Everolimus and reduced cyclosporine trough levels in maintenance heart transplant recipients

Novel Immunosuppression in Solid Organ Transplantation

Solid organ transplantation and survival has improved tremendously in the last few decades, much of the success has been attributed to the advancements in immunosuppression. While steroids are being replaced and much of the immunosuppressive strategies focus on steroid free regimens, novel agents have introduced in the induction, maintenance, and treatment of acute rejection phase. MTOR inhibitors have helped with the renal sparing side effect from the calcineurin inhibitors, newer agents such as rituximab have decreased the incidence of donor-specific antibodies which led to decreased incidence of acute rejection reactions. In this chapter we discuss the newer therapies directed specifically for solid organ transplantation.

EBV Predicts Post-Pediatric Heart Transplant Malignancy; Induction Therapy and Tacrolimus Don't

BACKGROUND

Patients after heart transplantation are at increased risk for malignancy secondary to immunosuppression and oncogenic viral infections. Most common amongst children is post-transplant lymphoproliferative disorder (PTLD), occurring in 5-10% of patients. We utilized a national database to examine incidence and risk factors for post-transplant malignancy.

METHODS

The United Network for Organ Sharing (UNOS) database was queried for pediatric (<18 years) heart transplant recipients from 10/1987-10/2019. Kaplan-Meier analysis was performed to assess freedom from malignancy post-transplant. Cox regression was performed to generate hazard ratios (HR [95% CI]) for risk of malignancy development.

RESULTS

Of 8,581 pediatric heart transplant recipients, 8.1% developed malignancy over median follow-up time of 6.3 years, with PTLD compromising the majority (86.4%) of diagnosed cancers. The incidence of PTLD development was 1.3% and 4.5% at one and five years. Older age at the time of transplant was protective against the development of malignancy (HR 0.98 [0.96-0.99], p<0.001), whereas a history of previous malignancy (HR 1.9 [1.2-3.0], p=0.007) and Ebstein-Barr virus (EBV) recipient-donor mismatch (HR 1.7 [1.3-2.2], p<0.001) increased the risk. Use of induction therapy (utilized in 78.9% of the cohort) did not increase malignancy risk (p=0.355); nor did use of maintenance tacrolimus (p=0.912).

CONCLUSIONS

PTLD occurred after 7% of pediatric heart transplants, with risk increased by younger age and EBV mismatch, highlighting the importance of PTLD monitoring in EBV seronegative recipients. Induction therapy, utilized in the majority of pediatric heart transplants, does not seem to increase post-transplant malignancy, nor does the most commonly used calcineurin inhibitor tacrolimus.

Conversion to everolimus in pediatric heart transplant recipients is a safe treatment option with an impact on cardiac allograft vasculopathy and renal function

BACKGROUND

Cardiac allograft vasculopathy (CAV) and nephrotoxicity affect long-term survival after heart transplantation (HTX). Studies, mostly conducted in adults, showed a positive effect of everolimus (EVL) on these problems. We describe the effects of conversion of the immunosuppressive therapy to an everolimus including regime on CAV, renal function, and safety in heart transplanted children/adolescents.

METHODS

This retrospective single-center study included 36 participants (mean time after HTX 6.3 ± 4.7 years). Descriptive pre/post-comparisons were performed with an observation period partially up to 4 years. Impact on CAV was assessed based on intravascular imaging and Stanford grading. Safety analysis included cytomegalovirus (CMV)-infection and acute rejection.

RESULTS

In terms of CAV (9 out of 36 patients) four showed no progression, three an improvement, one a worsening; one new diagnosis. The average CrCl showed a significant improvement 6, 12, and 24 months after conversion regarding all patients (n = 29). There was no acute rejection or CMV-infection.

CONCLUSION

Conversion to an EVL-based therapy after pediatric HTX is a safe immunosuppressive regime without increasing risk of acute rejection or CMV-infection. There was some evidence of reduction in progression of CAV and a significant improvement of the renal function.

Twelve-month efficacy and safety of the conversion to everolimus in maintenance heart transplant recipients

AIM: To determine the clinical reasons for conversion to everolimus (EVL) and long-term outcomes in heart transplant (HT) recipients.

METHODS: A retrospective 12-mo study has been carried out in 14 Spanish centres to assess the efficacy and safety of conversion to EVL in maintenance HT recipients.

RESULTS: Two hundred and twenty-two patients were included (mean age: 53 ± 10.5 years; mean time from HT: 8.1 ± 4.5 years). The most common reasons for conversion were nephrotoxicity (30%), chronic allograft vasculopathy (20%) and neoplasms (17%). The doses and mean levels of EVL at baseline (conversion to EVL) and after one year were 1.3 ± 0.3 and 1.2 ± 0.6 mg/d and 6.4 ± 3.4 and 5.6 ± 2.5 ng/mL, respectively. The percentage of patients receiving calcineurin inhibitors (CNIs) at baseline and on the final visit was 95% and 65%, respectively. The doses and mean levels of CNIs decreased between baseline and month 12 from 142.2 ± 51.6 to 98.0 ± 39.4 mg/d (P < 0.001) and from 126.1 ± 50.9 to 89.2 ± 47.7 ng/mL (P < 0.001), respectively, for cyclosporine, and from 2.9 ± 1.8 to 2.6 ± 1.9 mg/d and from 8.3 ± 4.0 to 6.5 ± 2.7 ng/mL (P = 0.011) for tacrolimus. In the subgroup of patients converted because of nephrotoxicity, creatinine clearance increased from 34.9 ± 10.1 to 40.4 ± 14.4 mL/min (P < 0.001). There were 37 episodes of acute rejection in 24 patients (11%). The most frequent adverse events were oedemas (12%), infections (9%) and gastrointestinal problems (6%). EVL was suspended in 44 patients (20%). Since the database was closed at the end of the study, no further follow-up data is available.

CONCLUSION: Conversion to EVL in maintenance HT recipients allowed minimisation or suspension of the CNIs, with improved kidney function in the patients with nephrotoxicity, after 12 mo.

Chronic renal insufficiency in heart transplant recipients: risk factors and management options

Renal dysfunction after heart transplantation is a frequently observed complication, in some cases resulting in significant limitation of quality of life and reduced survival. Since the pathophysiology of renal failure (RF) is multifactorial, the current etiologic paradigm for chronic kidney disease after heart transplantation relies on the concept of calcineurin inhibitor (CNI)-related nephrotoxicity acting on a predisposed recipient. Until recently, the management of RF has been restricted to the minimization of CNI dosage and general avoidance of classic nephrotoxic risk factors, with somewhat limited success. The recent introduction of proliferation signal inhibitors (PSIs) (sirolimus and everolimus), a new class of immunosuppressive drugs lacking intrinsic nephrotoxicity, has provided a completely new alternative in this clinical setting. As clinical experience with these new drugs increases, new renal-sparing strategies are becoming available. PSIs can be used in combination with reduced doses of CNIs and even in complete CNI-free protocols. Different strategies have been devised, including de novo use to avoid acute renal toxicity in high-risk patients immediately after transplantation, or more delayed introduction in those patients developing chronic RF after prolonged CNI exposure. In this review, the main information on the clinical relevance and pathophysiology of RF after heart transplantation, as well as the currently available experience with renal-sparing immunosuppressive regimens, particularly focused on the use of PSIs, is reviewed and summarized, including the key practical points for their appropriate clinical usage.

Everolimus inhibits anti-HLA I antibody-mediated endothelial cell signaling, migration and proliferation more potently than sirolimus

Antibody (Ab) crosslinking of HLA I molecules on the surface of endothelial cells triggers proliferative and pro-survival intracellular signaling, which is implicated in the process of chronic allograft rejection, also known as transplant vasculopathy (TV). The purpose of this study was to investigate the role of mammalian target of rapamycin (mTOR) in HLA I Ab-induced signaling cascades. Everolimus provides a tool to establish how the mTOR signal network regulates HLA I-mediated migration, proliferation and survival. We found that everolimus inhibits mTOR complex 1 (mTORC1) by disassociating Raptor from mTOR, thereby preventing class I-induced phosphorylation of mTOR, p70S6K, S6RP and 4E-BP1, and resultant class I-stimulated cell migration and proliferation. Furthermore, we found that everolimus inhibits class I-mediated mTORC2 activation (1) by disassociating Rictor and Sin1 from mTOR; (2) by preventing class I-stimulated Akt phosphorylation and (3) by preventing class I-mediated ERK phosphorylation. These results suggest that everolimus is more effective than sirolimus at antagonizing both mTORC1 and mTORC2, the latter of which is critical in endothelial cell functional changes leading to TV in solid organ transplantation after HLA I crosslinking. Our findings point to a potential therapeutic effect of everolimus in prevention of chronic Ab-mediated rejection.

Use of mTOR inhibitors in chronic heart transplant recipients with renal failure: calcineurin-inhibitors conversion or minimization?

BACKGROUND

In the last decade, mTOR inhibitors (mTOR-is) have become the cornerstone of the calcineurin inhibitor (CNI)-reduced/free regimens aimed to the preservation of post-transplant renal function. We compared utility and safety of the total replacement of calcineurin inhibitors with a mTOR-i with a strategy based on calcineurin inhibitor minimization and concomitant use of m-TOR-i.

METHODS

In a retrospective multi-center cohort of 394 maintenance cardiac recipients with renal failure (GFR<60 mL/min/1.73 m(2)), we compared 235 patients in whom CNI was replaced with a mTOR-i (sirolimus or everolimus) with 159 patients in whom mTOR-is were used to minimize CNIs. A propensity score analysis was carried out to balance between group differences.

RESULTS

Overall, after a median time of 2 years from mTOR-i initiation, between group differences for the evolution of renal function were not observed. In a multivariate adjusted model, improvement of renal function was limited to patients with mTOR-i usage within 5years after transplantation, particularly with the conversion strategy, and in those patients who could maintain mTOR-i therapy. Significant differences between strategies were not found for mortality, infection and mTOR-i withdrawal due to drug-related adverse events. However, conversion group tended to have a higher acute rejection incidence than the minimization group (p=0.07).

CONCLUSION

In terms of renal benefits, our results support an earlier use of mTOR-is, irrespective of the strategy. The selection of either a conversion or a CNI minimization protocol should be based on the clinical characteristics of the patients, particularly their rejection risk.

Everolimus in different combinations as maintenance immunosuppressive therapy in heart transplant recipients

OBJECTIVES

We examined the experiences of heart transplant recipients receiving everolimus as maintenance therapy in different combinations over a long time.

MATERIALS AND METHODS

Between 2004 and 2009, forty patients (29 men, 11 women; mean age, 51.6 y) were switched from a routine immunosuppressive regimen to everolimus. Indications were other (2), renal insufficiency (17), cardiac allograft vasculopathy (14), and ongoing cellular rejection (7). Combinations were either along with cyclosporine (24), mycophenolate mofetil (14), or others (2). Indications for the introduction of everolimus including safety, efficacy, different combinations of everolimus, biopsy-proven acute rejections, renal function, and infections were evaluated retrospectively.

RESULTS

Five patients died, 4 of them were still on everolimus at the time of death; they died from intracerebral hemorrhage (1), embolism (1), cardiac arrest (2), and unknown (1). Everolimus was discontinued in 6 patients owing to severe adverse effects: Edema (2), gastrointestinal adverse effects (3), and dermal adverse effects (1). Mean everolimus trough levels were 5.8 μmol/L at 6 months and 4.9 at 60 months. Mean cyclosporine levels were 67.62 μmol/L at 6 months and 47.3 μmol/L at 60 months. Mean serum creatinine levels were stable (147.9 μmol/L after 60 months). Four life-threatening infections (all pneumonia) occurred but resulted in complete recovery.

CONCLUSIONS

Everolimus is safe with different immunosuppressive combinations after receiving a heart transplant.

A comprehensive review of everolimus clinical reports: a new mammalian target of rapamycin inhibitor

As new immunosuppressive agents are introduced to the market, clinicians are faced with the daunting task of sifting through the published literature to decide the value that the agent will add to their own practice. We often must extrapolate information provided through study in other solid-organ transplantation populations than our specific area of interest as we interpret the results and outcomes. With these challenges in mind, this compilation of published work for the newest mammalian target of rapamycin inhibitor everolimus (Certican; Novartis Pharmaceuticals, Hanover, NJ) (Zortress; Novartis Pharmaceuticals, Basel, Switzerland) is intended to provide a concise but thorough presentation of available literature so that the reader who may be unfamiliar with the agent can make their own judgment. Both Ovid and PubMed search engines were queried with a particular focus on high-impact articles noted in the Web of Science or Citation Index. Work described solely in abstract or case report form was excluded, as well as meta-analyses or those that were editorial or commentary in nature. Included were publications presented using the English language that described adult human subjects who received a heart, lung, kidney, or liver allograft. The goal of this strategy was to allow for the inclusion of pertinent literature in an unbiased fashion. Tables are provided that outline trial specific information, leaving a discussion of major outcomes to the text of the review.

Efficacy and safety of low-dose everolimus as maintenance immunosuppression in cardiac transplant recipients

For cardiac transplant (CTx) recipients, the recommended everolimus (EVL) dose is 0.75 mg bid or 1.5 mg bid and the target trough blood level is 3–8 μg/L. We studied a cohort of 56 CTx patients with chronic kidney disease receiving 0.75 mg bid EVL to maintain blood levels of 5–8 ug/L (designated RD group) and a cohort of 51 CTx patients with chronic kidney disease receiving 0.5 mg bid to maintain blood levels of 3–5 ug/L (designated LD group). The primary endpoint was a composite of death, rejection and premature EVL discontinuation up to 1 year after introduction of EVL. The primary endpoint was reached by 32% of patients in the LD group and by 41.1% of patients in the RD group (P = 0.361). Biochemical safety parameters were comparable in both groups. Our results indicate that low-dose EVL may be as effective and safe as regular dose EVL.

Efficacy and Safety of Low-Dose Cyclosporine with Everolimus and Steroids in de novo Heart Transplant Patients: A Multicentre, Randomized Trial

A six-month, multicenter, randomized, open-label study was undertaken to determine whether renal function is improved using reduced-exposure cyclosporine (CsA) versus standard-exposure CsA in 199 de novo heart transplant patients receiving everolimus and steroids ± induction therapy. Mean C(2) levels were at the low end of the target range in standard-exposure patients (n = 100) and exceeded target range in reduced-exposure patients (n = 99) throughout the study. Mean serum creatinine at Month 6 (the primary endpoint) was 141.0 ± 53.1 μmol/L in standard-exposure patients versus 130.1 ± 53.7 μmol/L in reduced-exposure patients (P = 0.093). The incidence of biopsy-proven acute rejection ≥3A at Month 6 was 21.0% (21/100) in the standard-exposure group and 16.2% (16/99) in the reduced-exposure group (n.s.). Adverse events and infections were similar between treatment groups. Thus, everolimus with reduced-exposure CsA resulted in comparable efficacy compared to standard-exposure CsA. No renal function benefits were demonstrated; that is possibly related to poor adherence to reduced CsA exposure.

Recurrent non-melanoma skin cancer: remission of field cancerization after conversion from calcineurin inhibitor- to proliferation signal inhibitor-based immunosuppression in a cardiac transplant recipient

Non-melanoma skin cancers (NMSCs) are the most common malignancies after solid organ transplantation. Their incidence increases with time after transplantation. Calcineurin-inhibitors (CNIs) and azathioprine are known as skin neoplasia-initiating and -enhancing immunosuppressants. In contrast, increasing clinical experience suggests a relevant antiproliferative effect of mammalian target of rapamycin inhibitors, also named proliferation signal inhibitors (PSIs). We report the case of a cardiac allograft recipient with an impressive and consolidated reduction of recurrent NMSC, observed after conversion from CNI-therapy to a PSI-based protocol.

Two-year outcomes in thoracic transplant recipients after conversion to everolimus with reduced calcineurin inhibitor within a multicenter, open-label, randomized trial

BACKGROUND

Use of the mammalian target of rapamycin inhibitor everolimus with an accompanying reduction in calcineurin inhibitor (CNI) exposure has shown promise in preserving renal function in maintenance thoracic transplant patients, but robust, long-term data are required.

METHODS

In a prospective, open-label, multicenter study, thoracic transplant recipients more than or equal to 1 year posttransplant with mild-to-moderate renal insufficiency were randomized to continue their current CNI-based immunosuppression or convert to everolimus with predefined CNI exposure reduction. After a 12-month core trial, patients were followed up to month 24 after randomization.

RESULTS

Of 245 patients who completed the month 12 visit, 235 patients (108 everolimus and 127 controls) entered the 12-month extension phase. At month 24, mean measured glomerular filtration rate had increased by 3.2±12.3 mL/min from the point of randomization in everolimus-treated patients and decreased by 2.4±9.0 mL/min in controls (P<0.001), a difference that was significant within both the heart and lung transplant subpopulations. During months 12 to 24, 5.6% of everolimus patients and 3.1% of controls experienced biopsy-proven acute rejection (P=0.76). There were no significant differences in the rate of adverse events or serious adverse events (including pneumonia) between groups during months 12 to 24.

CONCLUSIONS

Converting maintenance thoracic transplant recipients to everolimus with low-exposure CNI results in a renal benefit that is sustained to 2 years postconversion, with significantly improved measured glomerular filtration rate in both heart and lung transplant patients. Despite reductions of more than 50% in CNI exposure, there was no marked loss of efficacy. The safety profile of the everolimus-based regimen was acceptable.

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.

Everolimus with reduced calcineurin inhibitor in thoracic transplant recipients with renal dysfunction: a multicenter, randomized trial

BACKGROUND

The proliferation signal inhibitor everolimus offers the potential to reduce calcineurin inhibitor (CNI) exposure and alleviate CNI-related nephrotoxicity. Randomized trials in maintenance thoracic transplant patients are lacking.

METHODS

In a 12-month, open-labeled, multicenter study, maintenance thoracic transplant patients (glomerular filtration rate > or =20 mL/min/1.73m and <90 mL/min/1.73 m) >1 year posttransplant were randomized to continue their current CNI-based immunosuppression or start everolimus with predefined CNI exposure reduction.

RESULTS

Two hundred eighty-two patients were randomized (140 everolimus, 142 controls; 190 heart, 92 lung transplants). From baseline to month 12, mean cyclosporine and tacrolimus trough levels in the everolimus cohort decreased by 57% and 56%, respectively. The primary endpoint, mean change in measured glomerular filtration rate from baseline to month 12, was 4.6 mL/min with everolimus and -0.5 mL/min in controls (P<0.0001). Everolimus-treated heart and lung transplant patients in the lowest tertile for time posttransplant exhibited mean increases of 7.8 mL/min and 4.9 mL/min, respectively. Biopsy-proven treated acute rejection occurred in six everolimus and four control heart transplant patients (P=0.54). In total, 138 everolimus patients (98.6%) and 127 control patients (89.4%) experienced one or more adverse event (P=0.002). Serious adverse events occurred in 66 everolimus patients (46.8%) and 44 controls (31.0%) (P=0.02).

CONCLUSION

Introduction of everolimus with CNI reduction offers a significant improvement in renal function in maintenance heart and lung transplant recipients. The greatest benefit is observed in patients with a shorter time since transplantation.

Impact of different long-term maintenance immunosuppressive therapy strategies on patients' outcome after heart transplantation

The introduction of cyclosporine in the early 1980s meant a decisive improvement in post-transplant outcomes for all solid-organ transplants and, in particular, it allowed heart transplantation to emerge as a viable therapeutic option for patients with end-stage cardiac failure. Many factors, including recipient and donor selection, organ preservation and the technical aspects of the transplant itself, influence post-operative outcomes following heart transplantation but the continued need to treat the recipient's immune response plays a key role in determining long-term outcomes. Thereby interactions between immunosuppressive drugs used in different combinations play an important role in patients' outcome. After more than two decades, significant controversy still exists as to the best immunosuppressive regimen for long-term maintenance. During the 1990s and 2000s, newer immunosuppressive medications, specifically, tacrolimus, mycophenolate mofetil, sirolimus, everolimus and the IL-2 receptor blockers (daclizumab and basiliximab), were introduced that allow the clinician several options to try to minimize side effects and maximize the desired therapeutic effects. The side effects involve direct organ toxicity (e.g. renal and hepatic dysfunction), metabolic disturbances, (e.g. diabetes, hyperlipidemia and hypertension), neurotoxicity, and several other significant adverse events, such as cholestasis and myelosuppression. Newer immunosuppressive drugs can impair wound healing, induce lung toxicity and produce various cytopenic states. Steroids continue to plague patients with their well-known side effects. This article reviews the current data on the benefits and risks of the various therapeutic regimens available, which are analyzed under three main themes: calcineurin inhibitor based therapies, calcineurin minimization protocols and calcineurin free regimens.

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.

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.

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.

Is there a role for proliferation signal/mTOR inhibitors in the prevention and treatment of de novo malignancies after heart transplantation? Lessons learned from renal transplantation and oncology

With the development of new immunosuppressive agents, the majority of transplant recipients are surviving for over a decade, and malignancy has become a major burden on long-term survival. Reducing the incidence of post-transplant malignancies is especially important in heart transplantation where the risk of malignancies is higher than in other organ transplants. Everolimus and sirolimus, the proliferation signal inhibitors (PSIs) or mammalian target-of-rapamycin (mTOR) inhibitors, now provide new strategies for immunosuppression because of their proven efficacy that translates to a reduction in doses of calcineurin inhibitors needed to prevent acute rejection. In addition, the anti-proliferative effects of this class of drugs raise the possibility that they may be effective for reducing the risk of malignancies after solid-organ transplantation. Despite the paucity of direct clinical evidence for this effect in heart transplant patients, observations from renal transplant recipients suggest that the anti-proliferative actions of PSIs/mTOR inhibitors may also protect against malignancies in heart transplant recipients. This potential for an anti-cancer effect is further supported by the emerging data on the use of PSIs/mTOR inhibitors in non-transplant oncology patients. Reviewed in this article are the incidence rates of malignancies after solid-organ transplantation, and the evidence for anti-cancer effects of PSIs/mTOR inhibitors in renal transplant recipients and in non-transplant patients. Also discussed are the implications of these observational data for future studies on the reduction of malignancies after heart transplantation.

Proliferation signal inhibitors in cardiac transplantation

PURPOSE OF REVIEW

Standard immunosuppression after cardiac transplantation includes a calcineurin inhibitor in combination with mycophenolate mofetil or azathioprine and corticosteroids. These agents have led to excellent outcomes but have shortcomings in terms of efficacy and toxicity. A new class of immunosuppressants, proliferation signal inhibitors, may meet some of these shortcomings.

RECENT FINDINGS

The efficacy of the available proliferation signal inhibitors - sirolimus and its derivative everolimus - has been compared with azathioprine in three randomized clinical trials. Sirolimus or everolimus use was associated with lower rates of acute rejection and reduced development of chronic allograft vasculopathy. Sirolimus was not found to be superior to mycophenolate mofetil in a randomized trial. Proliferation signal inhibitors have been reported to be effective in refractory recurrent acute rejection. Nonrandomized studies have demonstrated that proliferation signal inhibitor-based immunosuppression enables recovery from renal dysfunction secondary to calcineurin inhibitor treatment. Proliferation signal inhibitor-based treatment is associated with a lower risk of malignancy than calcineurin inhibitor-based regimens. Proliferation signal inhibitors have significant adverse effects that may limit widespread use.

SUMMARY

Proliferation signal inhibitors are important new immunosuppressive agents that have added considerably to the armamentarium allowing further tailored immunosuppression to individualize patient care after heart transplantation.

Possible Role of Everolimus in Improving Renal Function in Long-Term Heart Transplantation

Patient survival after heart transplantation has improved dramatically since the availability of calcineurine inhibitor (CNIs); the number of long-term patients is progressively increasing. However, in these patients, nephrotoxicity of CNIs has been largely responsible for the progressive development of renal dysfunction. Since impaired renal function is an important issue that reduces long-term patient survival, it is important to develop strategies to improve renal function while maintaining immunologic safety to preserve graft function. Everolimus is an mTOR inhibitor sirolimus analogue, that has proved, to be highly efficacious to prevent acute myocardial rejection and reduce the severity of cardiac allograft vasculopathy in de novo HTx patients. There is reasonable evidence that, in long term heart transplanted patients, renal function may improve when everolimus is administered associated with a progressive reduction of CNIs. So far there is no evidence to identify which patient may benefit from this therapeutic approach. Indeed everolimus alone may be equally effective to prevent rejection and improve renal function when CNIs are completely discontinued, but data are still lacking on the risks, dosages and side effects of this type of immunosuppression. Ongoing clinical studies will provide further guidance about the possibility to halt or reduce the progression of renal impairment in long term heart transplant patients.

Recommendations for the use of everolimus (Certican) in heart transplantation: results from the second German-Austrian Certican Consensus Conference

Everolimus (Certican; Novartis Pharma AG, Basel, Switzerland) represents the latest generation of proliferation signal inhibitors (PSIs). Everolimus is indicated for use as an immunosuppressive drug in renal and heart transplantation. This report reflects the recommendations of the second German-Austrian Certican Consensus Conference, held in January 2006, for the clinical use of everolimus.

Calcineurin inhibitor-free immunosuppression using everolimus (Certican) in maintenance heart transplant recipients: 6 months' follow-up

BACKGROUND

Everolimus is a proliferation signal-inhibitor recently introduced in heart transplant recipients. To date, little is known about calcineurin inhibitor (CNI)-free immunosuppression using everolimus. This study reports the results of CNI-free immunosuppression using everolimus.

METHODS

During a continuous 9-month period, 60 heart transplant recipients were enrolled. Reasons for switching to everolimus were side effects associated with prior CNI immunosuppression. All patients underwent standardized switching protocols and completed 6 months of follow-up. Blood was obtained for lipid status, renal function, routine controls, and levels of immunosuppressive agents. Echocardiography and a physical examination were performed on Days 0, 14, 28, and then every 3 months.

RESULTS

After switching to everolimus, most patients recovered from the side effects associated with CNIs. Renal function improved significantly after 6 months (creatinine, 2.1 +/- 0.6 vs 1.5 +/- 0.9 mg/dl, p = 0.001; creatinine clearance, 42.2 +/- 21.6 vs 61.8 +/- 23.4 ml/[min x 1.73 m2], p = 0.018). Arterial hypertension improved after 3 months and remained decreased during the observation period. Tremor, peripheral edema, hirsutism, and gingival hyperplasia markedly improved. Adverse events occurred in 8 patients (13.3%), including interstitial pneumonia (n = 2), skin disorders (n = 2), reactivated hepatitis B (n = 1), and fever of unknown origin (n = 3).

CONCLUSION

Preliminary data suggest that CNI-free immunosuppression using everolimus is safe, with excellent efficacy in maintenance heart transplant recipients. Arterial hypertension and renal function improved significantly. CNI-induced side effects such as tremor, peripheral edema, hirsutism, and gingival hyperplasia markedly improved in most patients.

A HPLC–mass spectrometric method suitable for the therapeutic drug monitoring of everolimus

We report here the validation of an HPLC-electrospray-tandem mass spectrometry method for the quantification of everolimus, an immunosuppressant drug. Whole blood samples (100 microl) were extracted by protein precipitation which involved sample pre-treatment with zinc sulphate followed by acetonitrile (containing internal standard, 40-O-(3'-hydroxy)propyl-rapamycin). HPLC was performed using a step-gradient at a flow rate of 0.6 ml/min on a Waters TDM C18 column (10 mm x 2.1mm I.D.) with a resultant chromatographic analysis time of 2 min. Mass spectrometric detection by selected reaction monitoring (everolimus m/z 975.5-->908.3; internal standard m/z 989.5-->922.3). The assay was linear from 0.5 to 40 microg/l (r2>0.994, n=11). The inter- and intra-day analytical recovery and imprecision for quality control samples (1.25, 12.5 and 30 microg/l) were 93.4-98.2% and <10.7%, respectively (n=10). At the lower limit of quantification (0.5 microg/l) the inter- and intra-day analytical recovery was 94.4-95.8% with imprecision of <14.1% (n=10). The absolute recovery of everolimus (6.5 microg/l) and internal standard (12.5 microg/l) was 96.5 and 88.3%, respectively (n=3). A comparison of our method against the mean of all HPLC methods for a series of samples from an external proficiency testing scheme revealed good correlation as shown by the regression analysis: y=0.973x+0.301 (r2=0.986, n=71). In conclusion, the method described is suited to the current requirements for therapeutic drug monitoring of everolimus.