Recommendations for Use of Everolimus After Heart Transplantation: Results From a Latin-American Consensus Meeting

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.

Benefit of early conversion from CNI-based to everolimus-based immunosuppression in heart transplantation

BACKGROUND

Calcineurin inhibitor (CNI)-induced nephrotoxicity is a feared adverse effect after heart transplantation (HTx). In patients with advanced renal failure we performed an overnight conversion from cyclosporine (CsA) to everolimus within the first year after HTx and compared changes in renal function to a similar switch performed in a group of long-term HTx survivors with 24-month follow up.

METHODS

Sixteen HTx recipients (Group 1), including 5 patients undergoing dialysis, were switched overnight from CsA to everolimus at 5.5 (range 1.3 to 8.5) months post-operatively, whereas 15 patients completed 24 months of follow-up. Fifteen long-term survivors (Group 2) were recruited at 96 (58 to 148) months post-HTx. Due to 3 withdrawals and 2 deaths, 10 of these 15 patients remained available for follow-up assessment.

RESULTS

In Group 1 patients, creatinine level improved from 211 (186 to 263) to 112 (98 to 140) mumol/liter and estimated glomerular filtration rate (eGFR) from 29 (20 to 35) to 62 (43 to 69) ml/min/1.73 m(2) (p < 0.001). In Group 2, creatinine decreased from 227 (188 to 255) to 193 (150 to 250) micromol/liter (p = 0.299), and eGFR increased from 26 (21 to 31) to 28 (22 to 35) ml/min/1.73 m(2) (p = 0.225). Four cellular rejections were treated successfully in Group 1. All together, 24 adverse events occurred.

CONCLUSIONS

These preliminary data are the first to suggest that the improvement in renal function after switching to CNI-free everolimus treatment has the greatest potential within the first year post-HTx. While we await randomized, controlled trials, it appears that conversion can be performed with acceptable safety in selected patients.

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.

mTOR Inhibitors: Do They Help Preserve Renal Function?

BACKGROUND

Renal function deterioration is one of the main problems facing heart transplant recipients. The mammalian target of rapamycin (mTOR) inhibitors, in combination with or replacing calcineurin inhibitors, may help preserve renal function. The aim of this study was to evaluate the progression of renal function after switching the immunosuppressive regimen.

PATIENTS AND METHODS

We studied 23 heart transplant recipients (5.5 +/- 4.5 years since transplantation). An mTOR inhibitor was introduced to replace cyclosporine (everolimus, 65%; sirolimus, 35%). Patient clinical characteristics and renal function were studied after switching. The statistical analysis used Student t test for paired data.

RESULTS

The reason for the transplantation was ischemic cardiopathy (52%), dilated myocardiopathy (39%), or other causes (9%). Mean age at time of transplantation was 52 +/- 9 years. Comorbidities were as follows hypertension (43%), insulin-dependent diabetes (22%), hypercholesterolemia (39%), and ex-smokers (70%). The reason for the switch was increased creatinine (65%), appearance of tumors (26%), or others (8%). Previous creatinine level was 1.89 +/- 0.6 mg/dL with clearance of 61.7 +/- 23 mL/min and at the end of follow-up (mean follow-up, 11 +/- 6 months) creatinine level was 2.0 +/- 1.45 mg/dL with clearance of 68.3 +/- 35 mL/min, namely, no significant difference (P = .49 and P = .57, respectively). In the subgroup of patients who switched treatment due to renal dysfunction, initial creatinine level was 2.38 +/- 0.4 mg/dL with clearance of 42.3 +/- 10 mL/min and at the end of follow-up it was 2.28 +/- 0.2 mg/dL and 43.6 +/- 11 mL/min, respectively (P = .68 for creatinine and clearance).

CONCLUSIONS

The introduction of mTOR inhibitors to the immunosuppressant regimen may be useful to delay renal functional deterioration caused by calcineurin inhibitors.

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.