Early Cyclosporine C0 and C2 Monitoring in De Novo Kidney Transplant Patients: A Prospective Randomized Single-Center Pilot Study

Therapeutic drug monitoring in pediatric renal transplantation

Finding the balance between clinical efficacy and toxicity of immunosuppressive drugs is a challenge in renal transplantation (RTx), but especially in pediatric RTx patients. Due to the expected longer life-span of pediatric transplant patients and the long-term consequences of drug-induced infectious, malignant and cardiovascular adverse effects, protocols which minimize immunosuppressive therapy make conceptual sense. In this context, therapeutic drug monitoring is a tool which provides support for the individualization of therapy. It has, however, limitations, and specific data in the pediatric cohort are comparatively sparse. There is large heterogeneity among the studies conducted to date in terms of methods, follow-up, endpoints, immunosuppressive regimens and patients. In addition, data from adult studies are not readily transferrable to the pediatric situation. This educational review gives a concise overview on aspects of therapeutic drug monitoring in pediatric RTx.

Cyclosporine C2 monitoring for the treatment of frequently relapsing nephrotic syndrome in children: a multicenter randomized phase II trial

BACKGROUND AND OBJECTIVES

An open-label, multicenter, randomized phase II trial was conducted from July 1, 2005 to March 29, 2011 to compare two protocols for treating children with frequently relapsing nephrotic syndrome using microemulsified cyclosporine.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Ninety-three children with frequently relapsing nephrotic syndrome were randomly assigned to group A (n=46) or group B (n=47). In both groups, the 2-hour postdose cyclosporine level was monitored. For group A, the cyclosporine target was set to 600-700 ng/ml for the first 6 months and 450-550 ng/ml for the next 18 months; for group B, it was set to 450-550 ng/ml for the first 6 months and 300-400 ng/ml for the next 18 months. The primary end point was the sustained remission rate. At the end of the study, if there was no difference in safety profile between the two groups and the sustained remission rate in group A was superior to group B with a decision threshold of 8%, then the regimen for group A would be determined the better treatment.

RESULTS

Eight children from an ineligible institution, where cyclosporine levels were not measured, were excluded from all analyses. At 24 months, the sustained remission rate was nonsignificantly higher in group A (n=43) than group B (n=42; 64.4% versus 50.0%; hazard ratio, 0.57; 95% confidence interval, 0.29 to 1.11; P=0.09), and the progression-free survival rate was significantly higher (88.1% versus 68.4%; hazard ratio, 0.33; 95% confidence interval, 0.12 to 0.94; P=0.03). The relapse rate was significantly lower in group A than group B (0.41 versus 0.95 times/person-year; hazard ratio, 0.43; 95% confidence interval, 0.19 to 0.84; P=0.02). The rate and severity of adverse events were similar in both treatment groups.

CONCLUSION

The sustained remission rate was not significantly different between the two treatment groups, but the regimen with the higher 2-hour postdose cyclosporine level target improved progression-free survival and reduced the relapse rate.

Pharmacokinetics of cyclosporin--a microemulsion in children with idiopathic nephrotic syndrome

OBJECTIVE

We present a prospective study of a microemulsion of cyclosporin to treat idiopathic nephrotic syndrome in ten children with normal renal function who presented cyclosporin trough levels between 50 and 150 ng/ml and achieved complete remission with cyclosporin. To compare the pharmacokinetic parameters of cyclosporin in idiopathic nephrotic syndrome during remission and relapse of the nephrotic state.

METHOD

The pharmacokinetic profile of cyclosporin was evaluated with the 12-hour area under the time-concentration curve (auc0-12) using seven time-point samples. This procedure was performed on each patient during remission and relapse with the same cyclosporin dose in mg/kg/day. The 12-hour area under the time-concentration curve was calculated using the trapezoidal rule. All of the pharmacokinetic parameters and the resumed 4-hour area under the time-concentration curve were correlated with the 12-hour area under the time-concentration curve. ClinicalTrials.gov: NCT01616446.

RESULTS

There were no significant differences in any parameters of the pharmacokinetic of cyclosporin during remission and relapse, even when the data were normalized by dose. The best correlation with the 12-hour area under the time-concentration curve was the 4-hour area under the time-concentration curve on remission and relapse of the disease, followed by the 2-hour level after cyclosporin (c2) dosing in both disease states.

CONCLUSIONS

These data indicate that the same parameters used for cyclosporin therapeutic monitoring estimated during the nephrotic state can also be used during remission. Larger controlled studies are needed to confirm these findings.

Use of kidney function end points in kidney transplant trials: a systematic review

BACKGROUND

Clinical trials in kidney transplantation are beginning to include markers of kidney function as end points now that traditional outcomes, such as acute rejection, become increasingly rare events. The frequency and type of kidney function end points used are unknown.

STUDY DESIGN

Systematic review.

SETTING & POPULATION

Randomized controlled trials in adult kidney transplant recipients reported in 5 major general medical journals and 5 major subspecialty journals in nephrology and transplantation between January 2003 and November 2008.

SELECTION CRITERIA

Inclusion of at least one kidney function end point at least 1 month posttransplant.

RESULTS

133 (79%) of 169 randomized trials identified used a kidney function end point. Of these, 37 (28%) used one or more measures of kidney function as the primary end point, and 81 (61%), as a secondary end point. For the primary end point, 21 (57%) trials used a creatinine-based estimated glomerular filtration rate (eGFR), 18 (49%) used serum creatinine level, and 7 (19%) used measured GFR. Overall, eGFR was an end point in 81 (61%) trials, and measured GFR, in 12 (9%) trials.

LIMITATIONS

This review is limited by the poor quality of the included trials, with many not defining either primary or secondary end points.

CONCLUSIONS

Measures of kidney function are used commonly as surrogate end points in kidney transplant trials, with eGFR becoming more frequently used over time. Further data are needed to properly validate these surrogate end points and fully understand their limitations when designing and interpreting randomized trials.

The impact of intercurrent EBV infection on ATP levels in CD4+ T cells of pediatric kidney transplant recipients

ImmuKnow measures ATP (ng/mL) in PHA-activated CD4+ T cells from patient's whole blood. According to published reports, median ImmuKnow is 258 ng/mL in stable pediatric kidney transplant (PKT) recipients > or =12 yr, and 165 ng/mL in those <12 yr. However, data on the effect of infection or AR on ImmuKnow are scarce. We studied the effect of Epstein-Barr virus (EBV) viremia on ImmuKnow in PKT with GD. Twenty-eight PKT with GD were reviewed. Group 1 has 19 PKT > or =12 yr, and group 2 has nine PKT <12 yr. Mean follow-up was 19.4 +/- 12 months. All ImmuKnow values discussed in this study were measured during GD +/- fever. None had ImmuKnow pretransplant. EBV DNA was isolated from patient blood by real-time PCR. Group 1 has eight boys and 11 girls (mean age = 16.6 +/- 2.4 yr). Group 2 has two boys and seven girls (mean age = 6 +/- 3.1 yr). Median ImmuKnow was 292 ng/mL in group 1, and 370 ng/mL in group 2. Nine children developed EBV viremia: two in group 1 (median ImmuKnow = 273 ng/mL), and seven in group 2 (median ImmuKnow = 475 ng/mL). Overall mean ImmuKnow in the nine EBV viremic patients was higher than that in the 19 non-viremic ones (422 +/- 176 ng/mL, and 302 +/- 113 ng/mL, respectively, unequal variance t-test, p = 0.08). Eight children developed AR (all in G1, median ImmuKnow = 272 ng/mL). In group 1, one patient developed concurrent EBV viremia and rejection, while another patient developed EBV viremia six months following a rejection episode. In group 2, none developed simultaneous AR, CMV, or BK virus infection with EBV viremia. None developed post-transplant lymphoproliferative disease. In summary, EBV viremia was paradoxically associated with high ImmuKnow in PKT <12 yr. This suggests strong co-stimulation of PHA-activated CD4+ T cells by EBV-transformed B cells.

KDIGO clinical practice guideline for the care of kidney transplant recipients

The 2009 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline on the monitoring, management, and treatment of kidney transplant recipients is intended to assist the practitioner caring for adults and children after kidney transplantation. The guideline development process followed an evidence-based approach, and management recommendations are based on systematic reviews of relevant treatment trials. Critical appraisal of the quality of the evidence and the strength of recommendations followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. The guideline makes recommendations for immunosuppression, graft monitoring, as well as prevention and treatment of infection, cardiovascular disease, malignancy, and other complications that are common in kidney transplant recipients, including hematological and bone disorders. Limitations of the evidence, especially on the lack of definitive clinical outcome trials, are discussed and suggestions are provided for future research.

A search for cyclophilin-A gene variants in cyclosporine A-treated renal transplanted patients

BACKGROUND

The cyclophilin A (CypA)-cyclosporine (CsA) complex promotes immune response. The variation at the CypA gene could explain CsA-pharmacokinetics and clinical outcomes among CsA-treated patients.

METHODS

The study included 290 kidney transplanted patients (65% male; mean age 51 +/- 15 yr), treated with CsA. The five CypA- exons and the promoter region were analysed through single-strand conformation analysis, denaturing high performance liquid chromatography, and direct sequencing. The effect of a promoter polymorphism (-11 G/C) on gene expression was analysed in cell-cultures.

RESULTS

We found two polymorphisms in the promoter (-11 G/C) and exon 1 (+36 G/A). Genotype frequencies did not differ between patients according to their pharmacokinetics status. In vitro studies showed that -11 G/C affected gene expression. The -11 G allele was significantly associated with clinical nephrotoxicity (p = 0.006). The strongest predictors for nephrotoxicity were a donor age > or =55 yr, and the promoter GG + GC genotypes.

CONCLUSIONS

Our work suggests that a CypA-promoter polymorphism (-11 G/C) could be associated with clinical nephrotoxicity. Replication of this study in other populations is necessary to define the role of CypA-variants in the main clinical outcomes among CsA-treated kidney-transplanted patients.

[Efficacy of therapeutic monitoring of cyclosporine through C2 and AUC(0-4) during the first 24 months following kidney transplantation]

BACKGROUND/AIM

Cyclosporine (CyA) therapeutic drug monitoring (TDM) through the measurement of drug concentration in blood two hours after the administration (C2), and/or according to the calculated value of the area under the concentration-time curve during the first four hours following administration (AUC(0-4)) shows favourable correlation with clinical manifestations in patients with kidney transplantation (Tx). The aim of this study was to analyze clinical efficiency and usability of TDM CyA through C2 and AUC(0-4) in the group of our kidney transplanted patients during the first 24 months following Tx.

METHODS

The study included 50 patients who had undergone kidney Tx using living donors at the Clinic of Nephrology Military Medical Academy, from 1996 to 2003. The first group (group C2) consisted of 25 patients in whom CyA dose was adjusted according to the target C2 and AUC(0-4) (calculated by the regression formula based on C1, C2 and C3), while the second group (group CO) consisted of 25 "historical" patients in whom the dose of this drug was adjusted according to CO.

RESULTS

On the 6th day the average daily dose of CyA in the group C2 was 10.1 +/- 0.8 mg/kg, while in the group CO it was 7.6 +/- 1.6 (p < 0.05). One month following the Tx, daily drug doses were quite similar in the two observed groups (6.2 mg/kg in CO and 6.6 mg/kg in group C2, p = NS). In the group C2, target C2/AUC(0-4) (C2 1700 ng/ml, AUC(0-4) 4400 ng h/ml) on the sixth day was achieved in 36.3%, and on day 14 in 76% of the patients. The target AUC(0-4), in relation with C2, in each observed time interval was reached in the higher number of patients. Maximum CyA concentrations in the group C2 were registered 2 hours following the administration (C2), when compared with the concentrations registered after the first and the third hour (C1 and C3). In relation with C1 and C3, C2 concentration correlated most favorably with AUC(0-4), both on the 6th (r = 0.85) and on the 9th day (r = 0.87). During the first three months following the Tx, in the group CO, 10 episodes (40%) of acute cell rejection (AR) were registered, while in the group C2, two episodes (8%, p = 0.07) were registered; in the observed period covering the first two years, a total of 13 (52%) AR episodes in the group CO and 5 AR episodes (20%) in the group C2 (p = 0.03) were registered. All of five episodes of steroid resistant AR were registered in the group CO. In the group C2, all five patients with AR had lower C2 during AR: the average C2 at the moment of AR was 933.8 ng/ml, and in the patients without rejections was 1364.2 ng/ml (p = 0.008). In the same group, the average C0 at the moment of AR was 263.2 ng/ml, and 240.0 ng/ml (p = 0.486) in the patients without AR. In the C0 group, average C0 concentration at the moment of AR was 227.1 ng/ml, while in the patients without AR it was 227.7 ng/ml (p = 0.95). Totally 68% of the patients showed signs of acute CyA nephrotoxicity during the first year in the group C2, and 52% in the group CO (p = 0.38). In seven patients (28%) of the group C2 and six patients of the group C0 (24%, p = 0.96) in the first two years following Tx, administration of CyA was interrupted due to nephrotoxicity. Overall graft function was good in both groups during the period of two years. One graft was lost in the group CO due to chronic allograft nephropathy. The patients in the group C2 had better early and the same late graft function. Five patients in the group C2 who did not reach the target C2/AUC during the first 30 days, did not have more AR or worse graft function, comparing with the patients who reached the target concentrations.

CONCLUSION

In the patients with CyA TDM through with the C2 and AUC(0-4), AR frequency was considerably lower, and AR episodes had a milder flow than in those with CyA TDM through the CO. The drug concentration in blood two hours after administration (C2) was a good predictor of acute graft rejection, while CO failed to point to the patients with the insufficient drug concentration. Higher drug doses were administered in the group C2 during the first month following Tx, and these patients did not show significantly higher frequency of acute nephrotoxicity and more frequent requirement of the drug use interruption. Graft function in both groups was good during the period of two years. CyA dose determination through C2 and AUC(0-4) is efficient TDM method, relatively simple for use in day to day clinical practice.

Correlation between finger-prick and venous ciclosporin levels: association with gingival overgrowth and hypertrichosis

The aims of this study were (1) to ascertain ciclosporin C(2) levels currently being achieved in children with steroid-sensitive nephrotic syndrome (SSNS) and renal transplants (RTs), (2) to determine the feasibility of the use of finger-prick samples for the measurement of ciclosporin levels, and (3) to identify any correlation between hypertrichosis or gingival overgrowth (GO) and level of ciclosporin 2 h post-dose (C(2)). Seventy-two children (39 with SSNS, 33 with RT) participated. Ciclosporin 12 h trough (C(12)) and C(2) levels were measured in venous and finger-prick samples by high-performance liquid chromatography tandem mass spectroscopy. Photographs of the teeth and back were taken for assessment of GO and hypertrichosis. Mean (+/-SD) C(2) levels in the SSNS and RT groups were 512 (+/-181) microg/l and 471 (+/-229) microg/l. There was a highly significant relationship between venous and finger-prick ciclosporin levels (r(2) = 0.96, P < 0.0001). Fourteen children had severe GO. There was a small, though statistically significant, impact of ciclosporin level on GO (C(2) r(2) = 0.12, P = 0.003 and C(12) r(2) = 0.06, P = 0.038) but no correlation with dose (milligrammes per kilogramme per day or milligrammes per square metre per day) or duration. Seventeen children had moderate or severe hypertrichosis, this being more common in children of South Asian ethnicity (P < 0.0001). There was no correlation between ciclosporin exposure or duration and hypertrichosis. Finger-prick blood sampling may serve as a practical alternative to venepuncture in children receiving ciclosporin.

The Clinical Benefits of Cyclosporine C2-Level Monitoring: A Systematic Review

BACKGROUND

Monitoring of cyclosporine microemulsion (Neoral) using 2-hour postdose (C2) levels is alleged to improve clinical outcomes, but the efficacy of this strategy is uncertain.

METHODS

A systematic literature search was performed for trials directly comparing patients monitored with C2 levels with those monitored by trough (C0) levels. Primary outcomes assessed were renal function and acute rejection.

RESULTS

A total of 29 studies met the inclusion criteria. Only 10 of these were randomized controlled trials. Overall quality was poor and this precluded meta-analysis. The most consistent finding in de novo renal, hepatic, and cardiac transplant recipients is a higher mean cyclosporine dose in the early postoperative period in C2 monitored patients. There is no clear evidence that this leads to impaired renal function. In the majority of studies, the monitoring strategy had no significant effect on the rate of acute rejection. In stable transplant recipients, the majority of studies show a reduction in mean cyclosporine dose with adoption of C2 monitoring. No obvious clinical benefit was derived from this reduction in dose.

CONCLUSION

In de novo transplant patients, there is little evidence from prospective studies to support the theoretical benefits of C2 monitoring. Potential dose reductions in stable patients may reduce costs, but no short-term clinical benefit is seen. Quality of studies in this area is poor, and the practical limitations of C2 monitoring mean that further evidence is required before a strategy for the administration of cyclosporine based on C2 levels can be recommended.

Posttransplant monitoring of pediatric lung transplant recipients

PURPOSE OF REVIEW

This article reviews current trends in pediatric lung posttransplant management, reveals pitfalls that exist, and introduces additional parameters that may have an impact on long-term survival.

RECENT FINDINGS

A number of parameters are monitored after transplantation to prevent or identify early complications related to lung transplantation in hope of reducing morbidity and mortality. These include routine laboratory studies, imaging, and monitoring of drug levels and lung function. Drug monitoring allows individualization of a patient's immunosuppressive therapy; however, drug levels alone may not reflect the patient's immune status. ImmuKnow is a general immune-monitoring assay that may help guide therapy. Two major complications are rejection and infection, and bronchoscopy is used to differentiate these two entities. Silent rejection may occur and increase the chance of developing bronchiolitis obliterans; therefore, many centers perform surveillance bronchoscopies. Recently, de-novo anti-histocompatibility locus antigen antibodies and gastroesophageal reflux have been associated with poor outcomes, and many centers are monitoring these entities as part of care following lung transplant.

SUMMARY

There has been little improvement in long-term outcomes of lung transplantation. Current monitoring methods are utilized to maintain or improve outcomes and recently additional monitoring parameters have been identified which hopefully will improve long-term outcomes.