Dosing in neonates: special considerations in physiology and trial design

Evaluation of Patient-Centric Sample Collection Technologies for Pharmacokinetic Assessment of Large and Small Molecules

Low-volume sampling devices offer the promise of lower discomfort and greater convenience for patients, potentially reducing patient burden and enabling decentralized clinical trials. In this study, we determined whether low-volume sampling devices produce pharmacokinetic (PK) data comparable to conventional venipuncture for a diverse set of monoclonal antibodies (mAbs) and small molecules. We adopted an open-label, non-randomized, parallel-group, single-site study design, with four cohorts of 10 healthy subjects per arm. The study drugs, doses, and routes of administration included: crenezumab (15 mg/kg, intravenous infusion), etrolizumab (210 mg, subcutaneous), GDC-X (oral), and hydroxychloroquine (HCQ, 200 mg, oral). Samples were collected after administration of a single dose of each drug using conventional venipuncture and three low-volume capillary devices: TassoOne Plus for liquid blood, Tasso-M20 for dry blood, both applied to the arm, and Neoteryx Mitra® for dry blood obtained from fingertips. Serum/plasma concentrations from venipuncture and TassoOne Plus samples overlapped and PK parameters were comparable for all drugs, except HCQ. After applying a baseline hematocrit value, the dry blood concentrations and PK parameters for the two monoclonal antibodies were comparable to those obtained from venipuncture. For the two small molecules, two bridging strategies were evaluated for converting dry blood concentrations to equivalent plasma concentrations. A baseline hematocrit correction and/or linear regression-based correction was effective for GDC-X, but not for HCQ. Additionally, the study evaluated the bioanalytical data quality and comparability from the various collection methods, as well as patient preference for the devices.

When will the Glomerular Filtration Rate in Former Preterm Neonates Catch up with Their Term Peers?

AIMS

Whether and when glomerular filtration rate (GFR) in preterms catches up with term peers is unknown. This study aims to develop a GFR maturation model for (pre)term-born individuals from birth to 18 years of age. Secondarily, the function is applied to data of different renally excreted drugs.

METHODS

We combined published inulin clearance values and serum creatinine (Scr) concentrations in (pre)term born individuals throughout childhood. Inulin clearance was assumed to be equal to GFR, and Scr to reflect creatinine synthesis rate/GFR. We developed a GFR function consisting of GFRbirth (GFR at birth), and an Emax model dependent on PNA (with GFRmax, PNA50 (PNA at which half ofGFR max is reached) and Hill coefficient). The final GFR model was applied to predict gentamicin, tobramycin and vancomycin concentrations.

RESULT

In the GFR model, GFRbirth varied with birthweight linearly while in the PNA-based Emax equation, GA was the best covariate for PNA50, and current weight for GFRmax. The final model showed that for a child born at 26 weeks GA, absolute GFR is 18%, 63%, 80%, 92% and 96% of the GFR of a child born at 40 weeks GA at 1 month, 6 months, 1 year, 3 years and 12 years, respectively. PopPK models with the GFR maturation equations predicted concentrations of renally cleared antibiotics across (pre)term-born neonates until 18 years well.

CONCLUSIONS

GFR of preterm individuals catches up with term peers at around three years of age, implying reduced dosages of renally cleared drugs should be considered below this age.

Pharmacokinetic and pharmacodynamic principles: unique considerations for optimal design of neonatal clinical trials

Core clinical pharmacology principles must be considered when designing and executing neonatal clinical trials. In this review, the authors discuss important aspects of drug dose selection, pharmacokinetics, pharmacogenetics and pharmacodynamics that stakeholders may consider when undertaking a neonatal or infant clinical trial.

Pharmacokinetic and Pharmacodynamic Considerations of Antibiotic Use in Neonates

The selection of an appropriate dose of a given antibiotic for a neonate not only requires knowledge of the drug's basic pharmacokinetic (PK) and pharmacodynamic (PD) properties but also the profound effects that organ development might have on the volume of distribution and clearance, both of which may affect the PK/PD of a drug. Interest has grown in alternative antibiotic dosing strategies that are better aligned with the antibiotic's PK and PD properties. These strategies should be used in conjunction with minimum inhibitory concentration measurements and therapeutic drug monitoring to measure their potential success. They can also guide the clinician in tailoring the delivery of antibiotics to suit an individual patient's needs. Model-informed precision dosing, such as Bayesian forecasting dosing software (which incorporates PK/PD population models), may be utilized to optimize antibiotic exposure in neonatal populations. Consequently, optimizing the antibiotic dose and exposure in each newborn requires expertise in different fields. It drives the collaboration of physicians together with lab technicians and quantitative clinical pharmacologists.

Off-Label Prescribing in Pediatric Population-Literature Review for 2012-2022

Off-label prescribing is widespread among pediatricians, and it is unlikely that this trend will soon be bound by a uniform legal framework. This is necessitated by the fact that there are four variables: the patient's health condition, the physician's experience and knowledge, the legislative measures (laws, directives, guidelines, and recommendations), and finally, the pharmaceutical industry. There is considerable concern worldwide about the use of off-label medicines in children. We may call it an enormous global problem that is much talked about and written about; however, we should not forget that the goal around which everyone should unite is the patient's life. For healthcare providers, the most important thing will always be the health and preservation of the patient's life, particularly when it comes to children with life-threatening conditions in neonatal and pediatric intensive care units (NICU and PICU). The study aimed to examine the prevalence of off-label drug use in pediatrics. Literature research was conducted, and we included studies from 2012 to 2022 that evaluated off-label drug prevalence in various pediatric patient populations.

Neonatal Drug Formularies-A Global Scope

Neonatal drug information (DI) is essential for safe and effective pharmacotherapy in (pre)term neonates. Such information is usually absent from drug labels, making formularies a crucial part of the neonatal clinician's toolbox. Several formularies exist worldwide, but they have never been fully mapped or compared for content, structure and workflow. The objective of this review was to identify neonatal formularies, explore (dis)similarities, and raise awareness of their existence. Neonatal formularies were identified through self-acquaintance, experts and structured search. A questionnaire was sent to all identified formularies to provide details on formulary function. An original extraction tool was employed to collect DI from the formularies on the 10 most commonly used drugs in pre(term) neonates. Eight different neonatal formularies were identified worldwide (Europe, USA, Australia-New Zealand, Middle East). Six responded to the questionnaire and were compared for structure and content. Each formulary has its own workflow, monograph template and style, and update routine. Focus on certain aspects of DI also varies, as well as the type of initiative and funding. Clinicians should be aware of the various formularies available and their differences in characteristics and content to use them properly for the benefit of their patients.

Cytotoxic and genotoxic effects of leaking chemicals from serum infusion sets: an in-vitro study

Safety concerns about medical devices playing important role in health sciences and bioengineering research are rising day by day. Although there are specific standards regarding disposable medical materials, the information is updating with the toxicological studies. In this study, cytotoxic/genotoxic effects of chemicals leaking from serum infusion sets that have an important place in the clinic were investigated. Media containing leakage chemicals were prepared from equal samples taken from the plastic line sections of 13 different brands of serum infusion sets containing phthalates and the effects on the cultured cells were compared with the untreated control groups. To obtain leaking chemicals, extracting period was selected as 72 h, a routine set-change time in the clinic as indicated in various publications. Neutral red uptake and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tests were performed in L929 cells to determine cytotoxicity, and cytokinesis blocked micronucleus technique was performed in lymphocytes to determine genotoxicity. Cytotoxic and genotoxic damage levels were compared by evaluating cell-viability rates relative to control, micronucleus frequency, and nuclear division index values. The results showed that all sets caused a decrease in cell viability revealing the effects both on lysosomal and mitochondrial activity and increase in micronucleus frequencies in general. The number of similar studies is extremely limited, and in this study in addition to the short-term effects of using the serum infusion sets, the information about the sample tests to determine the biosecurity of disposable medical materials is given.

Developmental Pharmacokinetics of Antibiotics Used in Neonatal ICU: Focus on Preterm Infants

Neonatal Infections are among the most common reasons for admission to the intensive care unit. Neonatal sepsis (NS) significantly contributes to mortality rates. Empiric antibiotic therapy of NS recommended by current international guidelines includes benzylpenicillin, ampicillin/amoxicillin, and aminoglycosides (gentamicin). The rise of antibacterial resistance precipitates the growth of the use of antibiotics of the Watch (second, third, and fourth generations of cephalosporines, carbapenems, macrolides, glycopeptides, rifamycins, fluoroquinolones) and Reserve groups (fifth generation of cephalosporines, oxazolidinones, lipoglycopeptides, fosfomycin), which are associated with a less clinical experience and higher risks of toxic reactions. A proper dosing regimen is essential for effective and safe antibiotic therapy, but its choice in neonates is complicated with high variability in the maturation of organ systems affecting drug absorption, distribution, metabolism, and excretion. Changes in antibiotic pharmacokinetic parameters result in altered efficacy and safety. Population pharmacokinetics can help to prognosis outcomes of antibiotic therapy, but it should be considered that the neonatal population is heterogeneous, and this heterogeneity is mainly determined by gestational and postnatal age. Preterm neonates are common in clinical practice, and due to the different physiology compared to the full terms, constitute a specific neonatal subpopulation. The objective of this review is to summarize the evidence about the developmental changes (specific for preterm and full-term infants, separately) of pharmacokinetic parameters of antibiotics used in neonatal intensive care units.

Fetal and Neonatal Anesthesia

Anesthesia for fetal and neonatal surgery requires subspecialized knowledge and expertise. Attention to important anatomic, physiologic, and metabolic differences seen in pregnancy and at birth are essential for the optimal care of these patients. Thorough preoperative evaluations tailored intraoperative strategies and careful postoperative management are critical when devising the anesthetic approach for each of these cases.

Assessment of Kidney Function in Children

A good understanding of kidney function tests is essential for patient care. Urinalysis is the commonest used test for screening purposes in ambulatory settings. Glomerular function is assessed further by urine protein excretion and estimated glomerular filtration rate and tubular function by various tests such as urine anion gap and excretion of sodium, calcium, and phosphate. In addition, kidney biopsy and/or genetic analyses may be required to further characterize the underlying kidney disease. In this article, we discuss maturation and the assessment of kidney function in children.

Non-static framework for understanding adaptive designs: an ethical justification in paediatric trials

Many drugs used in paediatric medicine are off-label. There is a rising call for the use of adaptive clinical trial designs (ADs) in responding to the need for safe and effective drugs given their potential to offer efficiency and cost-effective benefits compared with traditional clinical trials. ADs have a strong appeal in paediatric clinical trials given the small number of available participants, limited understanding of age-related variability and the desire to limit exposure to futile or unsafe interventions. Although the ethical value of adaptive trials has increasingly come under scrutiny, there is a paucity of literature on the ethical dilemmas that may be associated with paediatric adaptive designs (PADs). This paper highlights some of these ethical concerns around safety, scientific/social value and caregiver/guardian comprehension of the trial design. Against this background, the paper develops a non-static conceptual lens for understanding PADs. It shows that ADs are epistemically open and reduce some of the knowledge-associated uncertainties inherent in clinical trials as well as fast-track the time to draw conclusions about the value of evaluated drugs/treatments. On this note, the authors argue that PADs are ethically justifiable given they (1) have multiple layers of safety, exposing enrolled children to lesser potential risks, (2) create social/scientific value generally and for paediatric populations in particular, (3) specifically foster the flourishing of paediatric populations and (4) can significantly improve paediatric trial efficiency when properly designed and implemented. However, because PADs are relatively new and their regulatory, ethical and logistical characteristics are yet to be clarified in some jurisdictions, the cooperation of various public and private stakeholders is required to ensure that the interests of children, their caregivers and parents/guardians are best served while exposing paediatric research subjects to the most minimal of risks when they are enrolled in paediatric trials that use ADs.

Management Strategies in Perinatal HIV

Current management of perinatal HIV infections and exposures involves the administration of antiretroviral therapy to both the pregnant mother and to her child after delivery. Striving to achieve safe and effective medication management is key in preventing new pediatric HIV infections. Maternal HIV testing and subsequent monitoring can help to identify fetal HIV exposures during pregnancy, maternal nonadherence, insufficient treatment regimens, and otherwise undiscovered exposures during the delivery process. There are several well-constructed guidelines that offer expert references for healthcare providers. This chapter will summarize current recommendations from the United States, with a brief insight into select international guidelines. Although available guidelines provide a structured framework for the healthcare team, there has recently been a significant drive to advance current perinatal management and outcomes.

The Blind Spot of Pharmacology: A Scoping Review of Drug Metabolism in Prematurely Born Children

The limit for possible survival after extremely preterm birth has steadily improved and consequently, more premature neonates with increasingly lower gestational age at birth now require care. This specialized care often include intensive pharmacological treatment, yet there is currently insufficient knowledge of gestational age dependent differences in drug metabolism. This potentially puts the preterm neonates at risk of receiving sub-optimal drug doses with a subsequent increased risk of adverse or insufficient drug effects, and often pediatricians are forced to prescribe medication as off-label or even off-science. In this review, we present some of the particularities of drug disposition and metabolism in preterm neonates. We highlight the challenges in pharmacometrics studies on hepatic drug metabolism in preterm and particularly extremely (less than 28 weeks of gestation) preterm neonates by conducting a scoping review of published literature. We find that >40% of included studies failed to report a clear distinction between term and preterm children in the presentation of results making direct interpretation for preterm neonates difficult. We present summarized findings of pharmacokinetic studies done on the major CYP sub-systems, but formal meta analyses were not possible due the overall heterogeneous approaches to measuring the phase I and II pathways metabolism in preterm neonates, often with use of opportunistic sampling. We find this to be a testament to the practical and ethical challenges in measuring pharmacokinetic activity in preterm neonates. The future calls for optimized designs in pharmacometrics studies, including PK/PD modeling-methods and other sample reducing techniques. Future studies should also preferably be a collaboration between neonatologists and clinical pharmacologists.

Medication Use in the Neonatal Intensive Care Unit and Changes from 2010 to 2018

OBJECTIVE

To provide up-to-date medication prescribing patterns in US neonatal intensive care units (NICUs) and to examine trends in prescribing patterns over time.

STUDY DESIGN

We performed a cohort study of 799 016 infants treated in NICUs managed by the Pediatrix Medical Group from 2010 to 2018. We used 3 different methods to report counts of medication: exposure, courses, and days of use. We defined the change in frequency of medication administration by absolute change and relative change. We examined the Food and Drug Administration (FDA) package insert for each medication to determine whether a medication was labeled for use in infants and used PubMed to search for pharmacokinetics (PK) studies.

RESULTS

The most frequently prescribed medications included ampicillin, gentamicin, caffeine citrate, poractant alfa, morphine, vancomycin, furosemide, fentanyl, midazolam, and acetaminophen. Of the top 50 medications used in infants with extremely low birth weight, only 20 (40%) are FDA-labeled for use in infants; of the 30 that are not labeled for use in infants, 13 (43%) had at least 2 published PK studies. The medications with the greatest relative increase in use from 2010 to 2018 included dexmedetomidine, clonidine, rocuronium, levetiracetam, atropine, and diazoxide. The medications with the greatest relative decrease in use included tromethamine acetate, pancuronium, chloral hydrate, imipenem + cilastatin, and amikacin.

CONCLUSION

Trends of medication use in the NICU change substantially over time. It is imperative to identify changes in medication use in the NICU to better inform further prospective studies.

Pre- and Postnatal Maturation are Important for Fentanyl Exposure in Preterm and Term Newborns: A Pooled Population Pharmacokinetic Study

BACKGROUND AND OBJECTIVE

Fentanyl is an opioid commonly used to prevent and treat severe pain in neonates; however, its use is off label and mostly based on bodyweight. Given the limited pharmacokinetic information across the entire neonatal age range, we characterized the pharmacokinetics of fentanyl across preterm and term neonates to individualize dosing.

METHODS

We pooled data from two previous studies on 164 newborns with a median gestational age of 29.0 weeks (range 23.9-42.3), birthweight of 1055 g (range 390-4245), and postnatal age (PNA) of 1 day (range 0-68). In total, 673 plasma samples upon bolus dosing (69 patients; median dose 2.1 μg/kg, median 2 boluses per patient) or continuous infusions (95 patients; median dose 1.1 μg/kg/h for 30 h) with and without boluses were used for population pharmacokinetic modeling in NONMEM^® 7.4.

RESULTS

Clearance in neonates with birthweight of 2000 and 3000 g was 2.8- and 5.0-fold the clearance in a neonate with birthweight of 1000 g, respectively. Fentanyl clearance at PNA of 7, 14, and 21 days was 2.7-fold, 3.8-fold, and 4.6-fold the clearance at 1 day, respectively. Bodyweight-based dosing resulted in large differences in fentanyl concentrations. Depending on PNA and birthweight, fentanyl concentrations increased slowly after the start of therapy for both intermittent boluses and continuous infusion and reached a maximum concentration at 12-48 h.

CONCLUSIONS

As both prenatal and postnatal maturation are important for fentanyl exposure, we propose a birthweight- and PNA-based dosage regimen. To provide rapid analgesia in the first 24 h of treatment, additional loading doses need to be considered.

Validation of an HPLC method for estimation of cefotaxime from dried blood spot: alternative to plasma-based PK evaluation in neonates

Aim: Pharmacokinetic evaluation of cefotaxime in neonates is currently a challenge due to the large volume requirement of blood for its analysis by existing methods. A dried blood spot (DBS) based method is the best alternative. Materials & methods: We validated an HPLC method for estimation of cefotaxime from DBS and plasma. Extraction employed a simple procedure using acetonitrile and buffer. Selective separation of cefotaxime was achieved on a C8 column using gradient programming. Results & conclusion: The linearity of the method ranged from 2 to 200 μg/ml with acceptable precision and accuracy for both plasma and DBS. Hematocrit was not affecting the assay accuracy. A strong correlation and interchangeability observed with the plasma method proves its clinical validity for application to PK evaluations.

Safety and effectiveness of parent- or nurse-controlled analgesia in neonates: a systematic review

OBJECTIVE

The aim of this systematic review was to determine the safety and effectiveness of parent- or nurse-controlled analgesia on neonatal patient outcomes. More specifically, the objective was to determine the effect of parent- or nurse-controlled analgesia on neonatal pain scores, analgesic use, and incidence of iatrogenic withdrawal syndrome, as well as any opioid-associated adverse events.

INTRODUCTION

Despite recent innovations in neonatology leading to significant improvements in short- and long-term outcomes for newborns requiring intensive care, optimal management of pain and distress remains a challenge for the treating multidisciplinary team. The inability of neonates to communicate pain easily, inconsistent practice among health professionals, insufficient analgesic prescriptions, and delays in medical reviews all impact effective pain management. Exploring the effect of parent- or nurse-controlled analgesia may identify a modality that negates these concerns and improves the pharmacological management of pain in newborns.

INCLUSION CRITERIA

This review considered experimental and observational studies evaluating the safety and effectiveness of parent- or nurse-controlled analgesia that included babies born at 23 weeks' gestation to four weeks post-term. The interventions considered for inclusion were any type of analgesia delivered by an infusion pump that allowed bolus dosing or a continuous analgesic infusion with bolus dosing as required. Studies using algorithms and protocols to guide timing and dosage were eligible for inclusion. Comparators included the standard management of pain for neonates in the newborn intensive care unit. A modification to the a priori protocol was made to include all neonates nursed outside of a neonatal intensive care unit to ensure all studies that examined the use of parent- or nurse-controlled analgesia in the neonatal population were included in the review.

METHODS

An extensive search of six major databases was conducted (CINAHL, Cochrane Library, Embase, PubMed, PsycINFO, and Web of Science). Studies published from 1997 to 2020 in English were considered for inclusion in this review. Databases searched for unpublished studies included MedNar and ProQuest Dissertations and Theses.

RESULTS

Fourteen studies were included in this review: two randomized controlled trials, six quasi-experimental studies, one case-control study, and five case series. There was considerable heterogeneity in the interventions and study outcome measures within the studies, resulting in an inability to statistically pool results. The small sample sizes and inability to distinguish data specific to neonates in six of the studies resulted in low quality of evidence for the safety and effectiveness of parent- or nurse-controlled analgesia in neonates. However, studies reporting neonatal data demonstrated low pain scores and a trend in reduced opioid consumption when parent- or nurse-controlled analgesia was used.

CONCLUSIONS

The use of parent- or nurse-controlled analgesia in the neonatal population has shown some effect in reducing the amount of opioid analgesia required without compromising pain relief or increasing the risk of adverse events. Due to the paucity of evidence available, certainty of the results is compromised; therefore, larger trials exploring the use of parent- or nurse-controlled analgesia in neonates and the development of nurse-led models for analgesia delivery are needed.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42018114382.

Optimizing Meropenem Therapy for Severe Nosocomial Infections in Neonates

Meropenem pharmacokinetics in neonates exhibits large interindividual variability due to developmental changes occurring during the first month of life. The objective was to characterize meropenem pharmacokinetics through a population approach to determine effective dosing recommendations in neonates with severe nosocomial infections. Three blood samples from forty neonates were obtained once steady-state blood levels were achieved and plasma concentrations were determined with a validated chromatographic method. Data were used to develop and validate the one-compartment with first-order elimination population pharmacokinetic model obtained by non-linear mixed effect modeling. The final model was Clearance (L/h) = 2.23 × Creatinine Clearance (L/h) and Volume of distribution(L) = 6.06 × Body Surface Area(m²) × (1 + 0.60 if Fluticasone comedication). Doses should be adjusted based on said covariates to increase the likelihood of achieving therapeutic targets. This model explains 12.9% of the interindividual variability for meropenem clearance and 19.1% for volume of distribution. Stochastic simulations to establish initial dosing regimens to maximize the time above the MIC showed that the mean probabilities to achieve the PK/PD target (PTA) for microorganisms with a MIC of 2 and 8 µg/mL were 0.8 and 0.7 following i.v. bolus of 250 and 500 mg/m²/dose q8h, respectively. Meropenem extended 4h infusion would improve PTA in neonates with augmented creatinine clearance.

Preterm Physiologically Based Pharmacokinetic Model. Part II: Applications of the Model to Predict Drug Pharmacokinetics in the Preterm Population

BACKGROUND

Preterm neonates are usually not part of a traditional drug development programme, however they are frequently administered medicines. Developing modelling and simulation tools, such as physiologically based pharmacokinetic (PBPK) models that incorporate developmental physiology and maturation of drug metabolism, can be used to predict drug exposure in this group of patients, and may help to optimize drug dose adjustment.

OBJECTIVE

The aim of this study was to assess and verify the predictability of a preterm PBPK model using compounds that undergo diverse renal and/or hepatic clearance based on the knowledge of their disposition in adults.

METHODS

A PBPK model was developed in the Simcyp Simulator V17 to predict the pharmacokinetics (PK) of drugs in preterm neonates. Drug parameters for alfentanil, midazolam, caffeine, ibuprofen, gentamicin and vancomycin were collated from the literature. Predicted PK parameters and profiles were compared against the observed data.

RESULTS

The preterm PBPK model predicted the PK changes of the six compounds using ontogeny functions for cytochrome P450 (CYP) 1A2, CYP2C9 and CYP3A4 after oral and intravenous administrations. For gentamicin and vancomycin, the maturation of renal function was able to predict the exposure of these two compounds after intravenous administration. All PK parameter predictions were within a twofold error criteria.

CONCLUSION

While the developed preterm model for the prediction of PK behaviour in preterm patients is not intended to replace clinical studies, it can potentially help with deciding on first-time dosing in this population and study design in the absence of clinical data.

Physiologically Based Pharmacokinetic Modeling Framework to Predict Neonatal Pharmacokinetics of Transplacentally Acquired Emtricitabine, Dolutegravir, and Raltegravir

BACKGROUND AND OBJECTIVE

Little is understood about neonatal pharmacokinetics immediately after delivery and during the first days of life following intrauterine exposure to maternal medications. Our objective was to develop and evaluate a novel, physiologically based pharmacokinetic modeling workflow for predicting perinatal and postnatal disposition of commonly used antiretroviral drugs administered prenatally to pregnant women living with human immunodeficiency virus.

METHODS

Using previously published, maternal-fetal, physiologically based pharmacokinetic models for emtricitabine, dolutegravir, and raltegravir built with PK-Sim/MoBi^®, placental drug transfer was predicted in late pregnancy. The total drug amount in fetal compartments at term delivery was estimated and subsequently integrated as initial conditions in different tissues of a whole-body, neonatal, physiologically based pharmacokinetic model to predict drug concentrations in the neonatal elimination phase after birth. Neonatal elimination processes were parameterized according to published data. Model performance was assessed by clinical data.

RESULTS

Neonatal physiologically based pharmacokinetic models generally captured the initial plasma concentrations after delivery but underestimated concentrations in the terminal phase. The mean percentage error for predicted plasma concentrations was - 71.5%, - 33.8%, and 76.7% for emtricitabine, dolutegravir, and raltegravir, respectively. A sensitivity analysis suggested that the activity of organic cation transporter 2 and uridine diphosphate glucuronosyltransferase 1A1 during the first postnatal days in term newborns is ~11% and ~30% of that in adults, respectively.

CONCLUSIONS

These findings demonstrate the general feasibility of applying physiologically based pharmacokinetic models to predict washout concentrations of transplacentally acquired drugs in newborns. These models can increase the understanding of pharmacokinetics during the first postnatal days and allow the prediction of drug exposure in this vulnerable population.

Sociocultural Practices Affecting the Care of Preterm Infants in the Ghanaian Community

Introduction

Although culture is an integral part of health, there is scarcity of evidence on the influence of culture on caregiving experiences of parents of preterm infants. The aim of this study was to explore the influence of sociocultural practices on caring for preterm infants in the Ghanaian community.

Method

Narrative inquiry was utilized to explore the influence of sociocultural practices on the care of preterm infants from 21 mothers, 9 fathers, and 12 household members. Data were collected through face-to-face semistructured interviews and observations at participants’ homes.

Results

Analysis of data resulted in three threads/themes—respect for the elderly, use of herbal medicines, and communal living.

Discussion

Community and extended family members have great influence on the care of preterm infants. Traditional herbal medicines are considered effective in treating traditional illnesses among preterm infants. Understanding the influence of culture on the care of vulnerable preterm infants in the community is essential in developing interventions for infant survival.

Drug dosing in neonates

Neonates have specific physiological differences from older children and adults that influence drug pharmacokinetics (PK) and pharmacodynamics (PD). These differences necessitate adjustments in drug dosing in order to ensure efficacy and avoid toxicity in the perioperative period. Knowledge pertaining to the ontogeny of neonatal organ systems is required to ensure safety and optimal care of these patients. The myriad of moral and operational concerns pertaining to neonatal research limits our ability to perform prospective trials and gain sufficient data to determine ideal drug dosing in this heterogenous population. Certain advances in PK and PD modelling, especially allometric theories, have improved our recent understanding and highlighted that age, maturation of organ systems and patient size must be taken into account.

Pediatric Antiretroviral Therapy

Human immunodeficiency virus (HIV) is one of the most serious pediatric infectious diseases, affecting around 3 million children and adolescents worldwide. Lifelong antiretroviral treatment (ART) provides multiple benefits including sustained virologic suppression, restoration and preservation of immune function, decreased morbidity and mortality, and improved quality of life. However, access to ART, particularly among neonates and young infants, continues to be challenging due to limited number of suitable formulations and limited access to pediatric ARV drug. Moreover, children and adolescents living with HIV may experience long-term HIV- and ART-associated comorbidities including cardiovascular, renal, neurological, and metabolic complications. We provide an overview of currently available formulations, dosing, and safety considerations for pediatric antiretroviral drugs by drug classes and according to the three age groups including neonates, children, and adolescents.

Quantification of bis(2-ethylhexyl) phthalate released by medical devices during respiratory assistance and estimation of patient exposure

Bis(2-ethylhexyl) phthalate (DEHP) migration from polyvinyl chloride (PVC) has been studied with infusion, transfusion and extracorporeal oxygenation devices, but no study has been conducted to estimate its migration via respiratory medical devices (MDs). This work aims to develop an ex vivo model to quantify DEHP released doses by these MDs, which will then be used to estimate newborns DEHP exposure from respiratory assistance MDs. We followed the Frensh National Research and Safety Institute (INRS) recommendations for the validation of a collecting and analysing method of DEHP in air, which will be used to quantify DEHP in air passing through PVC respiratory assistance MDs. The developed method met all the validation criteria for DEHP determination in air. DEHP in air passing through MDs on the sixth day reached a cumulative quantity of 122.86 μg when using a flow rate of 4 L min^-1 of non-humidified air while it was of 49.22 μg; 58.12 μg and 29.61 μg with flow rates of 2 L min^-1 of humidified air, 2 L min^-1 of dry air and 4 L min^-1 of humidified air, respectively. Model application to two patients undergoing two different respiratory procedure demonstrated that noninvasive ventilation patient received higher dose of inhaled DEHP, confirmed by DEHP metabolites quantification in urine. Although the protective effect of air humidifiers on DEHP exposure was demonstrated, the effect of flow rate is difficult to be established. This developed method should be tested to verify its capacity to collect and quantify other plasticizers used in PVC MDs.

Dosing of Antimicrobials in the Neonatal Intensive Care Unit: Does Clinical Practice Reflect Pharmacokinetics-based Recommendations?

BACKGROUND

We sought to compare meropenem and fluconazole dosing in the neonatal intensive care unit with recommendations based on published pharmacokinetic (PK) studies in infants.

METHODS

We performed an observational cohort study of infants <90 days postnatal age who received a course of meropenem or fluconazole who were treated in neonatal intensive care units managed by the Pediatrix Medical Group (1997-2016). We defined any dose amount from 80% to 120% of the published recommendation to constitute an appropriate dose of either antimicrobial. We calculated the percentage of appropriately dosed courses overall and by discharge year. We then evaluated the change in appropriate dosing over time using a nonparametric test of trend to evaluate the proportion of appropriately dosed courses of each antimicrobial by discharge year.

RESULTS

A total of 3608 infants were administered 2025 courses of meropenem and 1201 courses of fluconazole. Of all meropenem courses, 32% were dosed appropriately (increased significantly over time; P = 0.01), while 17% of fluconazole courses were dosed appropriately (increased significantly over time; P = 0.01). Median dosing for both meropenem and fluconazole was at or below recommendations; therefore, under-dosing was more common.

CONCLUSIONS

There was marked discordance between actual fluconazole and meropenem dosing and dosing recommendation in PK publications, yet adherence to PK-based doses showed improvement over time.

Approaches to Dose Finding in Neonates, Illustrating the Variability between Neonatal Drug Development Programs

Drug dosing in neonates should be based on integrated knowledge concerning the disease to be treated, the physiological characteristics of the neonate, and the pharmacokinetics (PK) and pharmacodynamics (PD) of a given drug. It is critically important that all sources of information be leveraged to optimize dose selection for neonates. Sources may include data from adult studies, pediatric studies, non-clinical (juvenile) animal models, in vitro studies, and in silico models. Depending on the drug development program, each of these modalities could be used to varying degrees and with varying levels of confidence to guide dosing. This paper aims to illustrate the variability between neonatal drug development programs for neonatal diseases that are similar to those seen in other populations (meropenem), neonatal diseases related but not similar to pediatric or adult populations (clopidogrel, thyroid hormone), and diseases unique to neonates (caffeine, surfactant). Extrapolation of efficacy from older children or adults to neonates is infrequently used. Even if a disease process is similar between neonates and children or adults, such as with anti-infectives, additional dosing and safety information will be necessary for labeling, recognizing that dosing in neonates is confounded by maturational PK in addition to body size.

Neonatal pharmacology and clinical implications

During the neonatal period, there is physiological immaturity of organs, systems and metabolic pathways that influences the pharmacokinetics and pharmacodynamics of administered drugs, the dosage of which should be constantly amended, considering the progressive increase in weight and the maturation of the elimination pathways. In this article, we analyse the main pharmacokinetic aspects (absorption, distribution, metabolism and excretion) that exist during the neonatal period, to offer a description of the physiological background for variability in pharmacological dosing.

Pediatric drug development in China: Reforms and challenges

In China, child and adolescent pediatricians often face challenges in treating children with the appropriate medications. Within the last 8 years, the Chinese government has already initiated a series of policies to promote development of age-appropriate medicines for children. In this study,we introduced the current status of pediatric drugs, obstacles for pediatric drugs development and regulatory reforms in China. The lack of label information in drugs for children, inadequacy of age-appropriate dosage forms and strengths, and shortage of pediatric drugs are some of the problems commonly faced. There exists neither mandatory requirements nor enough financial drivers for development of pediatric medicines. Though some progress in terms of pediatric drugs development as well as distribution have been made by Chinese government over past years, further efforts are necessary to improve availability of pediatric medications.

Melatonin pharmacokinetics and dose extrapolation after enteral infusion in neonates subjected to hypothermia

INTRODUCTION

Neonates with hypoxic-ischemic encephalopathy (HIE) undergoing hypothermia may benefit from adjunctive therapy with melatonin. However, melatonin safety, pharmacokinetics (PK), and dosage in this sensitive population are still unknown.

METHODS AND RESULTS

This study assessed the PK and safety of melatonin enteral administration to neonates with HIE undergoing hypothermia. Melatonin was infused at 0.5 mg/kg in five neonates with HIE undergoing hypothermia. Infusion started 1 hour after the neonates reached the target temperature of 33.5°C. Blood samples were collected before and at selective times after melatonin infusion. Abdominal complications or clinically significant changes in patients' vital signs were not found during or after melatonin. The peak plasma concentration reached 0.25 µg/mL. The area under the curve in 24 hours was 4.35 µg/mL*h.

DISCUSSION

Melatonin half-life and clearance were prolonged, and the distribution volume decreased compared to adults. In silico simulation estimated that the steady state can be reached after four infusions. Hypothermia does not affect melatonin PK. In humans high blood concentrations with lower doses can be achieved compared to animal experimentation, although intravenous administration is advised in the neonate population. Our study is a preparatory step for future clinical studies aimed at assessing melatonin efficacy in HIE.

Best Practices to Maximize the Use and Reuse of Quantitative and Systems Pharmacology Models: Recommendations From the United Kingdom Quantitative and Systems Pharmacology Network

The lack of standardization in the way that quantitative and systems pharmacology (QSP) models are developed, tested, and documented hinders their reproducibility, reusability, and expansion or reduction to alternative contexts. This in turn undermines the potential impact of QSP in academic, industrial, and regulatory frameworks. This article presents a minimum set of recommendations from the UK Quantitative and Systems Pharmacology Network (UK QSP Network) to guide QSP practitioners seeking to maximize their impact, and stakeholders considering the use of QSP models in their environment.

Measurement of Neurovascular Coupling in Neonates

Neurovascular coupling refers to the mechanism that links the transient neural activity to the subsequent change in cerebral blood flow, which is regulated by both chemical signals and mechanical effects. Recent studies suggest that neurovascular coupling in neonates and preterm born infants is different compared to adults. The hemodynamic response after a stimulus is later and less pronounced and the stimulus might even result in a negative (hypoxic) signal. In addition, studies both in animals and neonates confirm the presence of a short hypoxic period after a stimulus in preterm infants. In clinical practice, different methodologies exist to study neurovascular coupling. The combination of functional magnetic resonance imaging or functional near-infrared spectroscopy (brain hemodynamics) with EEG (brain function) is most commonly used in neonates. Especially near-infrared spectroscopy is of interest, since it is a non-invasive method that can be integrated easily in clinical care and is able to provide results concerning longer periods of time. Therefore, near-infrared spectroscopy can be used to develop a continuous non-invasive measurement system, that could be used to study neonates in different clinical settings, or neonates with different pathologies. The main challenge for the development of a continuous marker for neurovascular coupling is how the coupling between the signals can be described. In practice, a wide range of signal interaction measures exist. Moreover, biomedical signals often operate on different time scales. In a more general setting, other variables also have to be taken into account, such as oxygen saturation, carbon dioxide and blood pressure in order to describe neurovascular coupling in a concise manner. Recently, new mathematical techniques were developed to give an answer to these questions. This review discusses these recent developments.

Medication Use During Pregnancy and Lactation in a Dutch Population

BACKGROUND:

Medication use during pregnancy and lactation can be unavoidable, but knowledge on safety for the fetus or breastfed infant is limited among patients and healthcare providers.

RESEARCH AIM:

This study aimed to determine (a) the prevalence of medication use in pregnant and lactating women in a tertiary academic center, (b) the types and safety of these medicines, and (c) the influence of medication use on initiation of breastfeeding.

METHODS:

This study used a cross-sectional survey among women ( N = 292) who underwent high-risk or low-risk deliveries. Data about their use of prescribed, over-the-counter, and homeopathic medication during pregnancy were obtained through a structured interview, followed by a questionnaire during lactation. Safety was classified according to the risk classification system from the Dutch Teratological Information Service.

RESULTS:

Overall, 95.5% of participants used medication. One third of participants used at least one medicine with an unknown risk for the fetus. Teratogenic medication was used by 6.5% of participants, whereas 29.5% used medication with a (suspected) pharmacological effect on the fetus. Lactation was initiated by 258 (88.7%) participants, of which 84.2% used medication while breastfeeding. In 3.8% of participants, this medication was classified unsafe, but none used medication with an unknown risk. One-third of the nonlactating participants decided not to initiate breastfeeding because of medication use. In 70% of participants, this decision was appropriate.

CONCLUSION:

The prevalence of overall use of medication in Dutch pregnant and lactating women admitted to a tertiary center was high. There is an urgent need for pharmacometric studies for determination of the safe use of the most frequently used medicines during pregnancy or lactation.

Pediatric Formulations: Knowledge Gaps Limiting the Expedited Preclinical to Clinical Translation in Children

Traditionally, drug discovery and development research have been primarily focused on the mitigation of disease treatment for the general adult population, often overlooking the medical needs of pediatric patients. While remarkable progress toward the discovery of better medicines has been made, the pharmacological differences between children and adults are often neglected as part of the translation process. In fact, until recently, children have been considered therapeutic orphans due to the lack of significant drug discovery, formulation development, and dosage form design specifically tailored for pediatric patients. Perhaps the least understood is the significant physiological changes that occur during the maturation process from birth to adulthood. It requires careful considerations to achieve age-specific-desired therapeutic outcomes with minimal toxicity. This introduces considerable risk into the preclinical and clinical testing of new medicaments, which until recently, was avoided based on the conventional approach where a demonstration of safe and efficacious use in adults over several years potentially would minimize the chance of adverse juvenile responses. However, the lack of appropriate drug products for children has led to off-label use of adult medicines with potential life-threatening adverse reactions and health complications. Recent developments and future considerations regarding pediatric drug discovery and development using a patient-centric approach in the context of ontogenic biopharmaceutical considerations are discussed below.

Clinical Pharmacology and Pharmacometrics to Better Understand Physiological Changes During Pregnancy and Neonatal Life

Pregnant women, fetuses, and newborns are particularly vulnerable patient populations. During pregnancy, the body is subject to physiological changes that influence the pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in pregnant women can result in sub-therapeutic or toxic effects, putting not only the pregnant woman but also her fetus at risk. During neonatal life, maturation processes also affect pharmacokinetics and pharmacodynamics of drugs. Inappropriate dosing in newborns leads not only to short-term complications but can also have a negative impact on the long-term development of infants and children. For these reasons, it is crucial to characterize physiological changes in pregnant women, describe placental transfer kinetics of drugs, and describe physiological changes related to the transition from intrauterine to extrauterine life and maturation processes in preterm and term neonates. Quantitative pharmacological approaches such as pharmacometric and physiologically-based modeling and model-based simulations can be useful to better understand and predict such physiological changes and their effects on drug exposure and response. This review article (1) gives an overview of physiological changes in pregnant women, their fetuses, and (pre)term neonates, (2) presents case studies to illustrate applications of new modeling and simulation approaches, and (3) discusses challenges and opportunities in optimizing and personalizing treatments during pregnancy and neonatal life.

Two decades of off-label prescribing in children: a literature review

BACKGROUND

In the past two decades, many legislative and regulatory initiatives were taken globally to improve drug use in children. However, children are still found to be prescribed with off-label drugs. This study was conducted to provide an overview of the worldwide trend in off-label prescribing in children from the year 1996 to 2016.

DATA SOURCES

The articles published in PubMed, MEDLINE and Google Scholar were searched using text words: off-label, unlicensed, paediatric and children. Additional articles were identified by reviewing the bibliography of the retrieved articles. Full-text articles published in English which reported on the prevalence of off-label prescribing in children between January 1996 and December 2016 were included.

RESULTS

A total of 101 studies met the inclusion criteria. Off-label prescribing definition included four main categories: age, indication, dose and route of administration. The three most common reference sources used in the studies were summary of product characteristics, national formularies and package inserts. Overall, the off-label prescribing rates in children ranged from 1.2 to 99.7%. The most common category of off-label prescribing in children was dose and age.

CONCLUSIONS

This review highlighted that off-label prescribing in children was found to be highly prevalent throughout the past two decades, persistently in the neonatal intensive care units. This suggests that besides legislative and regulatory initiatives, behavioural, knowledge aspects and efforts to integrate evidence into practice related to off-label prescribing also need to be evaluated and consolidated as part of the concerted efforts to narrow the gaps in prescribing for children.

Pharmacokinetics and Safety of Single Intravenous Doses of Ceftolozane/Tazobactam in Children With Proven or Suspected Gram-Negative Infection

BACKGROUND

Drug-resistant Gram-negative bacteria are a growing threat to children; thus new antibiotics are needed to treat infections caused by these pathogens. Ceftolozane/tazobactam is active against many Gram-negative pathogens and is approved for treatment of complicated intra-abdominal and urinary tract infections in adults, but has not been evaluated in children.

METHODS

This phase 1, noncomparative, open-label, multicenter study characterized the pharmacokinetics (by noncompartmental analysis), safety, and tolerability of single intravenous doses of ceftolozane/tazobactam in pediatric patients (birth [7 days postnatal] to < 18 years of age) with proven/suspected Gram-negative infection or receiving perioperative prophylaxis (clinicaltrials.gov NCT02266706). Patients were enrolled into 1 of 6 age groups to receive a single, age-based ceftolozane/tazobactam dose, with timed blood sample collection for determining plasma concentrations of ceftolozane and tazobactam. Safety and tolerability were also evaluated.

RESULTS

Thirty-seven patients received study drug; 34 were included in the pharmacokinetic population. Ceftolozane and tazobactam pharmacokinetic parameters were generally comparable for patients 3 months to < 18 years of age. Patients from birth (7 days postnatal) to < 3 months of age had lower clearance than older children, likely due to the immature renal function of these young infants. No deaths, study drug-related serious adverse events, or clinically significant laboratory abnormalities were observed after administration of ceftolozane/tazobactam.

CONCLUSIONS

The doses evaluated in this study yielded ceftolozane/tazobactam exposure levels generally comparable with those in adults. Single doses of ceftolozane/tazobactam were well-tolerated, and no safety concerns were identified. These data informed pharmacokinetic/pharmacodynamic models to derive pediatric dose recommendations for phase 2 ceftolozane/tazobactam clinical trials.

Population Pharmacokinetics and Exploratory Exposure-Response Relationships of Diazepam in Children Treated for Status Epilepticus

Diazepam is labeled for status epilepticus (SE) in children, but there are limited data characterizing its disposition in pediatric patients. We developed a population pharmacokinetic (PK) model of i.v. diazepam in children with SE. We evaluated relationships between PK parameters and both safety and efficacy, and simulated exposures using dosing regimens from the product label and clinical practice. The model was developed using prospective data from a pediatric clinical trial comparing diazepam to lorazepam for treatment of SE. Altogether, 87 patients aged ≥ 3 months to < 18 years contributed 162 diazepam concentrations. Diazepam PKs were well characterized by a two‐compartment model scaled by body size. No significant or clinically important relationships were observed between diazepam PKs and safety or efficacy. Simulations demonstrated that, compared with label dosing, the study dose (0.2 mg/kg i.v., maximum 8 mg) resulted in greater frequency in rapidly achieving the target therapeutic range of 200–600 ng/mL.

Large conductance voltage- and calcium-gated potassium channels (BK) in cerebral artery myocytes of perinatal fetal primates share several major characteristics with the adult phenotype

Large conductance voltage- and calcium-gated channels (BK) control fundamental processes, including smooth muscle contractility and artery diameter. We used a baboon (Papio spp) model of pregnancy that is similar to that of humans to characterize BK channels in the middle cerebral artery and its branches in near-term (165 dGa) primate fetuses and corresponding pregnant mothers. In cell-attached patches (K+pipette = 135 mM) on freshly isolated fetal cerebral artery myocytes, BK currents were identified by large conductance, and voltage- and paxilline-sensitive effects. Their calcium sensitivity was confirmed by a lower Vhalf (transmembrane voltage needed to reach half-maximal current) in inside-out patches at 30 versus 3 μM [Ca2+]free. Immunostaining against the BK channel-forming alpha subunit revealed qualitatively similar levels of BK alpha protein-corresponding fluorescence in fetal and maternal myocytes. Fetal and maternal BK currents recorded at 3 μM [Ca2+]free from excised membrane patches had similar unitary current amplitude, and Vhalf. However, subtle differences between fetal and maternal BK channel phenotypes were detected in macroscopic current activation kinetics. To assess BK function at the organ level, fetal and maternal artery branches were pressurized in vitro at 30 mmHg and probed with the selective BK channel blocker paxilline (1 μM). The degree of paxilline-induced constriction was similar in fetal and maternal arteries, yet the constriction of maternal arteries was achieved sooner. In conclusion, we present a first identification and characterization of fetal cerebral artery BK channels in myocytes from primates. Although differences in BK channels between fetal and maternal arteries exist, the similarities reported herein advance the idea that vascular myocyte BK channels are functional near-term, and thus may serve as pharmacological targets during the perinatal-neonatal period.

Suggestions for Model-Informed Precision Dosing to Optimize Neonatal Drug Therapy

Evidence for dosing, efficacy, and safety of most medications used to treat neonates is sparse. Thus, dosing is usually derived by extrapolation from adult and pediatric pharmacologic data with scaling by body weight or body surface area. This may lead to drug dosing that is unsafe or ineffective. However, new strategies are being developed and studied to dose medications in critically ill neonates. Mass spectroscopy technology capable of quickly analyzing drug levels is readily available. Software that integrates population pharmacokinetics and pharmacodynamics with data from sparse samples from neonates allows for timely adjustments of dosing to achieve the desired effect while minimizing adverse outcomes. Some genetic polymorphisms that affect drug response in neonates have also been reported. This review highlights aspects of drug response and how it is impacted by prematurity, assesses pharmacogenomic studies in neonates, and offers suggestions for innovative pharmacokinetic/pharmacodynamic model-based approaches that combine population- or physiology-based pharmacology data, Bayesian analysis, and electronic decision support tools for precision dosing in neonates while illustrating examples where this approach can be used to optimize medical therapy in neonates. Barriers to implementing precision dosing in neonates and how to overcome them are also discussed.

Pediatric Antibacterial and Antifungal Trials From 2007 to 2017

BACKGROUND AND OBJECTIVES

The impact of the Best Pharmaceuticals for Children Act (BPCA) and the Pediatric Research Equity Act (PREA) on pediatric antibacterial or antifungal drug trials is unknown. Our objective was to identify and characterize trials conducted under the BPCA and/or the PREA.

METHODS

Pediatric antibacterial and antifungal drug trials with industry or US federal funding registered in clinicaltrials.gov from 2007 to 2017 were identified. Those conducted under BPCA and/or PREA were identified through US Food and Drug Administration and National Institute of Child Health and Human Development databases.

RESULTS

Of 17 495 pediatric trials registered on clinicaltrials.gov between October 2007 and September 2017, 122 systemic antibacterial or antifungal drug trials with industry or US federal funding were identified. Of these 122 trials, 98 (80%) involved antibacterials only, 23 (19%) antifungals only, and 1 (1%) both antibacterials and antifungals. These represented <1% (122 of 17 495) of pediatric trials. Neither pediatric antibacterial nor antifungal drug trials commonly enrolled neonates 0 to 30 days old (30% [30 of 99] vs 42% [10 of 24], respectively). Pediatric antibacterial and antifungal trials were commonly industry funded (79% [78 of 99] and 83% [20 of 24], respectively). In total, 65% (79 of 122) of pediatric antibacterial and/or antifungal drug trials were conducted under BPCA and/or PREA. Researchers in trials conducted under BPCA and/or PREA, relative to non-BPCA and/or PREA trials, more often collected pharmacokinetic data (70% [55 of 79] vs 26% [11 of 43]).

CONCLUSIONS

Although the majority of pediatric antibacterial and/or antifungal drug trials were conducted under BPCA and/or PREA, the overall number was low. Greater effort is needed to stimulate such trials.

Biopharmaceutical considerations in paediatrics with a view to the evaluation of orally administered drug products - a PEARRL review

OBJECTIVES

In this review, the current biopharmaceutical approaches for evaluation of oral formulation performance in paediatrics are discussed.

KEY FINDINGS

The paediatric gastrointestinal (GI) tract undergoes numerous morphological and physiological changes throughout its development and growth. Some physiological parameters are yet to be investigated, limiting the use of the existing in vitro biopharmaceutical tools to predict the in vivo performance of paediatric formulations. Meals and frequencies of their administration evolve during childhood and affect oral drug absorption. Furthermore, the establishment of a paediatric Biopharmaceutics Classification System (pBCS), based on the adult Biopharmaceutics Classification System (BCS), requires criteria adjustments. The usefulness of computational simulation and modeling for extrapolation of adult data to paediatrics has been confirmed as a tool for predicting drug formulation performance. Despite the great number of successful physiologically based pharmacokinetic models to simulate drug disposition, the simulation of drug absorption from the GI tract is a complicating issue in paediatric populations.

SUMMARY

The biopharmaceutics tools for investigation of oral drug absorption in paediatrics need further development, refinement and validation. A combination of in vitro and in silico methods could compensate for the uncertainties accompanying each method on its own.

Pediatric physiology in relation to the pharmacokinetics of monoclonal antibodies

INTRODUCTION

Dose design for pediatric trials with monoclonal antibodies (mAbs) is often extrapolated from the adult dose according to weight, age, or body surface area. While these methods account for the size differences between adults and children, they do not account for the maturation of processes that may play a key role in the pharmacokinetics and/or pharmacodynamics of mAbs. With the same weight-based dose, infants and young children typically receive lower plasma exposures when compared to adults. Areas covered: The mechanistic features of mAb distribution, elimination, and absorption are explored in detail and literature-based hypotheses are generated to describe their age-dependence. This knowledge can be incorporated into a physiologically based pharmacokinetic (PBPK) modeling approach to pediatric dose determination. Expert opinion: As data from pediatric clinical trials become increasingly available, we have the opportunity to reflect on the physiologic drivers of pharmacokinetics, safety, and efficacy in children with mathematical models. A modeling approach that accounts for the age-related features of mAb disposition can be used to derive first-in-pediatric doses, design optimal sampling schemes for children in clinical trials and even explore new pharmacokinetic end-points as predictors of safety and efficacy in children.

Absorption and tolerability of taste-masked hydrocortisone granules in neonates, infants and children under 6 years of age with adrenal insufficiency

OBJECTIVES

There is no licensed, dose-appropriate formulation of hydrocortisone for children with adrenal insufficiency (AI) and patients rely on compounded adult medication. The aim of this study was to evaluate the absorption, palatability and safety of Infacort^® , an immediate-release, granule formulation of hydrocortisone with taste masking.

STUDY DESIGN

Single site with satellites attended by a "flying" doctor from investigator site. Open-label, single-dose study in three consecutive child cohorts (n = 24) with AI; Cohort 1, children aged 2 to <6 years (n = 12); Cohort 2, infants aged 28 days to <2 years (n = 6); Cohort 3, neonates aged 1 to <28 days (n = 6).

METHODS

Fasted children were given a single dose of Infacort^® as dry granules administered directly from a capsule or spoon followed by a drink. The primary end-point was the maximum serum cortisol concentration up to 240 minutes after Infacort^® administration. Secondary end-points were palatability and adverse events (AEs).

RESULTS

All children showed an increase in cortisol above baseline after Infacort^® (P < .0001), with geometric mean ± SD cortisol concentration at 60 minutes of 575.8 ± 299.5 nmol L^-1 . There was no failure in administration of Infacort^® , and 95.5% of parents/carers preferred Infacort^® to their child's current medication. In 7 children who completed the palatability questionnaire, 80% of responses were very good or neutral, and 20% were adverse. No serious or severe treatment-emergent AEs were reported.

CONCLUSIONS

Infacort^® is well tolerated, easy to administer to neonates, infants and children and shows good absorption, with cortisol levels at 60 minutes after administration similar to physiological cortisol levels in healthy children.

Prioritizing the most needed formulations to accelerate paediatric antiretroviral therapy scale-up

PURPOSE OF REVIEW

Initiatives are in place to reach super-fast targets by 2018 for paediatric patients living with HIV. However, these efforts are unlikely to be successful until better paediatric antiretrovirals and treatment strategies are available. This commentary reviews the specific features, challenges, and recent developments in paediatric HIV treatment to determine optimal regimen sequencing and use of available drug options. It also outlines a medium and long-term vision for treatment optimization as endorsed by the paediatric antiretroviral drug optimization group.

RECENT FINDINGS

Optimizing antiretroviral therapy (ART) is critical in the context of limited treatment options for children. A first-line dolutegravir-based regimen is the long-term goal for paediatric first-line ART across all age groups. Protease inhibitor-based regimens are expected to continue to play a critical role for second and third-line treatment. New efforts are urgently needed to optimize treatment for children, ensuring access to existing drugs and speeding up development of newer and better formulations moving forward.

SUMMARY

Over the last few years there have been a number of key developments in paediatric ART which offer the opportunity to reconsider the way ART is optimized for children. Additional evidence is needed to ensure optimal options are available from infancy through adulthood.