Preprandial C2 monitoring of cyclosporine treatment in children with nephrotic syndrome

Effectiveness and nephrotoxicity of a 2-year medium dose of cyclosporine in pediatric patients with steroid-dependent nephrotic syndrome: determination of the need for follow-up kidney biopsy

BACKGROUND

High dose of cyclosporine (CyA) for ≥2 years in children with steroid-dependent nephrotic syndrome (SDNS) increases the risk for nephropathy. Considering this, risk can be lowered with lower doses of CyA; we evaluated the effects of a medium dose of CyA, with target serum level, C2, of 450 ng/ml, over a 2-year period of observation, to determine the need for follow-up kidney biopsy.

METHODS

We retrospectively evaluated C2 levels in 38 patients (17 males, 5.2 ± 2.9 years old) with SDNS at treatment initiation, at 6, 12 and 18 months during treatment, and at the time of kidney biopsy, 2-year after treatment initiation. Fifteen patients were also treated with mizoribine or mycophenolate mofetil. A number of relapses-per-patient-per-year, relative to SDNS onset and initiation of CyA treatment, were evaluated. Serum levels of total protein, albumin and total cholesterol, blood urea nitrogen level, and the estimated glomerular filtration rate were measured at treatment initiation and at 1- and 2-year post-treatment initiation.

RESULTS

Only one very mild case of CyA-associated nephrotoxicity was identified based on biopsy results at 2-year post-treatment initiation. C2 concentrations were maintained at 422.2 ± 133.5 ng/ml and the number of relapses decreased from 3.0 relapses-per-patient-per-year prior to CyA treatment to 0.47 relapses-per-patient-per-year after CyA treatment. No effects of the treatment on the estimated glomerular filtration rate were noted.

CONCLUSION

A 2-year treatment with a medium dose of cyclosporine A with or without other immunosuppressive agents is relatively safe with regard to the development of cyclosporine A nephrotoxicity.

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.

Age effect on whole blood cyclosporine concentrations following oral administration in children with nephrotic syndrome

The aim of this study was to investigate age-related pharmacokinetic differences of cyclosporine (CyA) in children with nephrotic syndrome. Whole blood concentrations of CyA were monitored for a total of 96 times in 36 cases. The 25 male and 11 female patients ranged in age from 1.9 to 19.7 years with a mean age of 9.1 years. Renal biopsy showed minimal change in 33 patients and focal segmental glomerulosclerosis in three patients. CyA was orally administered in two divided doses just before meals. The doses of CyA administered were adjusted such that the target value for blood concentration at 2 h post-dose (C2) was 400-450 ng/ml. The 96 subjects were divided into three groups according to age: group I, 1-5 years (n = 30); group II, 6-10 years (n = 34); and group III, ≥ 11 years (n = 32). In all subjects, peak levels (Cmax) of CyA were reached at C1 or C2. There was no significant difference between the groups for C2, area under the whole blood concentration-time curve up to 4 h post-dose (AUC0-4), and Cmax. The mean CyA doses of groups I, II, and III were 4.8 ± 1.0 mg/kg/day, 3.8 ± 0.9 mg/kg/day, and 3.0 ± 0.6 mg/kg/day, respectively, and there were significant differences between every two groups. In addition, the dose-normalized Cmax (Cmax/dose) and AUC0-4 (AUC0-4/dose) values were significantly lower in the younger group than in the older group. These findings suggested that in children, when the same concentration is targeted, the required CyA dose would vary according to age but would be significantly higher for the younger children.

Single infusion of rituximab for persistent steroid-dependent minimal-change nephrotic syndrome after long-term cyclosporine

Rituximab (RTX) has been successfully used as a rescue therapy in children with steroid-dependent nephrotic syndrome (SDNS). However, little is known regarding maintenance therapy after a successful response to RTX in such patients. The efficacy and safety of a single RTX infusion (375 mg/m(2)) were assessed in ten patients who had persistent SDNS associated with minimal-change disease (MCD) despite the long-term use of cyclosporine (CsA). The mean follow-up after RTX infusion was 17 months. Applying RTX resulted in a significant reduction in the mean prednisolone (PSL) dose from 0.39 +/-0.18 to 0.15 +/- 0.14 mg/kg per day. The mean 12-month relapse rates significantly decreased from 4.1 +/- 1.7 to 0.6 +/- 0.6. All but one patient who had continued CsA as maintenance therapy after a single RTX infusion were able to withdraw from PSL without any relapses during the study period, whereas the remaining five patients who discontinued CsA experienced relapses after CD19 cells re-emerged, leading to the reintroduction of CsA or an additional RTX infusion. Infusion reactions occurred in five of ten patients. These data indicate that a single RTX infusion may improve response to CsA in patients with persistent SDNS due to the phenomenon of secondary resistance to CsA.

Population pharmacokinetic study of cyclosporine in patients with nephrotic syndrome

Cyclosporine (CsA) is widely used in the treatment of nephrotic syndrome (NS). A population pharmacokinetic (PopPK) model was developed using trough blood CsA concentration data from 106 patients with NS. The pharmacokinetic analysis was performed using NONMEM with 1-compartment linear model and first-order elimination. Proportional and additive error models were used to describe the interindividual and intraindividual variabilities, respectively. Body weight (WT), serum albumin level (ALB), and combination therapy with rifampicin were found to be the most significant covariates explaining the variability of the apparent clearance (CL/F) of CsA among patients. The final model was as follows: TVCL/F=34.1x(WT/67.6)(1.08)x(1+RFAx0.67)x(1-ALBx0.0088); TVV/F=3.5xWT; Ka=1.28 fixed; where RFA=1 with concurrent rifampicin use and 0 otherwise. The interindividual variabilities of CL/F and V/F were 18% and 27%, respectively. The residual error was 0.064 mg/L. The mean+/-SD of CL/F and V/F of the 106 patients were 23.5+/-7.2 L/h and 232.3+/-71.5 L, respectively. The reliability and stability of the PopPK model were confirmed by nonparametric bootstrap procedure.

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.

Independent risk factors for chronic cyclosporine induced nephropathy in children with nephrotic syndrome

BACKGROUND

Cyclosporine A (CsA) has been widely used in children with steroid dependent and steroid resistant nephrotic syndrome (NS) because of its efficacy in relieving these patients from systemic side effects of steroids. However, its long term use is controversial, since chronic CsA induced nephropathy (CsAN) may develop in a considerable number of patients.

AIMS AND METHODS

In order to clarify the risk factors for the development of CsAN, the clinical characteristics of children with steroid dependent or steroid resistant NS taking CsA (target blood trough levels 50-150 ng/ml) for more than six months, managed at a single centre, were retrospectively analysed.

RESULTS

Thirteen of 30 children (24 boys and 6 girls) taking CsA (mean duration 43 months, range 6-144) had CsAN defined as the presence of CsA associated arteriopathy with or without striped tubulointerstitial lesions. The multivariate analysis revealed that CsA treatment for more than 36 months and an age younger than 5 years at the start of CsA treatment were independent risk factors for the development of CsAN. The univariate analysis also showed that patients with CsAN had more frequent relapses during CsA treatment than those without CsAN.

CONCLUSION

An alternative treatment should be seriously considered after a 36 month administration of CsA in order to prevent CsAN. Data also suggest that CsA treatment in children younger than 5 years should be avoided if possible.