Prospective randomised study comparing tacrolimus (Prograf) and cyclosporin (Neoral) as primary immunosuppression in cadaveric renal transplants at a single institution: interim report of the first 80 cases

Maintenance immunosuppression in renal transplantation

The need to maintain allograft recipients on immunosuppression is nearly universal. Immunosuppressive agents used in organ transplantation target one or more steps of the host alloimmune response, specifically processes related to CD4-positive T lymphocytes. Calcineurin-inhibitor based steroid-containing regimens have been the mainstay of maintenance immunosuppression over the last two decades. Newer agents have shown efficacy in this role in recent trials with comparable allograft and patient outcomes. These agents have permitted calcineurin-inhibitor minimization and steroid-sparing strategies in selected groups of patients.

Therapeutic monitoring of calcineurin inhibitors for the nephrologist

The calcineurin inhibitors (CNI) cyclosporine and tacrolimus remain the backbone of immunosuppression for most kidney transplant recipients. Despite many years of experience, protocols that optimize efficacy with minimal toxicity remain a subject of debate. Nevertheless, studies of the pharmacokinetic properties of the CNI, particularly cyclosporine, have led to improved dosing strategies. The purpose of this article is to review the current understanding of CNI pharmacokinetics and its relevance to proper dosing and monitoring of these medications. This article also reviews the trials that have helped to define the optimal dosages and discusses the effect of adjunctive immunosuppressive agents on CNI pharmacokinetics and dosing.

Tacrolimus versus ciclosporin as primary immunosuppression for kidney transplant recipients: meta-analysis and meta-regression of randomised trial data

OBJECTIVE

To compare the positive and negative effects of tacrolimus and ciclosporin as initial treatment for renal transplant recipients.

DESIGN

Systematic review.

DATA SOURCES AND STUDY SELECTION

Reports of comparative randomised trials of tacrolimus and ciclosporin identified by searches of Medline, Embase, the Cochrane Register of Controlled Trials, the Cochrane Renal Group Specialist Register, and conference proceedings.

DATA EXTRACTION AND SYNTHESIS

Two reviewers assessed trials for eligibility and quality and extracted data independently. Data were synthesised (random effects model) and results expressed as relative risk (RR), with values < 1 favouring tacrolimus. Subgroup analysis and meta-regression were used to examine potential effect modification by differences in trial design and immunosuppressive co-interventions.

RESULTS

123 reports from 30 trials (4102 patients) were included. At six months, graft loss was significantly reduced in tacrolimus treated recipients (RR = 0.56, 95% confidence interval 0.36 to 0.86), and this effect persisted up to three years. The relative reduction in graft loss with tacrolimus diminished with higher concentrations of tacrolimus (P = 0.04) but did not vary with ciclosporin formulation (P = 0.97) or ciclosporin concentration (P = 0.38). At one year, tacrolimus treated patients had less acute rejection (RR = 0.69, 0.60 to 0.79) and less steroid resistant rejection (RR = 0.49, 0.37 to 0.64) but more diabetes mellitus requiring insulin (RR = 1.86, 1.11 to 3.09), tremor, headache, diarrhoea, dyspepsia, and vomiting. The relative excess of diabetes increased with higher concentrations of tacrolimus (P = 0.003). Ciclosporin treated recipients had significantly more constipation and cosmetic side effects. No differences were seen in infection or malignancy.

CONCLUSIONS

Treating 100 recipients with tacrolimus instead of ciclosporin for the first year after transplantation avoids 12 patients having acute rejection and two losing their graft but causes an extra five patients to develop insulin dependent diabetes. Optimal drug choice may vary between patients.

New onset diabetes mellitus in patients receiving calcineurin inhibitors: a systematic review and meta-analysis

New onset diabetes mellitus (NODM) is a serious complication of transplantation. This meta-analysis evaluates the reported incidence of NODM after solid organ transplantation in patients receiving CNI treatment. Databases from January 1992 to April 2002 were searched. Fifty-six publications providing NODM incidence data were reviewed. Sixteen prospective, randomized comparative studies providing information on incidence of insulin-dependent diabetes mellitus (IDDM) were subjected to meta-analysis. New onset diabetes mellitus was reported in 13.4% of patients after solid organ transplantation, with a higher incidence in patients receiving tacrolimus than cyclosporine (16.6% vs. 9.8%). This trend was observed across renal, liver, heart and lung transplant groups. Meta-analysis of 16 studies included patients receiving either tacrolimus (n=1636) or cyclosporine (n=1407). The incidence of IDDM was significantly higher among tacrolimus-treated patients (10.4% vs. 4.5%, p<0.00001), an effect observed in renal (9.8% vs. 2.7% p<0.00001) and nonrenal (11.1% vs. 6.2%; p<0.003) groups, and among patients receiving equal doses of concomitant medication in both treatment arms (12.0% vs. 3.0%; p<0.00001). The reported incidence of NODM during the past decade was significantly higher among patients receiving tacrolimus than cyclosporine. These data provide a quantitative foundation for studies designed to reduce the rates of NODM following solid organ transplantation.

Risks of allogeneic hand transplantation

A patient undergoing allogeneic hand transplantation needs lifelong immunosuppression with the risk of serious side effects, including life-threatening disease. The question remains: does the eventual improvement in function justify the risk? To answer this question, we try to assess the risks based on a large body of cumulative data derived from more 200,000 kidney transplants using the Collaborative Transplantation Study (CTS). Only selective data which apply to a patient population aged between 15-40 years were used (n = 58,310). Data are compared to the literature references and show superiority with respect to patient numbers, statistics, actuality, and methodology. The CTS data show that the incidence of de novo malignancies is lower than previously reported. The risk of developing any form of cancer is approximately 3%, of developing a skin cancer 1.1%, and of developing a lymphoma 0.58% within 5 years after transplantation. The risk of suffering from a cataract is 11% after 5 years, which is also lower than previously reported. Although the incidence of side effects (particularly malignant disease) is likely to be lower than previously thought, the risk-benefit question must be answered by each hand surgeon for each individual patient.

Cyclosporin: an updated review of the pharmacokinetic properties, clinical efficacy and tolerability of a microemulsion-based formulation (neoral)1 in organ transplantation

Cyclosporin is a lipophilic cyclic polypeptide immunosuppressant that interferes with the activity of T cells chiefly via calcineurin inhibition. The original oil-based oral formulation of this drug (Sandimmun)l was characterised by high intra- and interpatient pharmacokinetic variability, with poor bioavailability in many patients; a novel microemulsion formulation (Neoral)1 was therefore developed to circumvent these problems. Studies show increases, attributable chiefly to improved absorption in patients who absorb the drug only poorly from the original formulation, in mean systemic exposure to cyclosporin with the microemulsion, with no clinically significant differences in tolerability or drug interaction profiles. Cyclosporin microemulsion is at least as effective as the oil-based formulation in renal, liver and heart transplant recipients, with trends towards decreased incidence of acute rejection with the microemulsion formulation in some (statistically significant in a few) trials. Cyclosporin microemulsion and tacrolimus appear to have similar efficacy in preventing acute rejection episodes in most renal, pancreas-kidney, liver and heart transplant recipients. However, there are indications of superior efficacy for tacrolimus in some trials, particularly in the prevention of severe acute rejection and in Black transplant recipients. Current 12-month data also indicate equivalent efficacy of sirolimus in renal transplantation. Conversion from the oil-based to microemulsion formulation in stable renal, liver and heart transplant recipients is achievable with no change in acute rejection rates. The addition of an anti-interleukin-2 receptor monoclonal antibody and/or mycophenolate mofetil to cyclosporin microemulsion plus corticosteroids decreases rates of acute rejection; corticosteroid withdrawal without increased acute rejection rates was also achieved on the addition of these agents in some trials. Pharmacoeconomic analyses have shown savings in direct healthcare costs in kidney or liver transplantation when cyclosporin microemulsion is used in preference to the oil-based formulation, although studies incorporating indirect costs or expressing costs in terms of therapeutic outcomes are currently unavailable.

CONCLUSIONS

The introduction of cyclosporin microemulsion has consolidated the place of the drug as a mainstay of therapy in all types of solid organ transplantation; research into optimisation of outcomes through more effective therapeutic monitoring in patients receiving this formulation is ongoing. Several novel immunosuppressants have been introduced in recent years: further clinical and pharmacoeconomic research will be needed to clarify the relative positioning of these agents, particularly with respect to specific patient groups. Other new drugs (basiliximab/daclizumab and mycophenolate mofetil) offer particular advantages when used in combination with cyclosporin.

Cyclosporine microemulsion and tacrolimus are associated with decreased chronic allograft failure and improved long-term graft survival as compared with sandimmune

Tacrolimus and cyclosporine in the microemulsion formulation Neoral have demonstrated improvements in acute rejection rates after renal transplantation compared with conventional cyclosporine formulation, Sandimmune. To evaluate whether these drugs are also associated with improvements in chronic allograft failure (CAF) rates, we retrospectively analyzed 32,040 primary renal allograft recipients reported to the United States Renal Data System (USRDS) between 1994 and 1997. Graft loss secondary to CAF was defined as graft loss beyond 6 months post-transplant, censored for death, acute rejection, thrombosis, infections and noncompliance. A Cox proportional hazard model was used to investigate the relationship between graft loss secondary to CAF and the use of conventional cyclosporine formulation, as opposed to cyclosporine microemulsion and tacrolimus (Prograf). The analysis was corrected for confounding variables, such as acute rejection, sex, race, human leukocyte antigen (HLA) mismatch, % panel reactive antibodies (PRA), delayed graft function (DGF), cold ischemia time, induction therapy, dialysis time, etiology of end-stage renal disease, cytomegalovirus (CMV) risk group, donor source, era effect, and mycophenolate mofetil (MMF) use. Cyclosporine microemulsion use was associated with a significantly lower relative risk (RR = 0.6, Cl = 0.5-0.7) for CAF as opposed to conventional cyclosporine formulation. Likewise tacrolimus as compared with conventional cyclosporine formulation was associated with a significantly lower relative risk (RR = 0.7, CI = 0.6-0.8) for CAF. Conventional cyclosporine formulation treatment was associated with a 87.6% adjusted CAF-free survival rate at 4 years. Both tacrolimus and cyclosporine microemulsion were associated with a significantly better adjusted CAF-free survival at 4years (91.4 and 92.4%, respectively). Both cyclosporine microemulsion and tacrolimus are associated with improved graft survival and a decreased relative risk for CAF when compared with the older conventional cyclosporine formulation. This association is independent of the use of MMF or changes in era.