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Vancomycin is frequently used to treat Gram-positive bacterial infections in neonates. However, there is still no consensus on the optimal initial dosing regimen. This study aimed to assess the performance of pharmacokinetic model-based virtual trials to predict the dose-exposure relationship of vancomycin in neonates.The PubMed database was searched for clinical trials of vancomycin in neonates that reported the percentage of target attainment. Monte Carlo simulations were performed using nonlinear mixed-effect modeling to predict the dose-exposure relationship, and the differences in outcomes between virtual trials and real-world data in clinical studies were calculated.A total of 11 studies with 14 dosing groups were identified from the literature to evaluate dose-exposure relationships. For the ten dosing groups where the surrogate marker for exposure was the trough concentration, the mean ± standard deviation (SD) for the target attainment between original studies and virtual trials was 3.0 ± 7.3%. Deviations between - 10 and 10% accounted for 80% of the included dosing groups. For the other four dosing groups where the surrogate marker for exposure was concentration during continuous infusion, all deviations were between - 10 and 10%, and the mean ± SD value was 2.9 ± 4.5%.The pharmacokinetic model-based virtual trials of vancomycin exhibited good predictive performance for dose-exposure relationships in neonates. These results might be used to assist the optimization of dosing regimens in neonatal practice, avoiding the need for trial and error.

BACKGROUND Immunosuppressant Bayesian Dose Adjustment (ISBA) is an online expert system that estimates the area under the curve (AUC) of immunosuppressive drugs through pharmacokinetic modelling and Bayesian estimation to propose dose adjustments to reach predefined exposure targets. The ISBA database was retrospectively analyzed to describe tacrolimus pharmacokinetics and exposure, evaluate the efficiency of ISBA dose recommendations, and propose tacrolimus AUC0-12h target ranges for pediatric renal allograft recipients treated with immediate release tacrolimus. METHODS The database included 1935 tacrolimus dose adjustment requests from 419 patients

Vancomycin is one of the antibiotics most used in neonates. Continuous infusion has many advantages over intermittent infusions, but no consensus has been achieved regarding the optimal initial dose. The objectives of this study were: to develop a Machine learning (ML) algorithm based on pharmacokinetic profiles obtained by Monte Carlo simulations using a population pharmacokinetic model (POPPK) from the literature, in order to derive the best vancomycin initial dose in preterm and term neonates, and to compare ML performances with those of an literature equation (LE) derived from a POPPK previously published.The parameters of a previously published POPPK model of vancomycin in children and neonates were used in the mrgsolve R package to simulate 1900 PK profiles. ML algorithms were developed from these simulations using Xgboost, GLMNET and MARS in parallel, benchmarked and used to calculate the ML first dose. Performances were evaluated in a second simulation set and in an external set of 82 real patients and compared to those of a LE.The Xgboost algorithm yielded numerically best performances and target attainment rates: 46.9% in the second simulation set of 400-600 AUC/MIC ratio vs. 41.4% for the LE model (p = 0.0018); and 35.3% vs. 28% in real patients (p = 0.401), respectively). The Xgboost model resulted in less AUC/MIC 600, thus decreasing the risk of nephrotoxicity.The Xgboost algorithm developed to estimate the initial dose of vancomycin in term or preterm infants has better performances than a previous validated LE and should be evaluated prospectively.

What is known and objectives Thiopurines are cornerstone drugs in the treatment of acute lymphoblastic leukaemia (ALL), but their use can be complicated by the incidence of life-threatening leucopenia. Case description We describe a case of a 6-year-old Chinese boy with B-ALL receiving extremely low dose of 6-mercaptopurine (only 4% of recommended dose) during the ALL maintenance therapy phase. What is new and conclusion Complex pharmacogenetic tests and TDM should be recommended in children with complicated ALL to highlight the large individual variability in the responses to 6-MP exposure and the associated adverse effects.

To assess ceftriaxone population pharmacokinetics in a large pediatric population and describe the proper dose for establishing an optimized antibiotic regimen. From pediatric patients using ceftriaxone, blood samples were obtained and the concentration was measured using high-performance liquid chromatography ultraviolet detection. The NONMEM software program was used for population pharmacokinetic analysis, for which data from 99 pediatric patients (2 to 12 years old) was collected and 175 blood concentrations were obtained. The best fit with the data was shown by the one-compartment model with first-order elimination. According to covariate analysis, weight had a significant impact on the clearance of ceftriaxone. Using Monte Carlo simulation, in a pediatric population with community-acquired pneumonia, a dose regimen of 100 mg/kg every 24 h produced satisfactory target attainment rates while remaining within the required minimum inhibitory concentration (2 mg/L). Population pharmacokinetics of ceftriaxone was evaluated in children and an optimum dosing regimen was constructed on the basis of the pharmacokinetics-pharmacodynamics model-based approach.

AIMS: Chinese children are more susceptible to the development of thiopurine‐induced leukopenia compared with Caucasian populations. The aim of our study was to establish a 6‐mercaptopurine (6‐MP) dose–concentration–response relationship through exploration of pharmacogenetic factors involved in the thiopurine‐induced toxicities in Chinese paediatric patients afflicted by acute lymphoblastic leukaemia (ALL). METHODS: Blood samples were obtained from ALL children treated with 6‐MP. We determined the metabolite steady‐state concentrations of 6‐MP in red blood cells (RBCs) by using high‐performance liquid chromatography. Pharmacogenetic analysis was carried out on patients' genomic DNA using the MassArray genotyping platform. RESULTS: Sixty children afflicted by ALL who received 6‐MP treatment were enrolled in this study. The median concentration of 6‐thioguanine in patients afflicted by leukopenia was 235.83 pmol/8 × 10(8) RBCs, which was significantly higher than for patients unafflicted by leukopenia (178.90 pmol/8 × 10(8) RBCs; P = 0.029). We determined the population special target 6‐thioguanine threshold to have equalled 197.50 pmol/8 × 10(8) RBCs to predict leukopenia risk in Chinese paediatric patients afflicted by ALL. Among 36 candidate single nucleotide polymorphisms, our results indicated that NUDT15 (rs116855232) and IMPDH1 (rs2278293) were correlated with a 5.50‐fold and 5.80‐fold higher risk of leukopenia, respectively. MTHFR rs1801133 variants were found to have had a 4.46‐fold significantly higher risk of hepatotoxicity vs wild‐type genotype. CONCLUSION: Our findings support the idea that predetermination of genotypes and monitoring of thiopurine metabolism for Chinese paediatric patients afflicted by ALL is necessary to effectively predict the efficacy of treatments and to minimize the adverse effects of 6‐MP maintenance therapy.

As unlicensed or off-label drugs are frequently prescribed in children, the European Pediatric Regulation came into force in 2007 to improve the safe use of medicinal products in the pediatric population. This present report analyzes the pediatric research trials over 23 years in a clinical research center dedicated to children and the impact of regulation. The database of trial characteristics from 1998 to 2020 was analyzed. We also searched for differences between two periods (1998-2006 and 2007-2020) and between institutional and industrial sponsors during the whole period (1998-2020). A total of 379 pediatric trials were initiated at our center, corresponding to inclusion of 7955 subjects and 19448 on-site patient visits. The trials were predominantly drug evaluation trials (

Mycophenolate mofetil (MMF), a pro-drug of mycophenolic acid (MPA), has become a major therapeutic option in juvenile systemic lupus erythematosus (jSLE). Monitoring MPA exposure using area under curve (AUC) has proved its value to increase efficacy and safety in solid organ transplantation both in children and adults, but additional data are required in patients with autoimmune diseases. In order to facilitate MMF therapeutic drug monitoring (TDM) in children, Bayesian estimators (BE) of MPA AUCPharmacokinetic blood samples were collected from jSLE treated by MMF and MPA plasma concentrations were determined using high-performance liquid chromatography system with ultraviolet detection (HPLC-UV). Individual AUCWe received 41 rich pediatric PK at steady state from jSLE and calculated individual AUCAccording to our external validation of two LSS of drug exposure, the ISBA model is recommended for Bayesian estimation of MPA AUC

The EREMI project was set up to collect data on adverse drug reactions (ADRs) occurring due to off-label and/or unlicensed drugs prescribed to hospitalised children in France. These events were evaluated by a regional pharmacovigilance centre (RPC) and an adjudication committee (AC). The aim of this study was to assess the agreement between these two different entities on their evaluation of ADRs.The RPC first validated the ADRs and assessed their causality using the Naranjo scale. The AC assessed then ADRs using all available information, including the RPC evaluation. The agreement on severity and nature of ADRs, role of treatment (suspect or concomitant) and drug causality was calculated using Cohen's nonparametric kappa coefficient (k).Three hundred and eighty-six events were reported in 219 children. The RPC excluded 65 events and validated 321 ADRs. Agreement was very good on nature of ADRs (k=0.85) and role of treatment (k=0.81), moderate on severity of ADRs (k=0.60) and very poor on drug causality (k=0.05).Agreement between the RPC and the AC was not constant throughout this evaluation. They troubled to agree on severe ADRs and on drug causality.

Background Montelukast, a potent oral selective leukotriene-receptor antagonist, inhibits the action of cysteinyl-leukotriene in patients with asthma. Although pharmacokinetic studies of montelukast have been reported in Caucasian adults and children, and showed large inter-individual variability on pharmacokinetics, none of these studies has been explored in Chinese children. Given the potential inter-ethnic difference, the purpose of the present study was to evaluate the effects of developmental factors and pharmacogenetics of CYP2C8 and SLCO2B1 on montelukast clearance in Chinese pediatric patients. Methods After the administration of montelukast, blood samples were collected from children and plasma concentrations were determined using an adapted micro high-performance liquid chromatography coupled with the fluorescence detection (HPLC-FLD) method. A previously published pharmacokinetic model was validated using the opportunistic pharmacokinetic samples, and individual patient's clearance was calculated using the validated model. Population pharmacokinetic analysis was performed using a nonlinear mixed-effects model approach (NONMEM V 7.2.0) and variants of CYP2C8 and SLCO2B1 were genotyped. Results Fifty patients (age range: 0.7-10.0 years) with asthma were enrolled in this study. The clearance of montelukast was significantly higher in children with the SLCO2B1 c.935GA and c.935AA genotypes compared with that of children with the SLCO2B1 c.935GG genotype (0.94 ± 0.26 versus 0.77 ± 0.21, p = 0.020). The patient's weight was also found to be significantly corrected with montelukast clearance (p

A rapid and highly sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) assay was developed for quantification of 7 antibiotics in low sample volumes (50 μL): amoxicillin, azithromycin, cefotaxime, ciprofloxacin, meropenem, metronidazole and piperacillin, for both routine monitoring and pharmacokinetic studies. After protein precipitation by acetonitrile, the antibiotics were separated on an Acquity UPLC HSS T3 column (run time, 4 min). The mobile phase consisted of a mixture of (A) ammonium acetate (pH 2.4; 5 mM) and (B) acetonitrile acidified with 0.1% formic acid, delivered at 500 μl/min in a gradient elution mode. Total time run was 2.75 min. Ions were detected in the turbo-ion-spray-positive and multiple-reaction-monitoring modes. The assay was accurate and reproductible for the quantification of the seven antibiotics in serum samples over large concentration ranges.

International audience; The response to medications in children differs not only in comparison to adults but also between children of the different age groups and according to the disease. This is true for anti-infectives that are widely prescribed in children with malignancy. In the absence of pharmacokinetic/pharmacodynamic paediatric studies, dosage is frequently based on protocols adapted to adults. After a short presentation of the drugs, we reviewed the population pharmacokinetic studies available for glycopeptides (vancomycin and teicoplanin, n = 5) and antifungals (voriconazole, posaconazole, and amphotericin B, n = 9) currently administered in children with onco-hematological malignancies. For each of them, we reported the main study characteristics including identified covariates affecting pharmacokinetics and proposed paediatric dosage recommendations. This review highlighted the very limited amount of data available, the lack of consensus regarding PK/PD targets used for dosing optimization and regarding dosage recommendations when available. Additional PK studies are urgently needed in this specific patient population. In addition to pharmacokinetics, efficacy may be altered in immunocompromised patients and prospective clinical evaluation of new dosage regimen should be provided as they are missing in most cases. © Copyright © 2021 Leroux, Mechinaud-Heloury and Jacqz-Aigrain.

Summary Introduction To date, few studies have shown a significant association between off-label drug use and adverse drug reactions (ADRs). The main aims of this study is to evaluate the relationship between adverse drug reactions and unlicensed or off-label drugs in hospitalized children and to provide more information on prescribing practice, the amplitude, consequences of unlicensed or off-label drug use in pediatric inpatients. Methods In this multicenter prospective study started from 2013, we use the French summaries of product characteristics in Theriaque (a prescription products guide) as a primary reference source for determining pediatric drug labeling. The detection of ADRs is carried out spontaneously by health professionals and actively by research groups using a trigger tool and patients’ electronic health records. The causality between suspected ADRs and medication is evaluated using the Naranjo and the French methods of imputability independently by pharmacovigilance center. All suspected ADRs are submitted for a second evaluation by an independent pharmacovigilance experts. Strength and limitations of this study For our best knowledge, EREMI is the first large multicenter prospective and objective study in France with an active ADRs monitoring and independent ADRs validation. This study identifies the risk factors that could be used to adjust preventive actions in children's care, guides future research in the field and increases the awareness of physicians in off-label drug use and in detecting and declaring ADRs. As data are obtained through extraction of information from hospital database and medical records, there is likely to be some under-reporting of items or missing data. In this study the field specialists detect all adverse events, experts in pharmacovigilance centers assess them and finally only the ADRs assessed by the independent committee are confirmed. Although we recruit a high number of patients, this observational study is subject to different confounders.

Objectives Nowadays, real-world data can be used to improve currently available dosing guidelines and to support regulatory approval of drugs for use in neonates by overcoming practical and ethical hurdles. This proof-of-concept study aimed to assess the population pharmacokinetics of azlocillin in neonates using real-world data, to make subsequent dose recommendations and to test these in neonates with early-onset sepsis (EOS). Methods This prospective, open-label, investigator-initiated study of azlocillin in neonates with EOS was conducted using an adaptive two-step design. First, a maturational pharmacokinetic-pharmacodynamic model of azlocillin was developed, using an empirical dosing regimen combined with opportunistic samples resulting from waste material. Second, a Phase II clinical trial (ClinicalTrials.gov: NCT03932123) of this newly developed model-based dosing regimen of azlocillin was conducted to assure optimized target attainment [free drug concentration above MIC during 70% of the dosing interval (‘70% fT>MIC’)] and to investigate the tolerance and safety in neonates. Results A one-compartment model with first-order elimination, using 167 azlocillin concentrations from 95 neonates (31.7–41.6 weeks postmenstrual age), incorporating current weight and renal maturation, fitted the data best. For the second step, 45 neonates (30.3–41.3 weeks postmenstrual age) were subsequently included to investigate target attainment, tolerance and safety of the pharmacokinetic-pharmacodynamic model-based dose regimen (100 mg/kg q8h). Forty-three (95.6%) neonates reached their pharmacokinetic target and only two neonates experienced adverse events (feeding intolerance and abnormal liver function), possibly related to azlocillin. Conclusions Target attainment, tolerance and safety of azlocillin was shown in neonates with EOS using a pharmacokinetic-pharmacodynamic model developed with real-world data.

Aims The aim of the study was to evaluate the suitability of the current caffeine dosing regimen for the Chinese population using modelling and simulation approach. Methods Pharmacokinetic samples were collected from 99 Chinese newborns with premature apnoea. The median (range) of gestational age and postmenstrual age were 28.3 (25.0-33.4) weeks and 31.1 (26.4-38.0) weeks, respectively. Newborns were receiving caffeine citrate at a loading dose of 20 mg/kg/d and a maintenance dose of 5-10 mg/kg/d. Caffeine concentrations and CYP1A2 polymorphisms were investigated. Population pharmacokinetic modelling of caffeine in Chinese preterm newborn on a population-wide scale was conducted using NONMEM. Results A 1-compartment model with first-order elimination was used to describe population pharmacokinetic. With current weight implemented using 0.75 allometric scaling, clearance (CL) was positively related to current weight and postmenstrual age, but a negative relationship was observed with serum creatinine concentration. Eight genotypes of CYP1A2 were tested and none of them had a significant impact on caffeine pharmacokinetic parameters. Interindividual variability of CL and volume of distribution was 7.70 and 65.9%. The median (range) of 95% confidence intervals of CL were 0.0128 (0.0128-0.0131) L/h/kg. Monte Carlo simulation demonstrated that 80% (loading dose) and 98% (maintenance dose) of premature infants treated with a labelled dosing regimen attained the concentration target range of 5-20 mg/L. Conclusion A population PK model of caffeine was developed in Chinese newborns. Body weight-implemented allometric scaling, postmenstrual age and serum creatinine concentration markedly affected caffeine clearance. The labelled dosing regimen is suitable for Chinese premature infants.

AIMS The pharmacokinetics (PK) of fluconazole and micafungin differ in neonates compared with children and adults. Dosing instructions in product labels appear to be inconsistent with the emerging scientific evidence. Limited information is available on the safety profile of these agents in neonates. Our objective was to study the population PK and safety of both drugs, randomly administered in neonates with suspected or confirmed systemic candidiasis. METHODS Neonates were randomized 1:1 to fluconazole (loading dose 25 mg kg-1 ; maintenance dose 12 mg kg-1 day-1 or 20 mg kg-1 day-1 , respectively, for infants

Background Steroid-sensitive nephrotic syndrome (SSNS) is a childhood disease with unclear pathophysiology and genetic architecture. We investigated the genomic basis of SSNS in children recruited in Europe and the biopsy-based North American NEPTUNE cohort. Methods We performed three ancestry-matched, genome-wide association studies (GWAS) in 273 children with NS (Children Cohort Nephrosis and Virus [NEPHROVIR] cohort: 132 European, 56 African, and 85 Maghrebian) followed by independent replication in 112 European children, transethnic meta-analysis, and conditional analysis. GWAS alleles were used to perform glomerular cis -expression quantitative trait loci studies in 39 children in the NEPTUNE cohort and epidemiologic studies in GWAS and NEPTUNE (97 children) cohorts. Results Transethnic meta-analysis identified one SSNS-associated single-nucleotide polymorphism (SNP) rs1063348 in the 3′ untranslated region of HLA-DQB1 ( P =9.3×10 −23 ). Conditional analysis identified two additional independent risk alleles upstream of HLA-DRB1 (rs28366266, P =3.7×10 −11 ) and in the 3′ untranslated region of BTNL2 (rs9348883, P =9.4×10 −7 ) within introns of HCG23 and LOC101929163 . These three risk alleles were independent of the risk haplotype DRB1*07:01-DQA1*02:01-DQB1*02:02 identified in European patients. Increased burden of risk alleles across independent loci was associated with higher odds of SSNS. Increased burden of risk alleles across independent loci was associated with higher odds of SSNS, with younger age of onset across all cohorts, and with increased odds of complete remission across histologies in NEPTUNE children. rs1063348 associated with decreased glomerular expression of HLA-DRB1, HLA-DRB5, and HLA-DQB1. Conclusions Transethnic GWAS empowered discovery of three independent risk SNPs for pediatric SSNS. Characterization of these SNPs provide an entry for understanding immune dysregulation in NS and introducing a genomically defined classification.

Aims Nephrotic syndrome (NS) is the most common clinical manifestation of glomerular disease in children. Currently, tacrolimus (TAC) is widely used in children with NS. However, pharmacokinetic data in children with nephrotic syndrome is limited. This study was intended to evaluate the population pharmacokinetics (PPK) of TAC in paediatric NS and to optimize dosing regimen. Methods Blood samples from NS children treated with TAC were collected and the blood concentrations of TAC were detected using HPLC-MS/MS. A PPK model was developed using NONMEM software. Pharmacogenetic analysis was carried out in the CYP3A5 gene. Results The data from 28 children were used for PPK analysis. A one-compartment model and first-order elimination were accorded with the TAC data in paediatric NS. A covariate analysis showed that body weight and CYP3A5 genotype significantly affected TAC pharmacokinetics. Monte Carlo simulation indicated that NS children with CYP3A5*3/*3 receiving 0.10 mg kg-1 dose-1 twice daily and NS children with CYP3A5*1 receiving 0.25 mg kg-1 dose-1 twice daily TAC could achieve the target concentrations of 5-10 ng ml-1 . Conclusion The PPK of TAC was estimated in children with NS and a CYP3A5 genotype-based dosing regimen was set up based on simulations.

Identification of markers involved in drug disposition is crucial for drugs with a narrow therapeutic index. Individual genomic differences can affect the pharmacology of some drugs and participate to inter-individual variability in drug response. Pharmacogenetics is a useful tool in clinical practice for dosage adjustment and to limit drug toxicities. In pediatrics, physiological changes can also influence the disposition of drugs in infants, children and adolescents. The importance of ontogeny translates into different responses to the same drug in children and adults. Thus, interactions between the maturation of metabolism enzymes or transporters and genetics have a major impact on drug exposure leading to age-specific dosage requirements. This review aims to describe implementation of pharmacogenetics in personalized medicine and specifies pediatric characteristics with ethical considerations.

BackgroundTacrolimus is used off-label in the treatment of Henoch-Schönlein purpura nephritis (HSPN) in children, with limited evidence-based data. Based on clinical empirical experience and mechanism of action, tacrolimus might be promoted as treatment for childhood HSPN. The objectives of this pilot study were to assess its effectiveness and safety, and to explore the potential impact of CYP3A5 genotype.MethodsChildren with HSPN receiving tacrolimus as empirical treatment were included in this prospective, observational study. Effectiveness was classified as complete remission, partial remission or non-response. General safety data analyses during and after study drug exposure included adverse events, reasons for discontinuation, deaths, laboratory data and vital signs. Trough concentration was determined using high-performance liquid chromatography with tandem mass spectrometry. Pharmacogenetic analysis was performed on the CYP3A5 gene.ResultsA total of 20 patients with a mean age of 7.5 (SD 2.1) years participated in the whole process of the study. Twelve patients reached complete remission and eight patients reached partial remission at the end of 6-month treatment. No patients discontinued tacrolimus treatment due to adverse events, and no drug-related adverse events were shown to have a causal association with tacrolimus therapy. Dose-adjusted trough concentration was significantly higher in children with CYP3A5*1 allele as compared with patients with CYP3A5*3/*3 genotype (170.7±100.9 vs 79.8±47.4 (ng/mL)/(mg/kg)).ConclusionThis pilot study showed that tacrolimus might be an effective and well-tolerated drug for the treatment of HSPN in children. CYP3A5 polymorphism had a significant impact on tacrolimus concentration.

Aims Although substantial progress has been made in understanding of ontogeny of drug metabolism, there is still a gap of knowledge in developmental pharmacogenetics in neonates. We hypothesized that both age and pharmacogenetics might explain the developmental pattern of CYP2C19. We conducted a population pharmacokinetic–pharmacogenetic study to quantify the developmental pharmacogenetics of CYP2C19 in neonates and young infants using omeprazole as a probe drug. Methods Pharmacokinetic samples were collected from 51 Caucasian neonates and young infants, who were receiving omeprazole treatment. Population pharmacokinetic–pharmacogenetic analysis of omeprazole and its metabolites was performed using NONMEM. Results Data fitted a one-compartment parent and metabolite model with first-order absorption and elimination. CYP2C19 and CYP3A4 are predominantly involved in the metabolism of omeprazole despite their relatively low activities compared to adults. The clearance of omeprazole converted to 5-hydroxy-omeprazole (CLOMZ-M1) increases with postnatal age. In CYP2C19 poor and intermediate metabolizers, model-predicted CLOMZ-M1 are 12.5% (5–95% percentile: 3–14.9%) and 44.9% (5–95% percentile: 29.9–72.6%) of the value in extensive/ultrarapid metabolizer, respectively. Model-predicted absorption rate constant of omeprazole is 6.93 (5–95% percentile: 3.01–14.61) times higher in ABCB1 homozygous mutant patients, 1.86 (5–95% percentile: 0.86–3.47) times higher in ABCB1 heterozygous patients than that in ABCB1 homozygous wild-type patients. Conclusions Developmental pharmacogenetics of CYP2C19 was quantitatively described in neonates and young infants using omeprazole as a probe drug. Our findings emphasize the importance of semiphysiological developmental pharmacokinetic modelling approach when evaluating developmental pharmacogenetics of drugs with multiple routes of biotransformation.

Progress in immunosuppression has reduced acute rejection, graft loss and mortality after renal transplantation. Adverse drug reactions are well described in adults but few data are available in children. Our objectives were to analyse the adverse events reported in the first 3 years post-transplantation in children receiving tacrolimus or cyclosporine-based immunosuppression and compare them with the information of the Summary of Product Characteristics.This retrospective study included all children who underwent a renal transplant at Hospital Robert Debré between 2002 and 2015. Initial immunosuppression was based on induction, calcineurin inhibitor, mycophenolate mofetil and corticosteroids. Adverse events were collected from medical records and coded using the Medical Dictionary for Regulatory Activities and the implications of tacrolimus and cyclosporine analysed. Statistical analyses were performed using SAS 9.4.One hundred and twenty-five children were included. During the observation period [2.7 years (0.6-4.3)], 105 patients received tacrolimus and 39 received cyclosporine. The incidence rate for gastrointestinal disorders was 0.128 and 0.056 by patient-years of exposure (p 0.05), under tacrolimus and cyclosporine schedules. For neutropenia, it was 0.064 and 0.014 (p 0.05). The frequencies of toxic nephropathy and gastrointestinal pain were higher than those in the Summary of Product Characteristics of tacrolimus ( 20%) and cyclosporine ( 10%). Cosmetic events for cyclosporine and neutropenia for tacrolimus were frequently observed (18 and 14.3%, respectively), although uncommon in the Summary of Product Characteristics.The exposure-adjusted incidence rate of gastrointestinal disorders and neutropenia was higher in children under the tacrolimus schedule. Our findings contribute to the evaluation of the benefit-risk balance of immunosuppressive therapy following paediatric renal transplantation.

Aims: Inflammation and organ failure have been reported to impact cytochrome P450 (CYP) 3A-mediated clearance of midazolam in critically ill children. Our aim was to evaluate a previously developed population pharmacokinetic model in both critically ill children and other populations in order to allow the model to be used to guide dosing in clinical practice. Methods: The model was externally evaluated in 136 individuals, including (pre)term neonates, infants, children, and adults (body weight 0.77-90 kg, CRP 0.1-341 mg/L and 0-4 failing organs) using graphical and numerical diagnostics. Results: The pharmacokinetic model predicted midazolam clearance and plasma concentrations without bias in post-operative or critically ill paediatric patients and term neonates (median prediction error (MPE) 180%). Conclusion: The recently published pharmacokinetic model for midazolam, quantifying the influence of maturation, inflammation, and organ failure in children yields unbiased clearance predictions and can therefore be used for dosing instructions in term neonates, children, and adults with varying levels of critical illness including healthy adults, but not for extrapolation to preterm neonates.

Aim The objectives of this study were to characterize age-related changes in lamivudine pharmacokinetics in children and evaluate lamivudine exposure, followed by dose recommendations for subgroups in which target steady state area under the daily plasma concentration–time curve (AUC0–24h) is not reached. Methods Population pharmacokinetic modelling was performed in NONMEM using data from two model-building datasets and two external datasets [n = 180 (age 0.4–18 years, body weight 3.4–60.5 kg); 2061 samples (median 12 per child); daily oral dose 60–300 mg (3.9–17.6 mg kg–1)]. Steady state AUC0–24h was calculated per individual (adult target 8.9 mg·h l–1). Results A two-compartment model with sequential zero order and first order absorption best described the data. Apparent clearance and central volume of distribution (% RSE) were 13.2 l h–1 (4.2%) and 38.9 l (7.0%) for a median individual of 16.6 kg, respectively. Bodyweight was identified as covariate on apparent clearance and volume of distribution using power functions (exponents 0.506 (20.2%) and 0.489 (32.3%), respectively). The external evaluation supported the predictive ability of the final model. In 94.5% and 35.8% of the children with a body weight >14 kg and

Background: Polycystic ovary syndrome (PCOS) is more frequently observed in type 1 diabetes mellitus (T1DM) adult women than in nondiabetic women. No such prevalence has yet been studied in adolescent girls with T1DM. Aim: The aim of this study was to evaluate the prevalence of PCOS in adolescent girls with T1DM and to determine the clinical and hormonal features associated with the disorder. Methods: A cross-sectional study of 53 adolescent girls (gynecological age >2 years) referred for routine evaluation for T1DM was conducted. We diagnosed PCOS using the National Institutes of Health (NIH) and Rotterdam criteria. Results: 26.4 and 47.9% of adolescents had PCOS according to NIH (NIH-PCOS) and Rotterdam (Rotterdam-PCOS) criteria. 66.7% of NIH-PCOS adolescents had a complete phenotype associated with hyperandrogenism, oligomenorrhea, and polycystic ovarian morphology, unlike only 33.3% of the Rotterdam-PCOS adolescents. A family history of type 2 diabetes mellitus (T2DM) was more frequent in PCOS than in non-PCOS girls, whichever criteria were used. Late pubertal development and a T1DM diagnosis close to puberty were factors associated with NIH-PCOS. Conclusion: Adolescents with T1DM had a high prevalence of PCOS. More differences between PCOS and non-PCOS patients were found using the NIH criteria, suggesting that clinical characteristics might be more accurate for diagnosing PCOS in girls with T1DM. A family history of T2DM is associated with a high risk of PCOS.

BACKGROUND Valganciclovir, the ganciclovir prodrug, is an antiviral agent administered orally to prevent or treat cytomegalovirus infection in solid organ transplant recipients. Dosing regimen of valganciclovir is still controversial in children, as the number of patients reaching the Area Under the Curve at steady state (AUCss) target (40 - 60 mg.h/L) remains highly variable. The aim of this study was to determine the population pharmacokinetics of valganciclovir in paediatric renal transplant recipients and propose an appropriate dosing regimen. METHODS Renal transplant children who received valganciclovir to prevent or treat cytomegalovirus infection at Robert Debre University Hospital were included. Plasma ganciclovir concentrations were determined by high performance liquid chromatography and ultraviolet detection. Population pharmacokinetic analysis was performed with NONMEM software. RESULTS 104 patients, aged 2 to 20 years, treated with valganciclovir administered at a mean dose of 17.3 ± 6.1 mg/kg to prevent and/or treat cytomegalovirus infection after renal transplantation were included. A total of 1212 samples were available. A two-compartment model with first-order elimination best fitted the data: ganciclovir clearance increased with body surface area, was 15% higher in boys and decreased with increasing creatinine concentration. Central volume of distribution increased with body surface area and was 14% higher in boys. According to the personalized dosing regimen, 65.7% and 65.4% of children were predicted to achieve the AUCss target for cytomegalovirus prophylaxis and treatment, respectively. CONCLUSION A new pharmacokinetic model was built allowing to propose individualised dose adapted to renal transplanted paediatric patients characteristics.

ObjectivesTo evaluate the population pharmacokinetics of cefoperazone in children and establish an evidence-based dosing regimen using a developmental pharmacokinetic–pharmacodynamic approach in order to optimize cefoperazone treatment.MethodsA model-based, open-label, opportunistic-sampling pharmacokinetic study was conducted in China. Blood samples from 99 cefoperazone-treated children were collected and quantified by HPLC/MS. NONMEM software was used for population pharmacokinetic–pharmacodynamic analysis. This study was registered at ClinicalTrials.gov (NCT03113344).ResultsA two-compartment model with first-order elimination agreed well with the experimental data. Covariate analysis showed that current body weight had a significant effect on the pharmacokinetics of cefoperazone. Monte Carlo simulation showed that for bacteria for which cefoperazone has an MIC of 0.5 mg/L, 78.1% of hypothetical children treated with ‘40 mg/kg/day, q8h, IV drip 3 h’ would reach the pharmacodynamic target. For bacteria for which cefoperazone has an MIC of 8 mg/L, 88.4% of hypothetical children treated with 80 mg/kg/day (continuous infusion) would reach the treatment goal. A 160 mg/kg/day (continuous infusion) regimen can cover bacteria for which cefoperazone has an MIC of 16 mg/L. Nevertheless, even if using the maximum reported dose of 160 mg/kg/day (continuous infusion), the ratio of hypothetical children reaching the treatment target was only 9.9% for bacteria for which cefoperazone has an MIC of 32 mg/L.ConclusionsFor cefoperazone, population pharmacokinetics were evaluated in children and an appropriate dosing regimen was developed based on developmental pharmacokinetics–pharmacodynamics. The dose indicated in the instructions (20–160 mg/kg/day) can basically cover the clinically common bacteria for which cefoperazone has an MIC of ≤16 mg/L. However, for bacteria for which the MIC is >16 mg/L, cefoperazone is not a preferred choice.

Background Montelukast, a potent oral selective leukotriene-receptor antagonist, inhibits the action of cysteinyl-leukotriene in patients with asthma. Although pharmacokinetic studies of montelukast have been reported in Caucasian adults and children, and showed large inter-individual variability on pharmacokinetics, none of these studies has been explored in Chinese children. Given the potential inter-ethnic difference, the purpose of the present study was to evaluate the effects of developmental factors and pharmacogenetics of CYP2C8 and SLCO2B1 on montelukast clearance in Chinese pediatric patients. Methods After the administration of montelukast, blood samples were collected from children and plasma concentrations were determined using an adapted micro high-performance liquid chromatography coupled with the fluorescence detection (HPLC-FLD) method. A previously published pharmacokinetic model was validated using the opportunistic pharmacokinetic samples, and individual patient’s clearance was calculated using the validated model. Population pharmacokinetic analysis was performed using a nonlinear mixed-effects model approach (NONMEM V 7.2.0) and variants of CYP2C8 and SLCO2B1 were genotyped. Results Fifty patients (age range: 0.7–10.0 years) with asthma were enrolled in this study. The clearance of montelukast was significantly higher in children with the SLCO2B1 c.935GA and c.935AA genotypes compared with that of children with the SLCO2B1 c.935GG genotype (0.94 ± 0.26 versus 0.77 ± 0.21, p = 0.020). The patient’s weight was also found to be significantly corrected with montelukast clearance (p

Glomerular diseases are leading causes of end-stage renal disease in children. Tacrolimus is frequently used off-label in the treatment of glomerular diseases. The effectiveness, safety and pharmacokinetic data of tacrolimus in the treatment of glomerular diseases in children are reviewed in this paper to provide evidence to support its rational use in clinical practice. The remission rates in previously published studies were different. In 19 clinical trials on children with nephrotic syndrome, the overall remission rate was 52.6-97.6%. In four clinical trials on children with lupus nephritis, the overall remission rate was 81.8-89.5%. In a pilot study with paediatric Henoch-Schonlein purpura nephritis patients, the overall remission rate was 100.0%. Infection, nephrotoxicity, gastrointestinal symptoms and hypertension are the most common adverse events. Body weight, age, CYP3A5 genotype, cystatin-C and daily dose of tacrolimus may have significant effects on the pharmacokinetics of tacrolimus in children with glomerular disease. More prospective controlled trials with long follow-up are needed to demonstrate definitely the effectiveness, safety and pharmacokinetics of tacrolimus in children with glomerular diseases.

Objective: To evaluate the pharmacokinetic profile and tolerability of pitolisant, a selective histamine 3 (H3)−receptor antagonist/inverse agonist, in children and adolescents with narcolepsy. Methods: This multicenter, open-label, single-dose study of pitolisant 17.8 mg enrolled patients aged 6 through 17 years with a diagnosis of narcolepsy. Blood samples were collected at prespecified time points for analysis of pharmacokinetic parameters, including maximum serum concentration (Cmax) and area under the serum concentration–time curve from time 0–10 h (AUC0–10h). Pharmacokinetic parameters were compared across three prespecified age groups: younger pediatric patients (aged 6 to

We evaluated the population pharmacokinetics of caspofungin in children (2 to 12 years of age). The real-world data from 48 children were best fit by a two-compartment model with first-order elimination. Subsequent covariate analysis demonstrated that body surface area had a significant correlation with caspofungin pharmacokinetics, compared to body weight. The population pharmacokinetics of caspofungin confirmed that adjustment of caspofungin dosage based on body surface area is most appropriate for pediatric use.

ObjectivesThe primary objective of this study is to determine the current level of patient medication exposure in Level 3 Neonatal Wards (L3NW). The secondary objective is to evaluate in the first month of life the rate of medication prescription not cited in the Summary of Product Characteristics (SmPC). A database containing all the medication prescriptions is collected as part of a prescription benchmarking program in the L3NW.Material and methodsThe research is a two-year observational cohort study (2017-2018) with retrospective analysis of medications prescribed in 29 French L3NW. Seventeen L3NW are present since the beginning of the study and 12 have been progressively included. All neonatal units used the same computerized system of prescription, and all prescription data were completely de-identified within each hospital before being stored in a common data warehouse.ResultsThe study population includes 27,382 newborns. Two hundred and sixty-one different medications (International Nonproprietary Names, INN) were prescribed. Twelve INN (including paracetamol) were prescribed for at least 10% of patients, 55 for less than 10% but at least 1% and 194 to less than 1%. The lowest gestational ages (GA) were exposed to the greatest number of medications (18.0 below 28 weeks of gestation (WG) to 4.1 above 36 WG) (pConclusionNeonates remain therapeutic orphans. The consequences of polypharmacy in L3NW should be quickly assessed, especially in the most immature infants.

BackgroundClinical trials are conducted during pregnancy to evaluate benefits and risks of medicines for mother and child. The safety of maternal treatments is a key issue for healthcare professionals and parents.ObjectiveTo analyse offspring data reported in clinical trials in pregnant women with diabetes, HIV infection or hypertension (three of the most common diseases in women of childbearing potential) and either treated prior to pregnancy for these chronic diseases or diagnosed and treated during pregnancy.MethodsPubMed and Embase (1 January 1997 to 31 December 2017) were searched for drug trials in pregnant women with diabetes, HIV infection or hypertension. Titles and abstracts were screened, followed by a full-text review of eligible articles. Inclusion criteria were interventional clinical trials in pregnant women treated with medication and full text in English. Trial characteristics, maternal and offspring data were extracted. Data were summarised by disease and study. Twelve key items were considered for the offspring.ResultsOverall, 196 articles reporting 132 clinical trials (diabetes n=55; HIV n=59; hypertension n=18) were included. Key offspring data were frequently not reported, for example, number of births (diabetes: 22/55, 40%; HIV: 14/59, 24%; hypertension: 10/18, 56%). Congenital malformations were often not reported with sufficient detail (diabetes: 40/55, 73%; HIV: 39/59, 66%; hypertension: 17/18, 94%). Similar observations were made for other key items (eg, fetal losses, neonatal deaths).ConclusionUnder-reporting of key data for the offspring was frequent in publications of clinical trials in pregnant women with diabetes, HIV infection or hypertension making the assessment of the benefit-risk ratio of treatment options during pregnancy difficult.Trial registration numberCRD42017057024.

Amoxicillin is widely used to treat bacterial infections in neonates. However, considerable intercenter variability in dosage regimens of antibiotics exists in clinical practice. The pharmacokinetics of amoxicillin has been described in only a few preterm neonates. Thus, we aimed to evaluate the population pharmacokinetics of amoxicillin through a large sample size covering the entire age range of neonates and young infants and to establish evidence-based dosage regimens based on developmental pharmacokinetics-pharmacodynamics. This is a prospective, multicenter, pharmacokinetic study using an opportunistic sampling design. Amoxicillin plasma concentrations were determined using high-performance liquid chromatography. Population pharmacokinetic analysis was performed using NONMEM. A total of 224 pharmacokinetic samples from 187 newborns (postmenstrual age range, 28.4 to 46.3 weeks) were available for analysis. A two-compartment model with first-order elimination was used to describe population pharmacokinetics. Covariate analysis showed that current weight, postnatal age, and gestational age were significant covariates. The final model was further validated for predictive performance in an independent cohort of patients. Monte Carlo simulation demonstrated that for early-onset sepsis, the currently used dosage regimen (25 mg/kg twice daily [BID]) resulted in 99.0% of premature neonates and 87.3% of term neonates achieving the pharmacodynamic target (percent time above MIC), using a MIC breakpoint of 1 mg/liter. For late-onset sepsis, 86.1% of premature neonates treated with 25 mg/kg three times a day (TID) and 79.0% of term neonates receiving 25 mg/kg four times a day (QID) reached the pharmacodynamic target, using a MIC breakpoint of 2 mg/liter. The population pharmacokinetics of amoxicillin was assessed in neonates and young infants. A dosage regimen was established based on developmental pharmacokinetics-pharmacodynamics.

Imipenem is widely used for the treatment of children with serious infections. Currently, studies on the pharmacokinetics of imipenem in children with hematological malignancies are lacking. Given the significant impact of disease on pharmacokinetics and increased resistance, we aimed to conduct a population pharmacokinetic study of imipenem and optimize the dosage regimens for this vulnerable population. After children were treated with imipenem-cilastatin (IMP-CS), blood samples were collected from the children and the concentrations of imipenem were quantified using high-performance liquid chromatography with UV detection. Then, a population-level pharmacokinetic analysis was conducted using NONMEM software. Data were collected from 56 children (age range, 2.03 to 11.82 years) with hematological malignancies to conduct a population pharmacokinetic analysis. In this study, a two-compartment model that followed first-order elimination was found to be the most suitable. The parameters of current weight, age, and creatinine elimination rate were significant covariates that influenced imipenem pharmacokinetics. As a result, 41.4%, 56.1%, and 67.1% of the children reached the pharmacodynamic target (the percentage of the time during the total dosing interval that the free drug concentration remains above the MIC of 70%) against sensitive pathogens with an MIC of 0.5 mg/liter with imipenem at 15, 20, and 25 mg/kg of body weight every 6 h (q6h), respectively. However, only 11.1% of the children achieved the pharmacodynamic target against Pseudomonas aeruginosa isolates with an MIC of 2 mg/liter at a dose of 25 mg/kg q6h. The population pharmacokinetics of imipenem were assessed in children. The current dosage regimens of imipenem result in underdosing against resistant pathogens, including Pseudomonas aeruginosa and Acinetobacter baumannii. However, for sensitive pathogens, imipenem has an acceptable pharmacodynamic target rate at a dosage of 25 mg/kg q6h. (The study discussed in this paper has been registered at ClinicalTrials.gov under identifier {"type":"clinical-trial","attrs":{"text":"NCT03113344","term_id":"NCT03113344"}}NCT03113344.)

There is wide variation in neonatal dosages of antibiotics in clinical practice, both nationally and internationally. This reflects the lack of evaluation of drugs in this therapeutic class, although widely prescribed. Given this situation, optimization of antibiotic prescription is required to ensure efficacy and safety of neonatal treatment and reduce microbial resistance. Rational prescription should be based on the knowledge of developmental pharmacokinetics and pharmacodynamics. Rigorous studies, conducted in collaboration between neonatologists and pharmacologists, are essential to develop and validate evidence-based neonatal dosage regimens.

Background Congenital cytomegalovirus (CMV) infection is the leading infectious cause of birth defects, mental retardation and non-genetic sensorineural hearing loss. Murine models have been developed in order to understand the pathophysiological mechanisms underlying these lesions. These models are being proposed for the validation of therapeutic protocols for clinical use. The aim of this preclinical study was to assess the pharmacokinetics of the reference antiviral molecule, ganciclovir, in order to optimize these protocols and confirm the diffusion of the molecule to the appropriate target zones. Methods Transplacental and intracochlear diffusion of ganciclovir was evaluated in mice and rats. Pharmacokinetics was assessed in adult mice and pups after 5 consecutive days of intraperitoneal injection of ganciclovir. The occurrence of hematological side effects of ganciclovir was evaluated in the different blood cell lineages. Results In adult rats, the intracochlear diffusion of ganciclovir was shown to achieve the same concentration as in blood. In gestating mice, transplacental diffusion was observed, with a fetal-to-maternal blood ratio of 0.5. In newborn mice, the plasma concentration profile of ganciclovir showed a peak at 2 h followed by a gradual decrease. In adult mice, the concentration peaked at 1 h, but became undetectable by 2 h after injection. Counts of white blood cells, red blood cells and platelets decreased significantly in ganciclovir-treated newborn mice. Conclusion Our data provide evidence for the intracochlear diffusion of the molecule, which may be relevant for the treatment of sensorineural hearing loss in congenitally-infected children.

Aim Term and preterm neonates are at high risk for serious adverse drug reactions (ADRs). Methods A descriptive study of reports registered in the French pharmacovigilance database from 1986 to 2012 were obtained. All reports concerning neonates (≤1 month of life) with direct drug exposure were retrieved. Characteristics of the reports, including reported ADR(s), drug(s) and the causality assessment using the French causality assessment method, were described. Results A total of 1688 reports were analyzed and more than half of them were classified as serious (n = 995). Median age at ADR occurrence was 9 days. Overall, 3127 ADRs were described in these reports in relation to 2238 suspect/interacting drugs. The most commonly reported system organ classes (SOCs) were injury, poisoning and procedural complications (16%), general disorders and administration site conditions (12.5%) and blood and lymphatic system disorders (12%). In the majority of ADRs reported (73%), infants fully recovered and less than 4% of neonates deceased as a consequence of the reported ADR. One out of five ADRs was associated with drug administration errors. Therapeutic classes commonly incriminated were anti-infectives, nervous system and alimentary tract drugs. Substances most frequently related to serious ADRs were zidovudine, ibuprofen and nevirapine. Among the 10 most frequently encountered drug−ADR pairs, two substances were mainly implicated, zidovudine in haematological adverse reactions and phytomenadione in maladministrations. Conclusions Anti-infective drugs, mainly antiretroviral therapy, account for the majority of ADRs reported in neonates. The specific issue of drug maladministration and medication errors remains to be addressed in neonates.

OBJECTIVES CoNS are the most common cause of neonatal late-onset sepsis. Information on the vancomycin pharmacokinetics/pharmacodynamics against CoNS is limited. The aim of this study was to characterize vancomycin pharmacokinetic/pharmacodynamic relationships for CoNS and investigate neonatal optimal dosage regimens. METHODS A hollow fibre and a novel rabbit model of neonatal central line-associated bloodstream CoNS infections were developed. The results were then bridged to neonates by use of population pharmacokinetic techniques and Monte Carlo simulations. RESULTS There was a dose-dependent reduction in the total bacterial population and C-reactive protein levels. The AUC/MIC and Cmax/MIC ratios were strongly linked with total and mutant resistant cell kill. Maximal amplification of resistance was observed in vitro at an fAUC/MIC of 200 mg · h/L. Simulations predicted that neonates

Background Large sample sizes are often required to detect statistically significant associations between pharmacogenetic markers and treatment response. Meta-analysis may be performed to synthesize data from several studies, increasing sample size and, consequently, power to detect significant genetic effects. However, performing robust synthesis of data from pharmacogenetic studies is often challenging because of poor reporting of key data in study reports. There is currently no guideline for the reporting of pharmacogenetic studies that has been developed using a widely accepted robust methodology. The objective of this project was to develop the STrengthening the Reporting Of Pharmacogenetic Studies (STROPS) guideline. Methods and findings We established a preliminary checklist of reporting items to be considered for inclusion in the guideline. We invited representatives of key stakeholder groups to participate in a 2-round Delphi survey. A total of 52 individuals participated in both rounds of the survey, scoring items with regards to their importance for inclusion in the STROPS guideline. We then held a consensus meeting, at which 8 individuals considered the results of the Delphi survey and voted on whether each item ought to be included in the final guideline. The STROPS guideline consists of 54 items and is accompanied by an explanation and elaboration document. The guideline contains items that are particularly important in the field of pharmacogenetics, such as the drug regimen of interest and whether adherence to treatment was accounted for in the conducted analyses. The guideline also requires that outcomes be clearly defined and justified, because in pharmacogenetic studies, there may be a greater number of possible outcomes than in other types of study (for example, disease–gene association studies). A limitation of this project is that our consensus meeting involved a small number of individuals, the majority of whom are based in the United Kingdom. Conclusions Our aim is for the STROPS guideline to improve the transparency of reporting of pharmacogenetic studies and also to facilitate the conduct of high-quality systematic reviews and meta-analyses. We encourage authors to adhere to the STROPS guideline when publishing pharmacogenetic studies., Marty Chaplin and co-authors recount the development of a guideline for reporting pharmacogenetic studies.

Context Growth hormone (GH) therapy may improve statural growth outcomes in patients with severe juvenile idiopathic arthritis (JIA). Objectives To evaluate the effect of GH treatment on adult height and to identify determinants of growth outcomes in JIA. Design and Patients Data from 58 patients with JIA, including 53 receiving GH, enrolled in three prospective clinical trials between 1997 and 2002 were analyzed. Intervention GH (0.056 mg/kg/d [interquartile range (IQR), 0.050 to 0.062]) for a median duration of 6.5 years (IQR, 4.7 to 7.9 years). Main Outcome Measures Factors associated with a favorable growth outcome (adult height - target height ≤ -1.5 standard deviations) were identified by multivariate logistic regression. Results Adult height was available for 48 patients 8.6 years after GH initiation (IQR, 6.0 to 10.2 years). Height standard deviation score (SDS) increased from -2.9 (IQR, -4.4 to -1.6) at baseline to -1.7 (IQR, -3.9 to -0.1) in adulthood (P < 0.001). Median adult height was below target height [SDS, -0.2 (IQR, -1.4 to 0.4); P < 0.001]. Corrected adult height SDS was -1.3 (IQR, -3.0 to -0.2). Growth outcome was favorable in 24 (52.2%) patients. Significant independent determinants of growth outcome were age at GH initiation [adjusted odds ratio (aOR), 0.68 per additional year; 95% confidence interval (CI), 0.47 to 0.99], height at GH initiation (aOR, 2.6 per additional SDS; 95% CI, 1.15 to 5.9), and mean C-reactive protein levels during follow up (aOR, 0.51 per additional 10 mg/L; 95% CI, 0.28 to 0.92). Conclusion Long-term GH treatment significantly increased growth in patients with JIA but did not fully restore the genetic growth potential. The response showed marked interindividual variability and was weaker in patients with severe inflammation.

Individual genomic differences may affect drug disposition and effects of many drugs, and identification of biomarkers are crucial to personalize dosage and optimize response. In children, developmental changes associated with growth and maturation translate into different relationships between genotype and phenotype and different responses to treatment compared to adults. This review aims to summarize some developmental aspects of pharmacogenetics, based on practical examples.

Background Multicenter neonatal clinical trials aim to provide evidence-based drug evaluation, but recruiting neonates requires collaboration, standard procedures, and trained neonatologists. Methods A questionnaire based on a previous Delphi study was sent to European neonatal intensive care units (NICUs) to collect their research experience and identify areas for improvement. Results Of 247 NICUs,79 (32%) responded: 69 were level III units and 10 were level II units. In level III centers, 62% had medical staff dedicated to research and 65% conducted regular in-house audits. Similarities were observed in the median number of trials per year (level II: 2; level III: 5), Good Clinical Practice training (level II: 78%; level III: 66%), and standard operating procedures (level II: 63%; level III: 71%). Most NICUs had access to scientific advice for trial design, conduct, data management, and regulatory aspects. Involvement of patient advocacy groups was more common in level II units (level II: 75%; level III: 59%). A “quality” score of 34 “quality” research items was calculated for all centers (mean: 23.2 ± 6.2; range: 6–34). Conclusion Research experience and processes vary across Europe. Harmonizing research practices and setting standards will allow building a European neonatal network for effective, safe, and quality neonatal drug development.

Cefotaxime is the first-line treatment for meningitis in neonates and young infants. However, limited data on cefotaxime cerebrospinal fluid (CSF) concentrations in neonates and young infants were available. The aim of the present study was to evaluate the penetration of cefotaxime into CSF in neonates and young infants. Blood and CSF samples were collected from neonates and young infants treated with cefotaxime using an opportunistic pharmacokinetic sampling strategy, and concentrations were quantified by high-performance liquid chromatography-tandem mass spectrometry. The analysis was performed using NONMEM and R software. Thirty neonates and young infants (postmenstrual age range, 25.4 to 47.4 weeks) were included. A total of 67 plasma samples and 30 CSF samples were available for analysis. Cefotaxime plasma and CSF concentrations ranged from 2.30 to 175.42 mg/liter and from 0.39 to 25.38 mg/liter, respectively. The median ratio of the CSF concentration to the plasma concentration was 0.28 (range, 0.06 to 0.76). Monte Carlo simulation demonstrated that 88.4% and 63.9% of hypothetical neonates treated with 50 mg/kg of body weight three times a day (TID) would reach the pharmacodynamic target (the percentage of the dosing interval that the free antimicrobial drug concentration remains above the MIC, 70%) using the standard EUCAST MIC susceptibility breakpoints of 2 mg/liter and 4 mg/liter, respectively. The penetration of cefotaxime into the CSF of neonates and young infants was evaluated using an opportunistic sampling approach. A dosage regimen of 50 mg/kg TID could cover the most causative pathogens with MICs of Staphylococcus aureus .

Objectives To determine the ciprofloxacin population pharmacokinetics in paediatric patients and the impact of underlying disease and evaluate the appropriateness of current dosage regimens. Patients and methods Plasma concentrations of ciprofloxacin from children treated with ciprofloxacin were measured by HPLC. The pharmacokinetic population analysis was performed using NONMEM v7.2 (Icon Development Solutions, USA). Results Two datasets were combined and 128 plasma concentrations in 60 patients aged 5.6 years (range 0.3-18.9), treated with a median daily dose of 30.0 mg/kg (range 6.5-52.0) presenting with sickle cell disease (SCD; n = 20, 33%), haemopathy (n = 15, 25%), cystic fibrosis (CF; n = 3, 5%) and other diseases (n = 22, 37%) were analysed. Data were best described by a two-compartment model with first-order elimination. Ciprofloxacin clearance (mean ± SD) was 0.81 ± 0.30 L/h/kg, increased allometrically with weight, decreased with increasing creatinine concentration, was 89% higher in SCD compared with non-SCD patients and increased by 0.95 L/h/kg per year of age. The volume of distribution was 6.9 L/kg and depended only on the weight. Monte Carlo simulations were performed separately in SCD and non-SCD patients to target an AUC/MIC ratio >125 at steady-state, required for antibacterial efficacy, and recommendations of dosing regimens were proposed. Conclusions In addition to known covariates, ciprofloxacin clearance is greater in SCD children compared with non-SCD patients. The dosing of this agent needs to be adapted to this subgroup of patients.

Objectives Early target attainment is the key factor influencing the outcome of antimicrobial therapy. The objective of the present study was to evaluate the relationship between azithromycin concentrations during the first 24-48 h of therapy and the clinical outcome in order to optimize antimicrobial therapy. Methods All children with lower respiratory tract infections receiving intravenous azithromycin monotherapy were included. The relationship between azithromycin trough concentrations during the first 24-48 h and the effectiveness and safety was explored. Results Data from 44 children [mean (SD) age = 5.25 (3.72) years] were available for final analysis. Children with trough concentrations >0.25 mg/L (n = 8) had a more significant improvement in antibacterial efficacy in terms of decreased C-reactive protein (P = 0.006) and the percentage of neutrophils (P = 0.043) compared with children with trough concentrations ≤0.25 mg/L (n = 36). No drug-related adverse events were shown to have a causal association with azithromycin therapy. Conclusions Our study showed the clinical benefits of early target attainment of azithromycin therapy. A target trough concentration of 0.25 mg/L in the first 24-48 h of hospitalization was required to ensure better antibacterial efficacy.

AIMS: Nephrotic syndrome (NS) is the most common clinical manifestation of glomerular disease in children. Currently, tacrolimus (TAC) is widely used in children with NS. However, pharmacokinetic data in children with nephrotic syndrome is limited. This study was intended to evaluate the population pharmacokinetics (PPK) of TAC in paediatric NS and to optimize dosing regimen. METHODS: Blood samples from NS children treated with TAC were collected and the blood concentrations of TAC were detected using HPLC‐MS/MS. A PPK model was developed using NONMEM software. Pharmacogenetic analysis was carried out in the CYP3A5 gene. RESULTS: The data from 28 children were used for PPK analysis. A one‐compartment model and first‐order elimination were accorded with the TAC data in paediatric NS. A covariate analysis showed that body weight and CYP3A5 genotype significantly affected TAC pharmacokinetics. Monte Carlo simulation indicated that NS children with CYP3A5*3/*3 receiving 0.10 mg kg(−1) dose(−1) twice daily and NS children with CYP3A5*1 receiving 0.25 mg kg(−1) dose(−1) twice daily TAC could achieve the target concentrations of 5–10 ng ml(−1). CONCLUSION: The PPK of TAC was estimated in children with NS and a CYP3A5 genotype‐based dosing regimen was set up based on simulations.

Newborns with congenital cytomegalovirus (CMV) infection are at high risk for developing permanent sequelae. Intravenous ganciclovir therapy is frequently used for the treatment of congenital CMV infection. A target area under the concentration-time curve from 0 to 24 h (AUC 0–24 ) of 40 to 50 μg · h/ml is recommended. The standard dose has resulted in a large variability in ganciclovir exposure in newborns, indicating the unmet need of dosage individualization for this vulnerable population, but the implementation of this strategy remains challenging in clinical practice. We aim to evaluate the clinical utility of model-based dosage individualization of ganciclovir in newborns using an opportunistic sampling approach. The predictive performance of a published ganciclovir population pharmacokinetic model was evaluated using an independent patient cohort. The individual dose was adjusted based on the target AUC 0–24 to ensure its efficacy. A total of 26 newborns with congenital CMV infection were included in the present study. Only 11 (42.3%) patients achieved the target AUC 0–24 after being given the standard dose. For all the subtherapeutic patients (achieving n = 5), a model-based dosage adjustment was performed using the Bayesian estimation method combined with the opportunistic sampling strategy. The adjusted doses were increased by 28.6% to 60.0% in these five patients, and all adapted AUC 0–24 values achieved the target (range, 48.6 to 66.1 μg · h/ml). The clinical utility of model-based dosing individualization of ganciclovir was demonstrated in newborns with congenital CMV infection. The population pharmacokinetic model combined with the opportunistic sampling strategy provides a clinically feasible method to adapt the ganciclovir dose in neonatal clinical practice. (This study has been registered at ClinicalTrials.gov under registration no. NCT03113344.)