The Neonatal and Juvenile Pig in Pediatric Drug Discovery and Development

Human milk improves the oral bioavailability of the poorly water-soluble drug clofazimine

Clofazimine is an emerging drug for the treatment of cryptosporidiosis in infants. As a poorly water-soluble drug, the formulation of clofazimine in age-appropriate vehicles is challenging and often results in the use of off-label formulations. Milk-based vehicles such as human milk and bovine milk have been investigated as age-appropriate formulations and shown to increase the solubilisation of poorly water-soluble drugs via enhanced solubility in lipid digestion products in vitro. We hypothesised that administration of clofazimine within a milk-based vehicle would enhance bioavailability for infant patients. Towards this objective, suspensions of clofazimine in human and bovine milk were orally administered separately to piglets and rats and the subsequent plasma concentrations were compared to those after administration of an aqueous drug suspension. Initial investigations with a rodent model showed a significant increase (258%) in the oral bioavailability of clofazimine when administered with human milk. Similarly, the oral bioavailability of clofazimine was significantly higher when administered in both human (154%) and bovine milk (175%) using a neonatal piglet model, suggesting comparable enhancement in oral bioavailability could be achieved with human or bovine milk. These findings demonstrate the potential of human milk in particular to provide an effective administration vehicle for clofazimine administration to infants without the need for additional excipients.

Opportunities and challenges for use of minipigs in nonclinical pharmaceutical development: Results of a follow-up IQ DruSafe survey

Minipigs are valid nonrodent species infrequently utilized for pharmaceutical research and development (R&D) compared with dogs or nonhuman primates (NHPs). A 2022 IQ DruSafe survey revealed a modest increase in minipig use by pharmaceutical companies compared with a prior 2014 survey, primarily in the development of oral small molecules and parenteral protein molecules. Some companies considered using minipigs more often due to NHP shortages and regional ethical concerns with using NHPs and dogs. However, for most pharmaceutical companies, minipigs still represent ≤5% of their nonrodent animal use. Key challenges noted by companies to wider adoption of minipigs were high test article requirement, limited historical control data, and lack of relevant reagents or assays. Additionally, some companies expressed uncertainties about contract research organization (CRO) capabilities and experience, a perception not shared by respondent CROs. These latest survey results indicate persistence of many concerns previously identified in 2014. Several case studies are included to illustrate areas of expanded minipig use as well as the challenges that hinder broader adoption. Ongoing, focused, and industry-wide initiatives to address the identified or perceived challenges may lead to more frequent or routine consideration of minipigs as a test species in pharmaceutical R&D.

A pilot pharmacokinetic and Metabolite identification study of Erinacine A in a Single landrace pig model

Erinacine A has been proven to have the ability to protect nerves and have the benefit of neurohealth. However, the pharmacokinetic and metabolites study of erinacine A in pigs, whose physiology and anatomy are similar to humans, have not been reported. In this study, 5 mg/kg of erinacine A was intravenously administered to the landrace pig. Blood, cerebrospinal fluid, and brain tissue samples were collected and analyzed by HPLC-QQQ/MS and UPLC-QTOF/MS. The results indicated the following pharmacokinetic parameters in plasma samples: with an area under the plasma concentration versus time curve (AUC) were 38.02 ± 0.03 mg∙min/L (AUC0-60) and 43.60 ± 0.06 mg∙min/L (AUC0-∞), clearance (CL) was 0.11 ± 0.00 L/min∙kg, volume of distribution (Vd) was 4.24 ± 0.00 L/kg, and terminal half-life (T1/2β) was 20.85 ± 0.03 min. In the cerebrospinal fluid samples, erinacine A was detected after 15 min and the highest concentration (5.26 ± 0.58 μg/L) was observed at 30 min. In the brain tissue sample, 77.45 ± 0.58 μg/L of erinacine A was found. In the study of metabolites, there were 6 identical metabolites in plasma and brain tissue. To our surprise, erinacine B was found to be the metabolite of erinacine A, and its concentration increased over time as erinacine A was metabolized. In summary, this study is the first to demonstrate that erinacine A can be found in the cerebrospinal fluid of landrace pigs. Additionally, the metabolite identification of erinacine A in landrace pigs is also investigated.

Nanomedicine Therapies for Pediatric Diseases

In 2020, the top 10 causes of death among children and adolescents between the ages of 1 and 19 years old included cancer, congenital anomalies, heart disease, and chronic respiratory disease; all these conditions are potentially treatable with medical intervention. However, children exhibit specific physiological and developmental characteristics that can significantly impact drug pharmacokinetics, pharmacodynamics, and safety profile. These factors illustrate the importance of a heightened focus on pediatric drug development. Traditional drugs lack proper circulation, permeability, targeting, accumulation, and release, and they often require dose adjustments or modifications, which can result in suboptimal therapeutic outcomes and increased risks of adverse effects in pediatric patients. Nanomedicines have emerged as efficient drug delivery systems because of their unique properties, which can improve the solubility and stability of drugs by encapsulating them in different forms of nanoparticles. This review discusses the challenges of pediatric therapy, and the current state of nanomedicines for pediatric diseases in terms of Food and Drug Administration-approved nanomedicines, the types of diseases treated or diagnosed, and preclinical studies that have the potential to be translated to the clinic. In summary, nanomedicine holds significant potential for addressing the unique and pressing challenges associated with diagnosing and treating pediatric diseases.

Human-Induced Pluripotent Stem Cell-Derived Neural Stem Cell Therapy Limits Tissue Damage and Promotes Tissue Regeneration and Functional Recovery in a Pediatric Piglet Traumatic-Brain-Injury Model

Traumatic brain injury (TBI) is a leading cause of death and disability in pediatric patients and often results in delayed neural development and altered connectivity, leading to lifelong learning, memory, behavior, and motor function deficits. Induced pluripotent stem cell-derived neural stem cells (iNSCs) may serve as a novel multimodal therapeutic as iNSCs possess neuroprotective, regenerative, and cell-replacement capabilities post-TBI. In this study, we evaluated the effects of iNSC treatment on cellular, tissue, and functional recovery in a translational controlled cortical impact TBI piglet model. Five days post-craniectomy (n = 6) or TBI (n = 18), iNSCs (n = 7) or PBS (n = 11) were injected into perilesional brain tissue. Modified Rankin Scale (mRS) neurological evaluation, magnetic resonance imaging, and immunohistochemistry were performed over the 12-week study period. At 12-weeks post-transplantation, iNSCs showed long-term engraftment and differentiation into neurons, astrocytes, and oligodendrocytes. iNSC treatment enhanced endogenous neuroprotective and regenerative activities indicated by decreasing intracerebral immune responses, preserving endogenous neurons, and increasing neuroblast formation. These cellular changes corresponded with decreased hemispheric atrophy, midline shift, and lesion volume as well as the preservation of cerebral blood flow. iNSC treatment increased piglet survival and decreased mRS scores. The results of this study in a predictive pediatric large-animal pig model demonstrate that iNSC treatment is a robust multimodal therapeutic that has significant promise in potentially treating human pediatric TBI patients.

Drug Disposition in Neonatal Göttingen Minipigs: Exploring Effects of Perinatal Asphyxia and Therapeutic Hypothermia

Asphyxiated neonates often undergo therapeutic hypothermia (TH) to reduce morbidity and mortality. Since both perinatal asphyxia (PA) and TH influence physiology, altered pharmacokinetics (PK) and pharmacodynamics (PD) are expected. Given that TH is the standard of care for PA with moderate to severe hypoxic-ischemic encephalopathy, disentangling the effect of PA versus TH on PK/PD is not possible in clinical settings. However, animal models can provide insights into this matter. The (neonatal) Göttingen Minipig, the recommended strain for nonclinical drug development, was selected as translational model. Four drugs-midazolam (MDZ), fentanyl (FNT), phenobarbital (PHB), and topiramate (TPM)-were intravenously administered under four conditions: control (C), therapeutic hypothermia (TH), hypoxia (H), and hypoxia plus TH (H+TH). Each group included six healthy male neonatal Göttingen Minipigs anesthetized for 24 hours. Blood samples were drawn at 0 (predose) and 0.5, 2, 2.5, 3, 4, 4.5, 6, 8, 12, and 24 hours post drug administration. Drug plasma concentrations were determined using validated bioanalytical assays. The PK parameters were estimated through compartmental and noncompartmental PK analysis. The study showed a statistically significant decrease in FNT clearance (CL; 66% decrease), with an approximately threefold longer half-life (t1/2) in the TH group. The H+TH group showed a 17% reduction in FNT CL, with a 62% longer t1/2 compared with the C group; however, it was not statistically significant. Although not statistically significant, trends toward lower CL and longer t1/2 were observed in the TH and H+TH groups for MDZ and PHB. Additionally, TPM demonstrated a 28% decrease in CL in the H group compared with controls. SIGNIFICANCE STATEMENT: The overarching goal of this study using the neonatal Göttingen Minipig model was to disentangle the effects of systemic hypoxia and TH on PK using four model drugs. Such insights can subsequently be used to inform and develop a physiologically based pharmacokinetic model, which is useful for drug exposure prediction in human neonates.

Swine models in translational research and medicine

Swine are increasingly studied as animal models of human disease. The anatomy, size, longevity, physiology, immune system, and metabolism of swine are more like humans than traditional rodent models. In addition, the size of swine is preferred for surgical placement and testing of medical devices destined for humans. These features make swine useful for biomedical, pharmacological, and toxicological research. With recent advances in gene-editing technologies, genetic modifications can readily and efficiently be made in swine to study genetic disorders. In addition, gene-edited swine tissues are necessary for studies testing and validating xenotransplantation into humans to meet the critical shortfall of viable organs versus need. Underlying all of these biomedical applications, the knowledge of husbandry, background diseases and lesions, and biosecurity needs are important for productive, efficient, and reproducible research when using swine as a human disease model for basic research, preclinical testing, and translational studies.

Analysis of production efficiency of cloned transgenic Yucatan miniature pigs according to recipient breeds with embryo transfer conditions

The purpose of this study was to compare the efficiency of the production of cloned transgenic Yucatan miniature pigs (YMPs) using two recipient breeds, i.e., YMPs and domestic pigs (DPs), under various embryo transfer conditions. We initially assessed the in vitro developmental competence of embryos obtained via somatic cell nuclear transfer (SCNT) from three different transgenic donor cells. No difference was observed among the three groups regarding developmental competence. Furthermore, the cloning efficiency remained consistent among the three groups after the transfer of the SCNT embryos to each surrogate mother. Subsequently, to compare the efficiency of the production of cloned transgenic YMPs between the two recipient breeds using varying parameters, including ovulation status (preovulation and postovulation), duration of in vitro culture (IVC) (incubated within 24 h and 24-48 h), and the number of transferred SCNT embryos (less than and more than 300), we assessed the pregnancy rates, delivery rates, mean offspring counts, and cloning efficiency. Regarding the ovulation status, YMPs exhibited higher pregnancy rates, delivery rates, and cloning efficiency compared with DPs in both statuses. Moreover, the pregnancy rates, delivery rates, and cloning efficiency were affected by the ovulation status in DPs, but not in YMPs. The comparison of IVC duration between groups revealed that YMPs had higher pregnancy rates vs. DPs in both conditions. SCNT embryos cultured for 24-48 h in YMPs yielded higher delivery rates and cloning efficiency compared with those cultured for less than 24 h in DPs. Finally, the analysis based on the number of transferred SCNT embryos showed that both the pregnancy and delivery rates were higher in YMPs vs. DPs. However, the highest average number of offspring was obtained when more than 300 SCNT embryos were transferred into DPs, whereas the cloning efficiency was higher in YMPs vs. DPs. Our results suggest that YMPs are more suitable recipients than are DPs under various conditions for the production of cloned transgenic YMPs.

The Use of Population Pharmacokinetics to Extrapolate Food Effects from Human Adults and Beagle Dogs to the Pediatric Population Illustrated with Paracetamol as a Test Case

To date, food-drug interactions in the pediatric population remain understudied. The current food effect studies are mostly performed in adults and do not mimic the real-life situation in the pediatric population. Since the potential benefits of food effect studies performed in pediatrics should be counterbalanced with the burden that these studies pose to the patients, alternative research strategies should be evaluated. The present study aimed to evaluate whether population pharmacokinetics (popPK) using data in beagle dogs and human adults could reliably assess food effects relevant for the pediatric population. PopPK was utilized to understand the performance of paracetamol under different dosing conditions (when the participants were fasted, with a reference meal, and with infant formula) in human adults (n = 8) and beagle dogs (n = 6) by constructing models to derive the pharmacokinetic parameters and to evaluate the food effects in both species. A two-compartment model with a single input function for the absorption phase best described the profiles of paracetamol in the beagle dogs. In the human adults, a one-compartment model with a dual input function for the absorption phase best described the data. The simulated profiles for the different dosing conditions demonstrated that both the human adults' and beagle dogs' simulations were able to acceptably describe the plasma concentration-time profiles of paracetamol observed in a representative pediatric population, which opens up perspectives on pediatric-relevant food effect predictions. However, the obtained results should be carefully interpreted, since an accurate validation of these findings was not possible due to the scarcity of the literature on observed pediatric data.

Pharmacokinetics during therapeutic hypothermia in neonates: from pathophysiology to translational knowledge and physiologically-based pharmacokinetic (PBPK) modeling

INTRODUCTION

Perinatal asphyxia (PA) still causes significant morbidity and mortality. Therapeutic hypothermia (TH) is the only effective therapy for neonates with moderate to severe hypoxic-ischemic encephalopathy after PA. These neonates need additional pharmacotherapy, and both PA and TH may impact physiology and, consequently, pharmacokinetics (PK) and pharmacodynamics (PD).

AREAS COVERED

This review provides an overview of the available knowledge in PubMed (until November 2022) on the pathophysiology of neonates with PA/TH. In vivo pig models for this setting enable distinguishing the effect of PA versus TH on PK and translating this effect to human neonates. Available asphyxia pig models and methodological considerations are described. A summary of human neonatal PK of supportive pharmacotherapy to improve neurodevelopmental outcomes is provided.

EXPERT OPINION

To support drug development for this population, knowledge from clinical observations (PK data, real-world data on physiology), preclinical (in vitro and in vivo (minipig)) data, and molecular and cellular biology insights can be integrated into a predictive physiologically-based PK (PBPK) framework, as illustrated by the I-PREDICT project (Innovative physiology-based pharmacokinetic model to predict drug exposure in neonates undergoing cooling therapy). Current knowledge, challenges, and expert opinion on the future directions of this research topic are provided.

Development of a neonatal Göttingen Minipig model for dose precision in perinatal asphyxia: technical opportunities, challenges, and potential further steps

Animal models provide useful information on mechanisms in human disease conditions, but also on exploring (patho)physiological factors affecting pharmacokinetics, safety, and efficacy of drugs in development. Also, in pediatric patients, nonclinical data can be critical for better understanding the disease conditions and developing new drug therapies in this age category. For perinatal asphyxia (PA), a condition defined by oxygen deprivation in the perinatal period and possibly resulting in hypoxic ischemic encephalopathy (HIE) or even death, therapeutic hypothermia (TH) together with symptomatic drug therapy, is the standard approach to reduce death and permanent brain damage in these patients. The impact of the systemic hypoxia during PA and/or TH on drug disposition is largely unknown and an animal model can provide useful information on these covariates that cannot be assessed separately in patients. The conventional pig is proven to be a good translational model for PA, but pharmaceutical companies do not use it to develop new drug therapies. As the Göttingen Minipig is the commonly used pig strain in nonclinical drug development, the aim of this project was to develop this animal model for dose precision in PA. This experiment consisted of the instrumentation of 24 healthy male Göttingen Minipigs, within 24 h of partus, weighing approximately 600 g, to allow the mechanical ventilation and the multiple vascular catheters inserted for maintenance infusion, drug administration and blood sampling. After premedication and induction of anesthesia, an experimental protocol of hypoxia was performed, by decreasing the inspiratory oxygen fraction (FiO₂) at 15%, using nitrogen gas. Blood gas analysis was used as an essential tool to evaluate oxygenation and to determine the duration of the systemic hypoxic insult to approximately 1 h. The human clinical situation was mimicked for the first 24 h after birth in case of PA, by administering four compounds (midazolam, phenobarbital, topiramate and fentanyl), frequently used in a neonatal intensive care unit (NICU). This project aimed to develop the first neonatal Göttingen Minipig model for dose precision in PA, allowing to separately study the effect of systemic hypoxia versus TH on drug disposition. Furthermore, this study showed that several techniques that were thought to be challenging or even impossible in these very small animals, such as endotracheal intubation and catheterization of several veins, are feasible by trained personnel. This is relevant information for laboratories using the neonatal Göttingen Minipig for other disease conditions or drug safety testing.

Current knowledge, challenges and innovations in developmental pharmacology: A combined conect4children Expert Group and European Society for Developmental, Perinatal and Paediatric Pharmacology White Paper

Developmental pharmacology describes the impact of maturation on drug disposition (pharmacokinetics, PK) and drug effects (pharmacodynamics, PD) throughout the paediatric age range. This paper, written by a multidisciplinary group of experts, summarizes current knowledge, and provides suggestions to pharmaceutical companies, regulatory agencies and academicians on how to incorporate the latest knowledge regarding developmental pharmacology and innovative techniques into neonatal and paediatric drug development. Biological aspects of drug absorption, distribution, metabolism and excretion throughout development are summarized. Although this area made enormous progress during the last two decades, remaining knowledge gaps were identified. Minimal risk and burden designs allow for optimally informative but minimally invasive PK sampling, while concomitant profiling of drug metabolites may provide additional insight in the unique PK behaviour in children. Furthermore, developmental PD needs to be considered during drug development, which is illustrated by disease- and/or target organ-specific examples. Identifying and testing PD targets and effects in special populations, and application of age- and/or population-specific assessment tools are discussed. Drug development plans also need to incorporate innovative techniques such as preclinical models to study therapeutic strategies, and shift from sequential enrolment of subgroups, to more rational designs. To stimulate appropriate research plans, illustrations of specific PK/PD-related as well as drug safety-related challenges during drug development are provided. The suggestions made in this joint paper of the Innovative Medicines Initiative conect4children Expert group on Developmental Pharmacology and the European Society for Developmental, Perinatal and Paediatric Pharmacology, should facilitate all those involved in drug development.

A genetically modified minipig model for Alzheimer’s disease with SORL1 haploinsufficiency

The established causal genes in Alzheimer’s disease (AD), APP, PSEN1, and PSEN2, are functionally characterized using biomarkers, capturing an in vivo profile reflecting the disease’s initial preclinical phase. Mutations in SORL1, encoding the endosome recycling receptor SORLA, are found in 2%–3% of individuals with early-onset AD, and SORL1 haploinsufficiency appears to be causal for AD. To test whether SORL1 can function as an AD causal gene, we use CRISPR-Cas9-based gene editing to develop a model of SORL1 haploinsufficiency in Göttingen minipigs, taking advantage of porcine models for biomarker investigations. SORL1 haploinsufficiency in young adult minipigs is found to phenocopy the preclinical in vivo profile of AD observed with APP, PSEN1, and PSEN2, resulting in elevated levels of β-amyloid (Aβ) and tau preceding amyloid plaque formation and neurodegeneration, as observed in humans. Our study provides functional support for the theory that SORL1 haploinsufficiency leads to endosome cytopathology with biofluid hallmarks of autosomal dominant AD.

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Minipig model of Alzheimer’s disease by CRISPR knockout of the causal gene SORL1

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Young SORL1 het minipigs phenocopy a preclinical CSF biomarker profile of individuals with AD

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SORL1 haploinsufficiency causes enlarged endosomes similar to neuronal AD pathology

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A minipig model bridging the translational gap between AD mouse models and affected individuals

Ultrasound-guided percutaneous central venous access in a neonatal porcine model

Percutaneous catheterization is currently utilized for central venous access in adult and adolescent porcine models; however, neonatal models require a cut down to gain venous access. This approach requires general anesthesia and can result in systemic inflammation, which can confound studies investigating other inflammatory triggers. Here we present the first successful series of percutaneous, ultrasound-guided, durable central venous access in newborn piglets weighing 1 kg with a novel method of tunneling the catheter subcutaneously using a needle. Catheters (3-5 Fr, single- or double-lumen) were successfully placed in the right jugular vein of eight piglets weighing 1.3 ± 0.4 kg (mean ± standard deviation) with an average duration of catheter patency of 4.5 ± 2.1 days. There were no adverse events from catheter placement, though one catheter was inadvertently removed. This technique is a safe, minimally invasive method for obtaining secure central venous access in a neonatal porcine model.

Catching Them Early: Framework Parameters and Progress for Prenatal and Childhood Application of Advanced Therapies

Advanced therapy medicinal products (ATMPs) are medicines for human use based on genes, cells or tissue engineering. After clear successes in adults, the nascent technology now sees increasing pediatric application. For many still untreatable disorders with pre- or perinatal onset, timely intervention is simply indispensable; thus, prenatal and pediatric applications of ATMPs hold great promise for curative treatments. Moreover, for most inherited disorders, early ATMP application may substantially improve efficiency, economy and accessibility compared with application in adults. Vindicating this notion, initial data for cell-based ATMPs show better cell yields, success rates and corrections of disease parameters for younger patients, in addition to reduced overall cell and vector requirements, illustrating that early application may resolve key obstacles to the widespread application of ATMPs for inherited disorders. Here, we provide a selective review of the latest ATMP developments for prenatal, perinatal and pediatric use, with special emphasis on its comparison with ATMPs for adults. Taken together, we provide a perspective on the enormous potential and key framework parameters of clinical prenatal and pediatric ATMP application.

Transcriptional Profiling in a Novel Swine Model of Traumatic Brain Injury

Transcriptomic investigations of traumatic brain injury (TBI) can give us deep insights into the pathological and compensatory processes post-injury. Thus far, transcriptomic studies in TBI have mostly used microarrays and have focused on rodent models. However, a large animal model of TBI bears a much stronger resemblance to human TBI with regard to the anatomical details, mechanics of injury, genetics, and, possibly, molecular response. Because of the advantages of a large animal TBI model, we investigated the gene expression changes between injured and uninjured sides of pig cerebral cortex after TBI. Given acute inflammation that follows after TBI and the important role that immune response plays in neuroplasticity and recovery, we hypothesized that transcriptional changes involving immune function will be upregulated. Eight female 4-week-old piglets were injured on the right hemisphere with controlled cortical impact (CCI). At 5 days after TBI, pericontusional cortex tissues from the injured side and contralateral cortical tissues were collected. After RNA extraction, library preparation and sequencing as well as gene expression changes between the ipsi- and contralateral sides were compared. There were 6642 genes that were differentially expressed between the ipsi- and contralateral sides, and 1993 genes among them had at least 3-fold differences. Differentially expressed genes were enriched for biological processes related to immune system activation, regulation of immune response, and leukocyte activation. Many of the differentially expressed genes, such as CD4, CD86, IL1A, IL23R, and IL1R1, were major regulators of immune function. This study demonstrated some of the major transcriptional changes between the pericontusional and contralateral tissue at an acute time point after TBI in pigs.

Development of microglia in fetal and postnatal neocortex of the pig, the European wild boar (Sus scrofa)

Knowledge on cortical development is based mainly on rodents besides primates and carnivores, all being altricial. Here, we analyzed a precocial animal, the pig, looking at dorsoparietal cortex from E45 to P90. At E45, most ionized calcium-binding adapter molecule 1-positive (Iba1+) cells had a macrophage-like morphology and resided in meninges and choroid plexus. Only a few cells were scattered in the ventricular and subventricular zone (VZ and SVZ). At E60/E70, all laminar compartments displayed microglia cells at a low-to-moderate density, being highest in VZ and SVZ followed by intermediate zone/white matter (IZ/WM). The cortical plate and marginal zone displayed only a few Iba1+ cells. Cells were intensely labeled, but still had poorly arborized somata and many resembled ameboid, macrophage-like microglia. Concurrent with a massive increase in cortical volume, microglia cell density increased until E85, and further until E100/E110 (birth at E114) to densities that resemble those seen postnatally. A fraction of microglia colabeled with Ki67 suggesting proliferation in all laminar compartments. Cell-to-cell distance decreased substantially during this time, and the fraction of microglia to all nuclei and to neurons increases in the laminar compartments. Eventually, of all cortical DAPI+ nuclei 7-12% were Iba1+ microglia. From E70 onwards, more and more cells with ramified processes were present in MZ down to IZ/WM, showing, for instance, a close association with NeuN+, NPY+, and GAD65/67+ somata and axon initial segments. These results suggested that the development of microglia cell density and morphology proceeds rapidly from mid-gestation onwards reaching near-adult status already before birth.

Safety Testing of an Antisense Oligonucleotide Intended for Pediatric Indications in the Juvenile Göttingen Minipig, including an Evaluation of the Ontogeny of Key Nucleases

The adult Göttingen Minipig is an acknowledged model for safety assessment of antisense oligonucleotide (ASO) drugs developed for adult indications. To assess whether the juvenile Göttingen Minipig is also a suitable nonclinical model for pediatric safety assessment of ASOs, we performed an 8-week repeat-dose toxicity study in different age groups of minipigs ranging from 1 to 50 days of age. The animals received a weekly dose of a phosphorothioated locked-nucleic-acid-based ASO that was assessed previously for toxicity in adult minipigs. The endpoints included toxicokinetic parameters, in-life monitoring, clinical pathology, and histopathology. Additionally, the ontogeny of key nucleases involved in ASO metabolism and pharmacologic activity was investigated using quantitative polymerase chain reaction and nuclease activity assays. Similar clinical chemistry and toxicity findings were observed; however, differences in plasma and tissue exposures as well as pharmacologic activity were seen in the juvenile minipigs when compared with the adult data. The ontogeny study revealed a differential nuclease expression and activity, which could affect the metabolic pathway and pharmacologic effect of ASOs in different tissues and age groups. These data indicate that the juvenile Göttingen Minipig is a promising nonclinical model for safety assessment of ASOs intended to treat disease in the human pediatric population.

Oral delivery of peptide therapeutics in infants: Challenges and opportunities

The vast majority of drugs are not designed or developed for pediatric and infant populations. Peptide drugs, which have become increasingly relevant in the past several decades, are no exception. Unfortunately, nearly all of the 60+ approved peptide drugs are formulated for injection, a particularly unfriendly mode of administration for infants. Although three peptide drugs were recently approved for oral formulations, this major advance in peptide drug delivery is available only for adults. In this review, we consider the current challenges and opportunities for the oral formulation of peptide therapeutics, specifically for infant populations. We describe the strategies that enable oral protein delivery and the potential impact of infant physiology on those strategies. We also detail the limited but encouraging progress towards 1) adapting conventional drug development and delivery approaches to infants and 2) designing novel infant-centric formulations. Together, these efforts underscore the feasibility of oral peptide delivery in infants and provide motivation to increase attention paid to this underserved area of drug delivery and formulation.

Preterm Birth Affects Early Motor Development in Pigs

Background: Preterm infants frequently show neuromotor dysfunctions, but it is not clear how reduced gestational age at birth may induce developmental coordination disorders. Advancing postnatal age, not only post-conceptional age, may determine neuromuscular development, and early interventions in preterm newborns may improve their later motor skills. An animal model of preterm birth that allows early postnatal detection of movement patterns may help to investigate this hypothesis. Methods: Using pigs as a model for moderately preterm infants, preterm (106-day gestation, equivalent to 90% of normal gestation time; n = 38) and term (115-day gestation, equivalent to 99% of normal gestation time; n = 20) individuals were delivered by cesarean section and artificially reared until postnatal day 19 (preweaning period). The neuromotor skills of piglets were documented using spatiotemporal gait analyses on video recordings of locomotion at self-selected speed at postnatal age 3, 4, 5, 8, and 18 days. Results were controlled for effects of body weight and sex. Results: Both preterm and term piglets reached mature neuromotor skills and performance between postnatal days 3-5. However, preterm pigs took shorter steps at a higher frequency, than term piglets, irrespective of their body size. Within preterm pigs, males and low birth weight individuals took the shortest steps, and with the highest frequency. Conclusion: Postnatal development of motor skills and gait characteristics in pigs delivered in late gestation may show similarity to the compromised development of gait pattern in preterm infants. Relative to term pigs, the postnatal delay in gait development in preterm pigs was only few days, that is, much shorter than the 10-day reduction in gestation length. This indicates rapid postnatal adaptation of gait pattern after reduced gestational age at birth. Early-life physical training and medical interventions may support both short- and long-term gait development after preterm birth in both pigs and infants.