RESUMEN

OBJECTIVES: Cyclosporin has been used for the treatment of pediatric refractory nephrotic syndrome (PRNS). However, the narrow therapeutic window and large pharmacokinetic variability make it difficult to individualize cyclosporin administration. Meanwhile, spironolactone has been reported to affect cyclosporin metabolism in PRNS patients. This study aims to explore the initial dosage optimization of cyclosporin in PRNS based on the impact of spironolactone co-administration. METHODS: Monte Carlo simulation based on a previously established cyclosporin population pharmacokinetic model for PRNS was used to design cyclosporin dosing regimen. RESULTS: In this study, the probability of drug concentration reaching the target and the convenience of times of administration were considered comprehensively. The optimal administration regimen in PRNS without spironolactone was 6, 5, 4 and 3 mg/kg cyclosporin split into two doses for the body weight of 5-8, 8-18, 18-46 and 46-70 kg, respectively. The optimal administration regimen in PRNS with spironolactone was 4, 3, 2 mg/kg cyclosporin split into two doses for body weight of 5-14, 14-65, and 65-70 kg, respectively. CONCLUSION: The cyclosporin dosing regimen for PRNS based on Monte Carlo simulation was systematically developed and the initial dosage optimization of cyclosporin in PRNS was recommended for the first time.

Asunto(s)

Ciclosporina , Inmunosupresores , Método de Montecarlo , Síndrome Nefrótico , Espironolactona , Humanos , Síndrome Nefrótico/tratamiento farmacológico , Espironolactona/administración & dosificación , Espironolactona/farmacocinética , Ciclosporina/administración & dosificación , Ciclosporina/farmacocinética , Niño , Inmunosupresores/administración & dosificación , Inmunosupresores/farmacocinética , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Preescolar

RESUMEN

The present study aimed to optimize the tacrolimus initial dosing scheme in pediatric refractory nephrotic syndrome patients based on population pharmacokinetics and pharmacogenomics.Demographic characteristics, concomitant medication, laboratory data, pharmacogenomics were collected to build the model and Monte Carlo was used to simulate the optimization of initial dosing scheme.Weight, the polymorphisms of CYP3A5, and concomitant medication of wuzhi-capsule were included into the covariates affecting tacrolimus clearance. In addition, with the same weight, there was difference in tacrolimus clearance in patients who carry CYP3A5*3/*3 and no coadministration of wuzhi-capsule, patients who carry CYP3A5*1 allele and no coadministration of wuzhi-capsule, patients who carry CYP3A5*3/*3 and coadministration of wuzhi-capsule, patients who carry CYP3A5*1 allele and coadministration of wuzhi-capsule, and their clearance ratios were 1:1.5:0.697:1.0455, respectively. Based on the differences of clearance in the above cases, we simulated different dosing regimens and obtained the optimal initial dose in each case.The present study recommended the tacrolimus initial dosing scheme in pediatric refractory nephrotic syndrome patients based on CYP3A5 genotype and coadministration with wuzhi-capsule.

Asunto(s)

Inmunosupresores/administración & dosificación , Síndrome Nefrótico/metabolismo , Tacrolimus/administración & dosificación , Niño , Citocromo P-450 CYP3A , Combinación de Medicamentos , Medicamentos Herbarios Chinos/administración & dosificación , Humanos , Inmunosupresores/farmacocinética , Variantes Farmacogenómicas , Tacrolimus/farmacocinética

RESUMEN

Different models of population pharmacokinetics (PPK) of cyclosporin have been established in various populations. However, the cyclosporin PPK model in patients with pediatric refractory nephrotic syndrome (PRNS) has yet to be constructed. The present study aimed to establish the cyclosporin PPK model in PRNS, and to identify factors that may account for any variability. Chinese patients with PRNS treated with cyclosporin between June 2014 and June 2018 at the Children's Hospital of Fudan University (Shanghai, China) were retrospectively analyzed. The impact of demographic features, laboratory parameters and concomitant medications was evaluated. A total of 18 PRNS patients from real-world studies were analyzed by non-linear mixed-effects modeling. A one-compartment model with first-order absorption and elimination was selected as the appropriate model in PRNS. Body weight (WT) and spirolactone intake were included as significant covariates for the apparent oral clearance (CL/F), and the WT was revealed to significantly influence the apparent volume of distribution (V/F). The final covariate models were as follows: CL/F=80.7 × (WT/70)0.75 × (1-0.265×θspirolactone), and V/F=2,030 × (WT/70), where θspirolactone is the coefficient of spirolactone. The inter-individual variability in CL/F and V/F was 44.6 and 53.1%, respectively. In conclusion, in the present study, a cyclosporin PPK model for patients with PRNS was successfully constructed, and the presence of a clinically significant interaction between spirolactone and cyclosporin in PRNS patients was determined based on real-world studies, indicating that concomitant medication with spirolactone was able to reduce cyclosporin clearance in the patients with PRNS.

RESUMEN

Different tacrolimus (TAC) population pharmacokinetic (PPK) models have been established in various pediatric disease populations. However, a TAC PPK model for pediatric refractory nephrotic syndrome (PRNS) has not been well characterized. The current study aimed to establish a TAC PPK model in Chinese PRNS and provide a summary of previous literature concerning TAC PPK models in different pediatric diseases. A total of 147 TAC conventional therapeutic drug monitoring (TDM) data from multiple blood samples obtained from 65 Chinese patients with PRNS were characterized using nonlinear mixed-effects modeling. The impacts of demographic features, biological characteristics and drug combination were evaluated. Model validation was assessed using the bootstrap method. A one-compartment model with first-order absorption and elimination was determined to be the most suitable model for TDM data in PRNS. The absorption rate constant (Ka) was set at 4.48 h-1. The typical values of apparent oral clearance (CL/F) and apparent volume of distribution (V/F) in the final model were 5.46 l/h and 57.1 l, respectively. The inter-individual variability of CL/F and V/F were 22.2 and 0.2%, respectively. The PPK equation for TAC was: CL/F = 5.46 × exponential function (EXP)(0.0323 × age) × EXP(-0.359 × cystatin-C) × EXP(0.148 × daily dose of TAC). No significant effects of covariates on V/F were observed. In conclusion, the current study developed and validated the first TAC PPK model for patients with PRNS. The study also provided a summary of previous literature concerning other TAC PPK models in different pediatric diseases.