Comparison of conventional oral cyclosporine and cyclosporine microemulsion formulations in children with a liver transplant

C2 blood concentrations of orally administered cyclosporine in pediatric liver graft recipients with a body weight below 10 kg

Pharmacokinetic studies in adult and pediatric liver transplant recipients have shown that the C(2) monitoring is superior to the traditional determination of CsA trough levels (C(0)) as an estimate of CsA exposure. However, target reference values for C(2) in very small infants have not been established yet. The objective of our study was to assess the distribution of C(2) levels in the first week following Ltx and to analyze enteral absorption of CsA for this group of patients. We documented CsA C(0) and C(2) levels in 25 infants with a body weight below 10 kg (median 6.8 kg; range 3.0-9.8 kg) in the first 7 days after Ltx. The infants had a median age at transplantation of 7 months (range 0.3-20.0 months). The underlying diagnoses were biliary atresia (n = 17), acute liver failure (n = 4), metabolic disease (n = 4). All children received CsA microemulsion (Neoral, initial 10 mg/kg/day), prednisolone, and two single doses of basiliximab as immunosuppressive drugs. The mean C(0) and C(2) levels were as follows: day 1: C(0) 77.0 +/- 39.6, C(2) 340.5 +/- 140.0 ng/mL; day 2: C(0) 135.5 +/- 53.2, C(2) 467.0 +/- 168.2 ng/mL; day 3: C(0) 146.5 +/- 70.8, C(2) 519.0 +/- 219.1 ng/mL; day 4: C(0) 168.5 +/- 55.1, C(2) 570.0 +/- 163.7 ng/mL; day 5: C(0) 156.5 +/- 38.0, C(2) 612.0 +/- 132.4 ng/mL; day 6: C(0) 177.0 +/- 41.1, C(2) 606.0 +/- 149.2 ng/mL; day 7: C(0) 174.0 +/- 27.2, C(2) 622.0 +/- 98.8 ng/mL (r = 0.82, p < 0.05). This analysis demonstrates that there is a good enteral absorption of CsA in very small children post-Ltx in the early post-operative period. Based on the C(2) levels achieved, we conclude that there is a good correlation between C(0) and C(2) levels even in very small infants.

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.

Two-hour cyclosporine concentration determination: an appropriate tool to monitor neoral therapy?

Cyclosporine is a critical dose drug for which individualisation by therapeutic drug monitoring is indisputable. Current evidence suggests that a single concentration (C2) taken two hours after cyclosporine administration with the microemulsion formulation better predicts exposure and events than the trough concentration (C(0)), which is routinely used for adjusting the dosage of this drug. Studies have shown that the greatest calcineurin inhibition and the maximum inhibition of IL-2 production occur in the first 1 to 2 hours after dosing. These findings support the concept that the C2 level better reflects immunosuppressive efficacy than the trough concentration. Preliminary data from an outcome study in liver transplant recipients have shown that the incidence of biopsy proven moderate to severe acute rejection was significantly lower in patients managed by C2 monitoring compared with those monitored by C(0). The critical importance of achieving adequate cyclosporine exposure during the first 3 to 5 posttransplant days to prevent acute rejection has been documented in prospective studies with de novo renal and liver transplant recipients. Conversion of maintenance liver and heart transplant patients to C2 monitoring resulted in an amelioration of renal function. Time-dependent target values have been proposed for liver and renal transplant recipients. These require further prospective validation. For routine monitoring of C2 levels on-site validated dilution guidelines are necessary for most of the available immunoassays. C2 monitoring necessitates further organizational requirements which may be judged differently between transplant centers. In particular during the early posttransplant period C2 monitoring is a promising new option to make immunosuppressive therapy with the microemulsion formulation of cyclosporine safer and more efficient.

Liver transplantation. The pediatric challenge

Successful liver transplantation in a child is often a hard-won victory, requiring all the combined expertise of a dedicated pediatric transplant team. This article outlines the considerable challenges still facing pediatric liver transplant physicians and surgeons. In looking to the future, where should priorities lie to enhance the success already achieved? First, solutions to the donor shortage must be sought aggressively by increasing the use of from split-liver transplants, judicious application of living-donor programs, and increasing the donation rate, perhaps by innovative means. The major immunologic barriers, to successful xenotransplantation make it unlikely that this option will be tenable in the near future. Second, current immunosuppression is nonspecific, toxic, and unable to be individually adjusted to the patient's immune response. The goal of achieving donor-specific tolerance will require new consideration of induction protocols. Developing a clinically applicable method to measure the recipient's immunoreactivity is of paramount importance, for future studies of new immunosuppressive strategies and to address the immediate concern of long-term over-immunosuppression. The inclusion of pediatric patients in new protocols will require the ongoing insistence of pediatric transplant investigators. Third, the current immunosuppressive drugs have a long-term morbidity and mortality of their own. These long-term effects are particularly important in children who may well have decades of exposure to these therapies. There is now some understanding of their long-term renal toxicity and the risk of malignancy. New drugs may obviate renal toxicity, whereas the risk of malignancy is inherent in any nonspecific immunosuppressive regimen. Although progress is being made in preventing and recognizing PTLD, this entity remains an important ongoing concern. The global effect of long-term immunosuppression on the child's growth, development, and intellectual potential is unknown. Of particular concern is the potential for neurotoxicity from the calcineurin inhibitors. Fourth, recurrent disease and new diseases, perhaps potentiated by immunosuppressive drugs, must be considered. Already the recurrence of autoimmune disease and cryptogenic cirrhosis have been documented in pediatric patients. Now, a new lesion, a nonspecific hepatitis, sometimes with positive autoimmune markers, that may progress to cirrhosis has been recognized. It is not known whether this entity is an unusual form of rejection, an unrecognized viral infection, or a response to immunosuppressive drugs themselves. Finally, pediatric transplant recipients, like any other children, must be protected and nourished physically and mentally if they are to fulfill their potential. After liver transplantation the child's growth, intellectual functioning, and psychologic adaptation may all require special attention from parents, teachers, and physicians alike. There is limited understanding of how the enormous physical intervention of a liver transplantation affects a child's cognitive and psychologic function as the child progresses through life. The persons caring for these children have the difficult responsibility of providing services to evaluate these essential measures of children's health over the long term and to intervene if necessary. Part of the transplant physician's our duty to protect and advocate for children is to fight for equal access to health care. In most of the developing world, economic pressures make it impossible to consider liver transplantation a health care priority. In the United States and in other countries with the medical infrastructure to support liver transplantation, however, health care professionals must strive to be sure that the policies governing candidacy for transplantation and allocation of organs are applied justly and uniformly to all children whose lives are threatened by liver disease. In the current regulatory climate that increasingly takes medical decisions out of the hands of physicians, pediatricians must be even more prepared to protect the unique and often complicated needs of children both before and after transplantation. Only in this way can the challenges of the present and the future be met.

Neoral use in the pediatric transplant recipient

This review and critical analysis of current trends of immunosuppression management in pediatric transplantation provides evidence and support for the continued role of Neoral as an indispensable part of immunosuppressive protocols. CyA formulation influences clinical outcomes such as acute rejection, as confirmed by two studies. The CyA microemulsion formulation provides more reliable and effective absorption. An advanced TDM strategy to determine CyA bioavailability can improve the effectiveness and safety of immunosuppression in de novo liver transplant patients. especially in the younger de novo patient. Neoral is an indispensable part of combination protocols in pediatric transplantation.

The evaluation of the safety and tolerability of two formulations of cyclosporine: neoral and sandimmune. A meta-analysis

BACKGROUND

Neoral, a microemulsion formulation of cyclosporine, was approved for use in the United States in 1995. Many studies comparing Neoral and Sandimmune have been conducted, and although most state that Neoral is the superior cyclosporine formulation, results have failed to conclusively demonstrate this claim. The aim of this meta-analysis was to compare the safety and efficacy of Neoral and Sandimmune.

METHODS

Publications comparing the use of Neoral and Sandimmune were reviewed for demographic variables, adverse events, rejection incidence, graft losses, and serum creatinine. Neoral and Sandimmune were compared in all patients and in the following subgroups: (1) age (adult or pediatric), (2) transplant type (kidney, liver, or heart), (3) indication (de novo or stable), and (4) study design (randomized prospective trials versus nonrandomized, blinded versus open-labeled studies).

RESULTS

The rate of graft loss was similar when comparing Neoral and Sandimmune in all analyses. The incidence of rejection was lower in Neoral-treated de novo renal, liver, and cardiac transplants (P<0.05). There were significantly more adverse events in Sandimmune-treated de novo liver transplants than Neoral-treated de novo liver transplants (P<0.00001). When considering only randomized prospective trials, the incidence of rejection was lower in Neoral-treated de novo and stable patients (P<0.05). However, there were more adverse events in Neoral-treated stable patients (P<0.00001). When considering only blinded studies, there were more adverse events in Neoral-treated patients (P<0.05), whereas in open-labeled studies there was no difference in adverse events comparing Neoral and Sandimmune (P=NS).

CONCLUSIONS

Considering all published trials, the data seem to indicate that Neoral therapy is preferred because of a lower rejection incidence, with a trend toward less adverse events. However, when limiting the analysis to only randomized prospective trials, and specifically assessing blinded studies, the data become less clear. Neoral use was associated with more adverse events in blinded studies, and Sandimmune use was associated with more adverse events in open-labeled studies. Careful individual consideration must be given in choosing the best possible cyclosporine formulation.

Improving the therapeutic monitoring of cyclosporin A

The narrow therapeutic window of cyclosporin A (CsA) and the variable pharmacokinetics of the traditional preparation, CsA-SIM (Sandimmune), have made it difficult to establish its optimal use. The introduction of a microemulsion preparation, CsA-ME (Neoral), with less variable pharmacokinetics, has made it possible to attempt to define its use more closely. One hundred and one renal allograft recipients were converted from CsA-SIM to CsA-ME. Absorption was monitored using a standard pharmacokinetic 'profile' measuring 'whole blood' CsA levels at several time points following drug administration. Areas under the resulting time-versus-CsA concentration curve (AUC) were calculated. Surprisingly, many patients showed very little fluctuation in 'whole blood' levels after administration of the conventional preparation: 31% had a difference between trough (to) and maximal levels of < 100 micrograms/L. On microemulsion cyclosporin, there was much better correlation between AUC and several parameters incorporating elements of trough and peak values. The best correlation was with t0 + (t1/4), where t1 represents the concentration at 1 h following administration, (r2 = 0.779 for microemulsion cyclosporin). The use of this parameter is a practical possibility in an out-patient setting. The very common, but under-recognised, pattern of almost flat absorption profiles in patients on conventional CsA suggests that the use of CsA in numerous clinical contexts should be reviewed, since CsA immunosuppression may previously have been inadequately monitored.

Mycophenolate mofetil, microemulsion cyclosporine, and prednisone as primary immunosuppression for pediatric liver transplant recipients

Triple immunosuppressive therapy using mycophenolate mofetil (MMF), microemulsion cyclosporine (me-CsA), and prednisone offers the potential for potent immunosuppression without intravenous drug therapy or anti-T-cell antibody induction therapy. This report describes the application of an immunosuppressive protocol (CNp) using MMF, me-CsA, and prednisone as primary immunosuppression for pediatric liver transplant recipients at the University of California at San Francisco. From August 1995 through December 1996, 26 children (17 boys, 9 girls) aged 1 month to 16 years (mean +/- standard deviation, 58 +/- 62 months; median, 31 months) underwent liver transplantation at our institution, receiving CNp as primary immunosuppression. Posttransplantation renal function, incidence of leukopenia, and drug tolerance within the group receiving CNp as primary immunosuppression were compared with those of 19 children who received primary immunosuppression consisting of azathioprine, oil-based gel-encapsulated cyclosporine, and prednisone with anti-T-cell antibody induction therapy at the same institution from October 1993 through July 1995. No significant difference was observed between immunosuppressive protocols in serum creatinine level or incidence of leukopenia requiring medical therapy during the first year posttransplantation. Whereas gastrointestinal symptoms were observed in approximately 30% of CNp recipients during initial immunotherapy, tolerance of CNp primary immunotherapy was routinely achieved by the dose reduction of MMF. At 1 year posttransplantation, 20 children (77%) remained on CNp primary immunotherapy, 5 children (19%) were receiving tacrolimus-based immunotherapy secondary to rejection, and 1 patient (4%) converted to tacrolimus-based immunotherapy secondary to persistent gastrointestinal intolerance. In conclusion, CNp provides an alternative immunosuppressive protocol that eliminates the necessity of intravenous and induction immunosuppressive therapy with no increased incidence of posttransplantation renal dysfunction or leukopenia and is well tolerated in children.

Drug delivery systems for cyclosporine: achievements and complications

The review deals with the preparation, properties, and analysis of different kinds of cyclosporine delivery systems, such as solid formulations, liposomes, emulsions and microemulsions and targeted cyclosporine formulations. The review points out a key role of delivery systems in increasing the therapeutic effectiveness of cyclosporine. Comparative studies of the prior marketed formulation, Sandimmune, with a new microemulsion formulation, Neoral, are discussed including some data on clinical development of Neoral.

Neoral compared to Sandimmune is associated with a decrease in histologic severity of rejection in patients undergoing primary liver transplantation

BACKGROUND

In a randomized, controlled study we investigated the clinical efficacy of the microemulsion formulation of cyclosporine (Neoral) in comparison with Sandimmune (SIM) in the treatment of patients who underwent primary orthotopic liver transplantation (OLT).

METHODS

In total, 33 patients were randomized in a double-blind fashion before undergoing primary OLT to receive either Neoral or SIM. All 33 patients initially received intravenous cyclosporine, but as soon as it was tolerated, the oral study drug was initiated (median time, 3.6 days) and 17 patients received Neoral and 16 SIM (for both drugs, 10 mg/kg/day). Both groups were comparable with regard to age, sex, etiology of chronic liver disease, and hepatic biochemical profile. Episodes of rejection were diagnosed histologically and characterized as mild, moderate, or severe using criteria from the National Institute of Diabetes and Digestive and Kidney Diseases.

RESULTS

Patients were followed for 1 year. Four patients in each group were discontinued prematurely. The reason for discontinuation of cyclosporine was drug-related complications in two of the NEO patients and in three of the SIM group; the other three were non-drug-related. Rejection episodes occurred in 9 of 17 patients (52.90%) in the Neoral group and in 9 of 16 patients (56.3%) in the SIM group. The total number of rejection episodes in each group was 14. However, in evaluating the severity of rejection histologically, nine episodes of rejection were characterized as moderate/ severe in the SIM group compared with only three in the Neoral group (P=0.027). Five of the nine moderate/severe rejection episodes in the SIM group occurred within the first 2 weeks after transplant. In contrast, moderate/severe rejection did not occur in the Neoral group in this early period. Two patients in the SIM group and no patients in the Neoral group required treatment with OKT3 for steroid-resistant rejection. There were no differences in mean doses or trough levels when comparing the two study groups. The incidence of adverse effects was similar in the two groups.

CONCLUSIONS

Neoral is a safe and efficacious drug in the treatment of primary OLT patients. Given comparable doses of cyclosporine in each group over 1 year, there was no significant difference in the total number of rejection episodes between study groups. However, patients treated with Neoral had a lower incidence of moderate/severe histologic rejection and were free of steroid-resistant rejection when compared with SIM-treated patients.

Kidney function after 1:1 conversion to the cyclosporine microemulsion formulation in children with liver allografts

BACKGROUND

One-to-one (mg:mg) conversion from the conventional to the microemulsion formulation of cyclosporine (CsA) is advocated as a simple way to use the new therapeutic regimen. However, the potentially harmful effects of the conversion on kidney function in nonrenal transplant recipients are poorly known.

METHODS

Renal effects of the conversion were prospectively investigated in 22 pediatric liver transplant recipients (mean age, 8.4 years; mean time from transplantation, 3.2 years). Patients were followed for 12 months. Pharmacokinetic studies were performed at baseline and 5 days and 6 and 12 months after conversion.

RESULTS

Peak concentration, minimum concentration, average steady state concentration, and area under the concentration-versus-time curve increased by 60-130% after conversion. Graft losses, progressive deterioration of graft function, and acute rejection episodes did not occur. The mean glomerular filtration rate (GFR) was 103 ml/min/1.73 m2 at baseline and 100 ml/min/1.73 m2 after 12 months. However, 6 of the 22 patients showed at least a 15% (range, 16-38%) decrease in GFR between baseline and 6 months (P<0.01). They had a significantly higher increase in average steady state concentration between baseline and 6 months than the six patients with the best outcome in GFR during the same time period (164 ng/ml vs. 53 ng/ml, P<0.05). At this point (6 months), target CsA trough levels were reduced by 20-30%, while the mean area under the concentration-versus-time curve remained above that obtained at baseline. The GFR of three of the six patients subsequently improved.

CONCLUSIONS

One-to-one conversion can be performed safely in liver transplant recipients if strict follow-up is feasible.

Cyclosporin pharmacokinetics in paediatric transplant recipients

Cyclosporin is an essential component of the antirejection drug protocol used in the long term management of paediatric organ transplant recipients. This article looks at the pharmacokinetics of cyclosporin in paediatric kidney, heart, liver and bone marrow transplant recipients and critically evaluates its relationship to pharmacokinetic data in adult transplant recipients. There are limited data on the pharmacokinetics of cyclosporin in paediatric transplant recipients (14 publications provide the database) as compared with the adult transplant population. Study design, analytical methodology and age ranges of the individuals differ between studies, making comparative interpretation of pharmacokinetic data difficult. However, significant trends are noteworthy and these may influence dose administration guidelines and therapeutic monitoring standards for cyclosporin in the paediatric organ transplant recipient. The bioavailability of the oral formulations of cyclosporin is highly variable as with the adult population, but there appears to be a correlation between cyclosporin bioavailability and age with both the traditional oral formulation (Sandimmun) and the new microemulsion formulation (Neoral) in young liver transplant patients. Bowel length, presystemic metabolism in the gut wall, type of transplant and time since transplant are contributing factors in the variation of bioavailability patterns in paediatric transplant patients. The volume of distribution of cyclosporin does not appear to differ between paediatric and adult transplant recipients, but systemic clearance is comparatively higher in the paediatric population. In general, paediatric patients require higher doses of cyclosporin to achieve target blood concentrations of the drug which are equivalent to the values used in the adult population. Younger patients (less than 8 years of age) may be managed more effectively with a 3 times daily administration schedule rather than the twice daily schedule which is universally used for cyclosporin in the transplant population. The comparatively higher doses and more frequent administration schedule used in paediatric transplant recipients are the consequence of age-related differences in bioavailability and the possibility of increased metabolic clearance of the drug in younger patients.