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To ensure the safe and effective dosing of gentamicin in children, therapeutic drug monitoring (TDM) is recommended. TDM utilizing Bayesian forecasting software is recommended but is unavailable, as no population model that describes the pharmacokinetics of gentamicin in pediatric oncology patients exists. This study aimed to develop and externally evaluate a population pharmacokinetic model of gentamicin to support personalized dosing in pediatric oncology patients. A nonlinear mixed-effect population pharmacokinetic model was developed from retrospective data. Data were collected from 423 patients for model building and a further 52 patients for external evaluation. A two-compartment model with first-order elimination best described the gentamicin disposition. The final model included renal function (described by fat-free mass and postmenstrual age) and the serum creatinine concentration as covariates influencing gentamicin clearance (CL). Final parameter estimates were as follow CL, 5.77 liters/h/70 kg; central volume of distribution, 21.6 liters/70 kg; peripheral volume of distribution, 13.8 liters/70 kg; and intercompartmental clearance, 0.62 liter/h/70 kg. External evaluation suggested that current models developed in other pediatric cohorts may not be suitable for use in pediatric oncology patients, as they showed a tendency to overpredict the observations in this population. The final model developed in this study displayed good predictive performance during external evaluation (root mean square error, 46.0%; mean relative prediction error, Ϫ3.40%) and may therefore be useful for the personalization of gentamicin dosing in this cohort. Further investigations should focus on evaluating the clinical application of this model. KEYWORDS pharmacokinetics, gentamicin, NONMEM, pediatrics, oncology, pharmacometrics, population pharmacokinetics F ebrile neutropenia induced by chemotherapy is a common complication in pediatric oncology patients. Neutropenic patients are more susceptible to the development of infections (1). Sepsis is the primary cause of mortality and morbidity in pediatric oncology patients with febrile neutropenia (2). The rate of mortality due to sepsis is 1.6-fold higher for oncology pediatric patients than it is for other pediatric patients (3). Aminoglycoside antibiotics, such as gentamicin, in combination with other broad-spectrum antibacterial agents play an important role in managing infectious complications in these individuals and are used as second-line therapies when treating Gram-negative bacterial infections and when resistance to first-line agents develops (4).Gentamicin has a narrow therapeutic window and displays large pharmacokinetic variability. High levels of and prolonged exposure to gentamicin has been associated with nephro-and ototoxicity (5, 6). Pediatric oncology patients often receive long

Background Common genetic variance in apolipoprotein E (APOE), β‐glucocerebrosidase (GBA), microtubule‐associated protein tau (MAPT), and α‐synuclein (SNCA) has been linked to cognitive decline in Parkinson's disease (PD), although studies have yielded mixed results. Objectives To evaluate the effect of genetic variants in APOE, GBA, MAPT, and SNCA on cognitive decline and risk of dementia in a pooled analysis of six longitudinal, non‐selective, population‐based cohorts of newly diagnosed PD patients. Methods 1002 PD patients, followed for up to 10 years (median 7.2 years), were genotyped for at least one of APOE‐ε4, GBA mutations, MAPT H1/H2, or SNCA rs356219. We evaluated the effect of genotype on the rate of cognitive decline (Mini‐Mental State Examanation, MMSE) using linear mixed models and the development of dementia (diagnosed using standardized criteria) using Cox regression; multiple comparisons were accounted for using Benjamini−Hochberg corrections. Results Carriers of APOE‐ε4 (n = 281, 29.7%) and GBA mutations (n = 100, 10.3%) had faster cognitive decline and were at higher risk of progression to dementia (APOE‐ε4, HR 3.57, P < 0.001; GBA mutations, HR 1.76, P = 0.001) than non‐carriers. The risk of cognitive decline and dementia (HR 5.19, P < 0.001) was further increased in carriers of both risk genotypes (n = 23). No significant effects were observed for MAPT or SNCA rs356219. Conclusions GBA and APOE genotyping could improve the prediction of cognitive decline in PD, which is important to inform the clinical trial selection and potentially to enable personalized treatment © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society

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