focal, segmental necrosis of the glomerular tuft with the formation of segmental cellular crescents and increased endocapillary cellularity. IFL showed granular deposits of IgG, IgM, and C3 mostly along the capillary walls; it was negative for C4d. EM revealed electron-dense deposits within the glomerular basement membrane (GBM) and in the subendothelial region with significant reduction in the capillary lumina due to GBM reduplication and widening of lamina rara interna with the formation of fibrillary structures therein: focal, segmental glomerulosclerosis. EV was withdrawn and we administered tacrolimus and steroid pulses with improvement. Five months after the withdrawal of EV, a third graft biopsy showed remission of the necrotizing glomerulonephritis. However, the patient demanded dialysis at 17 months after conversion to EV. We concluded that necrotizing glomerulonephritis with immune complex deposition in a renal allograft was possibly induced by late conversion from CNI to EV. Reconversion to CNI may be recommended in cases of PSI-associated posttransplantation glomerulonephritis but the long-term prognosis is uncertain.

Everolimus: an update on the mechanism of action, pharmacokinetics and recent clinical trials

BACKGROUND

A growing body of evidence suggests that everolimus might offer effective immunosuppressive activity together with antiproliferative effects that may address some of the unmet needs in the long-term therapeutic management of the post-transplant patient.

OBJECTIVE

To summarize the emerging evidence for employing everolimus-based immunosuppression.

METHODS

A systematic review was conducted of the Medline, Embase and Renal Health Library (Cochrane Collaboration) databases, and of the summary publications from international transplant meetings and congresses during 2000-2008.

RESULTS

This article summarizes this analysis, with special focus on the pharmacokinetic characteristics of everolimus and on the results of its use in renal transplantation. Some data has also been included about the efficacy of the drug in other solid organ transplantation and in tumours.

CONCLUSIONS

Everolimus is an immunosuppressant drug with proven efficacy in transplantation. When used in combination with cyclosporin, better results are obtained in renal function with low cyclosporin doses. Adverse events related to this drug are frequent and lead to moderate dropout rates.