Use of Real-World Data and Physiologically-Based Pharmacokinetic Modeling to Characterize Enoxaparin Disposition in Children With Obesity

Clinical Pharmacology & Therapeutics August 2022

Gerhart JG, Carreño FO, Loop MS, Lee CR, Edginton AN, Sinha J, Kumar KR, Kirkpatrick CM, Hornik CP, Gonzalez D; Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee

 

Dosing guidance for children with obesity is often unknown despite the fact that nearly 20% of US children are classified as obese. Enoxaparin, a commonly prescribed low-molecular-weight heparin, is dosed based on body weight irrespective of obesity status to achieve maximum concentration within a narrow therapeutic or prophylactic target range. However, whether children with and without obesity experience equivalent enoxaparin exposure remains unclear. The study aimed to answer this clinical question. Enoxaparin exposure was better matched across age groups and obesity status using fat-free mass weight-based dosing.

 

Use of physiologically-based pharmacokinetic modeling to inform dosing of the opioid analgesics fentanyl and methadone in children with obesity

CPT: Pharmacometrics & Systems Pharmacology  June 2022

Gerhart JG, Carreno FO, Ford JL, Edginton AN, Perrin EM, Watt KM, Muller WJ, Atz AM, Al-Uzri A, Delmore P, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee

 

Children with obesity are commonly prescribed the opioids fentanyl and methadone, and accurate dosing is critical to reducing the risk of serious adverse events associated with overexposure. However, there is limited information to guide fentanyl and methadone dosing in these children. This study addresses the clinical knowledge gap using physiologically-based pharmacokinetic models of fentanyl and methadone developed in adults and scaled to children with and without obesity to explore the interplay of obesity, age, and pharmacogenomics.

 

 

Development and Evaluation of a Virtual Population of Children with Obesity for Physiologically Based Pharmacokinetic Modeling

Clinical Pharmacokinetics February 2022

Gerhart JG, Carreno FO, Edginton AN, Sinha J, Perrin E, Kumar KR, Rikhi A, Hornik CP, Harris V, Ganguly S, Cohen-Wolkowiez M, Gonzalez D; on behalf of the Best Pharmaceuticals for Children Act — Pediatric Trials Network Steering Committee

 

A virtual population of children with obesity was developed using national survey, electronic health record, and clinical trial data, as well as data extracted from the literature. The objective of this study was to develop a virtual population of children with obesity to enable physiologically based pharmacokinetic modeling, then use the novel virtual population in conjunction with previously developed models of clindamycin and trimethoprim/sulfamethoxazole to better understand dosing of these drugs in children with obesity. Model simulations supported current recommended weight-based dosing in children with obesity for clindamycin and trimethoprim/sulfamethoxazole, as they met target exposure despite these changes in clearance and volume of distribution.

 

 

Estimation of Body Fat Percentage for Clinical Pharmacokinetic Studies in Children

Clinical and Translational Science • March 2021

Green TP, Binns HJ, Wu H, Ariza AJ, Perrin EM, Quadri M, Hornik CP, Cohen-Wolkowiez M

Obesity is a prevalent childhood condition and the degree of adiposity is likely to be an important covariate in the pharmacokinetics (PKs) of many drugs. The goal of these studies was to facilitate the evaluation and, where appropriate, quantification of the covariate effect of body fat percentage (BF%) on PK parameters in children. Researchers examined two large databases to determine the values and variabilities of BF% in children with healthy body weights and in those with obesity, comparing the accuracy and precision of BF% estimation by both clinical methods and demographically derived techniques. They also conducted simulation studies to evaluate the utility of the several methods for application in clinical trials. The estimation of BF% from sex and obesity stage can routinely be applied to PK clinical trials to evaluate the contribution of BF% as a potential covariate.

 

Pharmacokinetics of Hydrochlorothiazide in Children: A Potential Surrogate for Renal Secretion Maturation

The Journal of Clinical Pharmacology • March 2021

Commander SJ, Wu H, Boakye-Agyeman F, Melloni C, Hornik CD, Zimmerman K, Al-Uzri A, Mendley SR, Harper B, Cohen-Wolkowiez M, Hornik CP
Hydrochlorothiazide (HCTZ) is a thiazide diuretic used in adults and children for the treatment of hypertension and edema. The pharmacokinetic (PK) properties of HCTZ in children are not well characterized, particularly among children with obesity who frequently suffer from hypertension and may, therefore, benefit from HCTZ therapy. Simulated exposure decreased with age and was likely due to older children receiving the maximum absolute doses of HCTZ. Further studies with more patients in each age group are required to confirm these PK findings of HCTZ in the children.

Dosing of Continuous Fentanyl Infusions in Obese Children: A Population Pharmacokinetic Analysis

The Journal of Clinical Pharmacology • December 2019

 

Maharaj AR, Wu H, Zimmerman KO, Speicher D, Sullivan JE, Watt K, Al-Uzri A, Payne E, Erinjeri J, Lin S, Harper B, Melloni C, Hornik CP; on behalf of the Best Pharmaceuticals for Children Act-Pediatric Trials Network Steering Committee
The impact of childhood obesity on fentanyl PK is relatively unknown. We developed a population pharmacokinetic (PopPK) model using opportunistically collected samples from a cohort of predominately obese children receiving fentanyl per the standard of care. Use of an allometric relationship between weight and clearance was appropriate for describing the PK of intravenous fentanyl in our cohort. Our proposed model-derived continuous infusion strategy maximized the probability of achieving target steady-state concentrations in children of varying weights.

Population Pharmacokinetics of Doxycycline in Children

Antimicrobial Agents and Chemotherapy • September 2019

Thompson EJ, Wu H, Melloni C, Balevic S, Sullivan JE, Laughon M, Clark KM, Kalra R, Mendley S, Payne E, Erinjeri J, Gelber C, Harper B, Cohen-Wolkoweiz M, Hornik CP

Doxycycline is a tetracycline-class antimicrobial labeled by the United States (U.S.) Food and Drug Administration for children >8 years of age for many common childhood infections. Doxycycline is not labeled for children ≤8 years of age, due to the association between tetracycline class antibiotics and tooth staining. We leveraged opportunistically-collected plasma samples after intravenous (IV) and oral doxycycline doses received per standard of care to characterize the pharmacokinetics (PK) of doxycycline in children of different ages between 0 and 18 years.

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Pharmacokinetics of Ceftazidime in Children and Adolescents with Obesity

Paediatric Drugs  September 2021

Maharaj AR, Wu H, Zimmerman KO, Muller WJ, Sullivan JE, Sherwin CMT, Autmizguine J, Rathore MH, Hornik CD, Al-Uzri A, Payne EH, Hornik CP, on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee

 

The aim of this study was to evaluate ceftazidime pharmacokinetics (PK) in a cohort that includes a predominate number of children and adolescents with obesity and assess the efficacy of competing dosing strategies.

 

Product Labeling of Drugs Commonly Administered to Children and Adults with Obesity

Pharmaceutical Regulatory Affairs  April 2019

Zimmerman KO, Benjamin DK ,Becker ML, Anand R, Hornik CP

 

Obesity is a major public health problem that can affect drug disposition and dosing, particularly in vulnerable pediatric populations. Despite potentially detrimental consequences from inappropriately dosed drugs in children with obesity, drug product labels largely fail to include dosing or guidance specific to this population. Using data from the PTN, this study explored possible ways to improve drug labeling in children with obesity.

 

A Population-Based Pharmacokinetic Model Approach to Pantoprazole Dosing for Obese Children and Adolescents

Pediatric Drugs • October 2018.

Shakhnovich V, Brian Smith P, Guptill JT, James LP, Collier DN, Wu H, Livingston CE, Zhao J, Kearns GL, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act–Pediatric Trials Network.

Pharmacokinetic data for proton pump inhibitors (PPIs), acid-suppression drugs commonly prescribed to children, are lacking for obese children who are at greatest risk for acid-related disease. In a recent multi-center investigation, we demonstrated decreased, total body weight adjusted, apparent clearance (CL/F) of the PPI pantoprazole for obese children compared with their non-obese peers.

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