Practical aspects in the use of cyclosporin in paediatric nephrology

Pathogenesis and Management of Acute Kidney Injury in Patients with Nephrotic Syndrome Due to Primary Glomerulopathies

Acute kidney injury in the context of nephrotic syndrome is a serious and alarming clinical problem. Largely, acute kidney injury is a relatively frequent complication among patients with comorbidities while it has been independently associated with an increased risk of adverse outcomes, including death and chronic kidney disease. Nephrotic syndrome, without hematuria or with minimal hematuria, includes a list of certain glomerulopathies; minimal change disease, focal segmental glomerulosclerosis and membranous nephropathy. In the light of primary nephrotic syndrome, pathophysiology of acute kidney injury is differentiated by the nature of the primary disease and the severity of the nephrotic state. This review aims to explore the clinical circumstances and pathogenetic mechanisms of acute kidney injury in patients with nephrotic syndrome due to primary glomerulopathies, focusing on newer perceptions regarding the pathogenesis and management of this complicated condition, for the prompt recognition and timely initiation of appropriate treatment in order to restore renal function to its baseline level. Prompt recognition of the precise cause of acute kidney injury is crucial for renal recovery. Clinical characteristics, laboratory and serological findings along with histopathological findings, if required, will reveal the implicated pathway leading to individualized approach and management.

Cyclosporine A vs. methylprednisolone for Henoch-Schönlein nephritis: a randomized trial

Knowledge about how to treat severe Henoch-Schönlein nephritis (HSN) is scarce. The aim of our study is to compare cyclosporine A (CyA) and methylprednisolone pulses (MP) in the treatment of severe HSN. Out of 24 pediatric HSN patients with nephrotic-range proteinuria or crescentic HSN in kidney biopsy, seven were randomized to receive CyA for 12 months at an initial dose of 5 mg/kg and eight to receive 3 MP pulses of 30 mg/kg followed by prednisone for 4 months. The other nine patients received identical treatment without randomization. Kidney biopsies were performed at inclusion and after 2 years. The primary outcomes were the duration of proteinuria and hematuria, estimated glomerular filtration rate, and renal biopsy histology. All the 11 CyA-treated patients achieved resolution of nephrotic-range proteinuria within 3 months, while the MP-group response was slower, and in 6/13 was not achieved with the initial treatment. Additional immunosuppressive treatment was needed in none of the CyA-treated patients but in six patients treated with MP (difference in proportion 46%, p = 0.008). The 2-year control biopsies were similarly improved in both groups. After mean 6.1 years (2.2-10.4 years), 16 patients (eight CyA, eight MP) had no renal symptoms and six (three CyA, three MP) had persistent nephropathy but normal renal function. One MP-treated patient had reduced renal function and another had developed ESRD and received a renal transplant. CyA gave a 100% resolution of nephrotic-range proteinuria and a 100% renal survival rate without additional therapy after a mean follow-up of 6 years. Treatment of HSN with CyA is efficacious, safe and not inferior to MP.

[Immunosuppressive treatment]

Immunosuppressive treatment following renal transplantation includes induction therapy during the initial period when the risk of rejection is higher. Depleting anti-lymphocyte antibodies are indicated mostly in patients who developped anti-HLA antibodies and following a second graft. Anti-IL2 receptor antibodies may be used in non-responders. After the first month, maintenance therapy mostly consists in the association of several immunosuppressants, mainly corticosteroids, an antimetabolic agent (azathioprine or mycophenolate mofetil) and a calcineurin inhibitor (cyclosporine or tacrolimus). Side effects associated with these treatments led to the development of new immunosuppressive protocols, with the reduction or withdrawal of corticosteroids treatment due to its deleterious effects on statural growth, and decreased doses of anti-calcineurin agents to reduce their nephrotoxic effect. These therapeutic options are possible in patients at low immunological risk.

Cyclosporine-A-induced nephrotoxicity in children with minimal-change nephrotic syndrome: long-term treatment up to 10 years

The impact of cyclosporine A (CsA) therapy in patients with steroid-dependent nephrotic-syndrome (SDNS) on long-term renal function is controversial. Data beyond 5 years are rare. Long-term renal function was evaluated in children with SDNS with and without CsA therapy, especially beyond 5 years. Twenty children were treated with CsA (study group) for a mean of 5.4 +/- 2.2 years (ten patients for 5-11 years). Glomerular filtration rate (GFR) was calculated before and after 3 and 12 months and at latest follow-up of therapy. Fifteen children with cyclophosphamide-treated SDNS without CsA served as controls. In the study group, GFR decreased within 12 months from 136 +/- 19 to 120 +/- 31, to 114 +/- 14 ml/min per 1.73 m(2) at latest follow-up (p < 0.0001). Patients with CsA > 5 years had a GFR of 111 +/- 14 ml/min per 1.73 m(2) at latest follow-up without a GFR below 90 ml/min per 1.73 m(2). No CsA toxicity was found in biopsies. In the control group, GFR dropped within 3 months, from 137 +/- 27 to 130 +/- 24, to 126 +/- 19 ml/min per 1.73 m(2) at latest follow-up (p = 0.1). Patients with and without nephrotoxic CsA therapy showed a drop in GFR. In CsA-treated patients, GFR was about 12% lower at latest follow-up compared with patients without nephrotoxic therapy but always remained within normal range. CsA seems to be safe, even in long-term treatment for more than 5 years.

Initial treatment of idiopathic nephrotic syndrome in children: prednisone versus prednisone plus cyclosporine A: a prospective, randomized trial

Previous studies of the Arbeitsgemeinschaft für Pädiatrische Nephrologie in children with steroid-sensitive nephrotic syndrome have shown that the length of initial prednisone therapy has an impact on the subsequent relapse rate. The aim of this randomized, prospective, multicenter study was to reduce the number of relapses further by increasing the initial immunosuppression: Patients with an initial attack of nephrotic syndrome were randomly allocated to treatment with 6 wk of 60 mg/m(2) per d prednisone followed by 6 wk of 40 mg/m(2) per 48 h (Pred group) or to the same prednisone treatment plus 8 wk of cyclosporine (Pred+CsA group). The primary end point was first relapse; follow-up was truncated at 2 yr. In the Pred+CsA group (n = 49 patients), the first relapse occurred later compared with the Pred group (n = 55 patients) (median 22.8 versus 12.5 mo). After 6 mo, 10.4% of patients in the Pred+CsA group experienced a first relapse versus 31.5% in the Pred group (P = 0.01); after 1 yr, 36.5 versus 51% (P = 0.15); and after 2 yr, 51 versus 50%. The mean relapse rate per patient was 0.12 versus 0.57 after 6 mo (P = 0.01), 0.63 versus 1.03 after 1 yr (P = 0.02), and 1.03 versus 2.06 after 2 yr (not significant). The significant benefit for adding CsA was lost after 9 to 12 mo. GFR remained unchanged. The subsequent treatment rate with cyclophosphamide was lower in the CsA group (five versus 12 patients) after 2 yr. With the use of logistic regression statistics, children who were younger than 7 yr show a significantly better sustained remission rate with initial CsA treatment for the 2-yr observation time (P = 0.03). It remains questionable, however, whether the intensified initial treatment with CsA could be recommended generally.

Pharmacokinetic of cyclosporine microemulsion in pediatric kidney recipients receiving A quadruple immunosuppressive regimen: the value of C2 blood levels

BACKGROUND

The management of cyclosporine therapy in pediatric kidney-transplant recipients is largely based on single center's experience rather than on a univocal pharmacokinetic approach based on therapeutic drug monitoring. A prospective multicenter trial was designed to address the question whether C2 blood level monitoring of cyclosporine microemulsion therapy is feasible in the pediatric setting.

METHODS

Sixty-four pediatric kidney-transplant recipients receiving a triple immunosuppressive regimen based on cyclosporine microemulsion had their cyclosporine dose adjusted to the same protocol-defined C2 targets from the time of the transplant until 2 years posttransplant. The interim analyses after 1 year of enrollment is presented in this study.

RESULTS

One-year patient and graft survival were 100% and 94.8%, respectively. One-year rejection rate was 15%. C2 management of cyclosporine did not affect graft function: 1-year serum creatinine and glomerular filtration rate were 1.3+/-1 mg/mL and 71.2+/-20 mL/min/1.73 m2, respectively. C2 was the best single-point predictor of the area under the concentration curve throughout the entire follow-up, with a mean coefficient of correlation of 0.97+/-0.01.

CONCLUSIONS

C2 management of cyclosporine microemulsion therapy is effective and safe in pediatric kidney-transplant recipients given a combined immunosuppressive treatment.

Experience with therapeutic drug monitoring of cyclosporine

During the past 20 years, cyclosporine (CsA) has become the main part of immunosuppressive protocols. Its impact to improve the quality and quantity of transplantation surgery has been enormous. Immunosuppression in allograft recipients 10 years after renal transplantation CsA continued to demonstrate benefits on graft survival without evidence of long-term morbidity. The pharmacokinetic properties of CsA show wide interpatient variation. After being subject of intense investigation for more than 20 years, it only recently has the full potential of the drug been realized, primarily due to two advances: first, the development of a microemulsified formulation, (Neoral), that improves drug delivery; second, substantial improvements in CsA monitoring. Sparse-sampling algorithms were developed specifically to predict AUCs. We prospectively investigated the practicality, intrapatient variability, and impact on the outcomes of toxicity and rejection episodes using an algorithm. Rejection episodes were diminished by 43.5% in the first 3 months compared to the results in the previous 3 years. Furthermore, the relation of the trough versus C2 concentrations performed at day 3 to 5 and 10 to 12 predicted the probability of an acute rejection episode. Using a truncated AUC to identify patients at risk for rejection episodes early provides optimal and individualized immunosuppression. This pharmacokinetic rationale has now eventuated in an international consensus statement that represents a further step toward optimal immunosuppression.

The impact of cyclosporine on the development of immunosuppressive therapy—pediatric transplantation using cyclosporine

Cyclosporine A (CsA) was introduced to pediatric renal transplantation more than 20 years ago, and it has greatly improved graft survival and made transplantation the treatment of choice for children with end-stage renal failure. Exposure to CsA was shown to be highly variable among transplant recipients. Therefore, major efforts have been employed to monitor CsA blood levels. The widely used trough levels had never been formally validated, and every center had defined its own target values. With the advanced microemulsion formula of CsA, drug exposure became more predictable, but scientifically evaluated monitoring concepts are still lacking. Monitoring the absorption phase using single time points (eg, 2 hours after ingestion) is promising, as shown in adult trials. In pediatric transplant recipients, randomized clinical trials have to be implemented urgently to fully exploit the potential of CsA in the prevention of graft rejection while minimizing toxicity. Although newer immunosuppressive drugs have been developed, further studies should be undertaken to define the role of CsA in combination protocols.

Cyclosporine in pediatric kidney transplantation

Before the era of cyclosporine (CsA), immunosuppression with azathioprine and steroids resulted in high rejection rates and severe growth retardation in pediatric renal transplant recipients. In the early 1980s, immunosuppression with CsA was introduced for children. Because of differences in metabolism rates and relation of weight and body surface area, special pediatric dosing regimens and monitoring strategies had to be developed. Use of CsA led to a decreased number of acute rejections and, consequently, to a marked increase in graft survival rates. The growth rates of transplanted children were significantly higher under CsA-based immunosuppression than with classical regimens. This was due to a decreased need of steroid co-administration. Main side effects of CsA in children were nephrotoxicity and hirsutism. The introduction of CsA microemulsion in the 1990s led to more reliable absorption profiles and to a lower interindividual variability of CsA area-under-the-curve concentrations and thus to another improvement in rejection rates. New monitoring strategies, based on CsA levels taken 2 hours' postdose, seem promising. In pediatric transplantation, CsA is often successfully combined with an antibody-induction therapy in order to reduce the number of early acute rejections. Combination with mycophenolate mofetil reduces the appearance of chronic rejection. Additional therapy with ToR inhibitors might enforce a reduction of CsA doses and therefore lead to a reduction of CsA toxic effects.

Pharmacology of calcineurin antagonists

Cyclosporine and tacrolimus share the same pharmacodynamic property of activated T-cell suppression via inhibition of calcineurin. The introduction of these drugs to the immunosuppressive repertoire of transplant management has greatly improved the outcomes in organ transplantation and constitutes arguably one of the major breakthroughs in modern medicine. To this date, calcineurin inhibitors are the mainstay of prevention of allograft rejection. The experience gained from the laboratory and clinical use of cyclosporine and tacrolimus has greatly advanced our knowledge about the nature of many aspects of immune response. However, the clinical practice still struggles with the shortcomings of these drugs: the significant inter- and intraindividual variability of their pharmacokinetics, the unpredictability of their pharmacodynamic effects, as well as complexity of interactions with other agents in transplant recipients. This article briefly reviews the pharmacological aspects of calcineurin antagonists as they relate to the mode of action and pharmacokinetics as well as drug interactions and monitoring.

Outcome after renal transplantation in children: results of follow-up by nephrologists in a primary referral center

Pediatric patients who receive a kidney transplant require extended follow-up to monitor graft function and for management of complications. Because of convenience, most patients are sent back to the nephrologists who referred them for transplantation (the primary nephrologist) for long-term care. As a consequence, many pediatric nephrologists who provide this extended care are not associated with a transplant center. It is not known if this arrangement yields satisfactory outcomes for children and adolescents who receive a kidney transplant. The objective was to determine if clinical outcomes are satisfactory in pediatric renal transplant recipients who were followed up by their primary nephrologists after the procedure. A chart review was carried out on all renal transplant recipients seen in the renal clinic at Schneider Children's Hospital (SCH) from 1982 to 2001. Patients were eligible if they were followed up by the primary referring nephrologists at SCH for a minimum of 6 months after transplantation. Relevant demographic and clinical outcome data were compiled. Twenty-eight patients who received a total of 33 renal allografts [living related donors (LRD) 15 and cadaveric donors (CD) 18] were seen during the study period. The transplantations in 19 children (68%) were carried out at Montefiore Hospital (Bronx, NY, USA), while the rest were performed at other centers. There were three (11%) deaths, two LRD patients and one CD patient. The group of 25 surviving patients consisted of 17 males and eight females, age range 4-28 yr (mean 17.2 yr). The mean duration of renal allograft survival was 6.3 +/- 5.3 yr and the mean duration of follow-up was 6.1 +/- 5.3 yr. The most recent serum creatinine ranged from 0.5 to 3.8 mg/dL with a mean of 1.3 +/- 0.8 mg/dL. There were several complications including acute rejection, renal artery stenosis, and hydronephrosis in the allograft. The team of primary referring nephrologists successfully treated all of these except the child with hydronephrosis. The primary nephrologist who refers pediatric patients to a tertiary care transplant center can accomplish long-term follow-up of renal transplant recipients after discharge from the transplant center. The clinical outcomes are acceptable and compare favorably with the results described in the literature that have been achieved in patients followed up at transplant centers. Problems rarely developed that required referral back to the transplant center for management. This approach to care is recommended because it is more likely to foster compliance by both patients and parents.

Report of the American Society of Transplantation conference on immunosuppressive drugs and the use of generic immunosuppressants

Considerable economic and health-related costs are associated with the life-long maintenance immunosuppressive therapy required to prevent transplant rejection. Generic medications have the potential of providing equivalent therapeutic efficacy at a lower economic cost. In 2001, the American Society of Transplantation invited experts to review the data and issues associated with the approval and use of generic immunosuppressants. A summary of that meeting is reported here. The generic medication approval process has been in effect for more than 30 years. All marketed generic cyclosporin formulations have met FDA criteria demonstrating bioequivalence in healthy subjects, and some were also tested in transplant recipients. Most participants agreed that generic narrow therapeutic index immunosuppressive agents provide adequate de novo immunosuppression in low-risk transplant recipients. However, some participants expressed concern regarding the currently unquantified risk that may be associated with switching immunosuppressive agents under uncontrolled circumstances. There was broad agreement among the participants that generic medications should be clearly labeled and distinguishable from innovator drugs, and that patients should be educated to inform their physicians of any switch to or among generic alternatives. There was also strong support in favor of requiring studies to demonstrate bioequivalence in potentially at-risk patient populations, specifically African-Americans and pediatric patients.

Management of nephrotic syndrome in children

Idiopathic childhood nephrotic syndrome generally has a favorable long-term prognosis. Prompt administration of and improved guidelines for monitoring therapy have decreased morbidity and mortality. The treatment goal is to induce prompt remission while minimizing complications and adverse events. Aggressive therapy induces remission and decreases the frequency of relapse in most patient populations; however, such treatment often results in unnecessary toxicity. We critically assessed the current clinical evidence that supports each pharmacologic therapy. For each drug regimen, the risks and monitoring parameters required to reduce complications and optimize therapy are discussed. Some of the treatments are the common corticosteroid approaches, cytotoxic therapies (chlorambucil, cyclophosphamide), cyclosporine, less frequently used drugs (e.g., levamisole), and experimental therapies. Further studies are needed to identify the most effective and least toxic therapeutic regimens for inducing and maintaining remission in children with nephrotic syndrome.

Cyclophosphamide in steroid-sensitive nephrotic syndrome: outcome and outlook

Steroid-sensitive nephrotic syndrome often follows a relapsing course with a substantial number of patients requiring cytotoxic therapy with cyclophosphamide (CP). However, the long-term success of CP treatment is difficult to predict. We retrospectively evaluated 106 patients after CP to identify parameters associated with sustained remission. The overall rate of cumulative sustained remission was 24% after 10 years. No gender difference was found. Several factors were significantly correlated with the rate of sustained remission: age at CP therapy (remission 34% versus 9% in children older or younger than 5.5 years, P<0.01), frequently relapsing versus steroid-dependent status (54% versus 17%, P<0.05), leukopenia under CP treatment (44% in children with leukopenia versus 19% in children without leukopenia, P<0.05), and a cumulative dosage per body surface area (BSA) of more or less than 5,040 mg/m(2) (45% versus 11%, P<0.01). In contrast, the cumulative dosage per kilogram body weight had no significant influence on long-term remission (23% in children with >168 mg/kg versus 26% in children with <168 mg/kg, P>0.05). The current concept of CP treatment of steroid-sensitive nephrotic syndrome is less effective in preschool children. CP therapy should be re-evaluated on a BSA-adjusted regimen.

Current immunosuppressant regimens: considerations for critical care

While current immunosuppressive drug regimens have significantly increased the rate of successful transplantation outcomes, they convey potentially serious and overlapping adverse effects. Cyclosporine and tacrolimus are the cornerstones of current immunosuppression, achieving excellent one-year renal graft survival rates. Other promising new drugs include sirolimus, which has been demonstrated to reduce efficacy failure rates among renal transplant recipients, and everolimus, which is currently undergoing clinical trials. Agents targeting novel sites in the immune response or disrupting the ischemia-reperfusion cascades are currently under development. Among them, only FTY720 is undergoing large-scale human clinical trials. With its unique mechanism of action and synergistic interactions with cyclosporine and sirolimus, it may provide the foundation for a new era in immunosuppression.

Statement of current majority practices in graft-versus-host disease prophylaxis and treatment in children

Great variations exist in the prophylaxis and treatment of GVHD in children undergoing allogeneic stem cell transplantation (SCT). The EBMT Working Party Paediatric Diseases (EBMT-WP PD) and the International BFM Study Group--Subcommittee Bone Marrow Transplantation (IBFM-SG), aimed at evaluating current local standards in the prevention and treatment of GVHD and steps which can be taken to achieve a uniform policy for the individual methods. Several conferences with their members assessed practices which are mainly applied or under investigation in children and identified where additional information is needed. For prevention of GVHD, the majority of the paediatric centres prefer CsA +/- MTX. Addition of folinic acid to MTX was considered for reduction of side-effects. During treatment of acute GVHD most centres administer prednisolone and whole blood level-adjusted CsA as medications of first choice. In cases of poor or no response to this therapy, additional immunosuppressive agents such as ATG, mycophenolate-mofetile and tacrolimus are being increasingly used. The treatment of chronic GVHD usually consists of various combinations of prednisolone and CsA. In severe cases, extracorporeal photopheresis, psoralene-UVA (PUVA) and thalidomide are administered.

Cyclosporine therapy for severe sight-threatening uveitis in children and adolescents

OBJECTIVE

To review the safety and efficacy of cyclosporine in the treatment of children with severe bilateral sight-threatening intermediate uveitis or panuveitis.

DESIGN/PARTICIPANTS

A retrospective chart review was performed on all children younger than 18 years of age with chronic bilateral sight-threatening uveitis who were treated with cyclosporine.

MAIN OUTCOME MEASURES

Assessment of the therapeutic efficacy and development of adverse effects of cyclosporine after 6 months, 2 years, and 4 years of therapy was performed.

RESULTS

Between 1983 and 1992, 15 children and adolescents were treated with cyclosporine. After 6 months, visual acuity improved or stabilized in 82.1% of eyes, while median vitreous inflammation decreased from 2.0 to 0.5. After 2 and 4 years, visual acuity improved or stabilized in 64% and 75% of eyes, respectively. Median vitreous inflammation remained 0.5 after 2 and 4 years of therapy. Mean creatinine clearance and hemoglobin values decreased and serum creatinine increased after 6 months. After 2 years, only mean hemoglobin values remained decreased. After 4 years, no significant differences were noted in any of the laboratory studies. The most frequently noted side effects included transient increases in serum creatinine in 53%, gingival hyperplasia in 40%, and hirsutism in 20% of patients.

CONCLUSIONS

The authors' results suggest that cyclosporine is a safe and effective therapy for the treatment of children with severe bilateral sight-threatening intermediate uveitis or panuveitis.

Breast-feeding during treatment with cyclosporine

BACKGROUND

Mothers treated with cyclosporine (CsA) have previously not been allowed to breast-feed due to the reported accumulation of the drug in breast milk. The purpose of this study was to evaluate the consequences of allowing breast-feeding.

METHODS

Seven infants were breast-fed by mothers who had undergone kidney transplantation alone (n=5) or simultaneous kidney and pancreas transplants (n=2). In addition to CsA, all mothers received prednisolone at 5-7.5 mg/day and six mothers received azathioprine at 50-100 mg. CsA concentration was measured in the whole blood of mothers and babies and in breast milk. Serum creatinine was measured in babies 1 week after birth and after 4-12 months of breast-feeding.

RESULTS

Blood CsA levels ranged from 55 to 130 ng/ml in mothers (12-hr trough), 50 to 227 ng/ml in breast milk (mean for each woman), and was below the detection limit of 30 ng/ml in all infants. Breast milk concentration ranged from 87 to 440 ng/ml in 16 samples obtained at various time points from one mother. Infants' serum creatinine ranged from 25 to 54 micromol/L at 1 week after birth and 23-52 micromol/L after breast-feeding. All babies thrived.

CONCLUSIONS

Breast-fed infants of mothers treated with CsA received less than 300 microg per day of CsA and absorbed undetectable amounts. There were no demonstrable nephrotoxic effects or other side effects. Thus, women with kidney transplants could be allowed to breast-feed.

Chronic cholestatic liver disease with associated tubulointerstitial nephropathy in early childhood

We report the clinical and morphological features of an unusual hepatorenal disorder in 2 patients. The main clinical features were early onset of cholestatic liver disease and progressive tubulointerstitial nephritis, leading to renal death in early childhood. Renal histology showed interstitial fibrosis, tubular atrophy and dilatation, glomerular cysts in the cortex and periglomerular fibrosis; liver histology was characterized by portal fibrosis and bile duct abnormalities. Evaluating the 12 patients published in the literature, the long-term prognosis of the liver function appears bad, suggesting the possibility of a combined liver and kidney transplantation.

Long-term cyclosporin A pharmacokinetic profiles in pediatric renal transplant recipients

To study the long-term effect of cyclosporin A (CyA), 94 6-h and 29 12-h pharmacokinetic profiles were evaluated in 32 children at least 1 year after renal transplantation. Children weighing less than 25 kg needed significantly higher doses of CyA than those weighing more than 25 kg (9.8 vs 5.3 mg/kg per day; P < 0.001) to achieve similar trough levels (TL). The average dose of CyA required to achieve the target TL declined gradually with time after transplantation. The average area under the curve over 6 h (AUC/6) correlated strongly with the AUC/12 (r = 0.967; P < 0.001). The AUC/6 of patients with biopsy-proven CyA toxicity was significantly higher than for those without toxicity (Mann-Whitney U-test P < 0.05) despite similar TL. We conclude that AUC monitoring for 6 h provides valuable information not only on TL but also on the absorption and elimination characteristics of CyA as well as on the potential for CyA toxicity.

Pharmacokinetics of cyclosporine after renal transplant in children

The pharmacokinetics of cyclosporine and the relationship between blood levels and average drug concentration were prospectively evaluated in 18 children 1 month after renal transplantation. All children had normal renal function and no hepatic or gastrointestinal dysfunction. Cyclosporine was administered after an overnight fast, and serial blood samples were drawn over a 24-hour period. Analysis of cyclosporine levels was performed by means of monoclonal radio immunoassay on whole blood. Children were divided into three age groups for comparison: 2-5 years, 5-10 years, and > 10 years. There were no differences between age groups in serum protein, serum lipids, or hemoglobin levels, or in the pharmacokinetic parameters of cyclosporine except as follows: significant differences were noted in cyclosporine dose based on body weight, apparent steady-state volume of distribution, and apparent blood clearance, with the youngest children (2-5) requiring higher doses, a relative greater distribution, and exhibiting more rapid drug clearance than those > 10 years of age. In addition, we observed diurnal variation in trough levels, with morning levels (0 hr) significantly higher than those obtained in the evening (12 hours after administration of cyclosporine). Trough levels demonstrated a fair correlation with area under the concentration-time curve (AUC) and average concentration (Cav), but an abbreviated kinetic profile using cyclosporine levels 1 and 3.5 hours after administration accurately predicted AUC.

Improved absorption of cyclosporin A from a new microemulsion formulation: implications for dosage and monitoring

Recently, a new oral microemulsion formulation of cyclosporin A (CsA)--Neoral (Sandoz, Basle, Switzerland)--with a higher bioavailability has become available. Ten stable paediatric renal transplant recipients with excessive variations in CsA trough levels with the original Sandimmun (Sandoz, Basle, Switzerland) preparation were switched to Neoral on a 1:1 basis. Pharmacokinetic studies revealed impaired absorption of Sandimmun in six patients. Compared with equal doses of Sandimmun, the 8-h area under the concentration-time curve increased from 1,422 to 2,657 ng x h/ml and the peak concentration rose from 319 to 824 ng/ml (P < 0.01). In six patients with Sandimmun malabsorption, conversion on a 1:1 basis led to a reduction in creatinine clearance which was reversible after dose reduction by 9%-25%. With trough levels at the lower end of the present target range, creatinine clearance stabilised around pre-conversion values.

Steroid-resistant, cyclosporine-responsive, relapsing nephrotic syndrome

Eighteen children with steroid-resistant nephrotic syndrome received cyclosporine A (CsA), including 7 patients with minimal change disease, 4 with focal segmental glomerulosclerosis and 7 with mesangial hypercellurarity. Doses were adjusted to maintain whole blood trough levels at 80-200 ng/ml and ranged from 5 to 10 mg/kg (mean 7 mg/kg). Fourteen patients responded after 2 months of therapy with either a complete or partial remission, and received a total of 12 months of CsA with low-dose corticosteroids. Remission rates were similar among the three histological types, although complete remissions occurred more commonly in minimal change disease, while the other two histological types tended to have partial responses. Serum creatinine values ranged from 0.3 to 1.2 mg/dl at the start of treatment and were stable in 17 of 18 patients during CsA therapy. CsA was discontinued after 12 months in 11 responders. Relapses were a significant problem. Nine patients had 16 relapses, all occurring within 6 months after discontinuing CsA; 13 of 16 relapses responded to CsA and corticosteroids. Five children had multiple relapses. Three patients who initially responded to treatment had CsA-resistant relapses. There were no differences among the histological types with respect to the occurrence of relapses or response to CsA after relapsing. Four patients developed chronic renal failure, including 2 of 4 who failed initial therapy and 2 of 3 who developed CsA-resistant relapses. In conclusion, initial therapy with CsA was effective in resolving nephrotic syndrome in steroid-resistant patients. However, CsA dependency, frequent relapses and the development of chronic renal failure presented significant problems.

Pediatric clinical use of the ketoconazole/cyclosporin interaction

Ketoconazole is known to inhibit the metabolism of cyclosporin through inhibition of cytochrome P-450. This pharmacological interaction was used in an 8-year-old renal transplant patient to successfully achieve therapeutic cyclosporin blood concentrations. The addition of ketoconazole to the cyclosporin regimen should be considered when difficulties are encountered in attaining satisfactory cyclosporin levels.

Cyclosporine pharmacokinetics in nephrotic and kidney-transplanted children

The pharmacokinetic parameters of cyclosporine (CsA) were determined in 23 kidney transplant recipients and 19 children with nephrotic syndrome, after intravenous and oral administration. The mean bioavailability was 39%, blood clearance was 0.55 l.h-1.kg-1 and volume of distribution at steady-state was 2.77 l.kg-1. The absorption profile was monophasic (67%), biphasic (29%) or poor (4%). The maximum blood concentration of CsA was significantly higher in children with a monophasic profile than in children with a biphasic profile (550 vs 380 ng.ml-1). Blood clearance was significantly higher in the transplant recipients than in the patients with nephrotic syndrome (0.65 vs 0.43 l.h-1.kg-1. Although age, haematocrit, creatinine clearance, serum albumin and cholesterol differed between the two groups, only haematocrit and creatinine clearance were significantly (negatively) correlated with CsA clearance.

The interaction of the calcium channel blockers verapamil and nifedipine with cyclosporin A in pediatric renal transplant patients

The elimination of cyclosporin A was assessed in eight pediatric renal transplant patients who received calcium channel blockers concomitantly with their immunosuppressive therapy. In three children, verapamil decreased the rate of elimination of cyclosporin A. In five children who received nifedipine, cyclosporin A elimination was also impaired, which contrasts with the reports in adult patients indicating that this calcium channel blocker has no effect on cyclosporin A elimination. When both calcium channel blockers were used on separate occasions in the same patient, nifedipine was less potent than verapamil in depressing cyclosporin A elimination. Although the number of subjects studied is small, these results likely indicate that nifedipine, as well as other calcium channel blocking drugs, must be used with caution in pediatric renal transplant patients.

Outcome of cadaver kidney transplantation in small children

Small children have often been reported to have poor outcome after kidney transplantation (KT). Recent reports from North America have shown that the use of living-related donors improves patient and graft survival. We report the experience in one centre of primary cadaveric KT using sequential immunosuppression in nine children aged 8-30 months and weighing 5.4-9.8 kg; donors were 0.7-12.3 years old. Four patients had pre-emptive KT and the other five were on peritoneal dialysis; the mean +/- SD waiting time was 2.0 +/- 2.4 months. Perioperative care has been published previously. The surgical approach was intraperitoneal if the aorta and vena cava were used (n = 7) and extraperitoneal for common iliac vessels anastomosis (n = 2); the duration of surgery was 3.5 +/- 0.9 h and the time for vascular anastomosis was 32 +/- 6 min. The recipients received ATG, azathioprine, prednisone and delayed administration of cyclosporin A. The patients were followed for 12-98 (median 41) months and showed good graft function (inulin clearance 63-100 ml/min/1.73 m2); only one child with recurrent haemolytic uraemic syndrome lost his graft three months post-transplantation and died after he had received a second graft. None of the recipients required post-transplant dialysis; arterial hypertension involved four children and was related to graft artery stenosis in two. Growth improved by 0.24 +/- 0.48 SD score of height per year.(ABSTRACT TRUNCATED AT 250 WORDS)

Paediatric aspects of renal transplantation: experience of a single centre

From 1970 to 1991 a total of 244 renal transplantations were performed in 203 children at the Medical School in Hannover. The mean patient age was 10.4 years with a range between 11 months and 16.9 years. Fifty-nine children received a living donor graft from one parent and 144 received cadaveric grafts. Forty-two children were transplanted without prior dialysis treatment. After 20 years the overall survival rates were 86% for the patients and 39% for the first grafts. Grafts from donors below 5 years of age had a less favourable survival (44% after 5 years). Pre-emptive transplantation yielded comparable results with the benefit of a shorter period of uraemia. Hypertension developed in 80% of transplanted patients. Only children with living related donor grafts had significantly less hypertensive problems independent of the immunosuppressive regimen. Post-transplantational growth improved under cyclosporin. Children with nephropathic cystinosis also showed catch up growth after transplantation under cyclosporin. The long-term outcome and rehabilitation of grown-up recipients were encouraging.