Everolimus (Certican) in renal transplantation: a review of clinical trial data, current usage, and future directions

Matrix Metalloproteinases and Glaucoma

Matrix metalloproteinases (MMPs) are enzymes that decompose extracellular matrix (ECM) proteins. MMPs are thought to play important roles in cellular processes, such as cell proliferation, differentiation, angiogenesis, migration, apoptosis, and host defense. MMPs are distributed in almost all intraocular tissues and are involved in physiological and pathological mechanisms of the eye. MMPs are also associated with glaucoma, a progressive neurodegenerative disease of the eyes. MMP activity affects intraocular pressure control and apoptosis of retinal ganglion cells, which are the pathological mechanisms of glaucoma. It also affects the risk of glaucoma development based on genetic pleomorphism. In addition, MMPs may affect the treatment outcomes of glaucoma, including the success rate of surgical treatment and side effects on the ocular surface due to glaucoma medications. This review discusses the various relationships between MMP and glaucoma.

Edema Associated With Everolimus de Novo

BACKGROUND

The appearance of edema limits the use of everolimus de novo together with tacrolimus and steroids in kidney transplantation. We aimed to investigate the frequency and characteristics of patients with edema and compare them according to the type of immunosuppression.

METHODS

We studied 150 kidney transplant recipients between 2015 and 2017 based on receiving everolimus de novo (group A) or mycophenolic acid derivatives (group B).

RESULTS

We analyzed 50 patients in group A and 100 in group B. Follow-up was 26.2 ± 10 months. Fifty-six patients presented edema (37.3%): 54% in group A and 29% in group B (P = .003). Edema was mild in 74% of patients in group A and 57.1% in group B. The probability of edema was 10.1%, 22.4%, and 41% at 3, 6, and 12 months, respectively, in group A vs 10.1%, 20.3%, and 25.4% in group B (P = .006). Patients were treated mostly with diuretics (14.3% in group A vs 27.6% in group B) and discontinuation of calcium channel blockers (46.4% in group A vs 48.3% in group B). Improvement was 70.4% in group A vs 60.7% in group B; patient worsening was 0% in group A vs 10.7% in group B; and there was no change in 29.6% in group A vs 28.6% in group B. We did not find differences in patient or graft survival in those who presented edema, regardless of the treatment group.

CONCLUSION

The use of everolimus and standard doses of tacrolimus caused edema in 54% of patients, with no impact on renal function or survival compared with mycophenolic acid derivatives. The edema was mostly of low intensity and improved in most patients.

An open-label randomized clinical trial to evaluate the efficacy of everolimus versus tacrolimus in triple maintenance immunosuppressive therapy for kidney transplant patients

Tacrolimus (TAC), a calcineurin inhibitor, and everolimus (EVL), an mTOR inhibitor, have been used as immunosuppressive (ISS) drugs in post-kidney transplantation therapy. The objective of this study was to compare the efficacy of EVL vs TAC in the ISS maintenance triple therapy. Ninety-seven kidney transplant patients, who received triple maintenance therapy with TAC, mycophenolate mofetil (MMF), and methyl prednisone (PRED), were evaluated. After four months of post-kidney transplant therapy, 30 patients enrolled in a randomized controlled clinical trial, in which 16 patients received TAC+MMF+PRED (cohort 1), and 14 patients switched to EVL+MMF+PRED (cohort 2). The patients were followed-up for 36 months. Two patients from cohort 1 lost their grafts after one year due to non-adherence. Two patients from cohort 2 had intolerance to mTOR inhibitors and were switched back to TAC from EVL. One case (6.25%) in cohort 1 and three cases (21.43%) in cohort 2 of acute T-cell-mediated rejection was observed. Antibody-mediated acute rejection (ABMAR) was observed in four patients (25.0%) in cohort 1, and antibody-mediated chronic rejection (ABMCR) was observed in two patients (12.50%). One patient from cohort 2 lost the graft after 15 months due to polyomavirus infection. The graft survival rate was 87.50% in cohort 1 and 92.86% in cohort 2. This clinical trial showed that the EVL+MMF+PRED triple maintenance therapy was efficacious compared with TAC during 32 months of follow-up. However, further studies are needed to confirm the efficacy of this regimen for long-term graft survival.

Effect of everolimus rescue therapy for acute cellular rejection following pediatric living donor liver transplantation: Report of one case

Acute cellular rejection (ACR) after pediatric living donor liver transplantation (LDLT) is often curable with steroid pulse therapy, but a few pediatric patients show steroid-resistant ACR, which is difficult to control. We report the effect of everolimus as a rescue therapy for ACR in a case of pediatric LDLT. The patient was a 11-year-old girl who was admitted due to subacute liver failure of unknown cause. LDLT operation using a modified right liver graft from her mother was performed. The graft-recipient weight ratio was 1.30. The explant liver showed massive hepatic necrosis. The patient recovered uneventfully with immunosuppression using tacrolimus and low-dose steroid. However, at postoperative day (POD) 20, the liver enzyme levels began to increase. The first liver biopsy taken at POD 25 showed moderate ACR with rejection activity index (RAI) score of 7. At that time, steroid pulse therapy was performed, but the patient did not respond and the liver enzyme levels increased further. The second liver biopsy taken at POD 40 showed moderate ACR with RAI score of 7. At this time, everolimus was administered, and soon after that, liver enzyme levels had gradually improved. Currently, the patient is doing well for 44 months to date without any abnormal findings. The maintenance target trough concentrations were tacrolimus 5 ng/ml and everolimus 3 ng/ml. Our case demonstrated the effect of rescue therapy using everolimus for ACR following pediatric LDLT. Further studies are needed to assess the role of everolimus in pediatric liver transplant recipients suffering from ACR.

Everolimus with cyclosporine withdrawal or low-exposure cyclosporine in kidney transplantation from Month 3: a multicentre, randomized trial

Background.

Randomized trials have shown that early adoption of everolimus-based immunosuppressive regimens without a calcineurin inhibitor (CNI) improves long-term kidney graft function, but the optimal strategy for CNI minimization remains uncertain.

Methods.

In a prospective, randomized, multicentre, 12-month trial, 499 de novo kidney transplant patients were randomized at Month 3 to (i) remain on standard CNI (cyclosporine) therapy with mycophenolic acid, (ii) convert to everolimus with mycophenolic acid or (iii) start everolimus with reduced CNI and no mycophenolic acid (clinical trials registry: ClinicalTrials.gov-NCT00514514).

Results.

The primary endpoint, change in estimated glomerular filtration rate (eGFR) (Nankivell) from randomization to Month 12, was significantly greater in the CNI-free arm versus standard CNI therapy: mean difference 5.6 mL/min/1.73 m 2 [95% confidence interval (CI) 2.8-8.3 mL/min/1.73 m 2 , P < 0.001]. The improvement in eGFR in the CNI-free arm was also higher than in the low-CNI group (mean difference 5.5 mL/min/1.73 m 2 , 95% CI 2.8-8.2 mL/min/1.73 m 2 , P < 0.001), while results were similar in the low-CNI and standard CNI arms. The post-randomization incidence of biopsy-proven acute rejection was 11.7%, 8.1% and 7.9% in the CNI-free, low-CNI and standard CNI groups, respectively (CNI-free versus standard CNI, P = 0.27; low-CNI versus standard CNI, P = 1.00). Adverse events led to study drug discontinuation in 28.7%, 15.5% and 15.2% of CNI-free, low-CNI and standard CNI patients, respectively.

Conclusions.

Everolimus initiation with CNI withdrawal at Month 3 after kidney transplantation achieves a significant improvement in renal function at 12 months, with a similar rate of acute rejection.

Everolimus for Treatment of Pseudomyogenic Hemangioendothelioma

Pseudomyogenic hemangioendothelioma (PMH) is a recently described vascular neoplasm that occurs most commonly in the soft tissue of the distal extremities of young adults. Metastatic PMH can be fatal and there are no effective medications. We describe a case of a 15-year-old boy with metastatic PMH, who responded to treatment with everolimus, a mammalian target of rapamycin inhibitor. Immunohistochemistry showed that mammalian target of rapamycin was expressed in PMH biopsy specimens, which may explain the reduction in PMH tumor size following treatment.

The Effect of Everolimus on Scar Formation in Glaucoma Filtering Surgery in a Rabbit Model

PURPOSE

To investigate the efficiency of everolimus on the prevention of postoperative scar in a rabbit model of glaucoma filtering surgery in comparison with mitomycin-C (MMC).

MATERIALS AND METHODS

Thirty New Zealand albino rabbits were randomly assigned into 3 groups, each including ten rabbits: an everolimus group (Group 1), a MMC group (Group 2), and a sham group (Group 3). A limbal-based trabeculectomy was performed on the right eyes of all the rabbits. For 28 days following surgery, the eyes were evaluated in terms of intraocular pressure (IOP), morphological and biomicroscopic changes, and complications in the bleb. On the 28th day, four eyes randomized from each group were enucleated and histologically and immunohistochemically analyzed. Transforming growth factor-β1 (TGF-β1), metalloproteinase (MMP-2, MMP-9), and proliferative cell nuclear antigen (PCNA) expressions in each group were evaluated. The terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method was used for apoptosis.

RESULTS

Bleb survival was statistically significantly longer for a period in Group 1 compared to Group 2. When postoperative IOPs of three groups were measured, it was seen that there is significant IOP reduction in all three groups. However, there were increases in the mean IOP values beginning from the 5th day in Group 2 and from the 3rd day in Group 3 while in Group 1 mean IOP values began to increase beginning from 10th day and the mean IOP values in Group 1 remained at a lower level in comparison to the other groups for 28 days (p < 0.05). The expressions of TGF-β1, MMP-2, MMP-9, and PCNA were reduced in Group 1 compared to other groups. TUNEL positive apoptotic cells were significantly increased in Group 1 compared to other groups (p < 0.05).

CONCLUSION

Everolimus appears to suppress the proliferation of fibroblast and thus may provide an effective treatment strategy in glaucoma filtering surgery.

Everolimus for Primary Intestinal Lymphangiectasia With Protein-Losing Enteropathy

Primary intestinal lymphangiectasia (PIL), also known as Waldmann's disease, is an exudative enteropathy resulting from morphologic abnormalities in the intestinal lymphatics. In this article, we describe a 12-year-old boy with PIL that led to protein-losing enteropathy characterized by diarrhea, hypoalbuminemia associated with edema (serum albumin level: 1.0 g/dL), and hypogammaglobulinemia (serum IgG level: 144 mg/dL). Severe hypoalbuminemia, electrolyte abnormalities, and tetany persisted despite a low-fat diet and propranolol. Everolimus (1.6 mg/m(2)/day) was added to his treatment as an antiangiogenic agent. With everolimus treatment, the patient's diarrhea resolved and replacement therapy for hypoproteinemia was less frequent. Hematologic and scintigraphy findings also improved (serum albumin level: 2.5 g/dL). There were no adverse reactions during the 12-month follow-up. To the best of our knowledge, this is the first report of everolimus use in a patient with PIL.

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.

New Recipes With Known Ingredients: Combined Therapy of Everolimus and Low-dose Tacrolimus in De Novo Renal Allograft Recipients

BACKGROUND

Calcineurin inhibitors (CNIs) are the cornerstones of immunosuppressive management in renal allograft recipients even though their nephrotoxicity may contribute to a reduced long-term graft survival. This has created a great interest in improving immunosuppressive strategies in the early post-transplantation period. Proliferation signal inhibitors (PSIs), such as everolimus, are promising alternatives, although their side effects may have a drawback in de novo renal transplant recipients, for instance, delaying renal function in the presence of renal ischemia/acute tubular necrosis and predisposing to lymphocele development.

STUDY AND METHODS

A retrospective study was developed to compare the combined therapy of low-dose tacrolimus and everolimus (study group) with mycophenolate mofetil/mycophenolic acid and standard-dose tacrolimus (control group) in the first 3 months post-transplantation. The study's end-points concerned renal graft function, proteinuria, incidence of biopsy-proven acute rejection, surgical complication rates, and incidence of new-onset diabetes after renal transplantation.

RESULTS

There was no more delayed graft function in the study group and graft function distribution was similar between groups. Median serum creatinine and eGFR were comparable as well as proteinuria levels. Generally, adverse events were rare in both groups and there were no significant statistical differences between them in terms of biopsy-proven acute rejection, surgical complication, and new-onset diabetes after renal transplantation rates.

CONCLUSION

Despite the slightly lower tendency for serum creatinine in the study group, renal allograft function wasn't statistically different between groups. Moreover, there weren't more metabolic or surgical complications in the study group. Everolimus may be a choice in tacrolimus-sparing strategies, but a larger study and a longer follow-up are still required.

Replacement of mycophenolate acid with everolimus in patients who became neutropenic after renal transplant

OBJECTIVES

Neutropenia after kidney transplant is an adverse event usually treated with a dosage reduction of mycophenolic acid. We evaluated the efficacy and safety of substituting mycophenolic acid with everolimus in patients with persistent neutropenia after kidney transplant.

MATERIALS AND METHODS

This study was a retrospective analysis. A total of 17 patients who were initially treated with mycophenolic acid (1912 ± 196 mg/d), calcineurin inhibitors, and methylprednisolone for kidney transplant were included.

RESULTS

In 15 patients, neutropenia occurred within the first 3 months (during valganciclovir administration), and in 2 patients between the fourth and sixth month after transplant. One hundred eighteen episodes of neutropenia were recorded, originally treated by reducing the dosage of mycophenolic acid (765 ± 390 mg/d) and administering granulocyte colony-stimulating factor. Three patients experienced acute rejection 5 to 10 days after reducing the dosage of mycophenolic acid, and they were successfully treated with pulse steroids. Five patients developed cytomegalovirus infection 108 ± 65 days after the onset of neutropenia. After replacing mycophenolic acid with everolimus, episodes of neutropenia were observed in 6 patients. In 1 patient, discontinuing everolimus was necessary after 1.5 months of treatment. In 5 patients with cytomegalovirus infection, neutropenia subsided after termination of valganciclovir treatment. In the remaining 11 patients, no episodes of neutropenia were observed. No episodes of acute rejection occurred, and renal function remained stable during a followup of 47 ± 30 months (estimated glomerular filtration rate [eGFRMDRD6]: 45 ± 14 mL/min/1.73 m2→47 ± 22 mL/min/1.73 m2].

CONCLUSIONS

Replacing mycophenolic acid with everolimus appears to be a safe and effective alternative treatment in neutropenic renal transplant recipients.

mTOR inhibitors in pediatric kidney transplantation

The mammalian target of the rapamycin (mTOR) inhibitors sirolimus and everolimus are increasingly being used in pediatric kidney transplantation in different combinations and doses. Several studies have shown beneficial effects of using mTOR inhibitors in children after pediatric renal transplantation. A switch to a low-dose calcineurin inhibitor (CNI) and mTOR inhibitor has been proven to stabilize the glomerular filtration rate. Additionally, de novo studies using a low-dose CNI and an mTOR inhibitor have shown good graft survival and a low number of rejections. Side effects of mTOR inhibitors, such as hyperlipidemia, wound healing problems, and proteinuria, mainly occur if high doses are given and if treatment is not combined with a CNI. Lower doses of mTOR inhibitors do not result in growth impairment or reduced testosterone levels. Treatment with mTOR inhibitors is also associated with a lower number of viral infections, especially cytomegalovirus. Due to their antiproliferative effect, mTOR inhibitors could theoretically reduce the risk of post-transplant lymphoproliferative disease. mTOR inhibitors, especially in combination with low-dose CNIs, can safely be used in children after kidney transplantation as de novo therapy or for conversion from CNI- and mycophenolate mofetil-based regimens.

Everolimus-coated tympanostomy tube on rat tympanic membrane

OBJECTIVES

Everolimus is an immunosuppressant and an antiproliferative macrolide agent which is used for coronary stent coating for local inhibition of in-stent restenosis. The aim of this study was to evaluate the effect of everolimus-coated tympanostomy tubes in rat tympanic membrane.

STUDY DESIGN

Prospective controlled animal study.

MATERIALS AND METHODS

Twenty-one Sprague-Dawley rats were included in the study. They were bilaterally myringotomized. An everolimus-coated fluoroplastic tympanostomy tube was inserted into one ear of each of the rats (everolimus-coated TT Group; n=21) and a standard fluoroplastic tympanostomy tube was applied to the contralateral ear of the same rats (Standard TT Group; n=21). Tympanic membranes and tubes were routinely examined otomicroscopically every other day for two months. Then the membranes were harvested and evaluated histologically.

RESULTS

In everolimus-coated tubes, the tube obstruction was found to be significantly lower than in standard tubes (p<0.05). The tube extrusion rate was less for everolimus-coated tubes than for standard tubes, but no statistically significant difference was observed between the two tubes. There was no statistically significant difference in the incidence of otorrhea between two tubes. Histopathological examination under light microscope revealed that everolimus-coated tubes resulted in less fibrosis and less inflammation in tympanic membranes than standard tubes (p<0.01).

CONCLUSION

The study shows the potential role of everolimus-coating of tympanostomy tubes in reducing tube obstruction. In addition, inflammatory reaction and fibrosis were observed to be significantly less with these tubes.

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.

Everolimus plus early tacrolimus minimization: a phase III, randomized, open-label, multicentre trial in renal transplantation

There is increasing interest in tacrolimus-minimization regimens. ASSET was an open-label, randomized, 12-month study of everolimus plus tacrolimus in de-novo renal-transplant recipients. Everolimus trough targets were 3-8 ng/ml throughout the study. Tacrolimus trough targets were 4-7 ng/ml during the first 3 months and 1.5-3 ng/ml (n = 107) or 4-7 ng/ml (n = 117) from Month 4. All patients received basiliximab induction and corticosteroids. The primary objective was to demonstrate superior estimated glomerular filtration rate (eGFR; MDRD-4) at Month 12 in the tacrolimus 1.5-3 ng/ml versus the 4-7 ng/ml group. Secondary endpoints included incidence of biopsy-proven acute rejection (BPAR; Months 4-12) and serious adverse events (SAEs; Months 0-12). Statistical significance was not achieved for the primary endpoint (mean eGFR: 57.1 vs. 51.7 ml/min/1.73 m(2)), potentially due to overlapping of achieved tacrolimus exposure levels (Month 12 mean ± SD, tacrolimus 1.5-3 ng/ml: 3.4 ± 1.4; tacrolimus 4-7 ng/ml: 5.5 ± 2.0 ng/ml). BPAR (months 4-12) and SAE rates were comparable between groups (2.7% vs. 1.1% and 58.7% vs. 51.3%; respectively). Everolimus-facilitated tacrolimus minimization, to levels lower than previously investigated, achieved good renal function, low BPAR and graft-loss rates, and an acceptable safety profile in renal transplantation over 12 months although statistically superior renal function of the 1.5-3 ng/ml tacrolimus group was not achieved.

Immunological advantages of everolimus versus cyclosporin A in liver-transplanted recipients, as revealed by polychromatic flow cytometry

Several immunosuppressive drugs with different mechanisms of action are available to inhibit organ rejection after transplant. We analyzed different phenotypic and functional immunological parameters in liver-transplanted patients who received cyclosporin A (CsA) or Everolimus (Evr). In peripheral blood mononuclear cells (PBMC) from 29 subjects receiving a liver transplant and treated with two different immunosuppressive regimens, we analyzed T cell activation and differentiation, regulatory T cells (Tregs) and Tregs expressing homing receptors such as the chemokine receptor CXCR3. T cell polyfunctionality was studied by stimulating cells with the superantigen staphylococcal enterotoxin B (SEB), and measuring the simultaneous production of interleukin (IL)-2 and interferon (IFN)-γ, along with the expression of a marker of cytotoxicity such as CD107a. The analyses were performed by polychromatic flow cytometry before transplantation, and at different time points, up to 220 days after transplant. Patients taking Evr had a higher percentage of total CD4⁺ and naïve CD4⁺ T cells than those treated with CsA; the percentage of CD8⁺ T cells was lower, but the frequency of naïve CD8⁺ T cells higher. Patients taking Evr showed a significantly higher percentage of Tregs, and Tregs expressing CXCR3. After stimulation with SEB, CD8⁺ T cells from Evr-treated patients displayed a lower total response, and less IFN-γ producing cells. The effects on the immune system, such as the preservation of the naïve T cell pool and the expansion of Tregs (that are extremely useful in inhibiting organ rejection), along with the higher tolerability of Evr, suggest that this drug can be safely used after liver transplantation, and likely offers immunological advantages.

The use of everolimus in pediatric liver transplant recipients: first experience in a single center

The role of mTOR inhibitors, such as EVL, has not been established for pediatric liver transplant recipients up to now, although data from adult solid organ graft transplantation are very promising. Major complications following pediatric liver transplantation in the long-term course include chronic graft rejection and CNI-derived nephrotoxicity. The purpose of our study was to report first results using EVL as a rescue therapy in pediatric liver transplant recipients for the following indications: chronic graft dysfunction n=12, suspected CNI toxicity n=3, hepatoblastoma n=2, and recurrence of primary sclerosing cholangitis post-Ltx n=1. Four patients with chronic graft dysfunction developed completely normal liver function tests using EVL, six patients showed partial improvement, and two patients did not respond at all. One patient with CNI-induced nephropathy showed a slightly improved GFR. Both patients with hepatoblastoma did not develop any metastasis post-Ltx. First experience with EVL in pediatric liver transplant recipients shows promising results in patients with chronic graft failure when standard immunosuppression has failed. The future role of EVL in immunosuppressive protocols for children post-Ltx has to be proven by controlled clinical trials.

Conversion from sirolimus to everolimus in kidney transplant recipients receiving a calcineurin-free regimen

BACKGROUND

Everolimus (EVL) and sirolimus (SRL) were introduced into immunosuppressive regimens, in an attempt to replace or reduce the dose of the nephrotoxic calcineurin inhibitors (CNI). In our institution, due to an administrative decision, conversion from SRL to EVL, was carried out, providing us the opportunity to investigate the effectiveness and safety profile of both drugs and to review the practical conversion dose between them.

METHODS

We retrospectively analyzed the medical records of 51 maintenance kidney transplant recipients receiving an SRL-based CNI-free regimen, who were switched to EVL. SRL dose was concentration controlled to a through level of 4-8 ng/mL. Patients were converted to a variable dose of EVL that was adjusted to achieve a trough concentration of 3-8 ng/mL.

RESULTS

SRL mean dose at time of conversion was 2.0 ± 0.9 mg/d. Initial EVL mean dose was 1.3 ± 0.5 mg/d. Six months after conversion, mean EVL trough level was 6.2 ± 2.8 ng/mL. EVL dose at this point was 2.0 ± 0.9 mg/d, which was not statistically different from SRL dose at the time of conversion (p = 0.575), suggesting a conversion factor of 1:1. During this six month period post conversion, no significant changes were observed in serum creatinine, hematocrit level, platelet count, proteinuria or lipid levels. No patient experienced an acute rejection episode.

CONCLUSIONS

Conversion from SRL to EVL in renal transplant recipients receiving a CNI-free immunosuppressive regimen can be performed safely with a low trough level range of EVL. We report for the first time a conversion factor between SRL and EVL.

Calcineurin inhibitor-free immunosuppression in pediatric renal transplantation: a viable option?

The introduction, in the mid-1980s, of calcineurin inhibitors - namely ciclosporin (cyclosporine) and later tacrolimus - has significantly improved short-term renal graft survival by lowering acute rejection rates in both adult and pediatric kidney transplantation. Nonetheless, long-term transplant survival is still not satisfactory, with calcineurin inhibitor-induced chronic nephrotoxicity being one of the main causes of progressive nephron loss and declining renal transplant function. Hence, different immunosuppressant regimens have been proposed to avoid or ameliorate calcineurin inhibitor-induced nephrotoxicity. These comprise the use of non-depleting or depleting antibodies for calcineurin inhibitor minimization, calcineurin inhibitor avoidance, or calcineurin inhibitor withdrawal from mycophenolate mofetil-based immunosuppressant protocols. De novo use of a mammalian target of rapamycin (mTOR) inhibitor (sirolimus or everolimus) or conversion from a calcineurin inhibitor to an mTOR inhibitor may constitute another therapeutic option to avoid or reduce calcineurin inhibitor-induced nephrotoxicity. To date, complete calcineurin inhibitor avoidance seems to be inappropriate because other relatively potent immunosuppressant agents such as lymphocyte-depleting antibodies are needed for rejection prophylaxis, which are frequently accompanied by a higher incidence of infections and an unacceptably high acute rejection rate under calcineurin inhibitor avoidance. In some studies, calcineurin inhibitor withdrawal in adult and pediatric kidney allograft recipients with stable or declining transplant function has been associated with an amelioration of renal function; however, this is attained at the cost of a higher acute rejection rate in 10-20% of patients. It has been frequently stressed that conversion from a calcineurin inhibitor-based regimen to an mTOR inhibitor-based immunosuppressant regimen should be performed early (e.g. 3 or 6 months post-transplant) in patients with well-preserved renal transplant function without significant proteinuria in order to prevent, or at least limit, calcineurin inhibitor-induced tissue damage and provide long-term benefit. It should be borne in mind though that the use of an mTOR inhibitor carries the risk of potential adverse events such as aggravation of proteinuria, hyperlipidemia, myelosuppression, and hypergonadotropic hypogonadism. Even though everolimus may be better tolerated than sirolimus, studies on everolimus for calcineurin inhibitor-free immunosuppression in the pediatric kidney transplant patient population are lacking. At present, the safest therapeutic strategy for pediatric renal allograft recipients with chronic calcineurin inhibitor-induced nephrotoxicity appears to be a mycophenolate mofetil-based regimen with low-dose calcineurin inhibitor therapy and corticosteroids; available published data show that dual immunosuppression with mycophenolate mofetil and corticosteroids, as well as an mTOR inhibitor plus mycophenolate mofetil plus corticosteroid-based regimens, are associated with an increased risk of acute rejection episodes. In individual patients with evidenced chronic allograft dysfunction and over-immunosuppression leading to recurrent infections, dual maintenance immunosuppression with mycophenolate mofetil and corticosteroids may be appropriate. As stated in the annual report issued by the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry, currently the most popular immunosuppressant protocol consists of a calcineurin inhibitor combined with mycophenolate mofetil and corticosteroids: 59.1% and 53.2% of patients with a functioning graft receive a calcineurin inhibitor plus mycophenolate mofetil plus corticosteroid-based immunosuppression at 1 and 5 years post-transplant, respectively. 91.4% and 87.8% of patients are administered a calcineurin inhibitor-containing regimen 1 and/or 5 years after transplantation, respectively. Undoubtedly, the use of calcineurin inhibitor-free immunosuppressant regimens with or without antibody induction, plus an mTOR inhibitor and mycophenolate mofetil, requires more comprehensive long-term investigations to determine whether acceptable rejection rates and conservation of renal function can be achieved.

Inhibitors of mTOR

Inhibitors of mammalian target of rapamycin (mTOR) have been approved for the treatment of renal cell carcinoma and appear to have a role in the treatment of other malignancies. The primary objective of this drug review is to provide pharmacokinetic and dynamic properties of the commonly used drugs everolimus and temsirolimus. Additionally, information on clinical use, mechanism of action, bioanalysis, drug-drug interactions, alterations with disease or age, pharmacogenetics, and drug resistance is given. This overview should assist the treating medical oncologist in adjusting treatment with mTOR inhibitors to individual patient circumstances.

Clinical recommendations for the use of everolimus in heart transplantation

Proliferation signal inhibitors (PSIs), everolimus (EVL), and sirolimus are a group of immunosuppressor agents indicated for the prevention of acute rejection in adult heart transplant recipients. Proliferation signal inhibitors have a mechanism of action with both immunosuppressive and antiproliferative effects, representing an especially interesting treatment option for the prevention and management of some specific conditions in heart transplant population, such as graft vasculopathy or malignancies. Proliferation signal inhibitors have been observed to work synergistically with calcineurin inhibitors (CNIs). Data from clinical trials and from the growing clinical experience show that when administered concomitantly with CNIs, PSIs allow significant dose reductions of the latter without loss of efficacy, a fact that has been associated with stabilization or significant improvement in renal function in patients with CNI-induced nephrotoxicity. The purpose of this article was to review the current knowledge of the role of PSIs in heart transplantation to provide recommendations for the proper use of EVL in cardiac transplant recipients, including indications, treatment regimens, monitoring, and management of the adverse events.

Renal function outcomes in kidney transplant recipients after conversion to everolimus-based immunosuppression regimen with CNI reduction or elimination

BACKGROUND

Chronic allograft nephropathy (CAN) is a major cause of progressive renal failure in kidney transplant recipients. Its etiology is multifactorial and can be due to immunologic or nonimmunologic conditions including calcineurin inhibitor (CNI) toxicity.

OBJECTIVE

To evaluate the effect of conversion from CNIs to everolimus in kidney transplant recipients with CAN.

PATIENTS AND METHODS

In this 12-month pilot study in renal transplant recipients with biopsy-proved CAN, therapy was changed to an everolimus-based immunosuppression regimen. Cyclosporine or tacrolimus dosage was reduced by 80% (group 1, n = 10) or discontinued (group 2, n = 10). Mycophenolate mofetil or azathioprine were withdrawn in group 1, whereas both agents were maintained in group 2. All patients received prednisone.

RESULTS

Twenty renal allograft recipients switched to an everolimus-based regimen, and patients were followed up for a mean (SD) of 12 (0.1) months. Baseline and end-of-study data were as follows: serum creatinine concentration, 1.27 (0.35) mg/dL vs 1.24 (0.4) mg/dL in group 1, and 1.27 mg/dL (0.36) vs 1.25 (0.3) mg/dL in group 2 (difference not significant); and estimated glomerular filtration rate, 72.4 (19.86) mL/min vs 76.26 (22.69) mL/min in group 1 (not significant), and 66.2 (12.95) mL/min vs 66.2 (13.73) mL/min in group 2 (not significant). One patient in group 1 experienced an acute rejection episode (Banff grade Ib), and 2 patients in group 1 and 1 patient in group 2 demonstrated borderline changes, all associated with everolimus blood concentration less than 3 ng/mL.

CONCLUSIONS

Reduction or withdrawal of CNI and introduction of everolimus may be useful to slow the rate of loss of renal function in patients with CAN.

Reduction of cyclosporine following the introduction of everolimus in maintenance heart transplant recipients: a pilot study

Data are scarce concerning the calcineurin inhibitor dose reduction required following introduction of everolimus in maintenance heart transplant recipients to maintain stable renal function. In a 48-week, multicenter, single-arm pilot study in heart transplant patients >12 months post-transplant, everolimus was started at 1.5 mg/day (subsequently adjusted to target C(0) 5-10 ng/ml). Mycophenolate mofetil or azathioprine was discontinued on the same day and cyclosporine (CsA) dose was reduced by 25%, with a further 25% reduction each time calculated glomerular filtration rate (cGFR) decreased to <75% of baseline. Of 36 patients enrolled, 25 were receiving everolimus at week 48. From baseline to week 48, there was a mean decrease of 44.5%, 50.9% and 44.6% in CsA dose, C(0) and C(2), respectively. Mean cGFR was 68.9 +/- 14.5 ml/min at baseline and 61.6 +/- 11.5 ml/min at week 48 (P = 0.018). The prespecified criterion for stable renal function was met, i.e. a mean decrease <or=25% of cGFR from baseline. Two patients experienced biopsy-proven acute rejection Grade 3A (5.6%). Between baseline and week 48, there were significant increases in total cholesterol, LDL cholesterol and triglycerides, and small but significant elevations in liver enzymes. This 1-year pilot study suggests that CsA dose reduction of ca. 40% after initiation of everolimus was associated with a decrease in cGFR, however, based on the prespecified criteria stable renal function was attained.

The use of proliferation signal inhibitors in the prevention and treatment of allograft vasculopathy in heart transplantation

Cardiac allograft vasculopathy (CAV) currently represents one of the most important causes of long-term morbidity and mortality in the heart transplant population. In well-designed studies with de novo patients, the use of proliferation signal inhibitors (PSIs; everolimus and sirolimus) has been shown to significantly prevent the intimal growth of graft coronary arteries in comparison to other immunosuppressive regimens, reducing the incidence of vasculopathy at 12 and 24 months. In addition, conversion to PSIs in maintenance patients with established CAV has also shown promising results in the reduction of the progression of the disease and its clinical consequences. For these reasons the interest shown by various transplantation units in the potential role of PSIs in this field is growing. The aim of the present article is to review the information obtained to date on the use of PSIs in heart transplant recipients, both in the prevention and the treatment of CAV. The principal published recommendations on the introduction and appropriate management of these drugs in clinical practice are also collected, as well as certain recommendations given by the authors based on their experience.

mTOR regulates vascular smooth muscle cell differentiation from human bone marrow-derived mesenchymal progenitors

OBJECTIVE

Vascular smooth muscle cells (VSMCs) and circulating mesenchymal progenitor cells (MSCs) with a VSMC phenotype contribute to neointima formation and lumen loss after angioplasty and during allograft arteriosclerosis. We hypothesized that phosphoinositol-Akt-mammalian target of rapamycin-p70S6 kinase (PI3K/Akt/mTOR/p70S6K) pathway activation regulates VSMC differentiation from MSCs.

METHODS AND RESULTS

We studied effects of PI3K/Akt/mTOR signaling on phenotypic modulation of MSC and VSMC marker expression, including L-type Ca(2+) channels. Phosphorylation of Akt and p70S6K featured downregulation of VSMC markers in dedifferentiated MSCs. mTOR inhibition with rapamycin at below pharmacological concentrations blocked p70S6K phosphorylation and induced a differentiated contractile phenotype with smooth muscle (sm)-calponin, sm-alpha-actin, and SM protein 22-alpha (SM22alpha) expression. The PI3K inhibitor Ly294002 abolished Akt and p70S6K phosphorylation and reversed the dedifferentiated phenotype via induction of sm-calponin, sm-alpha-actin, SM22alpha, and myosin light chain kinase. Rapamycin acted antiproliferative without impairing MSC viability. In VSMCs, rapamycin increased a homing chemokine for MSCs, stromal cell-derived factor-1-alpha, at mRNA and protein levels. The CXCR4-mediated MSC migration toward conditioned medium of rapamycin-treated VSMCs was enhanced.

CONCLUSIONS

We describe novel pleiotropic effects of rapamycin at very low concentrations that stabilized differentiated contractile VSMCs from MSCs in addition to exerting antiproliferative and enhanced homing effects.

Conversion therapy to everolimus in renal transplant recipients: results after one year

BACKGROUND

Two new diagnoses have been causing graft loss during long-term follow-up, namely, chronic nephropathy and anticalcineurinic toxicity. The advent of the mammalian target of rapamycin (m-TOR) obviates anticalcineurine toxicity and reduces posttransplant malignancy incidence with good inmunosuppressive potential. We examinated the renal and metabolic behavior in renal transplant recipients who required conversion from an anticalcineurinic (cyclosporine or tacrolimus) to an m-TOR inhibitor (everolimus) as part of their immunosuppressive maintenance therapy.

MATERIALS AND METHODS

Twenty-one first renal transplant recipients had everolimus added to their inmunosuppressive therapy combined with an antimetabolite (mycophenolate mofetil or sodium mycophenolate). The mean age of the patients was 35 +/- 17 years (range, 6 to 65). The prevalence of male recipients was 57%; the overall mean weight, 64 kg (range, 48 to 95). All patients were hispanic with 15 transplants from cadaveric donors (71%). The mean follow-up posttransplant was 18 months (range, 3 to 40) and the mean follow-up on everolimus, 10 months (range, 2 to 22).

RESULTS

There was no mortality or graft loss, but there were 3 (17%) biopsy-confirmed acute rejection episodes. There were no significant changes in metabolic function pre- or postconversion. Regarding renal function, the mean creatinine serum showed a trend to decline: preconversion 1.7 mg/dL; postconversion 1.5 mg/dL. In 10 patients, it was possible to discontinue at least one antihypertensive medication (48%).

CONCLUSIONS

Everolimus was an effective medication to manage renal transplant patients. It produced metabolic stability and low myelotoxicity, despite combination with an antimetabolite (mycophenolic acid). Also, reduction of antihypertensive medications was an additional benefits for many patients.

Multidisciplinary insights on clinical guidance for the use of proliferation signal inhibitors in heart transplantation

Proliferation signal or mammalian target-of-rapamycin inhibitors (PSI/mTOR inhibitors), everolimus and sirolimus, provide attractive options for use in heart transplantation because they are immunosuppressive and anti-proliferative. PSI/mTOR inhibitors work synergistically with calcineurin inhibitors (CNIs) and thus permit the minimization of CNIs without compromising efficacy. This approach is advantageous for the majority of heart transplant recipients and might provide particular benefit in specific cases, such as patients with cardiac allograft vasculopathy, malignancies and renal dysfunction, or in patients intolerant to other immunosuppressive agents. Drawing on the expertise of transplant cardiologists, cardiac surgeons and nephrologists, we addressed the assessment of renal function; management of adverse events associated with this class of drugs; and clinical guidance, specifically for the use of everolimus, including patient selection, indications for treatment and practicalities of drug initiation and monitoring.

Phase I pharmacokinetic and pharmacodynamic study of the oral mammalian target of rapamycin inhibitor everolimus in patients with advanced solid tumors

PURPOSE

To identify the optimal regimen and dosage of the oral mammalian target of rapamycin inhibitor everolimus (RAD001).

METHODS

We performed a dose-escalation study in advanced cancer patients administering oral everolimus 5 to 30 mg/wk, with pharmacokinetic (PK) and pharmacodynamic (PD) studies. PD data prompted investigation of 50 and 70 mg weekly and daily dosing at 5 and 10 mg.

RESULTS

Ninety-two patients were treated. Dose-limiting toxicity was seen in one patient each at 50 mg/wk (stomatitis and fatigue) and 10 mg/d (hyperglycemia); hence, the maximum-tolerated dose was not reached. S6 kinase 1 activity in peripheral-blood mononuclear cells was inhibited for at least 7 days at doses >or= 20 mg/wk. Area under the curve increased proportional to dose, but maximum serum concentration increased less than proportionally at doses >or= 20 mg/wk. Terminal half-life was 30 hours (range, 26 to 38 hours). Partial responses were observed in four patients, and 12 patients remained progression free for >or= 6 months, including five of 10 patients with renal cell carcinoma.

CONCLUSION

Everolimus was satisfactorily tolerated at dosages up to 70 mg/wk and 10 mg/d with predictable PK. Antitumor activity and PD in tumors require further clinical investigation. Doses of 20 mg/wk and 5 mg/d are recommended as appropriate starting doses for these studies.

Uneventful Thoracic Healing With Everolimus After Aortic Valve Replacement

Impaired wound healing problems constitute a frequent severe adverse event associated to de novo use of proliferation signal inhibitors sirolimus or everolimus in kidney, heart, and lung transplantation. No published experience on the best practice to manage these drugs in patients scheduled for elective thoracic surgery is available. Herein we present a renal allograft recipient with recurrent cutaneous neoplasia who was maintained on everolimus plus prednisone undergoing aortic valve replacement. Although the most advisable practice may be everolimus withdrawal during the perioperative period, everolimus was maintained with transient dose decrease without any wound healing problem.